Merge commit 'dev' into 'wip/cmake-merge'

Change-Id: I176c40d031be26a1dd1cf08843e448a660598783
author: Tobias Hunger <tobias.hunger@qt.io> 2019-04-16 16:32:08 +0200
committer: Tobias Hunger <tobias.hunger@qt.io> 2019-04-16 16:32:08 +0200
commit: 6630937e63ae5797487b86743a7733c8ae5cc42c (patch)
tree: 3d53dacf6430f9099e1fb20835881205de674961 /examples/widgets
parent: 37ed6dae00640f9cc980ffda05347c12a7eb5d7e (diff)
parent: c7af193d2e49e9f10b86262e63d8d13abf72b5cf (diff)
353 files changed, 2907 insertions, 2233 deletions
diff --git a/examples/widgets/animation/animatedtiles/main.cpp b/examples/widgets/animation/animatedtiles/main.cpp
index 8edd64e482..553b620e41 100644
--- a/examples/widgets/animation/animatedtiles/main.cpp
+++ b/examples/widgets/animation/animatedtiles/main.cpp
@@ -69,7 +69,7 @@ class Button : public QGraphicsWidget
 {
     Q_OBJECT
 public:
-    Button(const QPixmap &pixmap, QGraphicsItem *parent = 0)
+    Button(const QPixmap &pixmap, QGraphicsItem *parent = nullptr)
         : QGraphicsWidget(parent), _pix(pixmap)
     {
         setAcceptHoverEvents(true);
diff --git a/examples/widgets/animation/easing/window.cpp b/examples/widgets/animation/easing/window.cpp
index 8c03e0534d..aa12147388 100644
--- a/examples/widgets/animation/easing/window.cpp
+++ b/examples/widgets/animation/easing/window.cpp
@@ -66,11 +66,16 @@ Window::Window(QWidget *parent)
     m_ui.amplitudeSpinBox->setValue(dummy.amplitude());
     m_ui.overshootSpinBox->setValue(dummy.overshoot());
 
-    connect(m_ui.easingCurvePicker, SIGNAL(currentRowChanged(int)), this, SLOT(curveChanged(int)));
-    connect(buttonGroup, SIGNAL(buttonClicked(int)), this, SLOT(pathChanged(int)));
-    connect(m_ui.periodSpinBox, SIGNAL(valueChanged(double)), this, SLOT(periodChanged(double)));
-    connect(m_ui.amplitudeSpinBox, SIGNAL(valueChanged(double)), this, SLOT(amplitudeChanged(double)));
-    connect(m_ui.overshootSpinBox, SIGNAL(valueChanged(double)), this, SLOT(overshootChanged(double)));
+    connect(m_ui.easingCurvePicker, &QListWidget::currentRowChanged,
+            this, &Window::curveChanged);
+    connect(buttonGroup, QOverload<int>::of(&QButtonGroup::buttonClicked),
+            this, &Window::pathChanged);
+    connect(m_ui.periodSpinBox, QOverload<double>::of(&QDoubleSpinBox::valueChanged),
+            this, &Window::periodChanged);
+    connect(m_ui.amplitudeSpinBox, QOverload<double>::of(&QDoubleSpinBox::valueChanged),
+            this, &Window::amplitudeChanged);
+    connect(m_ui.overshootSpinBox, QOverload<double>::of(&QDoubleSpinBox::valueChanged),
+            this, &Window::overshootChanged);
     createCurveIcons();
 
     QPixmap pix(QLatin1String(":/images/qt-logo.png"));
diff --git a/examples/widgets/animation/easing/window.h b/examples/widgets/animation/easing/window.h
index 2b7b2a5bf3..541377a981 100644
--- a/examples/widgets/animation/easing/window.h
+++ b/examples/widgets/animation/easing/window.h
@@ -66,7 +66,7 @@ public:
 class Window : public QWidget {
     Q_OBJECT
 public:
-    Window(QWidget *parent = 0);
+    Window(QWidget *parent = nullptr);
 private slots:
     void curveChanged(int row);
     void pathChanged(int index);
diff --git a/examples/widgets/animation/moveblocks/main.cpp b/examples/widgets/animation/moveblocks/main.cpp
index 6d17696108..d03b57cd5e 100644
--- a/examples/widgets/animation/moveblocks/main.cpp
+++ b/examples/widgets/animation/moveblocks/main.cpp
@@ -169,7 +169,8 @@ class GraphicsView : public QGraphicsView
 {
     Q_OBJECT
 public:
-    GraphicsView(QGraphicsScene *scene, QWidget *parent = NULL) : QGraphicsView(scene, parent)
+    GraphicsView(QGraphicsScene *scene, QWidget *parent = nullptr)
+        : QGraphicsView(scene, parent)
     {
     }
 
@@ -214,7 +215,7 @@ int main(int argc, char **argv)
     QTimer timer;
     timer.setInterval(1250);
     timer.setSingleShot(true);
-    QObject::connect(group, SIGNAL(entered()), &timer, SLOT(start()));
+    QObject::connect(group, &QState::entered, &timer, QOverload<>::of(&QTimer::start));
 //![2]
 
 //![3]
@@ -302,7 +303,7 @@ int main(int argc, char **argv)
 //![7]
     StateSwitcher *stateSwitcher = new StateSwitcher(&machine);
     stateSwitcher->setObjectName("stateSwitcher");
-    group->addTransition(&timer, SIGNAL(timeout()), stateSwitcher);
+    group->addTransition(&timer, &QTimer::timeout, stateSwitcher);
     stateSwitcher->addState(state1, &animationGroup);
     stateSwitcher->addState(state2, &animationGroup);
 //![7]
diff --git a/examples/widgets/animation/states/main.cpp b/examples/widgets/animation/states/main.cpp
index 14d193c301..0f61b7457a 100644
--- a/examples/widgets/animation/states/main.cpp
+++ b/examples/widgets/animation/states/main.cpp
@@ -214,7 +214,7 @@ int main(int argc, char *argv[])
     state3->assignProperty(p5, "opacity", qreal(1));
     state3->assignProperty(p6, "opacity", qreal(1));
 
-    QAbstractTransition *t1 = state1->addTransition(button, SIGNAL(clicked()), state2);
+    QAbstractTransition *t1 = state1->addTransition(button, &QAbstractButton::clicked, state2);
     QSequentialAnimationGroup *animation1SubGroup = new QSequentialAnimationGroup;
     animation1SubGroup->addPause(250);
     animation1SubGroup->addAnimation(new QPropertyAnimation(box, "geometry"));
@@ -239,7 +239,7 @@ int main(int argc, char *argv[])
     t1->addAnimation(new QPropertyAnimation(p5, "opacity"));
     t1->addAnimation(new QPropertyAnimation(p6, "opacity"));
 
-    QAbstractTransition *t2 = state2->addTransition(button, SIGNAL(clicked()), state3);
+    QAbstractTransition *t2 = state2->addTransition(button, &QAbstractButton::clicked, state3);
     t2->addAnimation(new QPropertyAnimation(box, "geometry"));
     t2->addAnimation(new QPropertyAnimation(widget, "geometry"));
     t2->addAnimation(new QPropertyAnimation(p1, "pos"));
@@ -261,7 +261,7 @@ int main(int argc, char *argv[])
     t2->addAnimation(new QPropertyAnimation(p5, "opacity"));
     t2->addAnimation(new QPropertyAnimation(p6, "opacity"));
 
-    QAbstractTransition *t3 = state3->addTransition(button, SIGNAL(clicked()), state1);
+    QAbstractTransition *t3 = state3->addTransition(button, &QAbstractButton::clicked, state1);
     t3->addAnimation(new QPropertyAnimation(box, "geometry"));
     t3->addAnimation(new QPropertyAnimation(widget, "geometry"));
     t3->addAnimation(new QPropertyAnimation(p1, "pos"));
diff --git a/examples/widgets/animation/stickman/animation.cpp b/examples/widgets/animation/stickman/animation.cpp
index 94a92749bc..5c2d1682af 100644
--- a/examples/widgets/animation/stickman/animation.cpp
+++ b/examples/widgets/animation/stickman/animation.cpp
@@ -159,18 +159,16 @@ void Animation::save(QIODevice *device) const
     QDataStream stream(device);
     stream << m_name;
     stream << m_frames.size();
-    foreach (Frame *frame, m_frames) {
+    for (const Frame *frame : qAsConst(m_frames)) {
         stream << frame->nodeCount();
-        for (int i=0; i<frame->nodeCount(); ++i)
+        for (int i = 0; i < frame->nodeCount(); ++i)
             stream << frame->nodePos(i);
     }
 }
 
 void Animation::load(QIODevice *device)
 {
-    if (!m_frames.isEmpty())
-        qDeleteAll(m_frames);
-
+    qDeleteAll(m_frames);
     m_frames.clear();
 
     QDataStream stream(device);
diff --git a/examples/widgets/animation/stickman/graphicsview.cpp b/examples/widgets/animation/stickman/graphicsview.cpp
index 9cb57fcd9e..7058e15345 100644
--- a/examples/widgets/animation/stickman/graphicsview.cpp
+++ b/examples/widgets/animation/stickman/graphicsview.cpp
@@ -55,7 +55,9 @@
 #include <QtWidgets/QGraphicsScene>
 #include <QtWidgets/QGraphicsView>
 
-GraphicsView::GraphicsView(QWidget *parent) : QGraphicsView(parent), m_editor(0) {}
+GraphicsView::GraphicsView(QWidget *parent)
+    : QGraphicsView(parent), m_editor(nullptr)
+{}
 
 void GraphicsView::keyPressEvent(QKeyEvent *e)
 {
diff --git a/examples/widgets/animation/stickman/graphicsview.h b/examples/widgets/animation/stickman/graphicsview.h
index 56396bb780..361fee219d 100644
--- a/examples/widgets/animation/stickman/graphicsview.h
+++ b/examples/widgets/animation/stickman/graphicsview.h
@@ -58,7 +58,7 @@ class GraphicsView: public QGraphicsView
 {
     Q_OBJECT
 public:
-    GraphicsView(QWidget *parent = 0);
+    GraphicsView(QWidget *parent = nullptr);
 
 protected:
     void resizeEvent(QResizeEvent *event) override;
diff --git a/examples/widgets/animation/stickman/lifecycle.cpp b/examples/widgets/animation/stickman/lifecycle.cpp
index dbe9a299b4..046e3f4cd1 100644
--- a/examples/widgets/animation/stickman/lifecycle.cpp
+++ b/examples/widgets/animation/stickman/lifecycle.cpp
@@ -61,11 +61,11 @@ class KeyPressTransition: public QSignalTransition
 {
 public:
     KeyPressTransition(GraphicsView *receiver, Qt::Key key)
-        : QSignalTransition(receiver, SIGNAL(keyPressed(int))), m_key(key)
+        : QSignalTransition(receiver, &GraphicsView::keyPressed), m_key(key)
     {
     }
     KeyPressTransition(GraphicsView *receiver, Qt::Key key, QAbstractState *target)
-        : QSignalTransition(receiver, SIGNAL(keyPressed(int))), m_key(key)
+        : QSignalTransition(receiver, &GraphicsView::keyPressed), m_key(key)
     {
         setTargetState(target);
     }
@@ -132,8 +132,10 @@ LifeCycle::LifeCycle(StickMan *stickMan, GraphicsView *keyReceiver)
     QTimer *timer = new QTimer(lightningBlink);
     timer->setSingleShot(true);
     timer->setInterval(100);
-    QObject::connect(lightningBlink, SIGNAL(entered()), timer, SLOT(start()));
-    QObject::connect(lightningBlink, SIGNAL(exited()), timer, SLOT(stop()));
+    QObject::connect(lightningBlink, &QAbstractState::entered,
+                     timer, QOverload<>::of(&QTimer::start));
+    QObject::connect(lightningBlink, &QAbstractState::exited,
+                     timer, &QTimer::stop);
 //! [5]
 
     m_dead = new QState(m_machine);
@@ -151,7 +153,7 @@ LifeCycle::LifeCycle(StickMan *stickMan, GraphicsView *keyReceiver)
     // Lightning strikes at random
     m_alive->addTransition(new LightningStrikesTransition(lightningBlink));
 //! [0]
-    lightningBlink->addTransition(timer, SIGNAL(timeout()), m_dead);
+    lightningBlink->addTransition(timer, &QTimer::timeout, m_dead);
 //! [0]
 
     m_machine->setInitialState(m_alive);
@@ -173,9 +175,8 @@ void LifeCycle::addActivity(const QString &fileName, Qt::Key key, QObject *sende
     QState *state = makeState(m_alive, fileName);
     m_alive->addTransition(new KeyPressTransition(m_keyReceiver, key, state));
 
-    if((sender != NULL) || (signal != NULL)) {
+    if (sender || signal)
         m_alive->addTransition(sender, signal, state);
-    }
 }
 
 QState *LifeCycle::makeState(QState *parentState, const QString &animationFileName)
@@ -190,7 +191,7 @@ QState *LifeCycle::makeState(QState *parentState, const QString &animationFileNa
     }
 
     const int frameCount = animation.totalFrames();
-    QState *previousState = 0;
+    QState *previousState = nullptr;
     for (int i=0; i<frameCount; ++i) {
         animation.setCurrentFrame(i);
 
@@ -202,18 +203,18 @@ QState *LifeCycle::makeState(QState *parentState, const QString &animationFileNa
 //! [1]
 
         frameState->setObjectName(QString::fromLatin1("frame %0").arg(i));
-        if (previousState == 0)
+        if (previousState == nullptr)
             topLevel->setInitialState(frameState);
         else
 //! [2]
-            previousState->addTransition(previousState, SIGNAL(propertiesAssigned()), frameState);
+            previousState->addTransition(previousState, &QState::propertiesAssigned, frameState);
 //! [2]
 
         previousState = frameState;
     }
 
     // Loop
-    previousState->addTransition(previousState, SIGNAL(propertiesAssigned()), topLevel->initialState());
+    previousState->addTransition(previousState, &QState::propertiesAssigned, topLevel->initialState());
 
     return topLevel;
 
diff --git a/examples/widgets/animation/stickman/stickman.cpp b/examples/widgets/animation/stickman/stickman.cpp
index b7a2d87ada..5725f64eec 100644
--- a/examples/widgets/animation/stickman/stickman.cpp
+++ b/examples/widgets/animation/stickman/stickman.cpp
@@ -126,7 +126,7 @@ StickMan::StickMan()
     // Set up start position of limbs
     for (int i=0; i<NodeCount; ++i) {
         m_nodes[i] = new Node(QPointF(Coords[i * 2], Coords[i * 2 + 1]), this);
-        connect(m_nodes[i], SIGNAL(positionChanged()), this, SLOT(childPositionChanged()));
+        connect(m_nodes[i], &Node::positionChanged, this, &StickMan::childPositionChanged);
     }
 
     for (int i=0; i<BoneCount; ++i) {
@@ -176,8 +176,7 @@ Node *StickMan::node(int idx) const
 {
     if (idx >= 0 && idx < NodeCount)
         return m_nodes[idx];
-    else
-        return 0;
+    return nullptr;
 }
 
 void StickMan::timerEvent(QTimerEvent *)
diff --git a/examples/widgets/animation/sub-attaq/animationmanager.cpp b/examples/widgets/animation/sub-attaq/animationmanager.cpp
index b6e399967f..a611641613 100644
--- a/examples/widgets/animation/sub-attaq/animationmanager.cpp
+++ b/examples/widgets/animation/sub-attaq/animationmanager.cpp
@@ -56,7 +56,7 @@
 #include <QtCore/QDebug>
 
 // the universe's only animation manager
-AnimationManager *AnimationManager::instance = 0;
+AnimationManager *AnimationManager::instance = nullptr;
 
 AnimationManager::AnimationManager()
 {
@@ -71,7 +71,7 @@ AnimationManager *AnimationManager::self()
 
 void AnimationManager::registerAnimation(QAbstractAnimation *anim)
 {
-    QObject::connect(anim, SIGNAL(destroyed(QObject*)), this, SLOT(unregisterAnimation_helper(QObject*)));
+    QObject::connect(anim, &QObject::destroyed, this, &AnimationManager::unregisterAnimation_helper);
     animations.append(anim);
 }
 
@@ -82,7 +82,7 @@ void AnimationManager::unregisterAnimation_helper(QObject *obj)
 
 void AnimationManager::unregisterAnimation(QAbstractAnimation *anim)
 {
-    QObject::disconnect(anim, SIGNAL(destroyed(QObject*)), this, SLOT(unregisterAnimation_helper(QObject*)));
+    QObject::disconnect(anim, &QObject::destroyed, this, &AnimationManager::unregisterAnimation_helper);
     animations.removeAll(anim);
 }
 
@@ -93,14 +93,14 @@ void AnimationManager::unregisterAllAnimations()
 
 void AnimationManager::pauseAll()
 {
-    foreach (QAbstractAnimation* animation, animations) {
+    for (QAbstractAnimation *animation : qAsConst(animations)) {
         if (animation->state() == QAbstractAnimation::Running)
             animation->pause();
     }
 }
 void AnimationManager::resumeAll()
 {
-    foreach (QAbstractAnimation* animation, animations) {
+    for (QAbstractAnimation *animation : qAsConst(animations)) {
         if (animation->state() == QAbstractAnimation::Paused)
             animation->resume();
     }
diff --git a/examples/widgets/animation/sub-attaq/boat.cpp b/examples/widgets/animation/sub-attaq/boat.cpp
index 145d373e99..9037d54878 100644
--- a/examples/widgets/animation/sub-attaq/boat.cpp
+++ b/examples/widgets/animation/sub-attaq/boat.cpp
@@ -92,8 +92,9 @@ static QAbstractAnimation *setupDestroyAnimation(Boat *boat)
 
 
 
-Boat::Boat() : PixmapItem(QString("boat"), GraphicsScene::Big),
-    speed(0), bombsAlreadyLaunched(0), direction(Boat::None), movementAnimation(0)
+Boat::Boat()
+    : PixmapItem(QString("boat"), GraphicsScene::Big),
+      speed(0), bombsAlreadyLaunched(0), direction(Boat::None)
 {
     setZValue(4);
     setFlags(QGraphicsItem::ItemIsFocusable);
@@ -148,8 +149,8 @@ Boat::Boat() : PixmapItem(QString("boat"), GraphicsScene::Big),
     stopState->addTransition(leftMoveStop);
 
     //The animation is finished, it means we reached the border of the screen, the boat is stopped so we move to the stop state
-    moveStateLeft->addTransition(movementAnimation, SIGNAL(finished()), stopState);
-    moveStateRight->addTransition(movementAnimation, SIGNAL(finished()), stopState);
+    moveStateLeft->addTransition(movementAnimation, &QAbstractAnimation::finished, stopState);
+    moveStateRight->addTransition(movementAnimation, &QAbstractAnimation::finished, stopState);
 
     //We set up the keys for dropping bombs
     KeyLaunchTransition *upFireLeft = new KeyLaunchTransition(this, QEvent::KeyPress, Qt::Key_Up);
@@ -187,13 +188,13 @@ Boat::Boat() : PixmapItem(QString("boat"), GraphicsScene::Big),
     destroyedState->setAnimation(destroyAnimation);
 
     //Play a nice animation when the boat is destroyed
-    moving->addTransition(this, SIGNAL(boatDestroyed()), destroyedState);
+    moving->addTransition(this, &Boat::boatDestroyed, destroyedState);
 
     //Transition to final state when the destroyed animation is finished
-    destroyedState->addTransition(destroyedState, SIGNAL(animationFinished()), final);
+    destroyedState->addTransition(destroyedState, &QAnimationState::animationFinished, final);
 
     //The machine has finished to be executed, then the boat is dead
-    connect(machine,SIGNAL(finished()), this, SIGNAL(boatExecutionFinished()));
+    connect(machine,&QState::finished, this, &Boat::boatExecutionFinished);
 
 }
 
diff --git a/examples/widgets/animation/sub-attaq/boat_p.h b/examples/widgets/animation/sub-attaq/boat_p.h
index de11ff9555..8ebfeb27f5 100644
--- a/examples/widgets/animation/sub-attaq/boat_p.h
+++ b/examples/widgets/animation/sub-attaq/boat_p.h
@@ -146,7 +146,8 @@ private:
 class MoveStateRight : public QState
 {
 public:
-    explicit MoveStateRight(Boat *boat,QState *parent = 0) : QState(parent), boat(boat)
+    explicit MoveStateRight(Boat *boat, QState *parent = nullptr)
+        : QState(parent), boat(boat)
     {
     }
 protected:
@@ -163,7 +164,8 @@ private:
 class MoveStateLeft : public QState
 {
 public:
-    explicit MoveStateLeft(Boat *boat,QState *parent = 0) : QState(parent), boat(boat)
+    explicit MoveStateLeft(Boat *boat, QState *parent = nullptr)
+        : QState(parent), boat(boat)
     {
     }
 protected:
@@ -180,7 +182,8 @@ private:
 class StopState : public QState
 {
 public:
-    explicit StopState(Boat *boat,QState *parent = 0) : QState(parent), boat(boat)
+    explicit StopState(Boat *boat, QState *parent = nullptr)
+        : QState(parent), boat(boat)
     {
     }
 protected:
@@ -198,13 +201,14 @@ private:
 class LaunchStateRight : public QState
 {
 public:
-    explicit LaunchStateRight(Boat *boat,QState *parent = 0) : QState(parent), boat(boat)
+    explicit LaunchStateRight(Boat *boat, QState *parent = nullptr)
+        : QState(parent), boat(boat)
     {
     }
 protected:
     void onEntry(QEvent *) override
     {
-        Bomb *b = new Bomb();
+        Bomb *b = new Bomb;
         b->setPos(boat->x()+boat->size().width(),boat->y());
         GraphicsScene *scene = static_cast<GraphicsScene *>(boat->scene());
         scene->addItem(b);
@@ -219,13 +223,14 @@ private:
 class LaunchStateLeft : public QState
 {
 public:
-    explicit LaunchStateLeft(Boat *boat,QState *parent = 0) : QState(parent), boat(boat)
+    explicit LaunchStateLeft(Boat *boat, QState *parent = nullptr)
+        : QState(parent), boat(boat)
     {
     }
 protected:
     void onEntry(QEvent *) override
     {
-        Bomb *b = new Bomb();
+        Bomb *b = new Bomb;
         b->setPos(boat->x() - b->size().width(), boat->y());
         GraphicsScene *scene = static_cast<GraphicsScene *>(boat->scene());
         scene->addItem(b);
diff --git a/examples/widgets/animation/sub-attaq/bomb.cpp b/examples/widgets/animation/sub-attaq/bomb.cpp
index a80d2d46c5..2b865137dd 100644
--- a/examples/widgets/animation/sub-attaq/bomb.cpp
+++ b/examples/widgets/animation/sub-attaq/bomb.cpp
@@ -83,8 +83,8 @@ void Bomb::launch(Bomb::Direction direction)
     anim->setEndValue(QPointF(x() + delta*2,scene()->height()));
     anim->setDuration(y()/2*60);
     launchAnimation->addAnimation(anim);
-    connect(anim,SIGNAL(valueChanged(QVariant)),this,SLOT(onAnimationLaunchValueChanged(QVariant)));
-    connect(this, SIGNAL(bombExploded()), launchAnimation, SLOT(stop()));
+    connect(anim,&QVariantAnimation::valueChanged,this,&Bomb::onAnimationLaunchValueChanged);
+    connect(this, &Bomb::bombExploded, launchAnimation, &QAbstractAnimation::stop);
     //We setup the state machine of the bomb
     QStateMachine *machine = new QStateMachine(this);
 
@@ -98,13 +98,13 @@ void Bomb::launch(Bomb::Direction direction)
     machine->setInitialState(launched);
 
     //### Add a nice animation when the bomb is destroyed
-    launched->addTransition(this, SIGNAL(bombExploded()),final);
+    launched->addTransition(this, &Bomb::bombExploded,final);
 
     //If the animation is finished, then we move to the final state
-    launched->addTransition(launched, SIGNAL(animationFinished()), final);
+    launched->addTransition(launched, &QAnimationState::animationFinished, final);
 
     //The machine has finished to be executed, then the boat is dead
-    connect(machine,SIGNAL(finished()),this, SIGNAL(bombExecutionFinished()));
+    connect(machine,&QState::finished,this, &Bomb::bombExecutionFinished);
 
     machine->start();
 
@@ -112,7 +112,9 @@ void Bomb::launch(Bomb::Direction direction)
 
 void Bomb::onAnimationLaunchValueChanged(const QVariant &)
 {
-    foreach (QGraphicsItem * item , collidingItems(Qt::IntersectsItemBoundingRect)) {
+    const QList<QGraphicsItem *> colItems =
+            collidingItems(Qt::IntersectsItemBoundingRect);
+    for (QGraphicsItem *item : colItems) {
         if (item->type() == SubMarine::Type) {
             SubMarine *s = static_cast<SubMarine *>(item);
             destroy();
diff --git a/examples/widgets/animation/sub-attaq/graphicsscene.cpp b/examples/widgets/animation/sub-attaq/graphicsscene.cpp
index e0913f99f6..8f0dfc1357 100644
--- a/examples/widgets/animation/sub-attaq/graphicsscene.cpp
+++ b/examples/widgets/animation/sub-attaq/graphicsscene.cpp
@@ -191,15 +191,15 @@ void GraphicsScene::setupScene(QAction *newAction, QAction *quitAction)
     lettersFadingState->setAnimation(lettersGroupFading);
 
     //if new game then we fade out the welcome screen and start playing
-    lettersMovingState->addTransition(newAction, SIGNAL(triggered()), lettersFadingState);
-    lettersFadingState->addTransition(lettersFadingState, SIGNAL(animationFinished()), gameState);
+    lettersMovingState->addTransition(newAction, &QAction::triggered, lettersFadingState);
+    lettersFadingState->addTransition(lettersFadingState, &QAnimationState::animationFinished, gameState);
 
     //New Game is triggered then player start playing
-    gameState->addTransition(newAction, SIGNAL(triggered()), gameState);
+    gameState->addTransition(newAction, &QAction::triggered, gameState);
 
     //Wanna quit, then connect to CTRL+Q
-    gameState->addTransition(quitAction, SIGNAL(triggered()), final);
-    lettersMovingState->addTransition(quitAction, SIGNAL(triggered()), final);
+    gameState->addTransition(quitAction, &QAction::triggered, final);
+    lettersMovingState->addTransition(quitAction, &QAction::triggered, final);
 
     //Welcome screen is the initial state
     machine->setInitialState(lettersMovingState);
@@ -207,27 +207,27 @@ void GraphicsScene::setupScene(QAction *newAction, QAction *quitAction)
     machine->start();
 
     //We reach the final state, then we quit
-    connect(machine, SIGNAL(finished()), qApp, SLOT(quit()));
+    connect(machine, &QStateMachine::finished, qApp, &QApplication::quit);
 }
 
 void GraphicsScene::addItem(Bomb *bomb)
 {
     bombs.insert(bomb);
-    connect(bomb,SIGNAL(bombExecutionFinished()),this, SLOT(onBombExecutionFinished()));
+    connect(bomb,&Bomb::bombExecutionFinished,this, &GraphicsScene::onBombExecutionFinished);
     QGraphicsScene::addItem(bomb);
 }
 
 void GraphicsScene::addItem(Torpedo *torpedo)
 {
     torpedos.insert(torpedo);
-    connect(torpedo,SIGNAL(torpedoExecutionFinished()),this, SLOT(onTorpedoExecutionFinished()));
+    connect(torpedo,&Torpedo::torpedoExecutionFinished,this, &GraphicsScene::onTorpedoExecutionFinished);
     QGraphicsScene::addItem(torpedo);
 }
 
 void GraphicsScene::addItem(SubMarine *submarine)
 {
     submarines.insert(submarine);
-    connect(submarine,SIGNAL(subMarineExecutionFinished()),this, SLOT(onSubMarineExecutionFinished()));
+    connect(submarine,&SubMarine::subMarineExecutionFinished,this, &GraphicsScene::onSubMarineExecutionFinished);
     QGraphicsScene::addItem(submarine);
 }
 
@@ -265,17 +265,17 @@ void GraphicsScene::onSubMarineExecutionFinished()
 
 void GraphicsScene::clearScene()
 {
-    foreach (SubMarine *sub, submarines) {
+    for (SubMarine *sub : qAsConst(submarines)) {
         sub->destroy();
         sub->deleteLater();
     }
 
-    foreach (Torpedo *torpedo, torpedos) {
+    for (Torpedo *torpedo : qAsConst(torpedos)) {
         torpedo->destroy();
         torpedo->deleteLater();
     }
 
-    foreach (Bomb *bomb, bombs) {
+    for (Bomb *bomb : qAsConst(bombs)) {
         bomb->destroy();
         bomb->deleteLater();
     }
diff --git a/examples/widgets/animation/sub-attaq/mainwindow.cpp b/examples/widgets/animation/sub-attaq/mainwindow.cpp
index b08a7d9f98..a4bb15b383 100644
--- a/examples/widgets/animation/sub-attaq/mainwindow.cpp
+++ b/examples/widgets/animation/sub-attaq/mainwindow.cpp
@@ -63,7 +63,8 @@
 # include <QtOpenGL/QtOpenGL>
 #endif
 
-MainWindow::MainWindow() : QMainWindow(0)
+MainWindow::MainWindow(QWidget *parent)
+    : QMainWindow(parent)
 {
     QMenu *file = menuBar()->addMenu(tr("&File"));
 
diff --git a/examples/widgets/animation/sub-attaq/mainwindow.h b/examples/widgets/animation/sub-attaq/mainwindow.h
index 8d3cc85cd1..c4fb9d324d 100644
--- a/examples/widgets/animation/sub-attaq/mainwindow.h
+++ b/examples/widgets/animation/sub-attaq/mainwindow.h
@@ -62,7 +62,7 @@ class MainWindow : public QMainWindow
 {
 Q_OBJECT
 public:
-    MainWindow();
+    MainWindow(QWidget *parent = nullptr);
 
 private:
     GraphicsScene *scene;
diff --git a/examples/widgets/animation/sub-attaq/pixmapitem.cpp b/examples/widgets/animation/sub-attaq/pixmapitem.cpp
index 0723cdfb5d..9475d5c3f8 100644
--- a/examples/widgets/animation/sub-attaq/pixmapitem.cpp
+++ b/examples/widgets/animation/sub-attaq/pixmapitem.cpp
@@ -54,7 +54,8 @@
 //Qt
 #include <QPainter>
 
-PixmapItem::PixmapItem(const QString &fileName,GraphicsScene::Mode mode, QGraphicsItem * parent) : QGraphicsObject(parent)
+PixmapItem::PixmapItem(const QString &fileName,GraphicsScene::Mode mode, QGraphicsItem * parent)
+    : QGraphicsObject(parent)
 {
     if (mode == GraphicsScene::Big)
         pix  = QPixmap(QStringLiteral(":/big/") + fileName);
diff --git a/examples/widgets/animation/sub-attaq/pixmapitem.h b/examples/widgets/animation/sub-attaq/pixmapitem.h
index de8ed67a38..ec5c01857f 100644
--- a/examples/widgets/animation/sub-attaq/pixmapitem.h
+++ b/examples/widgets/animation/sub-attaq/pixmapitem.h
@@ -60,7 +60,7 @@
 class PixmapItem : public QGraphicsObject
 {
 public:
-    PixmapItem(const QString &fileName, GraphicsScene::Mode mode, QGraphicsItem * parent = 0);
+    PixmapItem(const QString &fileName, GraphicsScene::Mode mode, QGraphicsItem *parent = nullptr);
     PixmapItem(const QString &fileName, QGraphicsScene *scene);
     QSizeF size() const;
     QRectF boundingRect() const override;
diff --git a/examples/widgets/animation/sub-attaq/qanimationstate.cpp b/examples/widgets/animation/sub-attaq/qanimationstate.cpp
index 82bfdbf4b9..ce99f9080d 100644
--- a/examples/widgets/animation/sub-attaq/qanimationstate.cpp
+++ b/examples/widgets/animation/sub-attaq/qanimationstate.cpp
@@ -73,21 +73,18 @@ QAnimationState *s = new QAnimationState(machine->rootState());
 QPropertyAnimation *animation = new QPropertyAnimation(obj, "pos");
 s->setAnimation(animation);
 QState *s2 = new QState(machine->rootState());
-s->addTransition(s, SIGNAL(animationFinished()), s2);
+s->addTransition(s, &QAnimationState::animationFinished, s2);
 machine.start();
 \endcode
 
 \sa QState, {The Animation Framework}
 */
 
-
-#ifndef QT_NO_ANIMATION
-
 /*!
   Constructs a new state with the given \a parent state.
 */
 QAnimationState::QAnimationState(QState *parent)
-    : QState(parent), m_animation(0)
+    : QState(parent), m_animation(nullptr)
 {
 }
 
@@ -110,18 +107,18 @@ void QAnimationState::setAnimation(QAbstractAnimation *animation)
 
     //Disconnect from the previous animation if exist
     if(m_animation)
-        disconnect(m_animation, SIGNAL(finished()), this, SIGNAL(animationFinished()));
+        disconnect(m_animation, &QAbstractAnimation::finished, this, &QAnimationState::animationFinished);
 
     m_animation = animation;
 
     if (m_animation) {
         //connect the new animation
-        connect(m_animation, SIGNAL(finished()), this, SIGNAL(animationFinished()));
+        connect(m_animation, &QAbstractAnimation::finished, this, &QAnimationState::animationFinished);
     }
 }
 
 /*!
-  Returns the animation handle by this animation state, or 0 if there is no animation.
+  Returns the animation handle by this animation state, or \nullptr if there is no animation.
 */
 QAbstractAnimation* QAnimationState::animation() const
 {
@@ -155,5 +152,3 @@ bool QAnimationState::event(QEvent *e)
 }
 
 QT_END_NAMESPACE
-
-#endif
diff --git a/examples/widgets/animation/sub-attaq/qanimationstate.h b/examples/widgets/animation/sub-attaq/qanimationstate.h
index 06ab4dfbcf..063b119058 100644
--- a/examples/widgets/animation/sub-attaq/qanimationstate.h
+++ b/examples/widgets/animation/sub-attaq/qanimationstate.h
@@ -61,9 +61,6 @@
 
 QT_BEGIN_NAMESPACE
 
-
-#ifndef QT_NO_ANIMATION
-
 class QAbstractAnimation;
 
 class QAnimationState : public QState
@@ -89,8 +86,6 @@ private:
     QAbstractAnimation *m_animation;
 };
 
-#endif
-
 QT_END_NAMESPACE
 
 #endif // QANIMATIONSTATE_H
diff --git a/examples/widgets/animation/sub-attaq/states.cpp b/examples/widgets/animation/sub-attaq/states.cpp
index e19704db7b..cda10ccdaf 100644
--- a/examples/widgets/animation/sub-attaq/states.cpp
+++ b/examples/widgets/animation/sub-attaq/states.cpp
@@ -67,11 +67,8 @@
 #include <QtCore/QRandomGenerator>
 
 PlayState::PlayState(GraphicsScene *scene, QState *parent)
-    : QState(parent),
-    scene(scene),
-    machine(0),
-    currentLevel(0),
-    score(0)
+    : QState(parent), scene(scene), machine(nullptr),
+      currentLevel(0), score(0)
 {
 }
 
@@ -124,7 +121,7 @@ void PlayState::onEntry(QEvent *)
     WinState *winState = new WinState(scene, this, machine);
 
     //The boat has been destroyed then the game is finished
-    levelState->addTransition(scene->boat, SIGNAL(boatExecutionFinished()),lostState);
+    levelState->addTransition(scene->boat, &Boat::boatExecutionFinished,lostState);
 
     //This transition check if we won or not
     WinTransition *winTransition = new WinTransition(scene, this, winState);
@@ -157,7 +154,7 @@ void PlayState::onEntry(QEvent *)
     winState->addTransition(spaceTransition);
 
     //We lost we should reach the final state
-    lostState->addTransition(lostState, SIGNAL(finished()), final);
+    lostState->addTransition(lostState, &QState::finished, final);
 
     machine->start();
 }
@@ -291,8 +288,8 @@ UpdateScoreState::UpdateScoreState(QState *parent) : QState(parent)
 
 /** Win transition */
 UpdateScoreTransition::UpdateScoreTransition(GraphicsScene *scene, PlayState *game, QAbstractState *target)
-    : QSignalTransition(scene,SIGNAL(subMarineDestroyed(int))),
-    game(game), scene(scene)
+    : QSignalTransition(scene, &GraphicsScene::subMarineDestroyed),
+      game(game), scene(scene)
 {
     setTargetState(target);
 }
@@ -309,8 +306,8 @@ bool UpdateScoreTransition::eventTest(QEvent *event)
 
 /** Win transition */
 WinTransition::WinTransition(GraphicsScene *scene, PlayState *game, QAbstractState *target)
-    : QSignalTransition(scene,SIGNAL(allSubMarineDestroyed(int))),
-    game(game), scene(scene)
+    : QSignalTransition(scene, &GraphicsScene::allSubMarineDestroyed),
+      game(game), scene(scene)
 {
     setTargetState(target);
 }
diff --git a/examples/widgets/animation/sub-attaq/submarine.cpp b/examples/widgets/animation/sub-attaq/submarine.cpp
index a451185ce0..775e75ceed 100644
--- a/examples/widgets/animation/sub-attaq/submarine.cpp
+++ b/examples/widgets/animation/sub-attaq/submarine.cpp
@@ -106,7 +106,7 @@ SubMarine::SubMarine(int type, const QString &name, int points) : PixmapItem(QSt
     //This is the initial state of the moving root state
     moving->setInitialState(movement);
 
-    movement->addTransition(this, SIGNAL(subMarineStateChanged()), moving);
+    movement->addTransition(this, &SubMarine::subMarineStateChanged, moving);
 
     //This is the initial state of the machine
     machine->setInitialState(moving);
@@ -115,23 +115,23 @@ SubMarine::SubMarine(int type, const QString &name, int points) : PixmapItem(QSt
     QFinalState *final = new QFinalState(machine);
 
     //If the moving animation is finished we move to the return state
-    movement->addTransition(movement, SIGNAL(animationFinished()), rotation);
+    movement->addTransition(movement, &QAnimationState::animationFinished, rotation);
 
     //If the return animation is finished we move to the moving state
-    rotation->addTransition(rotation, SIGNAL(animationFinished()), movement);
+    rotation->addTransition(rotation, &QAnimationState::animationFinished, movement);
 
     //This state play the destroyed animation
     QAnimationState *destroyedState = new QAnimationState(machine);
     destroyedState->setAnimation(setupDestroyAnimation(this));
 
     //Play a nice animation when the submarine is destroyed
-    moving->addTransition(this, SIGNAL(subMarineDestroyed()), destroyedState);
+    moving->addTransition(this, &SubMarine::subMarineDestroyed, destroyedState);
 
     //Transition to final state when the destroyed animation is finished
-    destroyedState->addTransition(destroyedState, SIGNAL(animationFinished()), final);
+    destroyedState->addTransition(destroyedState, &QAnimationState::animationFinished, final);
 
     //The machine has finished to be executed, then the submarine is dead
-    connect(machine,SIGNAL(finished()),this, SIGNAL(subMarineExecutionFinished()));
+    connect(machine,&QState::finished,this, &SubMarine::subMarineExecutionFinished);
 
     machine->start();
 }
diff --git a/examples/widgets/animation/sub-attaq/submarine_p.h b/examples/widgets/animation/sub-attaq/submarine_p.h
index 698b4b494f..1c2cb7ceac 100644
--- a/examples/widgets/animation/sub-attaq/submarine_p.h
+++ b/examples/widgets/animation/sub-attaq/submarine_p.h
@@ -80,7 +80,8 @@ public:
     explicit MovementState(SubMarine *submarine, QState *parent = 0) : QAnimationState(parent)
     {
         movementAnimation = new QPropertyAnimation(submarine, "pos");
-        connect(movementAnimation,SIGNAL(valueChanged(const QVariant &)),this,SLOT(onAnimationMovementValueChanged(const QVariant &)));
+        connect(movementAnimation, &QPropertyAnimation::valueChanged,
+                this, &MovementState::onAnimationMovementValueChanged);
         setAnimation(movementAnimation);
         AnimationManager::self()->registerAnimation(movementAnimation);
         this->submarine = submarine;
diff --git a/examples/widgets/animation/sub-attaq/torpedo.cpp b/examples/widgets/animation/sub-attaq/torpedo.cpp
index 2e9d970326..92a3833452 100644
--- a/examples/widgets/animation/sub-attaq/torpedo.cpp
+++ b/examples/widgets/animation/sub-attaq/torpedo.cpp
@@ -73,8 +73,8 @@ void Torpedo::launch()
     launchAnimation->setEndValue(QPointF(x(),qobject_cast<GraphicsScene *>(scene())->sealLevel() - 15));
     launchAnimation->setEasingCurve(QEasingCurve::InQuad);
     launchAnimation->setDuration(y()/currentSpeed*10);
-    connect(launchAnimation,SIGNAL(valueChanged(QVariant)),this,SLOT(onAnimationLaunchValueChanged(QVariant)));
-    connect(this,SIGNAL(torpedoExploded()), launchAnimation, SLOT(stop()));
+    connect(launchAnimation,&QVariantAnimation::valueChanged,this,&Torpedo::onAnimationLaunchValueChanged);
+    connect(this,&Torpedo::torpedoExploded, launchAnimation, &QAbstractAnimation::stop);
 
     //We setup the state machine of the torpedo
     QStateMachine *machine = new QStateMachine(this);
@@ -89,13 +89,13 @@ void Torpedo::launch()
     machine->setInitialState(launched);
 
     //### Add a nice animation when the torpedo is destroyed
-    launched->addTransition(this, SIGNAL(torpedoExploded()),final);
+    launched->addTransition(this, &Torpedo::torpedoExploded,final);
 
     //If the animation is finished, then we move to the final state
-    launched->addTransition(launched, SIGNAL(animationFinished()), final);
+    launched->addTransition(launched, &QAnimationState::animationFinished, final);
 
     //The machine has finished to be executed, then the boat is dead
-    connect(machine,SIGNAL(finished()),this, SIGNAL(torpedoExecutionFinished()));
+    connect(machine,&QState::finished,this, &Torpedo::torpedoExecutionFinished);
 
     machine->start();
 }
@@ -111,7 +111,9 @@ void Torpedo::setCurrentSpeed(int speed)
 
 void Torpedo::onAnimationLaunchValueChanged(const QVariant &)
 {
-    foreach (QGraphicsItem *item , collidingItems(Qt::IntersectsItemBoundingRect)) {
+    const QList<QGraphicsItem *> colItems =
+            collidingItems(Qt::IntersectsItemBoundingRect);
+    for (QGraphicsItem *item : colItems) {
         if (Boat *b = qgraphicsitem_cast<Boat*>(item))
             b->destroy();
     }
diff --git a/examples/widgets/desktop/screenshot/screenshot.cpp b/examples/widgets/desktop/screenshot/screenshot.cpp
index 80f26ae282..715e6c780e 100644
--- a/examples/widgets/desktop/screenshot/screenshot.cpp
+++ b/examples/widgets/desktop/screenshot/screenshot.cpp
@@ -139,7 +139,8 @@ void Screenshot::saveScreenshot()
     fileDialog.setFileMode(QFileDialog::AnyFile);
     fileDialog.setDirectory(initialPath);
     QStringList mimeTypes;
-    foreach (const QByteArray &bf, QImageWriter::supportedMimeTypes())
+    const QList<QByteArray> baMimeTypes = QImageWriter::supportedMimeTypes();
+    for (const QByteArray &bf : baMimeTypes)
         mimeTypes.append(QLatin1String(bf));
     fileDialog.setMimeTypeFilters(mimeTypes);
     fileDialog.selectMimeTypeFilter("image/" + format);
diff --git a/examples/widgets/desktop/systray/main.cpp b/examples/widgets/desktop/systray/main.cpp
index 49b0e10412..2d91e4ac36 100644
--- a/examples/widgets/desktop/systray/main.cpp
+++ b/examples/widgets/desktop/systray/main.cpp
@@ -59,10 +59,12 @@ int main(int argc, char *argv[])
 {
     Q_INIT_RESOURCE(systray);
 
+    QCoreApplication::setAttribute(Qt::AA_UseHighDpiPixmaps);
+
     QApplication app(argc, argv);
 
     if (!QSystemTrayIcon::isSystemTrayAvailable()) {
-        QMessageBox::critical(0, QObject::tr("Systray"),
+        QMessageBox::critical(nullptr, QObject::tr("Systray"),
                               QObject::tr("I couldn't detect any system tray "
                                           "on this system."));
         return 1;
diff --git a/examples/widgets/desktop/systray/window.cpp b/examples/widgets/desktop/systray/window.cpp
index 05944c92a7..31fcd84821 100644
--- a/examples/widgets/desktop/systray/window.cpp
+++ b/examples/widgets/desktop/systray/window.cpp
@@ -176,7 +176,7 @@ void Window::showMessage()
 //! [6]
 void Window::messageClicked()
 {
-    QMessageBox::information(0, tr("Systray"),
+    QMessageBox::information(nullptr, tr("Systray"),
                              tr("Sorry, I already gave what help I could.\n"
                                 "Maybe you should try asking a human?"));
 }
diff --git a/examples/widgets/dialogs/classwizard/classwizard.cpp b/examples/widgets/dialogs/classwizard/classwizard.cpp
index 3eab2f5fb2..81adf85b0d 100644
--- a/examples/widgets/dialogs/classwizard/classwizard.cpp
+++ b/examples/widgets/dialogs/classwizard/classwizard.cpp
@@ -139,7 +139,7 @@ void ClassWizard::accept()
 
     QFile headerFile(outputDir + '/' + header);
     if (!headerFile.open(QFile::WriteOnly | QFile::Text)) {
-        QMessageBox::warning(0, QObject::tr("Simple Wizard"),
+        QMessageBox::warning(nullptr, QObject::tr("Simple Wizard"),
                              QObject::tr("Cannot write file %1:\n%2")
                              .arg(headerFile.fileName())
                              .arg(headerFile.errorString()));
@@ -195,7 +195,7 @@ void ClassWizard::accept()
 
     QFile implementationFile(outputDir + '/' + implementation);
     if (!implementationFile.open(QFile::WriteOnly | QFile::Text)) {
-        QMessageBox::warning(0, QObject::tr("Simple Wizard"),
+        QMessageBox::warning(nullptr, QObject::tr("Simple Wizard"),
                              QObject::tr("Cannot write file %1:\n%2")
                              .arg(implementationFile.fileName())
                              .arg(implementationFile.errorString()));
diff --git a/examples/widgets/dialogs/classwizard/main.cpp b/examples/widgets/dialogs/classwizard/main.cpp
index 72eb1ae6ec..03ffe97a23 100644
--- a/examples/widgets/dialogs/classwizard/main.cpp
+++ b/examples/widgets/dialogs/classwizard/main.cpp
@@ -59,6 +59,8 @@ int main(int argc, char *argv[])
 {
     Q_INIT_RESOURCE(classwizard);
 
+    QCoreApplication::setAttribute(Qt::AA_UseHighDpiPixmaps);
+
     QApplication app(argc, argv);
 
 #ifndef QT_NO_TRANSLATION
diff --git a/examples/widgets/dialogs/extension/finddialog.cpp b/examples/widgets/dialogs/extension/finddialog.cpp
index 1321155f00..10a4ae1ac0 100644
--- a/examples/widgets/dialogs/extension/finddialog.cpp
+++ b/examples/widgets/dialogs/extension/finddialog.cpp
@@ -91,7 +91,7 @@ FindDialog::FindDialog(QWidget *parent)
     connect(moreButton, &QAbstractButton::toggled, extension, &QWidget::setVisible);
 
     QVBoxLayout *extensionLayout = new QVBoxLayout;
-    extensionLayout->setMargin(0);
+    extensionLayout->setContentsMargins(QMargins());
     extensionLayout->addWidget(wholeWordsCheckBox);
     extensionLayout->addWidget(backwardCheckBox);
     extensionLayout->addWidget(searchSelectionCheckBox);
diff --git a/examples/widgets/dialogs/findfiles/window.cpp b/examples/widgets/dialogs/findfiles/window.cpp
index 1b16cdcd35..e1f7ccdcc4 100644
--- a/examples/widgets/dialogs/findfiles/window.cpp
+++ b/examples/widgets/dialogs/findfiles/window.cpp
@@ -182,7 +182,7 @@ QStringList Window::findFiles(const QStringList &files, const QString &text)
 
     for (int i = 0; i < files.size(); ++i) {
         progressDialog.setValue(i);
-        progressDialog.setLabelText(tr("Searching file number %1 of %n...", 0, files.size()).arg(i));
+        progressDialog.setLabelText(tr("Searching file number %1 of %n...", nullptr, files.size()).arg(i));
         QCoreApplication::processEvents();
 //! [6]
 
@@ -237,7 +237,7 @@ void Window::showFiles(const QStringList &paths)
         filesTable->setItem(row, 0, fileNameItem);
         filesTable->setItem(row, 1, sizeItem);
     }
-    filesFoundLabel->setText(tr("%n file(s) found (Double click on a file to open it)", 0, paths.size()));
+    filesFoundLabel->setText(tr("%n file(s) found (Double click on a file to open it)", nullptr, paths.size()));
     filesFoundLabel->setWordWrap(true);
 }
 //! [8]
diff --git a/examples/widgets/dialogs/licensewizard/main.cpp b/examples/widgets/dialogs/licensewizard/main.cpp
index 025b79243c..ed46e792d0 100644
--- a/examples/widgets/dialogs/licensewizard/main.cpp
+++ b/examples/widgets/dialogs/licensewizard/main.cpp
@@ -59,6 +59,8 @@ int main(int argc, char *argv[])
 {
     Q_INIT_RESOURCE(licensewizard);
 
+    QCoreApplication::setAttribute(Qt::AA_UseHighDpiPixmaps);
+
     QApplication app(argc, argv);
 
 #ifndef QT_NO_TRANSLATION
diff --git a/examples/widgets/dialogs/standarddialogs/dialog.cpp b/examples/widgets/dialogs/standarddialogs/dialog.cpp
index 74a4131b38..1830b21e8f 100644
--- a/examples/widgets/dialogs/standarddialogs/dialog.cpp
+++ b/examples/widgets/dialogs/standarddialogs/dialog.cpp
@@ -65,7 +65,7 @@
 class DialogOptionsWidget : public QGroupBox
 {
 public:
-    explicit DialogOptionsWidget(QWidget *parent = 0);
+    explicit DialogOptionsWidget(QWidget *parent = nullptr);
 
     void addCheckBox(const QString &text, int value);
     void addSpacer();
@@ -99,9 +99,10 @@ void DialogOptionsWidget::addSpacer()
 int DialogOptionsWidget::value() const
 {
     int result = 0;
-    foreach (const CheckBoxEntry &checkboxEntry, checkBoxEntries)
+    for (const CheckBoxEntry &checkboxEntry : qAsConst(checkBoxEntries)) {
         if (checkboxEntry.first->isChecked())
             result |= checkboxEntry.second;
+    }
     return result;
 }
 
@@ -492,7 +493,7 @@ void Dialog::questionMessage()
 void Dialog::warningMessage()
 {
     QMessageBox msgBox(QMessageBox::Warning, tr("QMessageBox::warning()"),
-                       MESSAGE, 0, this);
+                       MESSAGE, nullptr, this);
     msgBox.setDetailedText(MESSAGE_DETAILS);
     msgBox.addButton(tr("Save &Again"), QMessageBox::AcceptRole);
     msgBox.addButton(tr("&Continue"), QMessageBox::RejectRole);
diff --git a/examples/widgets/dialogs/standarddialogs/main.cpp b/examples/widgets/dialogs/standarddialogs/main.cpp
index 150d07318e..a0cded4f47 100644
--- a/examples/widgets/dialogs/standarddialogs/main.cpp
+++ b/examples/widgets/dialogs/standarddialogs/main.cpp
@@ -59,6 +59,7 @@
 
 int main(int argc, char *argv[])
 {
+    QCoreApplication::setAttribute(Qt::AA_UseHighDpiPixmaps);
     QApplication app(argc, argv);
     QGuiApplication::setApplicationDisplayName(Dialog::tr("Standard Dialogs"));
 
diff --git a/examples/widgets/dialogs/trivialwizard/trivialwizard.cpp b/examples/widgets/dialogs/trivialwizard/trivialwizard.cpp
index fe49bf6304..ce13a59b0c 100644
--- a/examples/widgets/dialogs/trivialwizard/trivialwizard.cpp
+++ b/examples/widgets/dialogs/trivialwizard/trivialwizard.cpp
@@ -123,6 +123,8 @@ QWizardPage *createConclusionPage()
 int main(int argc, char *argv[])
 //! [9] //! [11]
 {
+    QCoreApplication::setAttribute(Qt::AA_UseHighDpiPixmaps);
+
     QApplication app(argc, argv);
 
 #ifndef QT_NO_TRANSLATION
diff --git a/examples/widgets/doc/dropsite.qdoc b/examples/widgets/doc/dropsite.qdoc
index 32bcfe8916..af8766a308 100644
--- a/examples/widgets/doc/dropsite.qdoc
+++ b/examples/widgets/doc/dropsite.qdoc
@@ -202,13 +202,7 @@
     \snippet draganddrop/dropsite/dropsitewindow.cpp updateFormatsTable() part1
 
     Once we are sure that \c mimeData is valid, we iterate through its
-    supported formats using the \l{The foreach Keyword}{foreach keyword}.
-    This keyword has the following format:
-
-    \include code/doc_src_examples_dropsite.qdoc 0
-
-    In our example, \c format is the \a variable and the \a container is a
-    QStringList, obtained from \c mimeData->formats().
+    supported formats.
 
     \note The \l{QMimeData::formats()}{formats()} function returns a
     QStringList object, containing all the formats supported by the
diff --git a/examples/widgets/doc/src/addressbook.qdoc b/examples/widgets/doc/src/addressbook.qdoc
index 1fa0bfa9d4..e5e7fe5c2c 100644
--- a/examples/widgets/doc/src/addressbook.qdoc
+++ b/examples/widgets/doc/src/addressbook.qdoc
@@ -90,8 +90,8 @@
     \snippet itemviews/addressbook/tablemodel.h 0
 
     Two constructors are used, a default constructor which uses
-    \c TableModel's own \c {QList<Contact>} and one that takes
-    \c {QList<Contact>} as an argument, for convenience.
+    \c TableModel's own \c {QVector<Contact>} and one that takes
+    \c {QVector<Contact>} as an argument, for convenience.
 
 
     \section1 TableModel Class Implementation
@@ -108,9 +108,6 @@
     \c columnCount()'s value is always 2 because we only need space
     for the \b Name and \b Address columns.
 
-    \note The \c Q_UNUSED() macro prevents the compiler from
-    generating warnings regarding unused parameters.
-
     \snippet itemviews/addressbook/tablemodel.cpp 1
 
     The \c data() function returns either a \b Name or
@@ -164,7 +161,7 @@
     them here so that we can reuse the model in other programs.
 
     The last function in \c {TableModel}, \c getContacts() returns the
-    QList<Contact> object that holds all the contacts in the address
+    QVector<Contact> object that holds all the contacts in the address
     book. We use this function later to obtain the list of contacts to
     check for existing entries, write the contacts to a file and read
     them back. Further explanation is given with \c AddressWidget.
@@ -233,7 +230,7 @@
 
     \image addressbook-signals.png Signals and Slots Connections
 
-    We provide 2 \c addEntry() functions: 1 which is intended to be
+    We provide two \c addEntry() functions: One which is intended to be
     used to accept user input, and the other which performs the actual
     task of adding new entries to the address book. We divide the
     responsibility of adding entries into two parts to allow
diff --git a/examples/widgets/doc/src/diagramscene.qdoc b/examples/widgets/doc/src/diagramscene.qdoc
index ca4876f2e8..860dcc5cb9 100644
--- a/examples/widgets/doc/src/diagramscene.qdoc
+++ b/examples/widgets/doc/src/diagramscene.qdoc
@@ -589,7 +589,7 @@
     \snippet graphicsview/diagramscene/diagramscene.cpp 14
 
     The scene has single selection, i.e., only one item can be
-    selected at any given time. The foreach will then loop one time
+    selected at any given time. The for loop will then loop one time
     with the selected item or none if no item is selected. \c
     isItemChange() is used to check whether a selected item exists
     and also is of the specified diagram \a type.
diff --git a/examples/widgets/doc/src/fetchmore.qdoc b/examples/widgets/doc/src/fetchmore.qdoc
index df0cf3b8ec..a27efaf071 100644
--- a/examples/widgets/doc/src/fetchmore.qdoc
+++ b/examples/widgets/doc/src/fetchmore.qdoc
@@ -29,7 +29,7 @@
     \example itemviews/fetchmore
     \title Fetch More Example
     \ingroup examples-itemviews
-    \brief The Fetch More example shows how two add items to an item view
+    \brief The Fetch More example shows how to add items to an item view
     model on demand.
 
     \image fetchmore-example.png
diff --git a/examples/widgets/doc/src/orderform.qdoc b/examples/widgets/doc/src/orderform.qdoc
index de59fc402d..5c63081a77 100644
--- a/examples/widgets/doc/src/orderform.qdoc
+++ b/examples/widgets/doc/src/orderform.qdoc
@@ -191,7 +191,7 @@
 
     We then set the \c{cursor}'s position back to its last position in
     \c topFrame and fill in the customer's name (provided by the constructor)
-    and address - using a \c foreach loop to traverse the QString, \c address.
+    and address - using a range-based for loop to traverse the QString, \c address.
 
     \snippet richtext/orderform/mainwindow.cpp 4
 
diff --git a/examples/widgets/doc/src/plugandpaint.qdoc b/examples/widgets/doc/src/plugandpaint.qdoc
index d3044860ab..b37176da0e 100644
--- a/examples/widgets/doc/src/plugandpaint.qdoc
+++ b/examples/widgets/doc/src/plugandpaint.qdoc
@@ -171,8 +171,8 @@
     \snippet tools/plugandpaint/app/mainwindow.cpp 8
 
     We use QDir::entryList() to get a list of all files in that
-    directory. Then we iterate over the result using \l foreach and
-    try to load the plugin using QPluginLoader.
+    directory. Then we iterate over the result using a range-based for loop
+    and try to load the plugin using QPluginLoader.
 
     The QObject provided by the plugin is accessible through
     QPluginLoader::instance(). If the dynamic library isn't a Qt
diff --git a/examples/widgets/doc/src/simpletreemodel.qdoc b/examples/widgets/doc/src/simpletreemodel.qdoc
index a50197b04d..f5fe93897c 100644
--- a/examples/widgets/doc/src/simpletreemodel.qdoc
+++ b/examples/widgets/doc/src/simpletreemodel.qdoc
@@ -170,9 +170,8 @@
 
     \snippet itemviews/simpletreemodel/treeitem.cpp 5
 
-    Column data is returned by the \c data() function, taking advantage of
-    QList's ability to provide sensible default values if the column number
-    is out of range:
+    Column data is returned by the \c data() function. The bounds are checked
+    before accessing the container with the data:
 
     \snippet itemviews/simpletreemodel/treeitem.cpp 6
 
diff --git a/examples/widgets/doc/src/stardelegate.qdoc b/examples/widgets/doc/src/stardelegate.qdoc
index 44d17662ca..0b91723a51 100644
--- a/examples/widgets/doc/src/stardelegate.qdoc
+++ b/examples/widgets/doc/src/stardelegate.qdoc
@@ -42,11 +42,11 @@
     editing takes place.
 
     Delegates are subclasses of QAbstractItemDelegate. Qt provides
-    QItemDelegate, which inherits QAbstractItemDelegate and handles
+    QStyledItemDelegate, which inherits QAbstractItemDelegate and handles
     the most common data types (notably \c int and QString). If we
     need to support custom data types, or want to customize the
     rendering or the editing for existing data types, we can subclass
-    QAbstractItemDelegate or QItemDelegate. See \l{Delegate Classes}
+    QAbstractItemDelegate or QStyledItemDelegate. See \l{Delegate Classes}
     for more information about delegates, and \l{Model/View
     Programming} if you need a high-level introduction to Qt's
     model/view architecture (including delegates).
@@ -62,9 +62,9 @@
        expressed as stars, such as "2 out of 5 stars" or "5 out of
        6 stars".
 
-    \li \c StarDelegate inherits QItemDelegate and provides support
+    \li \c StarDelegate inherits QStyledItemDelegate and provides support
        for \c StarRating (in addition to the data types already
-       handled by QItemDelegate).
+       handled by QStyledItemDelegate).
 
     \li \c StarEditor inherits QWidget and is used by \c StarDelegate
        to let the user edit a star rating using the mouse.
@@ -80,12 +80,12 @@
     \snippet itemviews/stardelegate/stardelegate.h 0
 
     All public functions are reimplemented virtual functions from
-    QItemDelegate to provide custom rendering and editing.
+    QStyledItemDelegate to provide custom rendering and editing.
 
     \section1 StarDelegate Class Implementation
 
     The \l{QAbstractItemDelegate::}{paint()} function is
-    reimplemented from QItemDelegate and is called whenever the view
+    reimplemented from QStyledItemDelegate and is called whenever the view
     needs to repaint an item:
 
     \snippet itemviews/stardelegate/stardelegate.cpp 0
@@ -93,7 +93,7 @@
     The function is invoked once for each item, represented by a
     QModelIndex object from the model. If the data stored in the item
     is a \c StarRating, we paint it ourselves; otherwise, we let
-    QItemDelegate paint it for us. This ensures that the \c
+    QStyledItemDelegate paint it for us. This ensures that the \c
     StarDelegate can handle the most common data types.
 
     If the item is a \c StarRating, we draw the background if the
diff --git a/examples/widgets/draganddrop/dropsite/dropsitewindow.cpp b/examples/widgets/draganddrop/dropsite/dropsitewindow.cpp
index 28a42ee614..2dae83bb22 100644
--- a/examples/widgets/draganddrop/dropsite/dropsitewindow.cpp
+++ b/examples/widgets/draganddrop/dropsite/dropsitewindow.cpp
@@ -113,7 +113,8 @@ void DropSiteWindow::updateFormatsTable(const QMimeData *mimeData)
 //! [updateFormatsTable() part1]
 
 //! [updateFormatsTable() part2]
-    for (const QString &format : mimeData->formats()) {
+    const QStringList formats = mimeData->formats();
+    for (const QString &format : formats) {
         QTableWidgetItem *formatItem = new QTableWidgetItem(format);
         formatItem->setFlags(Qt::ItemIsEnabled);
         formatItem->setTextAlignment(Qt::AlignTop | Qt::AlignLeft);
diff --git a/examples/widgets/effects/fademessage/fademessage.cpp b/examples/widgets/effects/fademessage/fademessage.cpp
index 9943147bb7..4c3a70bb4f 100644
--- a/examples/widgets/effects/fademessage/fademessage.cpp
+++ b/examples/widgets/effects/fademessage/fademessage.cpp
@@ -131,7 +131,7 @@ void FadeMessage::setupScene()
 
     QPushButton *press = new QPushButton;
     press->setText(tr("Press me"));
-    connect(press, SIGNAL(clicked()), SLOT(togglePopup()));
+    connect(press, &QAbstractButton::clicked, this, &FadeMessage::togglePopup);
     m_scene.addWidget(press);
 
     press->move(300, 500);
diff --git a/examples/widgets/gestures/imagegestures/imagewidget.cpp b/examples/widgets/gestures/imagegestures/imagewidget.cpp
index ca9affca70..0a6b963559 100644
--- a/examples/widgets/gestures/imagegestures/imagewidget.cpp
+++ b/examples/widgets/gestures/imagegestures/imagewidget.cpp
@@ -72,7 +72,7 @@ ImageWidget::ImageWidget(QWidget *parent)
 void ImageWidget::grabGestures(const QList<Qt::GestureType> &gestures)
 {
     //! [enable gestures]
-    foreach (Qt::GestureType gesture, gestures)
+    for (Qt::GestureType gesture : gestures)
         grabGesture(gesture);
     //! [enable gestures]
 }
diff --git a/examples/widgets/graphicsview/boxes/glbuffers.cpp b/examples/widgets/graphicsview/boxes/glbuffers.cpp
index 851cd17796..b52b26c4ef 100644
--- a/examples/widgets/graphicsview/boxes/glbuffers.cpp
+++ b/examples/widgets/graphicsview/boxes/glbuffers.cpp
@@ -218,14 +218,14 @@ GLTextureCube::GLTextureCube(int size)
     glBindTexture(GL_TEXTURE_CUBE_MAP, 0);
 }
 
-GLTextureCube::GLTextureCube(const QStringList& fileNames, int size)
+GLTextureCube::GLTextureCube(const QStringList &fileNames, int size)
 {
     // TODO: Add error handling.
 
     glBindTexture(GL_TEXTURE_CUBE_MAP, m_texture);
 
     int index = 0;
-    foreach (QString file, fileNames) {
+    for (const QString &file : fileNames) {
         QImage image(file);
         if (image.isNull()) {
             m_failed = true;
diff --git a/examples/widgets/graphicsview/boxes/glbuffers.h b/examples/widgets/graphicsview/boxes/glbuffers.h
index 03c24a91d3..e2363d561e 100644
--- a/examples/widgets/graphicsview/boxes/glbuffers.h
+++ b/examples/widgets/graphicsview/boxes/glbuffers.h
@@ -129,7 +129,7 @@ class GLTextureCube : public GLTexture
 {
 public:
     GLTextureCube(int size);
-    explicit GLTextureCube(const QStringList& fileNames, int size = 0);
+    explicit GLTextureCube(const QStringList &fileNames, int size = 0);
     void load(int size, int face, QRgb *data);
     void bind() override;
     void unbind() override;
diff --git a/examples/widgets/graphicsview/boxes/qtbox.cpp b/examples/widgets/graphicsview/boxes/qtbox.cpp
index 3a184dd0b6..68d5c251f4 100644
--- a/examples/widgets/graphicsview/boxes/qtbox.cpp
+++ b/examples/widgets/graphicsview/boxes/qtbox.cpp
@@ -127,10 +127,8 @@ void ItemBase::duplicateSelectedItems(QGraphicsScene *scene)
     if (!scene)
         return;
 
-    QList<QGraphicsItem *> selected;
-    selected = scene->selectedItems();
-
-    foreach (QGraphicsItem *item, selected) {
+    const QList<QGraphicsItem *> selected = scene->selectedItems();
+    for (QGraphicsItem *item : selected) {
         ItemBase *itemBase = qgraphicsitem_cast<ItemBase *>(item);
         if (itemBase)
             scene->addItem(itemBase->createNew(itemBase->m_size, itemBase->pos().x() + itemBase->m_size, itemBase->pos().y()));
@@ -142,10 +140,8 @@ void ItemBase::deleteSelectedItems(QGraphicsScene *scene)
     if (!scene)
         return;
 
-    QList<QGraphicsItem *> selected;
-    selected = scene->selectedItems();
-
-    foreach (QGraphicsItem *item, selected) {
+    const QList<QGraphicsItem *> selected = scene->selectedItems();
+    for (QGraphicsItem *item : selected) {
         ItemBase *itemBase = qgraphicsitem_cast<ItemBase *>(item);
         if (itemBase)
             delete itemBase;
@@ -157,10 +153,8 @@ void ItemBase::growSelectedItems(QGraphicsScene *scene)
     if (!scene)
         return;
 
-    QList<QGraphicsItem *> selected;
-    selected = scene->selectedItems();
-
-    foreach (QGraphicsItem *item, selected) {
+    const QList<QGraphicsItem *> selected = scene->selectedItems();
+    for (QGraphicsItem *item : selected) {
         ItemBase *itemBase = qgraphicsitem_cast<ItemBase *>(item);
         if (itemBase) {
             itemBase->prepareGeometryChange();
@@ -176,10 +170,8 @@ void ItemBase::shrinkSelectedItems(QGraphicsScene *scene)
     if (!scene)
         return;
 
-    QList<QGraphicsItem *> selected;
-    selected = scene->selectedItems();
-
-    foreach (QGraphicsItem *item, selected) {
+    const QList<QGraphicsItem *> selected = scene->selectedItems();
+    for (QGraphicsItem *item : selected) {
         ItemBase *itemBase = qgraphicsitem_cast<ItemBase *>(item);
         if (itemBase) {
             itemBase->prepareGeometryChange();
diff --git a/examples/widgets/graphicsview/boxes/scene.cpp b/examples/widgets/graphicsview/boxes/scene.cpp
index 1637c1f781..7f62ac894b 100644
--- a/examples/widgets/graphicsview/boxes/scene.cpp
+++ b/examples/widgets/graphicsview/boxes/scene.cpp
@@ -111,7 +111,7 @@ ColorEdit::ColorEdit(QRgb initialColor, int id)
     m_button->setFrameStyle(QFrame::StyledPanel | QFrame::Sunken);
     layout->addWidget(m_button);
 
-    connect(m_lineEdit, SIGNAL(editingFinished()), this, SLOT(editDone()));
+    connect(m_lineEdit, &QLineEdit::editingFinished, this, &ColorEdit::editDone);
 }
 
 void ColorEdit::editDone()
@@ -166,7 +166,7 @@ FloatEdit::FloatEdit(float initialValue, int id)
     m_lineEdit = new QLineEdit(QString::number(m_value));
     layout->addWidget(m_lineEdit);
 
-    connect(m_lineEdit, SIGNAL(editingFinished()), this, SLOT(editDone()));
+    connect(m_lineEdit, &QLineEdit::editingFinished, this, &FloatEdit::editDone);
 }
 
 void FloatEdit::editDone()
@@ -252,7 +252,7 @@ void TwoSidedGraphicsWidget::animateFlip()
         .translate(-r.width() / 2, -r.height() / 2));
 
     if ((m_current == 0 && m_angle > 0) || (m_current == 1 && m_angle < 180))
-        QTimer::singleShot(25, this, SLOT(animateFlip()));
+        QTimer::singleShot(25, this, &TwoSidedGraphicsWidget::animateFlip);
 }
 
 QVariant GraphicsWidget::itemChange(GraphicsItemChange change, const QVariant &value)
@@ -307,19 +307,17 @@ RenderOptionsDialog::RenderOptionsDialog()
     check->setCheckState(Qt::Unchecked);
     // Dynamic cube maps are only enabled when multi-texturing and render to texture are available.
     check->setEnabled(glActiveTexture && glGenFramebuffersEXT);
-    connect(check, SIGNAL(stateChanged(int)), this, SIGNAL(dynamicCubemapToggled(int)));
+    connect(check, &QCheckBox::stateChanged, this, &RenderOptionsDialog::dynamicCubemapToggled);
     layout->addWidget(check, 0, 0, 1, 2);
     ++row;
 
-    QPalette palette;
-
     // Load all .par files
     // .par files have a simple syntax for specifying user adjustable uniform variables.
-    QSet<QByteArray> uniforms;
-    QList<QString> filter = QStringList("*.par");
-    QList<QFileInfo> files = QDir(":/res/boxes/").entryInfoList(filter, QDir::Files | QDir::Readable);
+    const QList<QFileInfo> files = QDir(QStringLiteral(":/res/boxes/"))
+            .entryInfoList({ QStringLiteral("*.par") },
+                           QDir::Files | QDir::Readable);
 
-    foreach (QFileInfo fileInfo, files) {
+    for (const QFileInfo &fileInfo : files) {
         QFile file(fileInfo.absoluteFilePath());
         if (file.open(QIODevice::ReadOnly)) {
             while (!file.atEnd()) {
@@ -356,7 +354,7 @@ RenderOptionsDialog::RenderOptionsDialog()
                         ColorEdit *colorEdit = new ColorEdit(it->toUInt(&ok, 16), m_parameterNames.size() - 1);
                         m_parameterEdits << colorEdit;
                         layout->addWidget(colorEdit);
-                        connect(colorEdit, SIGNAL(colorChanged(QRgb,int)), this, SLOT(setColorParameter(QRgb,int)));
+                        connect(colorEdit, &ColorEdit::colorChanged, this, &RenderOptionsDialog::setColorParameter);
                         ++row;
                     } else if (type == "float") {
                         layout->addWidget(new QLabel(m_parameterNames.back()));
@@ -364,7 +362,7 @@ RenderOptionsDialog::RenderOptionsDialog()
                         FloatEdit *floatEdit = new FloatEdit(it->toFloat(&ok), m_parameterNames.size() - 1);
                         m_parameterEdits << floatEdit;
                         layout->addWidget(floatEdit);
-                        connect(floatEdit, SIGNAL(valueChanged(float,int)), this, SLOT(setFloatParameter(float,int)));
+                        connect(floatEdit, &FloatEdit::valueChanged, this, &RenderOptionsDialog::setFloatParameter);
                         ++row;
                     }
                 }
@@ -375,13 +373,15 @@ RenderOptionsDialog::RenderOptionsDialog()
 
     layout->addWidget(new QLabel(tr("Texture:")));
     m_textureCombo = new QComboBox;
-    connect(m_textureCombo, SIGNAL(currentIndexChanged(int)), this, SIGNAL(textureChanged(int)));
+    connect(m_textureCombo, QOverload<int>::of(&QComboBox::currentIndexChanged),
+            this, &RenderOptionsDialog::textureChanged);
     layout->addWidget(m_textureCombo);
     ++row;
 
     layout->addWidget(new QLabel(tr("Shader:")));
     m_shaderCombo = new QComboBox;
-    connect(m_shaderCombo, SIGNAL(currentIndexChanged(int)), this, SIGNAL(shaderChanged(int)));
+    connect(m_shaderCombo, QOverload<int>::of(&QComboBox::currentIndexChanged),
+            this, &RenderOptionsDialog::shaderChanged);
     layout->addWidget(m_shaderCombo);
     ++row;
 
@@ -402,7 +402,7 @@ int RenderOptionsDialog::addShader(const QString &name)
 
 void RenderOptionsDialog::emitParameterChanged()
 {
-    foreach (ParameterEdit *edit, m_parameterEdits)
+    for (ParameterEdit *edit : qAsConst(m_parameterEdits))
         edit->emitChange();
 }
 
@@ -439,15 +439,15 @@ ItemDialog::ItemDialog()
 
     button = new QPushButton(tr("Add Qt box"));
     layout->addWidget(button);
-    connect(button, SIGNAL(clicked()), this, SLOT(triggerNewQtBox()));
+    connect(button, &QAbstractButton::clicked, this, &ItemDialog::triggerNewQtBox);
 
     button = new QPushButton(tr("Add circle"));
     layout->addWidget(button);
-    connect(button, SIGNAL(clicked()), this, SLOT(triggerNewCircleItem()));
+    connect(button, &QAbstractButton::clicked, this, &ItemDialog::triggerNewCircleItem);
 
     button = new QPushButton(tr("Add square"));
     layout->addWidget(button);
-    connect(button, SIGNAL(clicked()), this, SLOT(triggerNewSquareItem()));
+    connect(button, &QAbstractButton::clicked, this, &ItemDialog::triggerNewSquareItem);
 
     layout->addStretch(1);
 }
@@ -506,21 +506,21 @@ Scene::Scene(int width, int height, int maxTextureSize)
     m_renderOptions->move(20, 120);
     m_renderOptions->resize(m_renderOptions->sizeHint());
 
-    connect(m_renderOptions, SIGNAL(dynamicCubemapToggled(int)), this, SLOT(toggleDynamicCubemap(int)));
-    connect(m_renderOptions, SIGNAL(colorParameterChanged(QString,QRgb)), this, SLOT(setColorParameter(QString,QRgb)));
-    connect(m_renderOptions, SIGNAL(floatParameterChanged(QString,float)), this, SLOT(setFloatParameter(QString,float)));
-    connect(m_renderOptions, SIGNAL(textureChanged(int)), this, SLOT(setTexture(int)));
-    connect(m_renderOptions, SIGNAL(shaderChanged(int)), this, SLOT(setShader(int)));
+    connect(m_renderOptions, &RenderOptionsDialog::dynamicCubemapToggled, this, &Scene::toggleDynamicCubemap);
+    connect(m_renderOptions, &RenderOptionsDialog::colorParameterChanged, this, &Scene::setColorParameter);
+    connect(m_renderOptions, &RenderOptionsDialog::floatParameterChanged, this, &Scene::setFloatParameter);
+    connect(m_renderOptions, &RenderOptionsDialog::textureChanged, this, &Scene::setTexture);
+    connect(m_renderOptions, &RenderOptionsDialog::shaderChanged, this, &Scene::setShader);
 
     m_itemDialog = new ItemDialog;
-    connect(m_itemDialog, SIGNAL(newItemTriggered(ItemDialog::ItemType)), this, SLOT(newItem(ItemDialog::ItemType)));
+    connect(m_itemDialog, &ItemDialog::newItemTriggered, this, &Scene::newItem);
 
     TwoSidedGraphicsWidget *twoSided = new TwoSidedGraphicsWidget(this);
     twoSided->setWidget(0, m_renderOptions);
     twoSided->setWidget(1, m_itemDialog);
 
-    connect(m_renderOptions, SIGNAL(doubleClicked()), twoSided, SLOT(flip()));
-    connect(m_itemDialog, SIGNAL(doubleClicked()), twoSided, SLOT(flip()));
+    connect(m_renderOptions, &RenderOptionsDialog::doubleClicked, twoSided, &TwoSidedGraphicsWidget::flip);
+    connect(m_itemDialog, &ItemDialog::doubleClicked, twoSided, &TwoSidedGraphicsWidget::flip);
 
     addItem(new QtBox(64, width - 64, height - 64));
     addItem(new QtBox(64, width - 64, 64));
@@ -531,7 +531,7 @@ Scene::Scene(int width, int height, int maxTextureSize)
 
     m_timer = new QTimer(this);
     m_timer->setInterval(20);
-    connect(m_timer, SIGNAL(timeout()), this, SLOT(update()));
+    connect(m_timer, &QTimer::timeout, this, [this](){ update(); });
     m_timer->start();
 
     m_time.start();
@@ -539,24 +539,15 @@ Scene::Scene(int width, int height, int maxTextureSize)
 
 Scene::~Scene()
 {
-    if (m_box)
-        delete m_box;
-    foreach (GLTexture *texture, m_textures)
-        if (texture) delete texture;
-    if (m_mainCubemap)
-        delete m_mainCubemap;
-    foreach (QGLShaderProgram *program, m_programs)
-        if (program) delete program;
-    if (m_vertexShader)
-        delete m_vertexShader;
-    foreach (QGLShader *shader, m_fragmentShaders)
-        if (shader) delete shader;
-    foreach (GLRenderTargetCube *rt, m_cubemaps)
-        if (rt) delete rt;
-    if (m_environmentShader)
-        delete m_environmentShader;
-    if (m_environmentProgram)
-        delete m_environmentProgram;
+    delete m_box;
+    qDeleteAll(m_textures);
+    delete m_mainCubemap;
+    qDeleteAll(m_programs);
+    delete m_vertexShader;
+    qDeleteAll(m_fragmentShaders);
+    qDeleteAll(m_cubemaps);
+    delete m_environmentShader;
+    delete m_environmentProgram;
 }
 
 void Scene::initGL()
@@ -601,15 +592,13 @@ void Scene::initGL()
 
     m_mainCubemap = new GLRenderTargetCube(512);
 
-    QStringList filter;
     QList<QFileInfo> files;
 
     // Load all .png files as textures
     m_currentTexture = 0;
-    filter = QStringList("*.png");
-    files = QDir(":/res/boxes/").entryInfoList(filter, QDir::Files | QDir::Readable);
+    files = QDir(":/res/boxes/").entryInfoList({ QStringLiteral("*.png") }, QDir::Files | QDir::Readable);
 
-    foreach (QFileInfo file, files) {
+    for (const QFileInfo &file : qAsConst(files)) {
         GLTexture *texture = new GLTexture2D(file.absoluteFilePath(), qMin(256, m_maxTextureSize), qMin(256, m_maxTextureSize));
         if (texture->failed()) {
             delete texture;
@@ -624,9 +613,8 @@ void Scene::initGL()
 
     // Load all .fsh files as fragment shaders
     m_currentShader = 0;
-    filter = QStringList("*.fsh");
-    files = QDir(":/res/boxes/").entryInfoList(filter, QDir::Files | QDir::Readable);
-    foreach (QFileInfo file, files) {
+    files = QDir(":/res/boxes/").entryInfoList({ QStringLiteral("*.fsh") }, QDir::Files | QDir::Readable);
+    for (const QFileInfo &file : qAsConst(files)) {
         QGLShaderProgram *program = new QGLShaderProgram;
         QGLShader* shader = new QGLShader(QGLShader::Fragment);
         shader->compileSourceFile(file.absoluteFilePath());
@@ -662,7 +650,7 @@ void Scene::initGL()
     m_renderOptions->emitParameterChanged();
 }
 
-static void loadMatrix(const QMatrix4x4& m)
+static void loadMatrix(const QMatrix4x4 &m)
 {
     // static to prevent glLoadMatrixf to fail on certain drivers
     static GLfloat mat[16];
@@ -1051,7 +1039,7 @@ void Scene::toggleDynamicCubemap(int state)
 void Scene::setColorParameter(const QString &name, QRgb color)
 {
     // set the color in all programs
-    foreach (QGLShaderProgram *program, m_programs) {
+    for (QGLShaderProgram *program : qAsConst(m_programs)) {
         program->bind();
         program->setUniformValue(program->uniformLocation(name), QColor(color));
         program->release();
@@ -1061,7 +1049,7 @@ void Scene::setColorParameter(const QString &name, QRgb color)
 void Scene::setFloatParameter(const QString &name, float value)
 {
     // set the color in all programs
-    foreach (QGLShaderProgram *program, m_programs) {
+    for (QGLShaderProgram *program : qAsConst(m_programs)) {
         program->bind();
         program->setUniformValue(program->uniformLocation(name), value);
         program->release();
diff --git a/examples/widgets/graphicsview/chip/chip.cpp b/examples/widgets/graphicsview/chip/chip.cpp
index 443994e121..3d2bbdfcef 100644
--- a/examples/widgets/graphicsview/chip/chip.cpp
+++ b/examples/widgets/graphicsview/chip/chip.cpp
@@ -79,9 +79,9 @@ void Chip::paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWid
 {
     Q_UNUSED(widget);
 
-    QColor fillColor = (option->state & QStyle::State_Selected) ? color.dark(150) : color;
+    QColor fillColor = (option->state & QStyle::State_Selected) ? color.darker(150) : color;
     if (option->state & QStyle::State_MouseOver)
-        fillColor = fillColor.light(125);
+        fillColor = fillColor.lighter(125);
 
     const qreal lod = option->levelOfDetailFromTransform(painter->worldTransform());
     if (lod < 0.2) {
@@ -105,7 +105,7 @@ void Chip::paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWid
 
     pen.setWidth(width);
     QBrush b = painter->brush();
-    painter->setBrush(QBrush(fillColor.dark(option->state & QStyle::State_Sunken ? 120 : 100)));
+    painter->setBrush(QBrush(fillColor.darker(option->state & QStyle::State_Sunken ? 120 : 100)));
 
     painter->drawRect(QRect(14, 14, 79, 39));
     painter->setBrush(b);
diff --git a/examples/widgets/graphicsview/chip/view.cpp b/examples/widgets/graphicsview/chip/view.cpp
index 491f1a54cf..9676c13ff7 100644
--- a/examples/widgets/graphicsview/chip/view.cpp
+++ b/examples/widgets/graphicsview/chip/view.cpp
@@ -190,22 +190,22 @@ View::View(const QString &name, QWidget *parent)
     topLayout->addWidget(resetButton, 2, 1);
     setLayout(topLayout);
 
-    connect(resetButton, SIGNAL(clicked()), this, SLOT(resetView()));
-    connect(zoomSlider, SIGNAL(valueChanged(int)), this, SLOT(setupMatrix()));
-    connect(rotateSlider, SIGNAL(valueChanged(int)), this, SLOT(setupMatrix()));
-    connect(graphicsView->verticalScrollBar(), SIGNAL(valueChanged(int)),
-            this, SLOT(setResetButtonEnabled()));
-    connect(graphicsView->horizontalScrollBar(), SIGNAL(valueChanged(int)),
-            this, SLOT(setResetButtonEnabled()));
-    connect(selectModeButton, SIGNAL(toggled(bool)), this, SLOT(togglePointerMode()));
-    connect(dragModeButton, SIGNAL(toggled(bool)), this, SLOT(togglePointerMode()));
-    connect(antialiasButton, SIGNAL(toggled(bool)), this, SLOT(toggleAntialiasing()));
-    connect(openGlButton, SIGNAL(toggled(bool)), this, SLOT(toggleOpenGL()));
-    connect(rotateLeftIcon, SIGNAL(clicked()), this, SLOT(rotateLeft()));
-    connect(rotateRightIcon, SIGNAL(clicked()), this, SLOT(rotateRight()));
-    connect(zoomInIcon, SIGNAL(clicked()), this, SLOT(zoomIn()));
-    connect(zoomOutIcon, SIGNAL(clicked()), this, SLOT(zoomOut()));
-    connect(printButton, SIGNAL(clicked()), this, SLOT(print()));
+    connect(resetButton, &QAbstractButton::clicked, this, &View::resetView);
+    connect(zoomSlider, &QAbstractSlider::valueChanged, this, &View::setupMatrix);
+    connect(rotateSlider, &QAbstractSlider::valueChanged, this, &View::setupMatrix);
+    connect(graphicsView->verticalScrollBar(), &QAbstractSlider::valueChanged,
+            this, &View::setResetButtonEnabled);
+    connect(graphicsView->horizontalScrollBar(), &QAbstractSlider::valueChanged,
+            this, &View::setResetButtonEnabled);
+    connect(selectModeButton, &QAbstractButton::toggled, this, &View::togglePointerMode);
+    connect(dragModeButton, &QAbstractButton::toggled, this, &View::togglePointerMode);
+    connect(antialiasButton, &QAbstractButton::toggled, this, &View::toggleAntialiasing);
+    connect(openGlButton, &QAbstractButton::toggled, this, &View::toggleOpenGL);
+    connect(rotateLeftIcon, &QAbstractButton::clicked, this, &View::rotateLeft);
+    connect(rotateRightIcon, &QAbstractButton::clicked, this, &View::rotateRight);
+    connect(zoomInIcon, &QAbstractButton::clicked, this, &View::zoomIn);
+    connect(zoomOutIcon, &QAbstractButton::clicked, this, &View::zoomOut);
+    connect(printButton, &QAbstractButton::clicked, this, &View::print);
 
     setupMatrix();
 }
diff --git a/examples/widgets/graphicsview/collidingmice/main.cpp b/examples/widgets/graphicsview/collidingmice/main.cpp
index 91aee70b86..dfb20815b9 100644
--- a/examples/widgets/graphicsview/collidingmice/main.cpp
+++ b/examples/widgets/graphicsview/collidingmice/main.cpp
@@ -92,7 +92,7 @@ int main(int argc, char **argv)
     view.show();
 
     QTimer timer;
-    QObject::connect(&timer, SIGNAL(timeout()), &scene, SLOT(advance()));
+    QObject::connect(&timer, &QTimer::timeout, &scene, &QGraphicsScene::advance);
     timer.start(1000 / 33);
 
     return app.exec();
diff --git a/examples/widgets/graphicsview/collidingmice/mouse.cpp b/examples/widgets/graphicsview/collidingmice/mouse.cpp
index 14f887f6e3..a8fcc05d76 100644
--- a/examples/widgets/graphicsview/collidingmice/mouse.cpp
+++ b/examples/widgets/graphicsview/collidingmice/mouse.cpp
@@ -160,11 +160,12 @@ void Mouse::advance(int step)
 
     // Try not to crash with any other mice
 //! [7]
-    QList<QGraphicsItem *> dangerMice = scene()->items(QPolygonF()
-                                                       << mapToScene(0, 0)
-                                                       << mapToScene(-30, -50)
-                                                       << mapToScene(30, -50));
-    foreach (QGraphicsItem *item, dangerMice) {
+    const QList<QGraphicsItem *> dangerMice = scene()->items(QPolygonF()
+                           << mapToScene(0, 0)
+                           << mapToScene(-30, -50)
+                           << mapToScene(30, -50));
+
+    for (const QGraphicsItem *item : dangerMice) {
         if (item == this)
             continue;
 
diff --git a/examples/widgets/graphicsview/diagramscene/diagramitem.cpp b/examples/widgets/graphicsview/diagramscene/diagramitem.cpp
index db6dabee56..3aa685635e 100644
--- a/examples/widgets/graphicsview/diagramscene/diagramitem.cpp
+++ b/examples/widgets/graphicsview/diagramscene/diagramitem.cpp
@@ -111,7 +111,7 @@ void DiagramItem::removeArrow(Arrow *arrow)
 //! [2]
 void DiagramItem::removeArrows()
 {
-    foreach (Arrow *arrow, arrows) {
+    for (Arrow *arrow : qAsConst(arrows)) {
         arrow->startItem()->removeArrow(arrow);
         arrow->endItem()->removeArrow(arrow);
         scene()->removeItem(arrow);
@@ -154,9 +154,8 @@ void DiagramItem::contextMenuEvent(QGraphicsSceneContextMenuEvent *event)
 QVariant DiagramItem::itemChange(GraphicsItemChange change, const QVariant &value)
 {
     if (change == QGraphicsItem::ItemPositionChange) {
-        foreach (Arrow *arrow, arrows) {
+        for (Arrow *arrow : qAsConst(arrows))
             arrow->updatePosition();
-        }
     }
 
     return value;
diff --git a/examples/widgets/graphicsview/diagramscene/diagramscene.cpp b/examples/widgets/graphicsview/diagramscene/diagramscene.cpp
index bbbc512b55..40272834c3 100644
--- a/examples/widgets/graphicsview/diagramscene/diagramscene.cpp
+++ b/examples/widgets/graphicsview/diagramscene/diagramscene.cpp
@@ -169,10 +169,10 @@ void DiagramScene::mousePressEvent(QGraphicsSceneMouseEvent *mouseEvent)
             textItem->setFont(myFont);
             textItem->setTextInteractionFlags(Qt::TextEditorInteraction);
             textItem->setZValue(1000.0);
-            connect(textItem, SIGNAL(lostFocus(DiagramTextItem*)),
-                    this, SLOT(editorLostFocus(DiagramTextItem*)));
-            connect(textItem, SIGNAL(selectedChange(QGraphicsItem*)),
-                    this, SIGNAL(itemSelected(QGraphicsItem*)));
+            connect(textItem, &DiagramTextItem::lostFocus,
+                    this, &DiagramScene::editorLostFocus);
+            connect(textItem, &DiagramTextItem::selectedChange,
+                    this, &DiagramScene::itemSelected);
             addItem(textItem);
             textItem->setDefaultTextColor(myTextColor);
             textItem->setPos(mouseEvent->scenePos());
@@ -234,12 +234,10 @@ void DiagramScene::mouseReleaseEvent(QGraphicsSceneMouseEvent *mouseEvent)
 //! [13]
 
 //! [14]
-bool DiagramScene::isItemChange(int type)
+bool DiagramScene::isItemChange(int type) const
 {
-    foreach (QGraphicsItem *item, selectedItems()) {
-        if (item->type() == type)
-            return true;
-    }
-    return false;
+    const QList<QGraphicsItem *> items = selectedItems();
+    const auto cb = [type](const QGraphicsItem *item) { return item->type() == type; };
+    return std::find_if(items.begin(), items.end(), cb) != items.end();
 }
 //! [14]
diff --git a/examples/widgets/graphicsview/diagramscene/diagramscene.h b/examples/widgets/graphicsview/diagramscene/diagramscene.h
index 95f7f3c621..15063d58b7 100644
--- a/examples/widgets/graphicsview/diagramscene/diagramscene.h
+++ b/examples/widgets/graphicsview/diagramscene/diagramscene.h
@@ -100,7 +100,7 @@ protected:
     void mouseReleaseEvent(QGraphicsSceneMouseEvent *mouseEvent) override;
 
 private:
-    bool isItemChange(int type);
+    bool isItemChange(int type) const;
 
     DiagramItem::DiagramType myItemType;
     QMenu *myItemMenu;
diff --git a/examples/widgets/graphicsview/diagramscene/mainwindow.cpp b/examples/widgets/graphicsview/diagramscene/mainwindow.cpp
index 36353674ea..3327d4d5df 100644
--- a/examples/widgets/graphicsview/diagramscene/mainwindow.cpp
+++ b/examples/widgets/graphicsview/diagramscene/mainwindow.cpp
@@ -67,12 +67,12 @@ MainWindow::MainWindow()
 
     scene = new DiagramScene(itemMenu, this);
     scene->setSceneRect(QRectF(0, 0, 5000, 5000));
-    connect(scene, SIGNAL(itemInserted(DiagramItem*)),
-            this, SLOT(itemInserted(DiagramItem*)));
-    connect(scene, SIGNAL(textInserted(QGraphicsTextItem*)),
-            this, SLOT(textInserted(QGraphicsTextItem*)));
-    connect(scene, SIGNAL(itemSelected(QGraphicsItem*)),
-            this, SLOT(itemSelected(QGraphicsItem*)));
+    connect(scene, &DiagramScene::itemInserted,
+            this, &MainWindow::itemInserted);
+    connect(scene, &DiagramScene::textInserted,
+            this, &MainWindow::textInserted);
+    connect(scene, &DiagramScene::itemSelected,
+            this, &MainWindow::itemSelected);
     createToolbars();
 
     QHBoxLayout *layout = new QHBoxLayout;
@@ -92,8 +92,8 @@ MainWindow::MainWindow()
 //! [1]
 void MainWindow::backgroundButtonGroupClicked(QAbstractButton *button)
 {
-    QList<QAbstractButton *> buttons = backgroundButtonGroup->buttons();
-    foreach (QAbstractButton *myButton, buttons) {
+    const QList<QAbstractButton *> buttons = backgroundButtonGroup->buttons();
+    for (QAbstractButton *myButton : buttons) {
         if (myButton != button)
             button->setChecked(false);
     }
@@ -115,8 +115,8 @@ void MainWindow::backgroundButtonGroupClicked(QAbstractButton *button)
 //! [2]
 void MainWindow::buttonGroupClicked(int id)
 {
-    QList<QAbstractButton *> buttons = buttonGroup->buttons();
-    foreach (QAbstractButton *button, buttons) {
+    const QList<QAbstractButton *> buttons = buttonGroup->buttons();
+    for (QAbstractButton *button : buttons) {
         if (buttonGroup->button(id) != button)
             button->setChecked(false);
     }
@@ -132,7 +132,8 @@ void MainWindow::buttonGroupClicked(int id)
 //! [3]
 void MainWindow::deleteItem()
 {
-    foreach (QGraphicsItem *item, scene->selectedItems()) {
+    QList<QGraphicsItem *> selectedItems = scene->selectedItems();
+    for (QGraphicsItem *item : qAsConst(selectedItems)) {
         if (item->type() == Arrow::Type) {
             scene->removeItem(item);
             Arrow *arrow = qgraphicsitem_cast<Arrow *>(item);
@@ -142,7 +143,8 @@ void MainWindow::deleteItem()
         }
     }
 
-    foreach (QGraphicsItem *item, scene->selectedItems()) {
+    selectedItems = scene->selectedItems();
+    for (QGraphicsItem *item : qAsConst(selectedItems)) {
          if (item->type() == DiagramItem::Type)
              qgraphicsitem_cast<DiagramItem *>(item)->removeArrows();
          scene->removeItem(item);
@@ -165,10 +167,10 @@ void MainWindow::bringToFront()
         return;
 
     QGraphicsItem *selectedItem = scene->selectedItems().first();
-    QList<QGraphicsItem *> overlapItems = selectedItem->collidingItems();
+    const QList<QGraphicsItem *> overlapItems = selectedItem->collidingItems();
 
     qreal zValue = 0;
-    foreach (QGraphicsItem *item, overlapItems) {
+    for (const QGraphicsItem *item : overlapItems) {
         if (item->zValue() >= zValue && item->type() == DiagramItem::Type)
             zValue = item->zValue() + 0.1;
     }
@@ -183,10 +185,10 @@ void MainWindow::sendToBack()
         return;
 
     QGraphicsItem *selectedItem = scene->selectedItems().first();
-    QList<QGraphicsItem *> overlapItems = selectedItem->collidingItems();
+    const QList<QGraphicsItem *> overlapItems = selectedItem->collidingItems();
 
     qreal zValue = 0;
-    foreach (QGraphicsItem *item, overlapItems) {
+    for (const QGraphicsItem *item : overlapItems) {
         if (item->zValue() <= zValue && item->type() == DiagramItem::Type)
             zValue = item->zValue() - 0.1;
     }
@@ -332,8 +334,8 @@ void MainWindow::createToolBox()
 {
     buttonGroup = new QButtonGroup(this);
     buttonGroup->setExclusive(false);
-    connect(buttonGroup, SIGNAL(buttonClicked(int)),
-            this, SLOT(buttonGroupClicked(int)));
+    connect(buttonGroup, QOverload<int>::of(&QButtonGroup::buttonClicked),
+            this, &MainWindow::buttonGroupClicked);
     QGridLayout *layout = new QGridLayout;
     layout->addWidget(createCellWidget(tr("Conditional"), DiagramItem::Conditional), 0, 0);
     layout->addWidget(createCellWidget(tr("Process"), DiagramItem::Step),0, 1);
@@ -359,8 +361,8 @@ void MainWindow::createToolBox()
     itemWidget->setLayout(layout);
 
     backgroundButtonGroup = new QButtonGroup(this);
-    connect(backgroundButtonGroup, SIGNAL(buttonClicked(QAbstractButton*)),
-            this, SLOT(backgroundButtonGroupClicked(QAbstractButton*)));
+    connect(backgroundButtonGroup, QOverload<QAbstractButton *>::of(&QButtonGroup::buttonClicked),
+            this, &MainWindow::backgroundButtonGroupClicked);
 
     QGridLayout *backgroundLayout = new QGridLayout;
     backgroundLayout->addWidget(createBackgroundCellWidget(tr("Blue Grid"),
@@ -395,44 +397,44 @@ void MainWindow::createActions()
                                 tr("Bring to &Front"), this);
     toFrontAction->setShortcut(tr("Ctrl+F"));
     toFrontAction->setStatusTip(tr("Bring item to front"));
-    connect(toFrontAction, SIGNAL(triggered()), this, SLOT(bringToFront()));
+    connect(toFrontAction, &QAction::triggered, this, &MainWindow::bringToFront);
 //! [23]
 
     sendBackAction = new QAction(QIcon(":/images/sendtoback.png"), tr("Send to &Back"), this);
     sendBackAction->setShortcut(tr("Ctrl+T"));
     sendBackAction->setStatusTip(tr("Send item to back"));
-    connect(sendBackAction, SIGNAL(triggered()), this, SLOT(sendToBack()));
+    connect(sendBackAction, &QAction::triggered, this, &MainWindow::sendToBack);
 
     deleteAction = new QAction(QIcon(":/images/delete.png"), tr("&Delete"), this);
     deleteAction->setShortcut(tr("Delete"));
     deleteAction->setStatusTip(tr("Delete item from diagram"));
-    connect(deleteAction, SIGNAL(triggered()), this, SLOT(deleteItem()));
+    connect(deleteAction, &QAction::triggered, this, &MainWindow::deleteItem);
 
     exitAction = new QAction(tr("E&xit"), this);
     exitAction->setShortcuts(QKeySequence::Quit);
     exitAction->setStatusTip(tr("Quit Scenediagram example"));
-    connect(exitAction, SIGNAL(triggered()), this, SLOT(close()));
+    connect(exitAction, &QAction::triggered, this, &QWidget::close);
 
     boldAction = new QAction(tr("Bold"), this);
     boldAction->setCheckable(true);
     QPixmap pixmap(":/images/bold.png");
     boldAction->setIcon(QIcon(pixmap));
     boldAction->setShortcut(tr("Ctrl+B"));
-    connect(boldAction, SIGNAL(triggered()), this, SLOT(handleFontChange()));
+    connect(boldAction, &QAction::triggered, this, &MainWindow::handleFontChange);
 
     italicAction = new QAction(QIcon(":/images/italic.png"), tr("Italic"), this);
     italicAction->setCheckable(true);
     italicAction->setShortcut(tr("Ctrl+I"));
-    connect(italicAction, SIGNAL(triggered()), this, SLOT(handleFontChange()));
+    connect(italicAction, &QAction::triggered, this, &MainWindow::handleFontChange);
 
     underlineAction = new QAction(QIcon(":/images/underline.png"), tr("Underline"), this);
     underlineAction->setCheckable(true);
     underlineAction->setShortcut(tr("Ctrl+U"));
-    connect(underlineAction, SIGNAL(triggered()), this, SLOT(handleFontChange()));
+    connect(underlineAction, &QAction::triggered, this, &MainWindow::handleFontChange);
 
     aboutAction = new QAction(tr("A&bout"), this);
     aboutAction->setShortcut(tr("F1"));
-    connect(aboutAction, SIGNAL(triggered()), this, SLOT(about()));
+    connect(aboutAction, &QAction::triggered, this, &MainWindow::about);
 }
 
 //! [24]
@@ -462,8 +464,8 @@ void MainWindow::createToolbars()
     editToolBar->addAction(sendBackAction);
 
     fontCombo = new QFontComboBox();
-    connect(fontCombo, SIGNAL(currentFontChanged(QFont)),
-            this, SLOT(currentFontChanged(QFont)));
+    connect(fontCombo, &QFontComboBox::currentFontChanged,
+            this, &MainWindow::currentFontChanged);
 
     fontSizeCombo = new QComboBox;
     fontSizeCombo->setEditable(true);
@@ -471,8 +473,8 @@ void MainWindow::createToolbars()
         fontSizeCombo->addItem(QString().setNum(i));
     QIntValidator *validator = new QIntValidator(2, 64, this);
     fontSizeCombo->setValidator(validator);
-    connect(fontSizeCombo, SIGNAL(currentIndexChanged(QString)),
-            this, SLOT(fontSizeChanged(QString)));
+    connect(fontSizeCombo, &QComboBox::currentTextChanged,
+            this, &MainWindow::fontSizeChanged);
 
     fontColorToolButton = new QToolButton;
     fontColorToolButton->setPopupMode(QToolButton::MenuButtonPopup);
@@ -480,8 +482,8 @@ void MainWindow::createToolbars()
     textAction = fontColorToolButton->menu()->defaultAction();
     fontColorToolButton->setIcon(createColorToolButtonIcon(":/images/textpointer.png", Qt::black));
     fontColorToolButton->setAutoFillBackground(true);
-    connect(fontColorToolButton, SIGNAL(clicked()),
-            this, SLOT(textButtonTriggered()));
+    connect(fontColorToolButton, &QAbstractButton::clicked,
+            this, &MainWindow::textButtonTriggered);
 
 //! [26]
     fillColorToolButton = new QToolButton;
@@ -490,8 +492,8 @@ void MainWindow::createToolbars()
     fillAction = fillColorToolButton->menu()->defaultAction();
     fillColorToolButton->setIcon(createColorToolButtonIcon(
                                      ":/images/floodfill.png", Qt::white));
-    connect(fillColorToolButton, SIGNAL(clicked()),
-            this, SLOT(fillButtonTriggered()));
+    connect(fillColorToolButton, &QAbstractButton::clicked,
+            this, &MainWindow::fillButtonTriggered);
 //! [26]
 
     lineColorToolButton = new QToolButton;
@@ -500,8 +502,8 @@ void MainWindow::createToolbars()
     lineAction = lineColorToolButton->menu()->defaultAction();
     lineColorToolButton->setIcon(createColorToolButtonIcon(
                                      ":/images/linecolor.png", Qt::black));
-    connect(lineColorToolButton, SIGNAL(clicked()),
-            this, SLOT(lineButtonTriggered()));
+    connect(lineColorToolButton, &QAbstractButton::clicked,
+            this, &MainWindow::lineButtonTriggered);
 
     textToolBar = addToolBar(tr("Font"));
     textToolBar->addWidget(fontCombo);
@@ -526,16 +528,16 @@ void MainWindow::createToolbars()
     pointerTypeGroup = new QButtonGroup(this);
     pointerTypeGroup->addButton(pointerButton, int(DiagramScene::MoveItem));
     pointerTypeGroup->addButton(linePointerButton, int(DiagramScene::InsertLine));
-    connect(pointerTypeGroup, SIGNAL(buttonClicked(int)),
-            this, SLOT(pointerGroupClicked(int)));
+    connect(pointerTypeGroup, QOverload<int>::of(&QButtonGroup::buttonClicked),
+            this, &MainWindow::pointerGroupClicked);
 
     sceneScaleCombo = new QComboBox;
     QStringList scales;
     scales << tr("50%") << tr("75%") << tr("100%") << tr("125%") << tr("150%");
     sceneScaleCombo->addItems(scales);
     sceneScaleCombo->setCurrentIndex(2);
-    connect(sceneScaleCombo, SIGNAL(currentIndexChanged(QString)),
-            this, SLOT(sceneScaleChanged(QString)));
+    connect(sceneScaleCombo, &QComboBox::currentTextChanged,
+            this, &MainWindow::sceneScaleChanged);
 
     pointerToolbar = addToolBar(tr("Pointer type"));
     pointerToolbar->addWidget(pointerButton);
diff --git a/examples/widgets/graphicsview/dragdroprobot/robot.cpp b/examples/widgets/graphicsview/dragdroprobot/robot.cpp
index 38552747af..cc70366872 100644
--- a/examples/widgets/graphicsview/dragdroprobot/robot.cpp
+++ b/examples/widgets/graphicsview/dragdroprobot/robot.cpp
@@ -113,7 +113,7 @@ void RobotHead::paint(QPainter *painter,
     Q_UNUSED(option);
     Q_UNUSED(widget);
     if (pixmap.isNull()) {
-        painter->setBrush(dragOver ? color.light(130) : color);
+        painter->setBrush(dragOver ? color.lighter(130) : color);
         painter->drawRoundedRect(-10, -30, 20, 30, 25, 25, Qt::RelativeSize);
         painter->setBrush(Qt::white);
         painter->drawEllipse(-7, -3 - 20, 7, 7);
@@ -173,7 +173,7 @@ void RobotTorso::paint(QPainter *painter,
     Q_UNUSED(option);
     Q_UNUSED(widget);
 
-    painter->setBrush(dragOver ? color.light(130) : color);
+    painter->setBrush(dragOver ? color.lighter(130) : color);
     painter->drawRoundedRect(-20, -20, 40, 60, 25, 25, Qt::RelativeSize);
     painter->drawEllipse(-25, -20, 20, 20);
     painter->drawEllipse(5, -20, 20, 20);
@@ -197,7 +197,7 @@ void RobotLimb::paint(QPainter *painter,
     Q_UNUSED(option);
     Q_UNUSED(widget);
 
-    painter->setBrush(dragOver ? color.light(130) : color);
+    painter->setBrush(dragOver ? color.lighter(130) : color);
     painter->drawRoundedRect(boundingRect(), 50, 50, Qt::RelativeSize);
     painter->drawEllipse(-5, -5, 10, 10);
 }
diff --git a/examples/widgets/graphicsview/elasticnodes/graphwidget.cpp b/examples/widgets/graphicsview/elasticnodes/graphwidget.cpp
index 81928a4ee1..6b817b2a21 100644
--- a/examples/widgets/graphicsview/elasticnodes/graphwidget.cpp
+++ b/examples/widgets/graphicsview/elasticnodes/graphwidget.cpp
@@ -164,16 +164,17 @@ void GraphWidget::timerEvent(QTimerEvent *event)
     Q_UNUSED(event);
 
     QList<Node *> nodes;
-    foreach (QGraphicsItem *item, scene()->items()) {
+    const QList<QGraphicsItem *> items = scene()->items();
+    for (QGraphicsItem *item : items) {
         if (Node *node = qgraphicsitem_cast<Node *>(item))
             nodes << node;
     }
 
-    foreach (Node *node, nodes)
+    for (Node *node : qAsConst(nodes))
         node->calculateForces();
 
     bool itemsMoved = false;
-    foreach (Node *node, nodes) {
+    for (Node *node : qAsConst(nodes)) {
         if (node->advancePosition())
             itemsMoved = true;
     }
@@ -246,7 +247,8 @@ void GraphWidget::scaleView(qreal scaleFactor)
 
 void GraphWidget::shuffle()
 {
-    foreach (QGraphicsItem *item, scene()->items()) {
+    const QList<QGraphicsItem *> items = scene()->items();
+    for (QGraphicsItem *item : items) {
         if (qgraphicsitem_cast<Node *>(item))
             item->setPos(-150 + QRandomGenerator::global()->bounded(300), -150 + QRandomGenerator::global()->bounded(300));
     }
diff --git a/examples/widgets/graphicsview/elasticnodes/node.cpp b/examples/widgets/graphicsview/elasticnodes/node.cpp
index 71737c984b..8d44a167fa 100644
--- a/examples/widgets/graphicsview/elasticnodes/node.cpp
+++ b/examples/widgets/graphicsview/elasticnodes/node.cpp
@@ -94,7 +94,8 @@ void Node::calculateForces()
     // Sum up all forces pushing this item away
     qreal xvel = 0;
     qreal yvel = 0;
-    foreach (QGraphicsItem *item, scene()->items()) {
+    const QList<QGraphicsItem *> items = scene()->items();
+    for (QGraphicsItem *item : items) {
         Node *node = qgraphicsitem_cast<Node *>(item);
         if (!node)
             continue;
@@ -113,7 +114,7 @@ void Node::calculateForces()
 //! [4]
     // Now subtract all forces pulling items together
     double weight = (edgeList.size() + 1) * 10;
-    foreach (Edge *edge, edgeList) {
+    for (const Edge *edge : qAsConst(edgeList)) {
         QPointF vec;
         if (edge->sourceNode() == this)
             vec = mapToItem(edge->destNode(), 0, 0);
@@ -176,8 +177,8 @@ void Node::paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWid
     if (option->state & QStyle::State_Sunken) {
         gradient.setCenter(3, 3);
         gradient.setFocalPoint(3, 3);
-        gradient.setColorAt(1, QColor(Qt::yellow).light(120));
-        gradient.setColorAt(0, QColor(Qt::darkYellow).light(120));
+        gradient.setColorAt(1, QColor(Qt::yellow).lighter(120));
+        gradient.setColorAt(0, QColor(Qt::darkYellow).lighter(120));
     } else {
         gradient.setColorAt(0, Qt::yellow);
         gradient.setColorAt(1, Qt::darkYellow);
@@ -194,7 +195,7 @@ QVariant Node::itemChange(GraphicsItemChange change, const QVariant &value)
 {
     switch (change) {
     case ItemPositionHasChanged:
-        foreach (Edge *edge, edgeList)
+        for (Edge *edge : qAsConst(edgeList))
             edge->adjust();
         graph->itemMoved();
         break;
diff --git a/examples/widgets/graphicsview/embeddeddialogs/customproxy.cpp b/examples/widgets/graphicsview/embeddeddialogs/customproxy.cpp
index 158c31d9c1..f510ebc07f 100644
--- a/examples/widgets/graphicsview/embeddeddialogs/customproxy.cpp
+++ b/examples/widgets/graphicsview/embeddeddialogs/customproxy.cpp
@@ -55,13 +55,13 @@
 #include <QGraphicsScene>
 
 CustomProxy::CustomProxy(QGraphicsItem *parent, Qt::WindowFlags wFlags)
-    : QGraphicsProxyWidget(parent, wFlags), popupShown(false), currentPopup(0)
+    : QGraphicsProxyWidget(parent, wFlags), popupShown(false), currentPopup(nullptr)
 {
     timeLine = new QTimeLine(250, this);
-    connect(timeLine, SIGNAL(valueChanged(qreal)),
-            this, SLOT(updateStep(qreal)));
-    connect(timeLine, SIGNAL(stateChanged(QTimeLine::State)),
-            this, SLOT(stateChanged(QTimeLine::State)));
+    connect(timeLine, &QTimeLine::valueChanged,
+            this, &CustomProxy::updateStep);
+    connect(timeLine, &QTimeLine::stateChanged,
+            this, &CustomProxy::stateChanged);
 }
 
 QRectF CustomProxy::boundingRect() const
@@ -133,7 +133,7 @@ QVariant CustomProxy::itemChange(GraphicsItemChange change, const QVariant &valu
                 currentPopup->installSceneEventFilter(this);
         } else if (scene()) {
             currentPopup->removeSceneEventFilter(this);
-            currentPopup = 0;
+            currentPopup = nullptr;
         }
     } else if (currentPopup && change == ItemSceneHasChanged) {
         currentPopup->installSceneEventFilter(this);
diff --git a/examples/widgets/graphicsview/embeddeddialogs/embeddeddialog.cpp b/examples/widgets/graphicsview/embeddeddialogs/embeddeddialog.cpp
index 0c3ed86565..9fa24fcd17 100644
--- a/examples/widgets/graphicsview/embeddeddialogs/embeddeddialog.cpp
+++ b/examples/widgets/graphicsview/embeddeddialogs/embeddeddialog.cpp
@@ -60,7 +60,8 @@ EmbeddedDialog::EmbeddedDialog(QWidget *parent)
     ui->setupUi(this);
     ui->layoutDirection->setCurrentIndex(layoutDirection() != Qt::LeftToRight);
 
-    foreach (QString styleName, QStyleFactory::keys()) {
+    const QStringList styleKeys = QStyleFactory::keys();
+    for (const QString &styleName : styleKeys) {
         ui->style->addItem(styleName);
         if (style()->objectName().toLower() == styleName.toLower())
             ui->style->setCurrentIndex(ui->style->count() - 1);
@@ -72,7 +73,7 @@ EmbeddedDialog::EmbeddedDialog(QWidget *parent)
             this, &EmbeddedDialog::spacingChanged);
     connect(ui->fontComboBox, &QFontComboBox::currentFontChanged,
             this, &EmbeddedDialog::fontChanged);
-    connect(ui->style, QOverload<const QString &>::of(&QComboBox::activated),
+    connect(ui->style, &QComboBox::textActivated,
             this, &EmbeddedDialog::styleChanged);
 }
 
@@ -101,7 +102,8 @@ static void setStyleHelper(QWidget *widget, QStyle *style)
 {
     widget->setStyle(style);
     widget->setPalette(style->standardPalette());
-    foreach (QObject *child, widget->children()) {
+    const QObjectList children = widget->children();
+    for (QObject *child : children) {
         if (QWidget *childWidget = qobject_cast<QWidget *>(child))
             setStyleHelper(childWidget, style);
     }
diff --git a/examples/widgets/graphicsview/embeddeddialogs/main.cpp b/examples/widgets/graphicsview/embeddeddialogs/main.cpp
index cbd5dd5890..501405e3ff 100644
--- a/examples/widgets/graphicsview/embeddeddialogs/main.cpp
+++ b/examples/widgets/graphicsview/embeddeddialogs/main.cpp
@@ -66,7 +66,7 @@ int main(int argc, char *argv[])
 
     for (int y = 0; y < gridSize; ++y) {
         for (int x = 0; x < gridSize; ++x) {
-            CustomProxy *proxy = new CustomProxy(0, Qt::Window);
+            CustomProxy *proxy = new CustomProxy(nullptr, Qt::Window);
             proxy->setWidget(new EmbeddedDialog);
 
             QRectF rect = proxy->boundingRect();
diff --git a/examples/widgets/graphicsview/flowlayout/flowlayout.cpp b/examples/widgets/graphicsview/flowlayout/flowlayout.cpp
index 065c3e00ea..ab6bbb7aa4 100644
--- a/examples/widgets/graphicsview/flowlayout/flowlayout.cpp
+++ b/examples/widgets/graphicsview/flowlayout/flowlayout.cpp
@@ -154,8 +154,7 @@ QSizeF FlowLayout::minSize(const QSizeF &constraint) const
     } else if (constraint.height() >= 0) {  // width for height?
         // not supported
     } else {
-        QGraphicsLayoutItem *item;
-        foreach (item, m_items)
+        for (const QGraphicsLayoutItem *item : qAsConst(m_items))
             size = size.expandedTo(item->effectiveSizeHint(Qt::MinimumSize));
         size += QSize(left + right, top + bottom);
     }
@@ -167,10 +166,9 @@ QSizeF FlowLayout::prefSize() const
     qreal left, right;
     getContentsMargins(&left, 0, &right, 0);
 
-    QGraphicsLayoutItem *item;
     qreal maxh = 0;
     qreal totalWidth = 0;
-    foreach (item, m_items) {
+    for (const QGraphicsLayoutItem *item : qAsConst(m_items)) {
         if (totalWidth > 0)
             totalWidth += spacing(Qt::Horizontal);
         QSizeF pref = item->effectiveSizeHint(Qt::PreferredSize);
@@ -187,10 +185,9 @@ QSizeF FlowLayout::prefSize() const
 
 QSizeF FlowLayout::maxSize() const
 {
-    QGraphicsLayoutItem *item;
     qreal totalWidth = 0;
     qreal totalHeight = 0;
-    foreach (item, m_items) {
+    for (const QGraphicsLayoutItem *item : qAsConst(m_items)) {
         if (totalWidth > 0)
             totalWidth += spacing(Qt::Horizontal);
         if (totalHeight > 0)
diff --git a/examples/widgets/graphicsview/padnavigator/roundrectitem.cpp b/examples/widgets/graphicsview/padnavigator/roundrectitem.cpp
index f629400a76..82205050ec 100644
--- a/examples/widgets/graphicsview/padnavigator/roundrectitem.cpp
+++ b/examples/widgets/graphicsview/padnavigator/roundrectitem.cpp
@@ -62,7 +62,7 @@ RoundRectItem::RoundRectItem(const QRectF &bounds, const QColor &color,
     gradient.setStart(bounds.topLeft());
     gradient.setFinalStop(bounds.bottomRight());
     gradient.setColorAt(0, color);
-    gradient.setColorAt(1, color.dark(200));
+    gradient.setColorAt(1, color.darker(200));
     setCacheMode(ItemCoordinateCache);
 }
 //! [0]
@@ -94,7 +94,7 @@ void RoundRectItem::paint(QPainter *painter, const QStyleOptionGraphicsItem *opt
     Q_UNUSED(widget);
     painter->setPen(Qt::NoPen);
     painter->setBrush(QColor(0, 0, 0, 64));
-    painter->drawRoundRect(bounds.translated(2, 2));
+    painter->drawRoundedRect(bounds.translated(2, 2), 25, 25, Qt::RelativeSize);
 //! [3]
 //! [4]
     if (fillRect)
@@ -102,7 +102,7 @@ void RoundRectItem::paint(QPainter *painter, const QStyleOptionGraphicsItem *opt
     else
         painter->setBrush(gradient);
     painter->setPen(QPen(Qt::black, 1));
-    painter->drawRoundRect(bounds);
+    painter->drawRoundedRect(bounds, 25,25, Qt::RelativeSize);
 //! [4]
 //! [5]
     if (!pix.isNull()) {
diff --git a/examples/widgets/graphicsview/padnavigator/splashitem.cpp b/examples/widgets/graphicsview/padnavigator/splashitem.cpp
index 0c3a05dd9a..7c3dfba588 100644
--- a/examples/widgets/graphicsview/padnavigator/splashitem.cpp
+++ b/examples/widgets/graphicsview/padnavigator/splashitem.cpp
@@ -79,7 +79,7 @@ void SplashItem::paint(QPainter *painter, const QStyleOptionGraphicsItem *option
     painter->setPen(QPen(Qt::black, 2));
     painter->setBrush(QColor(245, 245, 255, 220));
     painter->setClipRect(boundingRect());
-    painter->drawRoundRect(3, -100 + 3, 400 - 6, 250 - 6);
+    painter->drawRoundedRect(3, -100 + 3, 400 - 6, 250 - 6, 25, 25, Qt::RelativeSize);
 
     QRectF textRect = boundingRect().adjusted(10, 10, -10, -10);
     int flags = Qt::AlignTop | Qt::AlignLeft | Qt::TextWordWrap;
diff --git a/examples/widgets/itemviews/addressbook/adddialog.cpp b/examples/widgets/itemviews/addressbook/adddialog.cpp
index 1ce2d3110a..bf87307253 100644
--- a/examples/widgets/itemviews/addressbook/adddialog.cpp
+++ b/examples/widgets/itemviews/addressbook/adddialog.cpp
@@ -54,17 +54,16 @@
 
 //! [0]
 AddDialog::AddDialog(QWidget *parent)
-    : QDialog(parent)
+    : QDialog(parent),
+      nameText(new QLineEdit),
+      addressText(new QTextEdit)
 {
-    nameLabel = new QLabel("Name");
-    addressLabel = new QLabel("Address");
-    okButton = new QPushButton("OK");
-    cancelButton = new QPushButton("Cancel");
+    auto nameLabel = new QLabel(tr("Name"));
+    auto addressLabel = new QLabel(tr("Address"));
+    auto okButton = new QPushButton(tr("OK"));
+    auto cancelButton = new QPushButton(tr("Cancel"));
 
-    nameText = new QLineEdit;
-    addressText = new QTextEdit;
-
-    QGridLayout *gLayout = new QGridLayout;
+    auto gLayout = new QGridLayout;
     gLayout->setColumnStretch(1, 2);
     gLayout->addWidget(nameLabel, 0, 0);
     gLayout->addWidget(nameText, 0, 1);
@@ -72,13 +71,13 @@ AddDialog::AddDialog(QWidget *parent)
     gLayout->addWidget(addressLabel, 1, 0, Qt::AlignLeft|Qt::AlignTop);
     gLayout->addWidget(addressText, 1, 1, Qt::AlignLeft);
 
-    QHBoxLayout *buttonLayout = new QHBoxLayout;
+    auto buttonLayout = new QHBoxLayout;
     buttonLayout->addWidget(okButton);
     buttonLayout->addWidget(cancelButton);
 
     gLayout->addLayout(buttonLayout, 2, 1, Qt::AlignRight);
 
-    QVBoxLayout *mainLayout = new QVBoxLayout;
+    auto mainLayout = new QVBoxLayout;
     mainLayout->addLayout(gLayout);
     setLayout(mainLayout);
 
@@ -87,4 +86,21 @@ AddDialog::AddDialog(QWidget *parent)
 
     setWindowTitle(tr("Add a Contact"));
 }
+
+QString AddDialog::name() const
+{
+    return nameText->text();
+}
+
+QString AddDialog::address() const
+{
+    return addressText->toPlainText();
+}
+
+void AddDialog::editAddress(const QString &name, const QString &address)
+{
+    nameText->setReadOnly(true);
+    nameText->setText(name);
+    addressText->setPlainText(address);
+}
 //! [0]
diff --git a/examples/widgets/itemviews/addressbook/adddialog.h b/examples/widgets/itemviews/addressbook/adddialog.h
index 16fa7bc650..2867034122 100644
--- a/examples/widgets/itemviews/addressbook/adddialog.h
+++ b/examples/widgets/itemviews/addressbook/adddialog.h
@@ -66,15 +66,15 @@ class AddDialog : public QDialog
     Q_OBJECT
 
 public:
-    AddDialog(QWidget *parent = 0);
-    QLineEdit *nameText;
-    QTextEdit *addressText;
+    AddDialog(QWidget *parent = nullptr);
+
+    QString name() const;
+    QString address() const;
+    void editAddress(const QString &name, const QString &address);
 
 private:
-    QLabel *nameLabel;
-    QLabel *addressLabel;
-    QPushButton *okButton;
-    QPushButton *cancelButton;
+    QLineEdit *nameText;
+    QTextEdit *addressText;
 };
 //! [0]
 
diff --git a/examples/widgets/itemviews/addressbook/addresswidget.cpp b/examples/widgets/itemviews/addressbook/addresswidget.cpp
index 143f6266dd..b1b65174ee 100644
--- a/examples/widgets/itemviews/addressbook/addresswidget.cpp
+++ b/examples/widgets/itemviews/addressbook/addresswidget.cpp
@@ -48,21 +48,21 @@
 **
 ****************************************************************************/
 
-#include "adddialog.h"
 #include "addresswidget.h"
+#include "adddialog.h"
 
 #include <QtWidgets>
 
 //! [0]
 AddressWidget::AddressWidget(QWidget *parent)
-    : QTabWidget(parent)
+    : QTabWidget(parent),
+      table(new TableModel(this)),
+      newAddressTab(new NewAddressTab(this))
 {
-    table = new TableModel(this);
-    newAddressTab = new NewAddressTab(this);
     connect(newAddressTab, &NewAddressTab::sendDetails,
         this, &AddressWidget::addEntry);
 
-    addTab(newAddressTab, "Address Book");
+    addTab(newAddressTab, tr("Address Book"));
 
     setupTabs();
 }
@@ -73,17 +73,13 @@ void AddressWidget::showAddEntryDialog()
 {
     AddDialog aDialog;
 
-    if (aDialog.exec()) {
-        QString name = aDialog.nameText->text();
-        QString address = aDialog.addressText->toPlainText();
-
-        addEntry(name, address);
-    }
+    if (aDialog.exec())
+        addEntry(aDialog.name(), aDialog.address());
 }
 //! [2]
 
 //! [3]
-void AddressWidget::addEntry(QString name, QString address)
+void AddressWidget::addEntry(const QString &name, const QString &address)
 {
     if (!table->getContacts().contains({ name, address })) {
         table->insertRows(0, 1, QModelIndex());
@@ -107,12 +103,12 @@ void AddressWidget::editEntry()
     QSortFilterProxyModel *proxy = static_cast<QSortFilterProxyModel*>(temp->model());
     QItemSelectionModel *selectionModel = temp->selectionModel();
 
-    QModelIndexList indexes = selectionModel->selectedRows();
+    const QModelIndexList indexes = selectionModel->selectedRows();
     QString name;
     QString address;
     int row = -1;
 
-    foreach (QModelIndex index, indexes) {
+    for (const QModelIndex &index : indexes) {
         row = proxy->mapToSource(index).row();
         QModelIndex nameIndex = table->index(row, 0, QModelIndex());
         QVariant varName = table->data(nameIndex, Qt::DisplayRole);
@@ -127,15 +123,12 @@ void AddressWidget::editEntry()
 //! [4b]
     AddDialog aDialog;
     aDialog.setWindowTitle(tr("Edit a Contact"));
-
-    aDialog.nameText->setReadOnly(true);
-    aDialog.nameText->setText(name);
-    aDialog.addressText->setText(address);
+    aDialog.editAddress(name, address);
 
     if (aDialog.exec()) {
-        QString newAddress = aDialog.addressText->toPlainText();
+        const QString newAddress = aDialog.address();
         if (newAddress != address) {
-            QModelIndex index = table->index(row, 1, QModelIndex());
+            const QModelIndex index = table->index(row, 1, QModelIndex());
             table->setData(index, newAddress, Qt::EditRole);
         }
     }
@@ -149,52 +142,46 @@ void AddressWidget::removeEntry()
     QSortFilterProxyModel *proxy = static_cast<QSortFilterProxyModel*>(temp->model());
     QItemSelectionModel *selectionModel = temp->selectionModel();
 
-    QModelIndexList indexes = selectionModel->selectedRows();
+    const QModelIndexList indexes = selectionModel->selectedRows();
 
-    foreach (QModelIndex index, indexes) {
+    for (QModelIndex index : indexes) {
         int row = proxy->mapToSource(index).row();
         table->removeRows(row, 1, QModelIndex());
     }
 
-    if (table->rowCount(QModelIndex()) == 0) {
-        insertTab(0, newAddressTab, "Address Book");
-    }
+    if (table->rowCount(QModelIndex()) == 0)
+        insertTab(0, newAddressTab, tr("Address Book"));
 }
 //! [5]
 
 //! [1]
 void AddressWidget::setupTabs()
 {
-    QStringList groups;
-    groups << "ABC" << "DEF" << "GHI" << "JKL" << "MNO" << "PQR" << "STU" << "VW" << "XYZ";
+    const auto groups = { "ABC", "DEF", "GHI", "JKL", "MNO", "PQR", "STU", "VW", "XYZ" };
 
-    for (int i = 0; i < groups.size(); ++i) {
-        QString str = groups.at(i);
-        QString regExp = QString("^[%1].*").arg(str);
+    for (const QString &str : groups) {
+        const auto regExp = QRegularExpression(QString("^[%1].*").arg(str),
+                                               QRegularExpression::CaseInsensitiveOption);
 
-        proxyModel = new QSortFilterProxyModel(this);
+        auto proxyModel = new QSortFilterProxyModel(this);
         proxyModel->setSourceModel(table);
-        proxyModel->setFilterRegExp(QRegExp(regExp, Qt::CaseInsensitive));
+        proxyModel->setFilterRegularExpression(regExp);
         proxyModel->setFilterKeyColumn(0);
 
         QTableView *tableView = new QTableView;
         tableView->setModel(proxyModel);
-
         tableView->setSelectionBehavior(QAbstractItemView::SelectRows);
         tableView->horizontalHeader()->setStretchLastSection(true);
         tableView->verticalHeader()->hide();
         tableView->setEditTriggers(QAbstractItemView::NoEditTriggers);
         tableView->setSelectionMode(QAbstractItemView::SingleSelection);
-
         tableView->setSortingEnabled(true);
 
-        connect(tableView->selectionModel(),
-            &QItemSelectionModel::selectionChanged,
-            this, &AddressWidget::selectionChanged);
+        connect(tableView->selectionModel(), &QItemSelectionModel::selectionChanged,
+                this, &AddressWidget::selectionChanged);
 
-        connect(this, &QTabWidget::currentChanged, this, [this](int tabIndex) {
-            auto *tableView = qobject_cast<QTableView *>(widget(tabIndex));
-            if (tableView)
+        connect(this, &QTabWidget::currentChanged, this, [this, tableView](int tabIndex) {
+            if (widget(tabIndex) == tableView)
                 emit selectionChanged(tableView->selectionModel()->selection());
         });
 
@@ -214,7 +201,7 @@ void AddressWidget::readFromFile(const QString &fileName)
         return;
     }
 
-    QList<Contact> contacts;
+    QVector<Contact> contacts;
     QDataStream in(&file);
     in >> contacts;
 
diff --git a/examples/widgets/itemviews/addressbook/addresswidget.h b/examples/widgets/itemviews/addressbook/addresswidget.h
index de5a2da766..111ea98328 100644
--- a/examples/widgets/itemviews/addressbook/addresswidget.h
+++ b/examples/widgets/itemviews/addressbook/addresswidget.h
@@ -68,13 +68,13 @@ class AddressWidget : public QTabWidget
     Q_OBJECT
 
 public:
-    AddressWidget(QWidget *parent = 0);
+    AddressWidget(QWidget *parent = nullptr);
     void readFromFile(const QString &fileName);
     void writeToFile(const QString &fileName);
 
 public slots:
     void showAddEntryDialog();
-    void addEntry(QString name, QString address);
+    void addEntry(const QString &name, const QString &address);
     void editEntry();
     void removeEntry();
 
@@ -86,7 +86,6 @@ private:
 
     TableModel *table;
     NewAddressTab *newAddressTab;
-    QSortFilterProxyModel *proxyModel;
 };
 //! [0]
 
diff --git a/examples/widgets/itemviews/addressbook/mainwindow.cpp b/examples/widgets/itemviews/addressbook/mainwindow.cpp
index 6d8b15b032..42966de375 100644
--- a/examples/widgets/itemviews/addressbook/mainwindow.cpp
+++ b/examples/widgets/itemviews/addressbook/mainwindow.cpp
@@ -56,8 +56,9 @@
 
 //! [0]
 MainWindow::MainWindow()
+    : QMainWindow(),
+      addressWidget(new AddressWidget)
 {
-    addressWidget = new AddressWidget;
     setCentralWidget(addressWidget);
     createMenus();
     setWindowTitle(tr("Address Book"));
@@ -67,28 +68,29 @@ MainWindow::MainWindow()
 //! [1a]
 void MainWindow::createMenus()
 {
-    fileMenu = menuBar()->addMenu(tr("&File"));
+    QMenu *fileMenu = menuBar()->addMenu(tr("&File"));
 
-    openAct = new QAction(tr("&Open..."), this);
+    QAction *openAct = new QAction(tr("&Open..."), this);
     fileMenu->addAction(openAct);
     connect(openAct, &QAction::triggered, this, &MainWindow::openFile);
 //! [1a]
 
-    saveAct = new QAction(tr("&Save As..."), this);
+    QAction *saveAct = new QAction(tr("&Save As..."), this);
     fileMenu->addAction(saveAct);
     connect(saveAct, &QAction::triggered, this, &MainWindow::saveFile);
 
     fileMenu->addSeparator();
 
-    exitAct = new QAction(tr("E&xit"), this);
+    QAction *exitAct = new QAction(tr("E&xit"), this);
     fileMenu->addAction(exitAct);
     connect(exitAct, &QAction::triggered, this, &QWidget::close);
 
-    toolMenu = menuBar()->addMenu(tr("&Tools"));
+    QMenu *toolMenu = menuBar()->addMenu(tr("&Tools"));
 
-    addAct = new QAction(tr("&Add Entry..."), this);
+    QAction *addAct = new QAction(tr("&Add Entry..."), this);
     toolMenu->addAction(addAct);
-    connect(addAct, &QAction::triggered, addressWidget, &AddressWidget::showAddEntryDialog);
+    connect(addAct, &QAction::triggered,
+            addressWidget, &AddressWidget::showAddEntryDialog);
 
 //! [1b]
     editAct = new QAction(tr("&Edit Entry..."), this);
diff --git a/examples/widgets/itemviews/addressbook/mainwindow.h b/examples/widgets/itemviews/addressbook/mainwindow.h
index 3d323e5799..fca5934e68 100644
--- a/examples/widgets/itemviews/addressbook/mainwindow.h
+++ b/examples/widgets/itemviews/addressbook/mainwindow.h
@@ -72,12 +72,6 @@ private:
     void createMenus();
 
     AddressWidget *addressWidget;
-    QMenu *fileMenu;
-    QMenu *toolMenu;
-    QAction *openAct;
-    QAction *saveAct;
-    QAction *exitAct;
-    QAction *addAct;
     QAction *editAct;
     QAction *removeAct;
 };
diff --git a/examples/widgets/itemviews/addressbook/newaddresstab.cpp b/examples/widgets/itemviews/addressbook/newaddresstab.cpp
index f0a7369796..ef725d723f 100644
--- a/examples/widgets/itemviews/addressbook/newaddresstab.cpp
+++ b/examples/widgets/itemviews/addressbook/newaddresstab.cpp
@@ -48,24 +48,23 @@
 **
 ****************************************************************************/
 
-#include "adddialog.h"
 #include "newaddresstab.h"
+#include "adddialog.h"
 
 #include <QtWidgets>
 
 //! [0]
 NewAddressTab::NewAddressTab(QWidget *parent)
+    : QWidget(parent)
 {
-    Q_UNUSED(parent);
+    auto descriptionLabel = new QLabel(tr("There are currently no contacts in your address book. "
+                                          "\nClick Add to add new contacts."));
 
-    descriptionLabel = new QLabel(tr("There are currently no contacts in your address book. "
-                                      "\nClick Add to add new contacts."));
-
-    addButton = new QPushButton(tr("Add"));
+    auto addButton = new QPushButton(tr("Add"));
 
     connect(addButton, &QAbstractButton::clicked, this, &NewAddressTab::addEntry);
 
-    mainLayout = new QVBoxLayout;
+    auto mainLayout = new QVBoxLayout;
     mainLayout->addWidget(descriptionLabel);
     mainLayout->addWidget(addButton, 0, Qt::AlignCenter);
 
@@ -78,11 +77,7 @@ void NewAddressTab::addEntry()
 {
     AddDialog aDialog;
 
-    if (aDialog.exec()) {
-        QString name = aDialog.nameText->text();
-        QString address = aDialog.addressText->toPlainText();
-
-        emit sendDetails(name, address);
-    }
+    if (aDialog.exec())
+        emit sendDetails(aDialog.name(), aDialog.address());
 }
 //! [1]
diff --git a/examples/widgets/itemviews/addressbook/newaddresstab.h b/examples/widgets/itemviews/addressbook/newaddresstab.h
index 05c7a8dada..6a147e3c7c 100644
--- a/examples/widgets/itemviews/addressbook/newaddresstab.h
+++ b/examples/widgets/itemviews/addressbook/newaddresstab.h
@@ -65,19 +65,13 @@ class NewAddressTab : public QWidget
     Q_OBJECT
 
 public:
-    NewAddressTab(QWidget *parent = 0);
+    NewAddressTab(QWidget *parent = nullptr);
 
 public slots:
     void addEntry();
 
 signals:
-    void sendDetails(QString name, QString address);
-
-private:
-    QLabel *descriptionLabel;
-    QPushButton *addButton;
-    QVBoxLayout *mainLayout;
-
+    void sendDetails(const QString &name, const QString &address);
 };
 //! [0]
 
diff --git a/examples/widgets/itemviews/addressbook/tablemodel.cpp b/examples/widgets/itemviews/addressbook/tablemodel.cpp
index 674e312753..ddf79a3fa3 100644
--- a/examples/widgets/itemviews/addressbook/tablemodel.cpp
+++ b/examples/widgets/itemviews/addressbook/tablemodel.cpp
@@ -56,9 +56,9 @@ TableModel::TableModel(QObject *parent)
 {
 }
 
-TableModel::TableModel(QList<Contact> contacts, QObject *parent)
-    : QAbstractTableModel(parent)
-    , contacts(contacts)
+TableModel::TableModel(const QVector<Contact> &contacts, QObject *parent)
+    : QAbstractTableModel(parent),
+      contacts(contacts)
 {
 }
 //! [0]
@@ -66,14 +66,12 @@ TableModel::TableModel(QList<Contact> contacts, QObject *parent)
 //! [1]
 int TableModel::rowCount(const QModelIndex &parent) const
 {
-    Q_UNUSED(parent);
-    return contacts.size();
+    return parent.isValid() ? 0 : contacts.size();
 }
 
 int TableModel::columnCount(const QModelIndex &parent) const
 {
-    Q_UNUSED(parent);
-    return 2;
+    return parent.isValid() ? 0 : 2;
 }
 //! [1]
 
@@ -89,10 +87,14 @@ QVariant TableModel::data(const QModelIndex &index, int role) const
     if (role == Qt::DisplayRole) {
         const auto &contact = contacts.at(index.row());
 
-        if (index.column() == 0)
-            return contact.name;
-        else if (index.column() == 1)
-            return contact.address;
+        switch (index.column()) {
+            case 0:
+                return contact.name;
+            case 1:
+                return contact.address;
+            default:
+                break;
+        }
     }
     return QVariant();
 }
@@ -108,12 +110,10 @@ QVariant TableModel::headerData(int section, Qt::Orientation orientation, int ro
         switch (section) {
             case 0:
                 return tr("Name");
-
             case 1:
                 return tr("Address");
-
             default:
-                return QVariant();
+                break;
         }
     }
     return QVariant();
@@ -152,19 +152,21 @@ bool TableModel::removeRows(int position, int rows, const QModelIndex &index)
 bool TableModel::setData(const QModelIndex &index, const QVariant &value, int role)
 {
     if (index.isValid() && role == Qt::EditRole) {
-        int row = index.row();
-
+        const int row = index.row();
         auto contact = contacts.value(row);
 
-        if (index.column() == 0)
-            contact.name = value.toString();
-        else if (index.column() == 1)
-            contact.address = value.toString();
-        else
-            return false;
-
+        switch (index.column()) {
+            case 0:
+                contact.name = value.toString();
+                break;
+            case 1:
+                contact.address = value.toString();
+                break;
+            default:
+                return false;
+        }
         contacts.replace(row, contact);
-        emit(dataChanged(index, index));
+        emit dataChanged(index, index, {Qt::DisplayRole, Qt::EditRole});
 
         return true;
     }
@@ -184,7 +186,7 @@ Qt::ItemFlags TableModel::flags(const QModelIndex &index) const
 //! [7]
 
 //! [8]
-QList<Contact> TableModel::getContacts() const
+const QVector<Contact> &TableModel::getContacts() const
 {
     return contacts;
 }
diff --git a/examples/widgets/itemviews/addressbook/tablemodel.h b/examples/widgets/itemviews/addressbook/tablemodel.h
index 1004a35d31..e4025fc734 100644
--- a/examples/widgets/itemviews/addressbook/tablemodel.h
+++ b/examples/widgets/itemviews/addressbook/tablemodel.h
@@ -52,7 +52,7 @@
 #define TABLEMODEL_H
 
 #include <QAbstractTableModel>
-#include <QList>
+#include <QVector>
 
 //! [0]
 
@@ -82,8 +82,8 @@ class TableModel : public QAbstractTableModel
     Q_OBJECT
 
 public:
-    TableModel(QObject *parent = 0);
-    TableModel(QList<Contact> contacts, QObject *parent = 0);
+    TableModel(QObject *parent = nullptr);
+    TableModel(const QVector<Contact> &contacts, QObject *parent = nullptr);
 
     int rowCount(const QModelIndex &parent) const override;
     int columnCount(const QModelIndex &parent) const override;
@@ -93,10 +93,10 @@ public:
     bool setData(const QModelIndex &index, const QVariant &value, int role = Qt::EditRole) override;
     bool insertRows(int position, int rows, const QModelIndex &index = QModelIndex()) override;
     bool removeRows(int position, int rows, const QModelIndex &index = QModelIndex()) override;
-    QList<Contact> getContacts() const;
+    const QVector<Contact> &getContacts() const;
 
 private:
-    QList<Contact> contacts;
+    QVector<Contact> contacts;
 };
 //! [0]
 
diff --git a/examples/widgets/itemviews/chart/mainwindow.cpp b/examples/widgets/itemviews/chart/mainwindow.cpp
index 91e535a006..53f57fbb49 100644
--- a/examples/widgets/itemviews/chart/mainwindow.cpp
+++ b/examples/widgets/itemviews/chart/mainwindow.cpp
@@ -48,12 +48,13 @@
 **
 ****************************************************************************/
 
-#include <QtWidgets>
-
 #include "pieview.h"
 #include "mainwindow.h"
 
-MainWindow::MainWindow()
+#include <QtWidgets>
+
+MainWindow::MainWindow(QWidget *parent)
+    : QMainWindow(parent)
 {
     QMenu *fileMenu = new QMenu(tr("&File"), this);
     QAction *openAction = fileMenu->addAction(tr("&Open..."));
@@ -124,17 +125,18 @@ void MainWindow::loadFile(const QString &fileName)
         return;
 
     QTextStream stream(&file);
-    QString line;
 
     model->removeRows(0, model->rowCount(QModelIndex()), QModelIndex());
 
     int row = 0;
-    do {
-        line = stream.readLine();
+    while (!stream.atEnd()) {
+        const QString line = stream.readLine();
         if (!line.isEmpty()) {
             model->insertRows(row, 1, QModelIndex());
 
-            QStringList pieces = line.split(',', QString::SkipEmptyParts);
+            const QStringList pieces = line.split(',', QString::SkipEmptyParts);
+            if (pieces.size() < 3)
+                continue;
             model->setData(model->index(row, 0, QModelIndex()),
                            pieces.value(0));
             model->setData(model->index(row, 1, QModelIndex()),
@@ -143,7 +145,7 @@ void MainWindow::loadFile(const QString &fileName)
                            QColor(pieces.value(2)), Qt::DecorationRole);
             row++;
         }
-    } while (!line.isEmpty());
+    };
 
     file.close();
     statusBar()->showMessage(tr("Loaded %1").arg(fileName), 2000);
diff --git a/examples/widgets/itemviews/chart/mainwindow.h b/examples/widgets/itemviews/chart/mainwindow.h
index 058f5c7e90..51176d261b 100644
--- a/examples/widgets/itemviews/chart/mainwindow.h
+++ b/examples/widgets/itemviews/chart/mainwindow.h
@@ -56,7 +56,6 @@
 QT_BEGIN_NAMESPACE
 class QAbstractItemModel;
 class QAbstractItemView;
-class QItemSelectionModel;
 QT_END_NAMESPACE
 
 class MainWindow : public QMainWindow
@@ -64,7 +63,7 @@ class MainWindow : public QMainWindow
     Q_OBJECT
 
 public:
-    MainWindow();
+    MainWindow(QWidget *parent = nullptr);
 
 private slots:
     void openFile();
@@ -75,9 +74,8 @@ private:
     void setupViews();
     void loadFile(const QString &path);
 
-    QAbstractItemModel *model;
-    QAbstractItemView *pieChart;
-    QItemSelectionModel *selectionModel;
+    QAbstractItemModel *model = nullptr;
+    QAbstractItemView *pieChart = nullptr;
 };
 
 #endif // MAINWINDOW_H
diff --git a/examples/widgets/itemviews/chart/pieview.cpp b/examples/widgets/itemviews/chart/pieview.cpp
index 3f85e397ee..457ed8b4ec 100644
--- a/examples/widgets/itemviews/chart/pieview.cpp
+++ b/examples/widgets/itemviews/chart/pieview.cpp
@@ -48,30 +48,25 @@
 **
 ****************************************************************************/
 
-#include <QtWidgets>
-#include <qmath.h>
-#include <cmath>
 #include "pieview.h"
 
+#include <QtWidgets>
+
 PieView::PieView(QWidget *parent)
     : QAbstractItemView(parent)
 {
     horizontalScrollBar()->setRange(0, 0);
     verticalScrollBar()->setRange(0, 0);
-
-    margin = 8;
-    totalSize = 300;
-    pieSize = totalSize - 2 * margin;
-    validItems = 0;
-    totalValue = 0.0;
-    rubberBand = 0;
 }
 
 void PieView::dataChanged(const QModelIndex &topLeft,
                           const QModelIndex &bottomRight,
-                          const QVector<int> &)
+                          const QVector<int> &roles)
 {
-    QAbstractItemView::dataChanged(topLeft, bottomRight);
+    QAbstractItemView::dataChanged(topLeft, bottomRight, roles);
+
+    if (!roles.contains(Qt::DisplayRole))
+        return;
 
     validItems = 0;
     totalValue = 0.0;
@@ -79,7 +74,7 @@ void PieView::dataChanged(const QModelIndex &topLeft,
     for (int row = 0; row < model()->rowCount(rootIndex()); ++row) {
 
         QModelIndex index = model()->index(row, 1, rootIndex());
-        double value = model()->data(index).toDouble();
+        double value = model()->data(index, Qt::DisplayRole).toDouble();
 
         if (value > 0.0) {
             totalValue += value;
@@ -197,15 +192,14 @@ QRect PieView::itemRect(const QModelIndex &index) const
             listItem++;
     }
 
-    double itemHeight;
-
     switch (index.column()) {
-    case 0:
-        itemHeight = QFontMetrics(viewOptions().font).height();
+    case 0: {
+        const qreal itemHeight = QFontMetricsF(viewOptions().font).height();
 
         return QRect(totalSize,
-                     int(margin + listItem*itemHeight),
-                     totalSize - margin, int(itemHeight));
+                     qRound(margin + listItem * itemHeight),
+                     totalSize - margin, qRound(itemHeight));
+    }
     case 1:
         return viewport()->rect();
     }
@@ -235,7 +229,7 @@ QRegion PieView::itemRegion(const QModelIndex &index) const
             if (sliceIndex == index) {
                 QPainterPath slicePath;
                 slicePath.moveTo(totalSize / 2, totalSize / 2);
-                slicePath.arcTo(margin, margin, margin+pieSize, margin+pieSize,
+                slicePath.arcTo(margin, margin, margin + pieSize, margin + pieSize,
                                 startAngle, angle);
                 slicePath.closeSubpath();
 
@@ -342,7 +336,7 @@ void PieView::paintEvent(QPaintEvent *event)
         double value = model()->data(index).toDouble();
 
         if (value > 0.0) {
-            double angle = 360*value/totalValue;
+            double angle = 360 * value / totalValue;
 
             QModelIndex colorIndex = model()->index(row, 0, rootIndex());
             QColor color = QColor(model()->data(colorIndex, Qt::DecorationRole).toString());
@@ -480,16 +474,16 @@ void PieView::setSelection(const QRect &rect, QItemSelectionModel::SelectionFlag
     }
 
     if (indexes.size() > 0) {
-        int firstRow = indexes[0].row();
-        int lastRow = indexes[0].row();
-        int firstColumn = indexes[0].column();
-        int lastColumn = indexes[0].column();
+        int firstRow = indexes.at(0).row();
+        int lastRow = firstRow;
+        int firstColumn = indexes.at(0).column();
+        int lastColumn = firstColumn;
 
         for (int i = 1; i < indexes.size(); ++i) {
-            firstRow = qMin(firstRow, indexes[i].row());
-            lastRow = qMax(lastRow, indexes[i].row());
-            firstColumn = qMin(firstColumn, indexes[i].column());
-            lastColumn = qMax(lastColumn, indexes[i].column());
+            firstRow = qMin(firstRow, indexes.at(i).row());
+            lastRow = qMax(lastRow, indexes.at(i).row());
+            firstColumn = qMin(firstColumn, indexes.at(i).column());
+            lastColumn = qMax(lastColumn, indexes.at(i).column());
         }
 
         QItemSelection selection(
@@ -508,7 +502,7 @@ void PieView::setSelection(const QRect &rect, QItemSelectionModel::SelectionFlag
 void PieView::updateGeometries()
 {
     horizontalScrollBar()->setPageStep(viewport()->width());
-    horizontalScrollBar()->setRange(0, qMax(0, 2*totalSize - viewport()->width()));
+    horizontalScrollBar()->setRange(0, qMax(0, 2 * totalSize - viewport()->width()));
     verticalScrollBar()->setPageStep(viewport()->height());
     verticalScrollBar()->setRange(0, qMax(0, totalSize - viewport()->height()));
 }
@@ -546,7 +540,7 @@ QRegion PieView::visualRegionForSelection(const QItemSelection &selection) const
 
     QRegion region;
     for (int i = 0; i < ranges; ++i) {
-        QItemSelectionRange range = selection.at(i);
+        const QItemSelectionRange &range = selection.at(i);
         for (int row = range.top(); row <= range.bottom(); ++row) {
             for (int col = range.left(); col <= range.right(); ++col) {
                 QModelIndex index = model()->index(row, col, rootIndex());
diff --git a/examples/widgets/itemviews/chart/pieview.h b/examples/widgets/itemviews/chart/pieview.h
index aa397e6d55..22c74dde81 100644
--- a/examples/widgets/itemviews/chart/pieview.h
+++ b/examples/widgets/itemviews/chart/pieview.h
@@ -59,7 +59,7 @@ class PieView : public QAbstractItemView
     Q_OBJECT
 
 public:
-    PieView(QWidget *parent = 0);
+    PieView(QWidget *parent = nullptr);
 
     QRect visualRect(const QModelIndex &index) const override;
     void scrollTo(const QModelIndex &index, ScrollHint hint = EnsureVisible) override;
@@ -100,13 +100,13 @@ private:
     int rows(const QModelIndex &index = QModelIndex()) const;
     void updateGeometries() override;
 
-    int margin;
-    int totalSize;
-    int pieSize;
-    int validItems;
-    double totalValue;
+    int margin = 0;
+    int totalSize = 300;
+    int pieSize = totalSize - 2 * margin;
+    int validItems = 0;
+    double totalValue = 0.0;
+    QRubberBand *rubberBand = nullptr;
     QPoint origin;
-    QRubberBand *rubberBand;
 };
 //! [0]
 
diff --git a/examples/widgets/itemviews/coloreditorfactory/colorlisteditor.cpp b/examples/widgets/itemviews/coloreditorfactory/colorlisteditor.cpp
index 75d809a44f..0b65c53477 100644
--- a/examples/widgets/itemviews/coloreditorfactory/colorlisteditor.cpp
+++ b/examples/widgets/itemviews/coloreditorfactory/colorlisteditor.cpp
@@ -48,10 +48,10 @@
 **
 ****************************************************************************/
 
-#include <QtWidgets>
-
 #include "colorlisteditor.h"
 
+#include <QtWidgets>
+
 ColorListEditor::ColorListEditor(QWidget *widget) : QComboBox(widget)
 {
     populateList();
@@ -65,16 +65,16 @@ QColor ColorListEditor::color() const
 //! [0]
 
 //! [1]
-void ColorListEditor::setColor(QColor color)
+void ColorListEditor::setColor(const QColor &color)
 {
-    setCurrentIndex(findData(color, int(Qt::DecorationRole)));
+    setCurrentIndex(findData(color, Qt::DecorationRole));
 }
 //! [1]
 
 //! [2]
 void ColorListEditor::populateList()
 {
-    QStringList colorNames = QColor::colorNames();
+    const QStringList colorNames = QColor::colorNames();
 
     for (int i = 0; i < colorNames.size(); ++i) {
         QColor color(colorNames[i]);
diff --git a/examples/widgets/itemviews/coloreditorfactory/colorlisteditor.h b/examples/widgets/itemviews/coloreditorfactory/colorlisteditor.h
index f284c07c89..f9d736d298 100644
--- a/examples/widgets/itemviews/coloreditorfactory/colorlisteditor.h
+++ b/examples/widgets/itemviews/coloreditorfactory/colorlisteditor.h
@@ -65,11 +65,11 @@ class ColorListEditor : public QComboBox
     Q_PROPERTY(QColor color READ color WRITE setColor USER true)
 
 public:
-    ColorListEditor(QWidget *widget = 0);
+    ColorListEditor(QWidget *widget = nullptr);
 
 public:
     QColor color() const;
-    void setColor(QColor c);
+    void setColor(const QColor &color);
 
 private:
     void populateList();
diff --git a/examples/widgets/itemviews/coloreditorfactory/window.cpp b/examples/widgets/itemviews/coloreditorfactory/window.cpp
index f7ce821d31..e4a9379d8f 100644
--- a/examples/widgets/itemviews/coloreditorfactory/window.cpp
+++ b/examples/widgets/itemviews/coloreditorfactory/window.cpp
@@ -48,11 +48,11 @@
 **
 ****************************************************************************/
 
-#include <QtWidgets>
-
 #include "window.h"
 #include "colorlisteditor.h"
 
+#include <QtWidgets>
+
 //! [0]
 Window::Window()
 {
@@ -71,19 +71,18 @@ Window::Window()
 
 void Window::createGUI()
 {
-    QList<QPair<QString, QColor> > list;
-    list << QPair<QString, QColor>(tr("Alice"), QColor("aliceblue")) <<
-            QPair<QString, QColor>(tr("Neptun"), QColor("aquamarine")) <<
-            QPair<QString, QColor>(tr("Ferdinand"), QColor("springgreen"));
+    const QVector<QPair<QString, QColor> > list =
+        {{ tr("Alice"), QColor("aliceblue") },
+         { tr("Neptun"), QColor("aquamarine") },
+         { tr("Ferdinand"), QColor("springgreen") }};
 
     QTableWidget *table = new QTableWidget(3, 2);
-    table->setHorizontalHeaderLabels(QStringList() << tr("Name")
-                                                   << tr("Hair Color"));
+    table->setHorizontalHeaderLabels({ tr("Name"), tr("Hair Color") });
     table->verticalHeader()->setVisible(false);
     table->resize(150, 50);
 
     for (int i = 0; i < 3; ++i) {
-        QPair<QString, QColor> pair = list.at(i);
+        const QPair<QString, QColor> &pair = list.at(i);
 
         QTableWidgetItem *nameItem = new QTableWidgetItem(pair.first);
         QTableWidgetItem *colorItem = new QTableWidgetItem;
diff --git a/examples/widgets/itemviews/customsortfiltermodel/filterwidget.cpp b/examples/widgets/itemviews/customsortfiltermodel/filterwidget.cpp
index 74d88caae6..302042a6b3 100644
--- a/examples/widgets/itemviews/customsortfiltermodel/filterwidget.cpp
+++ b/examples/widgets/itemviews/customsortfiltermodel/filterwidget.cpp
@@ -52,13 +52,11 @@
 
 #include <QIcon>
 #include <QPixmap>
-#include <QImage>
 #include <QMenu>
 #include <QAction>
 #include <QActionGroup>
 #include <QToolButton>
 #include <QWidgetAction>
-#include <QDebug>
 
 FilterWidget::FilterWidget(QWidget *parent)
     : QLineEdit(parent)
@@ -127,7 +125,8 @@ QRegExp::PatternSyntax FilterWidget::patternSyntax() const
 
 void FilterWidget::setPatternSyntax(QRegExp::PatternSyntax s)
 {
-    foreach (QAction *a, m_patternGroup->actions()) {
+    const QList<QAction*> actions = m_patternGroup->actions();
+    for (QAction *a : actions) {
         if (patternSyntaxFromAction(a) == s) {
             a->setChecked(true);
             break;
diff --git a/examples/widgets/itemviews/customsortfiltermodel/filterwidget.h b/examples/widgets/itemviews/customsortfiltermodel/filterwidget.h
index ea12954e52..70214b862e 100644
--- a/examples/widgets/itemviews/customsortfiltermodel/filterwidget.h
+++ b/examples/widgets/itemviews/customsortfiltermodel/filterwidget.h
@@ -67,7 +67,7 @@ class FilterWidget : public QLineEdit
     Q_PROPERTY(Qt::CaseSensitivity caseSensitivity READ caseSensitivity WRITE setCaseSensitivity)
     Q_PROPERTY(QRegExp::PatternSyntax patternSyntax READ patternSyntax WRITE setPatternSyntax)
 public:
-    explicit FilterWidget(QWidget *parent = 0);
+    explicit FilterWidget(QWidget *parent = nullptr);
 
     Qt::CaseSensitivity caseSensitivity() const;
     void setCaseSensitivity(Qt::CaseSensitivity);
diff --git a/examples/widgets/itemviews/customsortfiltermodel/mysortfilterproxymodel.cpp b/examples/widgets/itemviews/customsortfiltermodel/mysortfilterproxymodel.cpp
index 35426657d9..4753d04d9b 100644
--- a/examples/widgets/itemviews/customsortfiltermodel/mysortfilterproxymodel.cpp
+++ b/examples/widgets/itemviews/customsortfiltermodel/mysortfilterproxymodel.cpp
@@ -48,10 +48,10 @@
 **
 ****************************************************************************/
 
-#include <QtWidgets>
-
 #include "mysortfilterproxymodel.h"
 
+#include <QtWidgets>
+
 //! [0]
 MySortFilterProxyModel::MySortFilterProxyModel(QObject *parent)
     : QSortFilterProxyModel(parent)
@@ -77,7 +77,7 @@ void MySortFilterProxyModel::setFilterMaximumDate(const QDate &date)
 
 //! [3]
 bool MySortFilterProxyModel::filterAcceptsRow(int sourceRow,
-        const QModelIndex &sourceParent) const
+                                              const QModelIndex &sourceParent) const
 {
     QModelIndex index0 = sourceModel()->index(sourceRow, 0, sourceParent);
     QModelIndex index1 = sourceModel()->index(sourceRow, 1, sourceParent);
diff --git a/examples/widgets/itemviews/customsortfiltermodel/window.cpp b/examples/widgets/itemviews/customsortfiltermodel/window.cpp
index bfd2350da0..3356c971ad 100644
--- a/examples/widgets/itemviews/customsortfiltermodel/window.cpp
+++ b/examples/widgets/itemviews/customsortfiltermodel/window.cpp
@@ -48,12 +48,12 @@
 **
 ****************************************************************************/
 
-#include <QtWidgets>
-
-#include "mysortfilterproxymodel.h"
 #include "window.h"
+#include "mysortfilterproxymodel.h"
 #include "filterwidget.h"
 
+#include <QtWidgets>
+
 //! [0]
 Window::Window()
 {
@@ -75,7 +75,7 @@ Window::Window()
 
     //! [3]
     filterWidget = new FilterWidget;
-    filterWidget->setText("Grace|Sports");
+    filterWidget->setText(tr("Grace|Sports"));
     connect(filterWidget, &FilterWidget::filterChanged, this, &Window::textFilterChanged);
 
     filterPatternLabel = new QLabel(tr("&Filter pattern:"));
@@ -137,6 +137,11 @@ void Window::setSourceModel(QAbstractItemModel *model)
 {
     proxyModel->setSourceModel(model);
     sourceView->setModel(model);
+
+    for (int i = 0; i < proxyModel->columnCount(); ++i)
+        proxyView->resizeColumnToContents(i);
+    for (int i = 0; i < model->columnCount(); ++i)
+        sourceView->resizeColumnToContents(i);
 }
 //! [7]
 
diff --git a/examples/widgets/itemviews/editabletreemodel/main.cpp b/examples/widgets/itemviews/editabletreemodel/main.cpp
index 80f6842730..5e9ff214a3 100644
--- a/examples/widgets/itemviews/editabletreemodel/main.cpp
+++ b/examples/widgets/itemviews/editabletreemodel/main.cpp
@@ -48,10 +48,10 @@
 **
 ****************************************************************************/
 
-#include <QApplication>
-
 #include "mainwindow.h"
 
+#include <QApplication>
+
 int main(int argc, char *argv[])
 {
     Q_INIT_RESOURCE(editabletreemodel);
diff --git a/examples/widgets/itemviews/editabletreemodel/mainwindow.cpp b/examples/widgets/itemviews/editabletreemodel/mainwindow.cpp
index 0c54d8930f..7faa325469 100644
--- a/examples/widgets/itemviews/editabletreemodel/mainwindow.cpp
+++ b/examples/widgets/itemviews/editabletreemodel/mainwindow.cpp
@@ -58,8 +58,7 @@ MainWindow::MainWindow(QWidget *parent)
 {
     setupUi(this);
 
-    QStringList headers;
-    headers << tr("Title") << tr("Description");
+    const QStringList headers({tr("Title"), tr("Description")});
 
     QFile file(":/default.txt");
     file.open(QIODevice::ReadOnly);
@@ -87,7 +86,7 @@ MainWindow::MainWindow(QWidget *parent)
 
 void MainWindow::insertChild()
 {
-    QModelIndex index = view->selectionModel()->currentIndex();
+    const QModelIndex index = view->selectionModel()->currentIndex();
     QAbstractItemModel *model = view->model();
 
     if (model->columnCount(index) == 0) {
@@ -99,10 +98,10 @@ void MainWindow::insertChild()
         return;
 
     for (int column = 0; column < model->columnCount(index); ++column) {
-        QModelIndex child = model->index(0, column, index);
-        model->setData(child, QVariant("[No data]"), Qt::EditRole);
+        const QModelIndex child = model->index(0, column, index);
+        model->setData(child, QVariant(tr("[No data]")), Qt::EditRole);
         if (!model->headerData(column, Qt::Horizontal).isValid())
-            model->setHeaderData(column, Qt::Horizontal, QVariant("[No header]"), Qt::EditRole);
+            model->setHeaderData(column, Qt::Horizontal, QVariant(tr("[No header]")), Qt::EditRole);
     }
 
     view->selectionModel()->setCurrentIndex(model->index(0, 0, index),
@@ -127,7 +126,7 @@ bool MainWindow::insertColumn()
 
 void MainWindow::insertRow()
 {
-    QModelIndex index = view->selectionModel()->currentIndex();
+    const QModelIndex index = view->selectionModel()->currentIndex();
     QAbstractItemModel *model = view->model();
 
     if (!model->insertRow(index.row()+1, index.parent()))
@@ -136,19 +135,18 @@ void MainWindow::insertRow()
     updateActions();
 
     for (int column = 0; column < model->columnCount(index.parent()); ++column) {
-        QModelIndex child = model->index(index.row()+1, column, index.parent());
-        model->setData(child, QVariant("[No data]"), Qt::EditRole);
+        const QModelIndex child = model->index(index.row() + 1, column, index.parent());
+        model->setData(child, QVariant(tr("[No data]")), Qt::EditRole);
     }
 }
 
 bool MainWindow::removeColumn()
 {
     QAbstractItemModel *model = view->model();
-    int column = view->selectionModel()->currentIndex().column();
+    const int column = view->selectionModel()->currentIndex().column();
 
     // Insert columns in each child of the parent item.
-    bool changed = model->removeColumn(column);
-
+    const bool changed = model->removeColumn(column);
     if (changed)
         updateActions();
 
@@ -157,7 +155,7 @@ bool MainWindow::removeColumn()
 
 void MainWindow::removeRow()
 {
-    QModelIndex index = view->selectionModel()->currentIndex();
+    const QModelIndex index = view->selectionModel()->currentIndex();
     QAbstractItemModel *model = view->model();
     if (model->removeRow(index.row(), index.parent()))
         updateActions();
@@ -165,19 +163,19 @@ void MainWindow::removeRow()
 
 void MainWindow::updateActions()
 {
-    bool hasSelection = !view->selectionModel()->selection().isEmpty();
+    const bool hasSelection = !view->selectionModel()->selection().isEmpty();
     removeRowAction->setEnabled(hasSelection);
     removeColumnAction->setEnabled(hasSelection);
 
-    bool hasCurrent = view->selectionModel()->currentIndex().isValid();
+    const bool hasCurrent = view->selectionModel()->currentIndex().isValid();
     insertRowAction->setEnabled(hasCurrent);
     insertColumnAction->setEnabled(hasCurrent);
 
     if (hasCurrent) {
         view->closePersistentEditor(view->selectionModel()->currentIndex());
 
-        int row = view->selectionModel()->currentIndex().row();
-        int column = view->selectionModel()->currentIndex().column();
+        const int row = view->selectionModel()->currentIndex().row();
+        const int column = view->selectionModel()->currentIndex().column();
         if (view->selectionModel()->currentIndex().parent().isValid())
             statusBar()->showMessage(tr("Position: (%1,%2)").arg(row).arg(column));
         else
diff --git a/examples/widgets/itemviews/editabletreemodel/mainwindow.h b/examples/widgets/itemviews/editabletreemodel/mainwindow.h
index dbc745e25d..314b0cb1fa 100644
--- a/examples/widgets/itemviews/editabletreemodel/mainwindow.h
+++ b/examples/widgets/itemviews/editabletreemodel/mainwindow.h
@@ -54,14 +54,13 @@
 #include "ui_mainwindow.h"
 
 #include <QMainWindow>
-#include <QModelIndex>
 
 class MainWindow : public QMainWindow, private Ui::MainWindow
 {
     Q_OBJECT
 
 public:
-    MainWindow(QWidget *parent = 0);
+    MainWindow(QWidget *parent = nullptr);
 
 public slots:
     void updateActions();
diff --git a/examples/widgets/itemviews/editabletreemodel/treeitem.cpp b/examples/widgets/itemviews/editabletreemodel/treeitem.cpp
index 8fbe86ad1e..027a5f8849 100644
--- a/examples/widgets/itemviews/editabletreemodel/treeitem.cpp
+++ b/examples/widgets/itemviews/editabletreemodel/treeitem.cpp
@@ -56,14 +56,11 @@
 
 #include "treeitem.h"
 
-#include <QStringList>
-
 //! [0]
 TreeItem::TreeItem(const QVector<QVariant> &data, TreeItem *parent)
-{
-    parentItem = parent;
-    itemData = data;
-}
+    : itemData(data),
+      parentItem(parent)
+{}
 //! [0]
 
 //! [1]
@@ -76,7 +73,9 @@ TreeItem::~TreeItem()
 //! [2]
 TreeItem *TreeItem::child(int number)
 {
-    return childItems.value(number);
+    if (number < 0 || number >= childItems.size())
+        return nullptr;
+    return childItems.at(number);
 }
 //! [2]
 
@@ -92,7 +91,6 @@ int TreeItem::childNumber() const
 {
     if (parentItem)
         return parentItem->childItems.indexOf(const_cast<TreeItem*>(this));
-
     return 0;
 }
 //! [4]
@@ -107,7 +105,9 @@ int TreeItem::columnCount() const
 //! [6]
 QVariant TreeItem::data(int column) const
 {
-    return itemData.value(column);
+    if (column < 0 || column >= itemData.size())
+        return QVariant();
+    return itemData.at(column);
 }
 //! [6]
 
@@ -136,7 +136,7 @@ bool TreeItem::insertColumns(int position, int columns)
     for (int column = 0; column < columns; ++column)
         itemData.insert(position, QVariant());
 
-    foreach (TreeItem *child, childItems)
+    for (TreeItem *child : qAsConst(childItems))
         child->insertColumns(position, columns);
 
     return true;
@@ -171,7 +171,7 @@ bool TreeItem::removeColumns(int position, int columns)
     for (int column = 0; column < columns; ++column)
         itemData.remove(position);
 
-    foreach (TreeItem *child, childItems)
+    for (TreeItem *child : qAsConst(childItems))
         child->removeColumns(position, columns);
 
     return true;
diff --git a/examples/widgets/itemviews/editabletreemodel/treeitem.h b/examples/widgets/itemviews/editabletreemodel/treeitem.h
index fd65f12268..867be5f380 100644
--- a/examples/widgets/itemviews/editabletreemodel/treeitem.h
+++ b/examples/widgets/itemviews/editabletreemodel/treeitem.h
@@ -51,7 +51,6 @@
 #ifndef TREEITEM_H
 #define TREEITEM_H
 
-#include <QList>
 #include <QVariant>
 #include <QVector>
 
@@ -59,7 +58,7 @@
 class TreeItem
 {
 public:
-    explicit TreeItem(const QVector<QVariant> &data, TreeItem *parent = 0);
+    explicit TreeItem(const QVector<QVariant> &data, TreeItem *parent = nullptr);
     ~TreeItem();
 
     TreeItem *child(int number);
@@ -75,7 +74,7 @@ public:
     bool setData(int column, const QVariant &value);
 
 private:
-    QList<TreeItem*> childItems;
+    QVector<TreeItem*> childItems;
     QVector<QVariant> itemData;
     TreeItem *parentItem;
 };
diff --git a/examples/widgets/itemviews/editabletreemodel/treemodel.cpp b/examples/widgets/itemviews/editabletreemodel/treemodel.cpp
index dbd53df1e6..836c2e8651 100644
--- a/examples/widgets/itemviews/editabletreemodel/treemodel.cpp
+++ b/examples/widgets/itemviews/editabletreemodel/treemodel.cpp
@@ -48,21 +48,21 @@
 **
 ****************************************************************************/
 
-#include <QtWidgets>
-
-#include "treeitem.h"
 #include "treemodel.h"
+#include "treeitem.h"
+
+#include <QtWidgets>
 
 //! [0]
 TreeModel::TreeModel(const QStringList &headers, const QString &data, QObject *parent)
     : QAbstractItemModel(parent)
 {
     QVector<QVariant> rootData;
-    foreach (QString header, headers)
+    for (const QString &header : headers)
         rootData << header;
 
     rootItem = new TreeItem(rootData);
-    setupModelData(data.split(QString("\n")), rootItem);
+    setupModelData(data.split('\n'), rootItem);
 }
 //! [0]
 
@@ -74,8 +74,9 @@ TreeModel::~TreeModel()
 //! [1]
 
 //! [2]
-int TreeModel::columnCount(const QModelIndex & /* parent */) const
+int TreeModel::columnCount(const QModelIndex &parent) const
 {
+    Q_UNUSED(parent);
     return rootItem->columnCount();
 }
 //! [2]
@@ -97,7 +98,7 @@ QVariant TreeModel::data(const QModelIndex &index, int role) const
 Qt::ItemFlags TreeModel::flags(const QModelIndex &index) const
 {
     if (!index.isValid())
-        return 0;
+        return Qt::NoItemFlags;
 
     return Qt::ItemIsEditable | QAbstractItemModel::flags(index);
 }
@@ -133,21 +134,20 @@ QModelIndex TreeModel::index(int row, int column, const QModelIndex &parent) con
 
 //! [6]
     TreeItem *parentItem = getItem(parent);
+    if (!parentItem)
+        return QModelIndex();
 
     TreeItem *childItem = parentItem->child(row);
     if (childItem)
         return createIndex(row, column, childItem);
-    else
-        return QModelIndex();
+    return QModelIndex();
 }
 //! [6]
 
 bool TreeModel::insertColumns(int position, int columns, const QModelIndex &parent)
 {
-    bool success;
-
     beginInsertColumns(parent, position, position + columns - 1);
-    success = rootItem->insertColumns(position, columns);
+    const bool success = rootItem->insertColumns(position, columns);
     endInsertColumns();
 
     return success;
@@ -156,10 +156,13 @@ bool TreeModel::insertColumns(int position, int columns, const QModelIndex &pare
 bool TreeModel::insertRows(int position, int rows, const QModelIndex &parent)
 {
     TreeItem *parentItem = getItem(parent);
-    bool success;
+    if (!parentItem)
+        return false;
 
     beginInsertRows(parent, position, position + rows - 1);
-    success = parentItem->insertChildren(position, rows, rootItem->columnCount());
+    const bool success = parentItem->insertChildren(position,
+                                                    rows,
+                                                    rootItem->columnCount());
     endInsertRows();
 
     return success;
@@ -172,9 +175,9 @@ QModelIndex TreeModel::parent(const QModelIndex &index) const
         return QModelIndex();
 
     TreeItem *childItem = getItem(index);
-    TreeItem *parentItem = childItem->parent();
+    TreeItem *parentItem = childItem ? childItem->parent() : nullptr;
 
-    if (parentItem == rootItem)
+    if (parentItem == rootItem || !parentItem)
         return QModelIndex();
 
     return createIndex(parentItem->childNumber(), 0, parentItem);
@@ -183,10 +186,8 @@ QModelIndex TreeModel::parent(const QModelIndex &index) const
 
 bool TreeModel::removeColumns(int position, int columns, const QModelIndex &parent)
 {
-    bool success;
-
     beginRemoveColumns(parent, position, position + columns - 1);
-    success = rootItem->removeColumns(position, columns);
+    const bool success = rootItem->removeColumns(position, columns);
     endRemoveColumns();
 
     if (rootItem->columnCount() == 0)
@@ -198,10 +199,11 @@ bool TreeModel::removeColumns(int position, int columns, const QModelIndex &pare
 bool TreeModel::removeRows(int position, int rows, const QModelIndex &parent)
 {
     TreeItem *parentItem = getItem(parent);
-    bool success = true;
+    if (!parentItem)
+        return false;
 
     beginRemoveRows(parent, position, position + rows - 1);
-    success = parentItem->removeChildren(position, rows);
+    const bool success = parentItem->removeChildren(position, rows);
     endRemoveRows();
 
     return success;
@@ -210,9 +212,9 @@ bool TreeModel::removeRows(int position, int rows, const QModelIndex &parent)
 //! [8]
 int TreeModel::rowCount(const QModelIndex &parent) const
 {
-    TreeItem *parentItem = getItem(parent);
+    const TreeItem *parentItem = getItem(parent);
 
-    return parentItem->childCount();
+    return parentItem ? parentItem->childCount() : 0;
 }
 //! [8]
 
@@ -225,7 +227,7 @@ bool TreeModel::setData(const QModelIndex &index, const QVariant &value, int rol
     bool result = item->setData(index.column(), value);
 
     if (result)
-        emit dataChanged(index, index);
+        emit dataChanged(index, index, {Qt::DisplayRole, Qt::EditRole});
 
     return result;
 }
@@ -236,7 +238,7 @@ bool TreeModel::setHeaderData(int section, Qt::Orientation orientation,
     if (role != Qt::EditRole || orientation != Qt::Horizontal)
         return false;
 
-    bool result = rootItem->setData(section, value);
+    const bool result = rootItem->setData(section, value);
 
     if (result)
         emit headerDataChanged(orientation, section, section);
@@ -246,8 +248,8 @@ bool TreeModel::setHeaderData(int section, Qt::Orientation orientation,
 
 void TreeModel::setupModelData(const QStringList &lines, TreeItem *parent)
 {
-    QList<TreeItem*> parents;
-    QList<int> indentations;
+    QVector<TreeItem*> parents;
+    QVector<int> indentations;
     parents << parent;
     indentations << 0;
 
@@ -261,14 +263,15 @@ void TreeModel::setupModelData(const QStringList &lines, TreeItem *parent)
             ++position;
         }
 
-        QString lineData = lines[number].mid(position).trimmed();
+        const QString lineData = lines[number].mid(position).trimmed();
 
         if (!lineData.isEmpty()) {
             // Read the column data from the rest of the line.
-            QStringList columnStrings = lineData.split("\t", QString::SkipEmptyParts);
+            const QStringList columnStrings = lineData.split('\t', QString::SkipEmptyParts);
             QVector<QVariant> columnData;
-            for (int column = 0; column < columnStrings.count(); ++column)
-                columnData << columnStrings[column];
+            columnData.reserve(columnStrings.size());
+            for (const QString &columnString : columnStrings)
+                columnData << columnString;
 
             if (position > indentations.last()) {
                 // The last child of the current parent is now the new parent
@@ -291,7 +294,6 @@ void TreeModel::setupModelData(const QStringList &lines, TreeItem *parent)
             for (int column = 0; column < columnData.size(); ++column)
                 parent->child(parent->childCount() - 1)->setData(column, columnData[column]);
         }
-
         ++number;
     }
 }
diff --git a/examples/widgets/itemviews/editabletreemodel/treemodel.h b/examples/widgets/itemviews/editabletreemodel/treemodel.h
index d76d138831..8419f9cb9d 100644
--- a/examples/widgets/itemviews/editabletreemodel/treemodel.h
+++ b/examples/widgets/itemviews/editabletreemodel/treemodel.h
@@ -64,7 +64,7 @@ class TreeModel : public QAbstractItemModel
 
 public:
     TreeModel(const QStringList &headers, const QString &data,
-              QObject *parent = 0);
+              QObject *parent = nullptr);
     ~TreeModel();
 //! [0] //! [1]
 
diff --git a/examples/widgets/itemviews/fetchmore/filelistmodel.cpp b/examples/widgets/itemviews/fetchmore/filelistmodel.cpp
index 086d45eca3..3ee80617c0 100644
--- a/examples/widgets/itemviews/fetchmore/filelistmodel.cpp
+++ b/examples/widgets/itemviews/fetchmore/filelistmodel.cpp
@@ -50,20 +50,18 @@
 
 #include "filelistmodel.h"
 
-#include <QApplication>
-#include <QBrush>
+#include <QGuiApplication>
 #include <QDir>
 #include <QPalette>
 
 FileListModel::FileListModel(QObject *parent)
-    : QAbstractListModel(parent)
-{
-}
+    : QAbstractListModel(parent), fileCount(0)
+{}
 
 //![4]
-int FileListModel::rowCount(const QModelIndex & /* parent */) const
+int FileListModel::rowCount(const QModelIndex &parent) const
 {
-    return fileCount;
+    return parent.isValid() ? 0 : fileCount;
 }
 
 QVariant FileListModel::data(const QModelIndex &index, int role) const
@@ -88,25 +86,26 @@ QVariant FileListModel::data(const QModelIndex &index, int role) const
 //![4]
 
 //![1]
-bool FileListModel::canFetchMore(const QModelIndex & /* index */) const
+bool FileListModel::canFetchMore(const QModelIndex &parent) const
 {
-    if (fileCount < fileList.size())
-        return true;
-    else
+    if (parent.isValid())
         return false;
+    return (fileCount < fileList.size());
 }
 //![1]
 
 //![2]
-void FileListModel::fetchMore(const QModelIndex & /* index */)
+void FileListModel::fetchMore(const QModelIndex &parent)
 {
+    if (parent.isValid())
+        return;
     int remainder = fileList.size() - fileCount;
     int itemsToFetch = qMin(100, remainder);
 
     if (itemsToFetch <= 0)
         return;
 
-    beginInsertRows(QModelIndex(), fileCount, fileCount+itemsToFetch-1);
+    beginInsertRows(QModelIndex(), fileCount, fileCount + itemsToFetch - 1);
 
     fileCount += itemsToFetch;
 
diff --git a/examples/widgets/itemviews/fetchmore/filelistmodel.h b/examples/widgets/itemviews/fetchmore/filelistmodel.h
index 9251eaf959..35cf6f7b46 100644
--- a/examples/widgets/itemviews/fetchmore/filelistmodel.h
+++ b/examples/widgets/itemviews/fetchmore/filelistmodel.h
@@ -52,7 +52,6 @@
 #define FILELISTMODEL_H
 
 #include <QAbstractListModel>
-#include <QList>
 #include <QStringList>
 
 //![0]
@@ -61,7 +60,7 @@ class FileListModel : public QAbstractListModel
     Q_OBJECT
 
 public:
-    FileListModel(QObject *parent = 0);
+    FileListModel(QObject *parent = nullptr);
 
     int rowCount(const QModelIndex &parent = QModelIndex()) const override;
     QVariant data(const QModelIndex &index, int role = Qt::DisplayRole) const override;
diff --git a/examples/widgets/itemviews/fetchmore/window.cpp b/examples/widgets/itemviews/fetchmore/window.cpp
index 886f76d6ab..d71ac7059d 100644
--- a/examples/widgets/itemviews/fetchmore/window.cpp
+++ b/examples/widgets/itemviews/fetchmore/window.cpp
@@ -48,8 +48,8 @@
 **
 ****************************************************************************/
 
-#include "filelistmodel.h"
 #include "window.h"
+#include "filelistmodel.h"
 
 #include <QtWidgets>
 
@@ -66,7 +66,7 @@ Window::Window(QWidget *parent)
     QListView *view = new QListView;
     view->setModel(model);
 
-    logViewer = new QTextBrowser;
+    logViewer = new QTextBrowser(this);
     logViewer->setSizePolicy(QSizePolicy(QSizePolicy::Preferred, QSizePolicy::Preferred));
 
     connect(lineEdit, &QLineEdit::textChanged,
diff --git a/examples/widgets/itemviews/fetchmore/window.h b/examples/widgets/itemviews/fetchmore/window.h
index f234683785..61bcb94bde 100644
--- a/examples/widgets/itemviews/fetchmore/window.h
+++ b/examples/widgets/itemviews/fetchmore/window.h
@@ -62,7 +62,7 @@ class Window : public QWidget
     Q_OBJECT
 
 public:
-    Window(QWidget *parent = 0);
+    Window(QWidget *parent = nullptr);
 
 public slots:
     void updateLog(int number);
diff --git a/examples/widgets/itemviews/interview/model.cpp b/examples/widgets/itemviews/interview/model.cpp
index a8f3a6f31e..feaf8bb98c 100644
--- a/examples/widgets/itemviews/interview/model.cpp
+++ b/examples/widgets/itemviews/interview/model.cpp
@@ -50,14 +50,13 @@
 
 #include "model.h"
 
-#include <QIcon>
 #include <QPixmap>
 
 Model::Model(int rows, int columns, QObject *parent)
     : QAbstractItemModel(parent),
       services(QPixmap(":/images/services.png")),
       rc(rows), cc(columns),
-      tree(new QVector<Node>(rows, Node(0)))
+      tree(new QVector<Node>(rows, Node()))
 {
 
 }
diff --git a/examples/widgets/itemviews/interview/model.h b/examples/widgets/itemviews/interview/model.h
index 969cf693b2..132f1d01aa 100644
--- a/examples/widgets/itemviews/interview/model.h
+++ b/examples/widgets/itemviews/interview/model.h
@@ -61,7 +61,7 @@ class Model : public QAbstractItemModel
     Q_OBJECT
 
 public:
-    Model(int rows, int columns, QObject *parent = 0);
+    Model(int rows, int columns, QObject *parent = nullptr);
     ~Model();
 
     QModelIndex index(int row, int column, const QModelIndex &parent) const override;
@@ -80,7 +80,7 @@ private:
 
     struct Node
     {
-        Node(Node *parent = 0) : parent(parent), children(0) {}
+        Node(Node *parent = nullptr) : parent(parent), children(nullptr) {}
         ~Node() { delete children; }
         Node *parent;
         QVector<Node> *children;
diff --git a/examples/widgets/itemviews/pixelator/mainwindow.cpp b/examples/widgets/itemviews/pixelator/mainwindow.cpp
index 63617f0169..f6b67e4dba 100644
--- a/examples/widgets/itemviews/pixelator/mainwindow.cpp
+++ b/examples/widgets/itemviews/pixelator/mainwindow.cpp
@@ -48,8 +48,8 @@
 **
 ****************************************************************************/
 
-#include "imagemodel.h"
 #include "mainwindow.h"
+#include "imagemodel.h"
 #include "pixeldelegate.h"
 
 #include <QtWidgets>
diff --git a/examples/widgets/itemviews/pixelator/pixeldelegate.cpp b/examples/widgets/itemviews/pixelator/pixeldelegate.cpp
index ecf44c1224..dc8736c836 100644
--- a/examples/widgets/itemviews/pixelator/pixeldelegate.cpp
+++ b/examples/widgets/itemviews/pixelator/pixeldelegate.cpp
@@ -54,10 +54,8 @@
 
 //! [0]
 PixelDelegate::PixelDelegate(QObject *parent)
-    : QAbstractItemDelegate(parent)
-{
-    pixelSize = 12;
-}
+    : QAbstractItemDelegate(parent), pixelSize(12)
+{}
 //! [0]
 
 //! [1]
@@ -70,11 +68,11 @@ void PixelDelegate::paint(QPainter *painter, const QStyleOptionViewItem &option,
 //! [1]
 
 //! [3]
-    int size = qMin(option.rect.width(), option.rect.height());
+    const int size = qMin(option.rect.width(), option.rect.height());
 //! [3] //! [4]
-    int brightness = index.model()->data(index, Qt::DisplayRole).toInt();
-    double radius = (size / 2.0) - (brightness / 255.0 * size / 2.0);
-    if (radius == 0.0)
+    const int brightness = index.model()->data(index, Qt::DisplayRole).toInt();
+    const double radius = (size / 2.0) - (brightness / 255.0 * size / 2.0);
+    if (qFuzzyIsNull(radius))
         return;
 //! [4]
 
diff --git a/examples/widgets/itemviews/pixelator/pixeldelegate.h b/examples/widgets/itemviews/pixelator/pixeldelegate.h
index d968d9e8d2..9f52221a28 100644
--- a/examples/widgets/itemviews/pixelator/pixeldelegate.h
+++ b/examples/widgets/itemviews/pixelator/pixeldelegate.h
@@ -61,7 +61,7 @@ class QObject;
 class QPainter;
 QT_END_NAMESPACE
 
-static const int ItemSize = 256;
+static constexpr int ItemSize = 256;
 
 //! [0]
 class PixelDelegate : public QAbstractItemDelegate
@@ -69,13 +69,13 @@ class PixelDelegate : public QAbstractItemDelegate
     Q_OBJECT
 
 public:
-    PixelDelegate(QObject *parent = 0);
+    PixelDelegate(QObject *parent = nullptr);
 
     void paint(QPainter *painter, const QStyleOptionViewItem &option,
                const QModelIndex &index) const override;
 
     QSize sizeHint(const QStyleOptionViewItem &option,
-                   const QModelIndex &index ) const override;
+                   const QModelIndex &index) const override;
 
 public slots:
     void setPixelSize(int size);
diff --git a/examples/widgets/itemviews/puzzle/piecesmodel.cpp b/examples/widgets/itemviews/puzzle/piecesmodel.cpp
index 28b46836f4..a9c53ed2cd 100644
--- a/examples/widgets/itemviews/puzzle/piecesmodel.cpp
+++ b/examples/widgets/itemviews/puzzle/piecesmodel.cpp
@@ -134,7 +134,7 @@ QMimeData *PiecesModel::mimeData(const QModelIndexList &indexes) const
 
     QDataStream stream(&encodedData, QIODevice::WriteOnly);
 
-    foreach (QModelIndex index, indexes) {
+    for (const QModelIndex &index : indexes) {
         if (index.isValid()) {
             QPixmap pixmap = qvariant_cast<QPixmap>(data(index, Qt::UserRole));
             QPoint location = data(index, Qt::UserRole+1).toPoint();
@@ -190,10 +190,7 @@ bool PiecesModel::dropMimeData(const QMimeData *data, Qt::DropAction action,
 
 int PiecesModel::rowCount(const QModelIndex &parent) const
 {
-    if (parent.isValid())
-        return 0;
-    else
-        return pixmaps.size();
+    return parent.isValid() ? 0 : pixmaps.size();
 }
 
 Qt::DropActions PiecesModel::supportedDropActions() const
@@ -201,7 +198,7 @@ Qt::DropActions PiecesModel::supportedDropActions() const
     return Qt::CopyAction | Qt::MoveAction;
 }
 
-void PiecesModel::addPieces(const QPixmap& pixmap)
+void PiecesModel::addPieces(const QPixmap &pixmap)
 {
     if (!pixmaps.isEmpty()) {
         beginRemoveRows(QModelIndex(), 0, pixmaps.size() - 1);
diff --git a/examples/widgets/itemviews/puzzle/piecesmodel.h b/examples/widgets/itemviews/puzzle/piecesmodel.h
index bd979f4c7e..2a96603707 100644
--- a/examples/widgets/itemviews/puzzle/piecesmodel.h
+++ b/examples/widgets/itemviews/puzzle/piecesmodel.h
@@ -52,10 +52,10 @@
 #define PIECESLIST_H
 
 #include <QAbstractListModel>
-#include <QList>
 #include <QPixmap>
 #include <QPoint>
 #include <QStringList>
+#include <QVector>
 
 QT_BEGIN_NAMESPACE
 class QMimeData;
@@ -66,7 +66,7 @@ class PiecesModel : public QAbstractListModel
     Q_OBJECT
 
 public:
-    explicit PiecesModel(int pieceSize, QObject *parent = 0);
+    explicit PiecesModel(int pieceSize, QObject *parent = nullptr);
 
     QVariant data(const QModelIndex &index, int role = Qt::DisplayRole) const override;
     Qt::ItemFlags flags(const QModelIndex &index) const override;
@@ -80,11 +80,11 @@ public:
     Qt::DropActions supportedDropActions() const override;
 
     void addPiece(const QPixmap &pixmap, const QPoint &location);
-    void addPieces(const QPixmap& pixmap);
+    void addPieces(const QPixmap &pixmap);
 
 private:
-    QList<QPoint> locations;
-    QList<QPixmap> pixmaps;
+    QVector<QPoint> locations;
+    QVector<QPixmap> pixmaps;
 
     int m_PieceSize;
 };
diff --git a/examples/widgets/itemviews/puzzle/puzzlewidget.cpp b/examples/widgets/itemviews/puzzle/puzzlewidget.cpp
index 06968da80f..974a972306 100644
--- a/examples/widgets/itemviews/puzzle/puzzlewidget.cpp
+++ b/examples/widgets/itemviews/puzzle/puzzlewidget.cpp
@@ -169,7 +169,7 @@ void PuzzleWidget::mousePressEvent(QMouseEvent *event)
     drag->setHotSpot(event->pos() - square.topLeft());
     drag->setPixmap(piece.pixmap);
 
-    if (drag->start(Qt::MoveAction) == Qt::IgnoreAction) {
+    if (drag->exec(Qt::MoveAction) == Qt::IgnoreAction) {
         pieces.insert(found, piece);
         update(targetSquare(event->pos()));
 
diff --git a/examples/widgets/itemviews/simpledommodel/domitem.cpp b/examples/widgets/itemviews/simpledommodel/domitem.cpp
index c8b35b2e0a..a2dc9530f0 100644
--- a/examples/widgets/itemviews/simpledommodel/domitem.cpp
+++ b/examples/widgets/itemviews/simpledommodel/domitem.cpp
@@ -53,23 +53,20 @@
 #include <QtXml>
 
 //! [0]
-DomItem::DomItem(QDomNode &node, int row, DomItem *parent)
-{
-    domNode = node;
+DomItem::DomItem(const QDomNode &node, int row, DomItem *parent)
+    : domNode(node),
 //! [0]
-    // Record the item's location within its parent.
+      // Record the item's location within its parent.
 //! [1]
-    rowNumber = row;
-    parentItem = parent;
-}
+      parentItem(parent),
+      rowNumber(row)
+{}
 //! [1]
 
 //! [2]
 DomItem::~DomItem()
 {
-    QHash<int,DomItem*>::iterator it;
-    for (it = childItems.begin(); it != childItems.end(); ++it)
-        delete it.value();
+    qDeleteAll(childItems);
 }
 //! [2]
 
@@ -90,21 +87,22 @@ DomItem *DomItem::parent()
 //! [5]
 DomItem *DomItem::child(int i)
 {
-    if (childItems.contains(i))
-        return childItems[i];
+    DomItem *childItem = childItems.value(i);
+    if (childItem)
+        return childItem;
 
+    // if child does not yet exist, create it
     if (i >= 0 && i < domNode.childNodes().count()) {
         QDomNode childNode = domNode.childNodes().item(i);
-        DomItem *childItem = new DomItem(childNode, i, this);
+        childItem = new DomItem(childNode, i, this);
         childItems[i] = childItem;
-        return childItem;
     }
-    return 0;
+    return childItem;
 }
 //! [5]
 
 //! [6]
-int DomItem::row()
+int DomItem::row() const
 {
     return rowNumber;
 }
diff --git a/examples/widgets/itemviews/simpledommodel/domitem.h b/examples/widgets/itemviews/simpledommodel/domitem.h
index b5db16009c..4a74db5139 100644
--- a/examples/widgets/itemviews/simpledommodel/domitem.h
+++ b/examples/widgets/itemviews/simpledommodel/domitem.h
@@ -58,16 +58,16 @@
 class DomItem
 {
 public:
-    DomItem(QDomNode &node, int row, DomItem *parent = 0);
+    DomItem(const QDomNode &node, int row, DomItem *parent = nullptr);
     ~DomItem();
     DomItem *child(int i);
     DomItem *parent();
     QDomNode node() const;
-    int row();
+    int row() const;
 
 private:
     QDomNode domNode;
-    QHash<int,DomItem*> childItems;
+    QHash<int, DomItem *> childItems;
     DomItem *parentItem;
     int rowNumber;
 };
diff --git a/examples/widgets/itemviews/simpledommodel/dommodel.cpp b/examples/widgets/itemviews/simpledommodel/dommodel.cpp
index f9ba0b5801..8e15252ebb 100644
--- a/examples/widgets/itemviews/simpledommodel/dommodel.cpp
+++ b/examples/widgets/itemviews/simpledommodel/dommodel.cpp
@@ -48,16 +48,17 @@
 **
 ****************************************************************************/
 
-#include "domitem.h"
 #include "dommodel.h"
+#include "domitem.h"
 
 #include <QtXml>
 
 //! [0]
-DomModel::DomModel(QDomDocument document, QObject *parent)
-    : QAbstractItemModel(parent), domDocument(document)
+DomModel::DomModel(const QDomDocument &document, QObject *parent)
+    : QAbstractItemModel(parent),
+      domDocument(document),
+      rootItem(new DomItem(domDocument, 0))
 {
-    rootItem = new DomItem(domDocument, 0);
 }
 //! [0]
 
@@ -69,8 +70,9 @@ DomModel::~DomModel()
 //! [1]
 
 //! [2]
-int DomModel::columnCount(const QModelIndex &/*parent*/) const
+int DomModel::columnCount(const QModelIndex &parent) const
 {
+    Q_UNUSED(parent);
     return 3;
 }
 //! [2]
@@ -84,28 +86,31 @@ QVariant DomModel::data(const QModelIndex &index, int role) const
     if (role != Qt::DisplayRole)
         return QVariant();
 
-    DomItem *item = static_cast<DomItem*>(index.internalPointer());
+    const DomItem *item = static_cast<DomItem*>(index.internalPointer());
 
-    QDomNode node = item->node();
+    const QDomNode node = item->node();
 //! [3] //! [4]
-    QStringList attributes;
-    QDomNamedNodeMap attributeMap = node.attributes();
 
     switch (index.column()) {
         case 0:
             return node.nodeName();
         case 1:
+        {
+            const QDomNamedNodeMap attributeMap = node.attributes();
+            QStringList attributes;
             for (int i = 0; i < attributeMap.count(); ++i) {
                 QDomNode attribute = attributeMap.item(i);
                 attributes << attribute.nodeName() + "=\""
-                              +attribute.nodeValue() + '"';
+                              + attribute.nodeValue() + '"';
             }
             return attributes.join(' ');
+        }
         case 2:
-            return node.nodeValue().split("\n").join(' ');
+            return node.nodeValue().split('\n').join(' ');
         default:
-            return QVariant();
+            break;
     }
+    return QVariant();
 }
 //! [4]
 
@@ -113,7 +118,7 @@ QVariant DomModel::data(const QModelIndex &index, int role) const
 Qt::ItemFlags DomModel::flags(const QModelIndex &index) const
 {
     if (!index.isValid())
-        return 0;
+        return Qt::NoItemFlags;
 
     return QAbstractItemModel::flags(index);
 }
@@ -132,17 +137,15 @@ QVariant DomModel::headerData(int section, Qt::Orientation orientation,
             case 2:
                 return tr("Value");
             default:
-                return QVariant();
+                break;
         }
     }
-
     return QVariant();
 }
 //! [6]
 
 //! [7]
-QModelIndex DomModel::index(int row, int column, const QModelIndex &parent)
-            const
+QModelIndex DomModel::index(int row, int column, const QModelIndex &parent) const
 {
     if (!hasIndex(row, column, parent))
         return QModelIndex();
@@ -159,8 +162,7 @@ QModelIndex DomModel::index(int row, int column, const QModelIndex &parent)
     DomItem *childItem = parentItem->child(row);
     if (childItem)
         return createIndex(row, column, childItem);
-    else
-        return QModelIndex();
+    return QModelIndex();
 }
 //! [8]
 
diff --git a/examples/widgets/itemviews/simpledommodel/dommodel.h b/examples/widgets/itemviews/simpledommodel/dommodel.h
index 411f58295c..a91bb33cf9 100644
--- a/examples/widgets/itemviews/simpledommodel/dommodel.h
+++ b/examples/widgets/itemviews/simpledommodel/dommodel.h
@@ -63,7 +63,7 @@ class DomModel : public QAbstractItemModel
     Q_OBJECT
 
 public:
-    explicit DomModel(QDomDocument document, QObject *parent = 0);
+    explicit DomModel(const QDomDocument &document, QObject *parent = nullptr);
     ~DomModel();
 
     QVariant data(const QModelIndex &index, int role) const override;
diff --git a/examples/widgets/itemviews/simpledommodel/mainwindow.cpp b/examples/widgets/itemviews/simpledommodel/mainwindow.cpp
index 7d43d0fc02..86543b07a6 100644
--- a/examples/widgets/itemviews/simpledommodel/mainwindow.cpp
+++ b/examples/widgets/itemviews/simpledommodel/mainwindow.cpp
@@ -48,22 +48,23 @@
 **
 ****************************************************************************/
 
-#include "dommodel.h"
 #include "mainwindow.h"
+#include "dommodel.h"
 
 #include <QDomDocument>
 #include <QTreeView>
 #include <QMenuBar>
 #include <QFileDialog>
 
-MainWindow::MainWindow() : QMainWindow(), model(0)
+MainWindow::MainWindow(QWidget *parent)
+    : QMainWindow(parent),
+      model(new DomModel(QDomDocument(), this)),
+      view(new QTreeView(this))
 {
     fileMenu = menuBar()->addMenu(tr("&File"));
     fileMenu->addAction(tr("&Open..."), this, &MainWindow::openFile, QKeySequence::Open);
     fileMenu->addAction(tr("E&xit"), this, &QWidget::close, QKeySequence::Quit);
 
-    model = new DomModel(QDomDocument(), this);
-    view = new QTreeView(this);
     view->setModel(model);
 
     setCentralWidget(view);
diff --git a/examples/widgets/itemviews/simpledommodel/mainwindow.h b/examples/widgets/itemviews/simpledommodel/mainwindow.h
index 938a1c54c1..b3f8d77f35 100644
--- a/examples/widgets/itemviews/simpledommodel/mainwindow.h
+++ b/examples/widgets/itemviews/simpledommodel/mainwindow.h
@@ -65,7 +65,7 @@ class MainWindow : public QMainWindow
     Q_OBJECT
 
 public:
-    MainWindow();
+    MainWindow(QWidget *parent = nullptr);
 
 public slots:
     void openFile();
diff --git a/examples/widgets/itemviews/simpletreemodel/treeitem.cpp b/examples/widgets/itemviews/simpletreemodel/treeitem.cpp
index e11639ff67..41fe24e737 100644
--- a/examples/widgets/itemviews/simpletreemodel/treeitem.cpp
+++ b/examples/widgets/itemviews/simpletreemodel/treeitem.cpp
@@ -54,16 +54,12 @@
     A container for items of data supplied by the simple tree model.
 */
 
-#include <QStringList>
-
 #include "treeitem.h"
 
 //! [0]
-TreeItem::TreeItem(const QList<QVariant> &data, TreeItem *parent)
-{
-    m_parentItem = parent;
-    m_itemData = data;
-}
+TreeItem::TreeItem(const QVector<QVariant> &data, TreeItem *parent)
+    : m_itemData(data), m_parentItem(parent)
+{}
 //! [0]
 
 //! [1]
@@ -83,7 +79,9 @@ void TreeItem::appendChild(TreeItem *item)
 //! [3]
 TreeItem *TreeItem::child(int row)
 {
-    return m_childItems.value(row);
+    if (row < 0 || row >= m_childItems.size())
+        return nullptr;
+    return m_childItems.at(row);
 }
 //! [3]
 
@@ -104,7 +102,9 @@ int TreeItem::columnCount() const
 //! [6]
 QVariant TreeItem::data(int column) const
 {
-    return m_itemData.value(column);
+    if (column < 0 || column >= m_itemData.size())
+        return QVariant();
+    return m_itemData.at(column);
 }
 //! [6]
 
diff --git a/examples/widgets/itemviews/simpletreemodel/treeitem.h b/examples/widgets/itemviews/simpletreemodel/treeitem.h
index 8d0bb49627..390433597d 100644
--- a/examples/widgets/itemviews/simpletreemodel/treeitem.h
+++ b/examples/widgets/itemviews/simpletreemodel/treeitem.h
@@ -51,14 +51,14 @@
 #ifndef TREEITEM_H
 #define TREEITEM_H
 
-#include <QList>
 #include <QVariant>
+#include <QVector>
 
 //! [0]
 class TreeItem
 {
 public:
-    explicit TreeItem(const QList<QVariant> &data, TreeItem *parentItem = 0);
+    explicit TreeItem(const QVector<QVariant> &data, TreeItem *parentItem = nullptr);
     ~TreeItem();
 
     void appendChild(TreeItem *child);
@@ -71,8 +71,8 @@ public:
     TreeItem *parentItem();
 
 private:
-    QList<TreeItem*> m_childItems;
-    QList<QVariant> m_itemData;
+    QVector<TreeItem*> m_childItems;
+    QVector<QVariant> m_itemData;
     TreeItem *m_parentItem;
 };
 //! [0]
diff --git a/examples/widgets/itemviews/simpletreemodel/treemodel.cpp b/examples/widgets/itemviews/simpletreemodel/treemodel.cpp
index 1de970d398..cfa65846ed 100644
--- a/examples/widgets/itemviews/simpletreemodel/treemodel.cpp
+++ b/examples/widgets/itemviews/simpletreemodel/treemodel.cpp
@@ -55,8 +55,8 @@
     models.
 */
 
-#include "treeitem.h"
 #include "treemodel.h"
+#include "treeitem.h"
 
 #include <QStringList>
 
@@ -64,10 +64,8 @@
 TreeModel::TreeModel(const QString &data, QObject *parent)
     : QAbstractItemModel(parent)
 {
-    QList<QVariant> rootData;
-    rootData << "Title" << "Summary";
-    rootItem = new TreeItem(rootData);
-    setupModelData(data.split(QString("\n")), rootItem);
+    rootItem = new TreeItem({tr("Title"), tr("Summary")});
+    setupModelData(data.split('\n'), rootItem);
 }
 //! [0]
 
@@ -83,8 +81,7 @@ int TreeModel::columnCount(const QModelIndex &parent) const
 {
     if (parent.isValid())
         return static_cast<TreeItem*>(parent.internalPointer())->columnCount();
-    else
-        return rootItem->columnCount();
+    return rootItem->columnCount();
 }
 //! [2]
 
@@ -107,7 +104,7 @@ QVariant TreeModel::data(const QModelIndex &index, int role) const
 Qt::ItemFlags TreeModel::flags(const QModelIndex &index) const
 {
     if (!index.isValid())
-        return 0;
+        return Qt::NoItemFlags;
 
     return QAbstractItemModel::flags(index);
 }
@@ -125,8 +122,7 @@ QVariant TreeModel::headerData(int section, Qt::Orientation orientation,
 //! [5]
 
 //! [6]
-QModelIndex TreeModel::index(int row, int column, const QModelIndex &parent)
-            const
+QModelIndex TreeModel::index(int row, int column, const QModelIndex &parent) const
 {
     if (!hasIndex(row, column, parent))
         return QModelIndex();
@@ -141,8 +137,7 @@ QModelIndex TreeModel::index(int row, int column, const QModelIndex &parent)
     TreeItem *childItem = parentItem->child(row);
     if (childItem)
         return createIndex(row, column, childItem);
-    else
-        return QModelIndex();
+    return QModelIndex();
 }
 //! [6]
 
@@ -180,8 +175,8 @@ int TreeModel::rowCount(const QModelIndex &parent) const
 
 void TreeModel::setupModelData(const QStringList &lines, TreeItem *parent)
 {
-    QList<TreeItem*> parents;
-    QList<int> indentations;
+    QVector<TreeItem*> parents;
+    QVector<int> indentations;
     parents << parent;
     indentations << 0;
 
@@ -195,14 +190,15 @@ void TreeModel::setupModelData(const QStringList &lines, TreeItem *parent)
             position++;
         }
 
-        QString lineData = lines[number].mid(position).trimmed();
+        const QString lineData = lines[number].mid(position).trimmed();
 
         if (!lineData.isEmpty()) {
             // Read the column data from the rest of the line.
-            QStringList columnStrings = lineData.split("\t", QString::SkipEmptyParts);
-            QList<QVariant> columnData;
-            for (int column = 0; column < columnStrings.count(); ++column)
-                columnData << columnStrings[column];
+            const QStringList columnStrings = lineData.split('\t', QString::SkipEmptyParts);
+            QVector<QVariant> columnData;
+            columnData.reserve(columnStrings.count());
+            for (const QString &columnString : columnStrings)
+                columnData << columnString;
 
             if (position > indentations.last()) {
                 // The last child of the current parent is now the new parent
@@ -222,7 +218,6 @@ void TreeModel::setupModelData(const QStringList &lines, TreeItem *parent)
             // Append a new item to the current parent's list of children.
             parents.last()->appendChild(new TreeItem(columnData, parents.last()));
         }
-
         ++number;
     }
 }
diff --git a/examples/widgets/itemviews/simpletreemodel/treemodel.h b/examples/widgets/itemviews/simpletreemodel/treemodel.h
index 800728fb82..76fd03f112 100644
--- a/examples/widgets/itemviews/simpletreemodel/treemodel.h
+++ b/examples/widgets/itemviews/simpletreemodel/treemodel.h
@@ -63,7 +63,7 @@ class TreeModel : public QAbstractItemModel
     Q_OBJECT
 
 public:
-    explicit TreeModel(const QString &data, QObject *parent = 0);
+    explicit TreeModel(const QString &data, QObject *parent = nullptr);
     ~TreeModel();
 
     QVariant data(const QModelIndex &index, int role) const override;
diff --git a/examples/widgets/itemviews/simplewidgetmapper/window.h b/examples/widgets/itemviews/simplewidgetmapper/window.h
index baa087f8ae..d04b528e16 100644
--- a/examples/widgets/itemviews/simplewidgetmapper/window.h
+++ b/examples/widgets/itemviews/simplewidgetmapper/window.h
@@ -69,7 +69,7 @@ class Window : public QWidget
     Q_OBJECT
 
 public:
-    Window(QWidget *parent = 0);
+    Window(QWidget *parent = nullptr);
 
 private slots:
     void updateButtons(int row);
diff --git a/examples/widgets/itemviews/spinboxdelegate/delegate.cpp b/examples/widgets/itemviews/spinboxdelegate/delegate.cpp
index e7e03688c3..f0fe524a60 100644
--- a/examples/widgets/itemviews/spinboxdelegate/delegate.cpp
+++ b/examples/widgets/itemviews/spinboxdelegate/delegate.cpp
@@ -68,8 +68,8 @@ SpinBoxDelegate::SpinBoxDelegate(QObject *parent)
 
 //! [1]
 QWidget *SpinBoxDelegate::createEditor(QWidget *parent,
-    const QStyleOptionViewItem &/* option */,
-    const QModelIndex &/* index */) const
+                                       const QStyleOptionViewItem &/* option */,
+                                       const QModelIndex &/* index */) const
 {
     QSpinBox *editor = new QSpinBox(parent);
     editor->setFrame(false);
@@ -105,7 +105,8 @@ void SpinBoxDelegate::setModelData(QWidget *editor, QAbstractItemModel *model,
 
 //! [4]
 void SpinBoxDelegate::updateEditorGeometry(QWidget *editor,
-    const QStyleOptionViewItem &option, const QModelIndex &/* index */) const
+                                           const QStyleOptionViewItem &option,
+                                           const QModelIndex &/* index */) const
 {
     editor->setGeometry(option.rect);
 }
diff --git a/examples/widgets/itemviews/spinboxdelegate/delegate.h b/examples/widgets/itemviews/spinboxdelegate/delegate.h
index 47ef1555f7..5dbdda9cd0 100644
--- a/examples/widgets/itemviews/spinboxdelegate/delegate.h
+++ b/examples/widgets/itemviews/spinboxdelegate/delegate.h
@@ -59,7 +59,7 @@ class SpinBoxDelegate : public QStyledItemDelegate
     Q_OBJECT
 
 public:
-    SpinBoxDelegate(QObject *parent = 0);
+    SpinBoxDelegate(QObject *parent = nullptr);
 
     QWidget *createEditor(QWidget *parent, const QStyleOptionViewItem &option,
                           const QModelIndex &index) const override;
@@ -68,8 +68,8 @@ public:
     void setModelData(QWidget *editor, QAbstractItemModel *model,
                       const QModelIndex &index) const override;
 
-    void updateEditorGeometry(QWidget *editor,
-        const QStyleOptionViewItem &option, const QModelIndex &index) const override;
+    void updateEditorGeometry(QWidget *editor, const QStyleOptionViewItem &option,
+                              const QModelIndex &index) const override;
 };
 //! [0]
 
diff --git a/examples/widgets/itemviews/spreadsheet/main.cpp b/examples/widgets/itemviews/spreadsheet/main.cpp
index 769edbdf03..548dc8d604 100644
--- a/examples/widgets/itemviews/spreadsheet/main.cpp
+++ b/examples/widgets/itemviews/spreadsheet/main.cpp
@@ -53,7 +53,8 @@
 #include <QApplication>
 #include <QLayout>
 
-int main(int argc, char** argv) {
+int main(int argc, char **argv)
+{
     Q_INIT_RESOURCE(spreadsheet);
     QApplication app(argc, argv);
     SpreadSheet sheet(10, 6);
diff --git a/examples/widgets/itemviews/spreadsheet/printview.cpp b/examples/widgets/itemviews/spreadsheet/printview.cpp
index 31424e9070..7db1a6bad9 100644
--- a/examples/widgets/itemviews/spreadsheet/printview.cpp
+++ b/examples/widgets/itemviews/spreadsheet/printview.cpp
@@ -48,12 +48,11 @@
 **
 ****************************************************************************/
 
+#include "printview.h"
+
 #ifndef QT_NO_PRINTER
 #include <QPrinter>
 #endif
-#include <QStyleOptionViewItem>
-
-#include "printview.h"
 
 PrintView::PrintView()
 {
diff --git a/examples/widgets/itemviews/spreadsheet/spreadsheet.cpp b/examples/widgets/itemviews/spreadsheet/spreadsheet.cpp
index 621f655b02..fc7fbb872c 100644
--- a/examples/widgets/itemviews/spreadsheet/spreadsheet.cpp
+++ b/examples/widgets/itemviews/spreadsheet/spreadsheet.cpp
@@ -48,36 +48,30 @@
 **
 ****************************************************************************/
 
-#include <QtWidgets>
-#if defined(QT_PRINTSUPPORT_LIB)
-#include <QtPrintSupport/qtprintsupportglobal.h>
-#if QT_CONFIG(printdialog)
-#include <QPrinter>
-#include <QPrintDialog>
-#endif
-#if QT_CONFIG(printpreviewdialog)
-#include <QPrintPreviewDialog>
-#endif
-#endif
-
 #include "spreadsheet.h"
 #include "spreadsheetdelegate.h"
 #include "spreadsheetitem.h"
 #include "printview.h"
 
+#include <QtWidgets>
+#if defined(QT_PRINTSUPPORT_LIB)
+#include <QtPrintSupport>
+#endif
+
 SpreadSheet::SpreadSheet(int rows, int cols, QWidget *parent)
-        : QMainWindow(parent)
+    : QMainWindow(parent),
+      toolBar(new QToolBar(this)),
+      cellLabel(new QLabel(toolBar)),
+      table(new QTableWidget(rows, cols, this)),
+      formulaInput(new QLineEdit(this))
 {
-    addToolBar(toolBar = new QToolBar());
-    formulaInput = new QLineEdit();
+    addToolBar(toolBar);
 
-    cellLabel = new QLabel(toolBar);
     cellLabel->setMinimumSize(80, 0);
 
     toolBar->addWidget(cellLabel);
     toolBar->addWidget(formulaInput);
 
-    table = new QTableWidget(rows, cols, this);
     table->setSizeAdjustPolicy(QTableWidget::AdjustToContents);
     for (int c = 0; c < cols; ++c) {
         QString character(QChar('A' + c));
@@ -88,7 +82,7 @@ SpreadSheet::SpreadSheet(int rows, int cols, QWidget *parent)
     table->setItemDelegate(new SpreadSheetDelegate());
 
     createActions();
-    updateColor(0);
+    updateColor(nullptr);
     setupMenuBar();
     setupContents();
     setupContextMenu();
@@ -103,7 +97,8 @@ SpreadSheet::SpreadSheet(int rows, int cols, QWidget *parent)
             this, &SpreadSheet::updateLineEdit);
     connect(table, &QTableWidget::itemChanged,
             this, &SpreadSheet::updateStatus);
-    connect(formulaInput, &QLineEdit::returnPressed, this, &SpreadSheet::returnPressed);
+    connect(formulaInput, &QLineEdit::returnPressed,
+            this, &SpreadSheet::returnPressed);
     connect(table, &QTableWidget::itemChanged,
             this, &SpreadSheet::updateLineEdit);
 
@@ -193,19 +188,19 @@ void SpreadSheet::updateColor(QTableWidgetItem *item)
     QPixmap pix(16, 16);
     QColor col;
     if (item)
-        col = item->backgroundColor();
+        col = item->background().color();
     if (!col.isValid())
         col = palette().base().color();
 
     QPainter pt(&pix);
     pt.fillRect(0, 0, 16, 16, col);
 
-    QColor lighter = col.light();
+    QColor lighter = col.lighter();
     pt.setPen(lighter);
     QPoint lightFrame[] = { QPoint(0, 15), QPoint(0, 0), QPoint(15, 0) };
     pt.drawPolyline(lightFrame, 3);
 
-    pt.setPen(col.dark());
+    pt.setPen(col.darker());
     QPoint darkFrame[] = { QPoint(1, 15), QPoint(15, 15), QPoint(15, 1) };
     pt.drawPolyline(darkFrame, 3);
 
@@ -240,18 +235,18 @@ void SpreadSheet::returnPressed()
 void SpreadSheet::selectColor()
 {
     QTableWidgetItem *item = table->currentItem();
-    QColor col = item ? item->backgroundColor() : table->palette().base().color();
+    QColor col = item ? item->background().color() : table->palette().base().color();
     col = QColorDialog::getColor(col, this);
     if (!col.isValid())
         return;
 
-    QList<QTableWidgetItem*> selected = table->selectedItems();
-    if (selected.count() == 0)
+    const QList<QTableWidgetItem *> selected = table->selectedItems();
+    if (selected.isEmpty())
         return;
 
-    foreach (QTableWidgetItem *i, selected) {
+    for (QTableWidgetItem *i : selected) {
         if (i)
-            i->setBackgroundColor(col);
+            i->setBackground(col);
     }
 
     updateColor(table->currentItem());
@@ -259,8 +254,8 @@ void SpreadSheet::selectColor()
 
 void SpreadSheet::selectFont()
 {
-    QList<QTableWidgetItem*> selected = table->selectedItems();
-    if (selected.count() == 0)
+    const QList<QTableWidgetItem *> selected = table->selectedItems();
+    if (selected.isEmpty())
         return;
 
     bool ok = false;
@@ -268,7 +263,7 @@ void SpreadSheet::selectFont()
 
     if (!ok)
         return;
-    foreach (QTableWidgetItem *i, selected) {
+    for (QTableWidgetItem *i : selected) {
         if (i)
             i->setFont(fnt);
     }
@@ -397,7 +392,7 @@ void SpreadSheet::actionSum()
     int col_last = 0;
     int col_cur = 0;
 
-    QList<QTableWidgetItem*> selected = table->selectedItems();
+    const QList<QTableWidgetItem *> selected = table->selectedItems();
 
     if (!selected.isEmpty()) {
         QTableWidgetItem *first = selected.first();
@@ -408,7 +403,7 @@ void SpreadSheet::actionSum()
         col_last = table->column(last);
     }
 
-    QTableWidgetItem *current = table->currentItem();
+    const QTableWidgetItem *current = table->currentItem();
 
     if (current) {
         row_cur = table->row(current);
@@ -435,7 +430,7 @@ void SpreadSheet::actionMath_helper(const QString &title, const QString &op)
     QString cell2 = "C2";
     QString out = "C3";
 
-    QTableWidgetItem *current = table->currentItem();
+    const QTableWidgetItem *current = table->currentItem();
     if (current)
         out = encode_pos(table->currentRow(), table->currentColumn());
 
@@ -468,8 +463,9 @@ void SpreadSheet::actionDivide()
 
 void SpreadSheet::clear()
 {
-    foreach (QTableWidgetItem *i, table->selectedItems())
-        i->setText("");
+    const QList<QTableWidgetItem *> selectedItems = table->selectedItems();
+    for (QTableWidgetItem *i : selectedItems)
+        i->setText(QString());
 }
 
 void SpreadSheet::setupContextMenu()
@@ -489,13 +485,13 @@ void SpreadSheet::setupContextMenu()
 
 void SpreadSheet::setupContents()
 {
-    QColor titleBackground(Qt::lightGray);
+    QBrush titleBackground(Qt::lightGray);
     QFont titleFont = table->font();
     titleFont.setBold(true);
 
     // column 0
     table->setItem(0, 0, new SpreadSheetItem("Item"));
-    table->item(0, 0)->setBackgroundColor(titleBackground);
+    table->item(0, 0)->setBackground(titleBackground);
     table->item(0, 0)->setToolTip("This column shows the purchased item/service");
     table->item(0, 0)->setFont(titleFont);
 
@@ -510,11 +506,11 @@ void SpreadSheet::setupContents()
     table->setItem(9, 0, new SpreadSheetItem("Total:"));
 
     table->item(9, 0)->setFont(titleFont);
-    table->item(9, 0)->setBackgroundColor(Qt::lightGray);
+    table->item(9, 0)->setBackground(titleBackground);
 
     // column 1
     table->setItem(0, 1, new SpreadSheetItem("Date"));
-    table->item(0, 1)->setBackgroundColor(titleBackground);
+    table->item(0, 1)->setBackground(titleBackground);
     table->item(0, 1)->setToolTip("This column shows the purchase date, double click to change");
     table->item(0, 1)->setFont(titleFont);
 
@@ -528,11 +524,11 @@ void SpreadSheet::setupContents()
     table->setItem(8, 1, new SpreadSheetItem("18/6/2006"));
 
     table->setItem(9, 1, new SpreadSheetItem());
-    table->item(9, 1)->setBackgroundColor(Qt::lightGray);
+    table->item(9, 1)->setBackground(titleBackground);
 
     // column 2
     table->setItem(0, 2, new SpreadSheetItem("Price"));
-    table->item(0, 2)->setBackgroundColor(titleBackground);
+    table->item(0, 2)->setBackground(titleBackground);
     table->item(0, 2)->setToolTip("This column shows the price of the purchase");
     table->item(0, 2)->setFont(titleFont);
 
@@ -546,11 +542,11 @@ void SpreadSheet::setupContents()
     table->setItem(8, 2, new SpreadSheetItem("1240"));
 
     table->setItem(9, 2, new SpreadSheetItem());
-    table->item(9, 2)->setBackgroundColor(Qt::lightGray);
+    table->item(9, 2)->setBackground(Qt::lightGray);
 
     // column 3
     table->setItem(0, 3, new SpreadSheetItem("Currency"));
-    table->item(0, 3)->setBackgroundColor(titleBackground);
+    table->item(0, 3)->setBackground(titleBackground);
     table->item(0, 3)->setToolTip("This column shows the currency");
     table->item(0, 3)->setFont(titleFont);
 
@@ -564,11 +560,11 @@ void SpreadSheet::setupContents()
     table->setItem(8, 3, new SpreadSheetItem("USD"));
 
     table->setItem(9, 3, new SpreadSheetItem());
-    table->item(9,3)->setBackgroundColor(Qt::lightGray);
+    table->item(9, 3)->setBackground(Qt::lightGray);
 
     // column 4
     table->setItem(0, 4, new SpreadSheetItem("Ex. Rate"));
-    table->item(0, 4)->setBackgroundColor(titleBackground);
+    table->item(0, 4)->setBackground(titleBackground);
     table->item(0, 4)->setToolTip("This column shows the exchange rate to NOK");
     table->item(0, 4)->setFont(titleFont);
 
@@ -582,11 +578,11 @@ void SpreadSheet::setupContents()
     table->setItem(8, 4, new SpreadSheetItem("7"));
 
     table->setItem(9, 4, new SpreadSheetItem());
-    table->item(9,4)->setBackgroundColor(Qt::lightGray);
+    table->item(9, 4)->setBackground(titleBackground);
 
     // column 5
     table->setItem(0, 5, new SpreadSheetItem("NOK"));
-    table->item(0, 5)->setBackgroundColor(titleBackground);
+    table->item(0, 5)->setBackground(titleBackground);
     table->item(0, 5)->setToolTip("This column shows the expenses in NOK");
     table->item(0, 5)->setFont(titleFont);
 
@@ -600,7 +596,7 @@ void SpreadSheet::setupContents()
     table->setItem(8, 5, new SpreadSheetItem("* C9 E9"));
 
     table->setItem(9, 5, new SpreadSheetItem("sum F2 F9"));
-    table->item(9,5)->setBackgroundColor(Qt::lightGray);
+    table->item(9, 5)->setBackground(titleBackground);
 }
 
 const char *htmlText =
diff --git a/examples/widgets/itemviews/spreadsheet/spreadsheet.h b/examples/widgets/itemviews/spreadsheet/spreadsheet.h
index a90d1d8c20..b36a377156 100644
--- a/examples/widgets/itemviews/spreadsheet/spreadsheet.h
+++ b/examples/widgets/itemviews/spreadsheet/spreadsheet.h
@@ -65,10 +65,8 @@ QT_END_NAMESPACE
 class SpreadSheet : public QMainWindow
 {
     Q_OBJECT
-
 public:
-
-    SpreadSheet(int rows, int cols, QWidget *parent = 0);
+    SpreadSheet(int rows, int cols, QWidget *parent = nullptr);
 
 public slots:
     void updateStatus(QTableWidgetItem *item);
diff --git a/examples/widgets/itemviews/spreadsheet/spreadsheetdelegate.cpp b/examples/widgets/itemviews/spreadsheet/spreadsheetdelegate.cpp
index aaf8902af5..eadd5fadb8 100644
--- a/examples/widgets/itemviews/spreadsheet/spreadsheetdelegate.cpp
+++ b/examples/widgets/itemviews/spreadsheet/spreadsheetdelegate.cpp
@@ -53,11 +53,12 @@
 #include <QtWidgets>
 
 SpreadSheetDelegate::SpreadSheetDelegate(QObject *parent)
-        : QItemDelegate(parent) {}
+    : QItemDelegate(parent)
+{}
 
 QWidget *SpreadSheetDelegate::createEditor(QWidget *parent,
-                                          const QStyleOptionViewItem &,
-                                          const QModelIndex &index) const
+                                           const QStyleOptionViewItem &,
+                                           const QModelIndex &index) const
 {
     if (index.column() == 1) {
         QDateTimeEdit *editor = new QDateTimeEdit(parent);
@@ -92,7 +93,7 @@ void SpreadSheetDelegate::commitAndCloseEditor()
 }
 
 void SpreadSheetDelegate::setEditorData(QWidget *editor,
-    const QModelIndex &index) const
+                                        const QModelIndex &index) const
 {
     QLineEdit *edit = qobject_cast<QLineEdit*>(editor);
     if (edit) {
@@ -109,7 +110,8 @@ void SpreadSheetDelegate::setEditorData(QWidget *editor,
 }
 
 void SpreadSheetDelegate::setModelData(QWidget *editor,
-    QAbstractItemModel *model, const QModelIndex &index) const
+                                       QAbstractItemModel *model,
+                                       const QModelIndex &index) const
 {
     QLineEdit *edit = qobject_cast<QLineEdit *>(editor);
     if (edit) {
diff --git a/examples/widgets/itemviews/spreadsheet/spreadsheetdelegate.h b/examples/widgets/itemviews/spreadsheet/spreadsheetdelegate.h
index 333467720f..c89459cadf 100644
--- a/examples/widgets/itemviews/spreadsheet/spreadsheetdelegate.h
+++ b/examples/widgets/itemviews/spreadsheet/spreadsheetdelegate.h
@@ -51,8 +51,6 @@
 #ifndef SPREADSHEETDELEGATE_H
 #define SPREADSHEETDELEGATE_H
 
-#include "spreadsheet.h"
-
 #include <QItemDelegate>
 
 class SpreadSheetDelegate : public QItemDelegate
@@ -60,7 +58,7 @@ class SpreadSheetDelegate : public QItemDelegate
     Q_OBJECT
 
 public:
-    SpreadSheetDelegate(QObject *parent = 0);
+    SpreadSheetDelegate(QObject *parent = nullptr);
     QWidget *createEditor(QWidget *parent, const QStyleOptionViewItem &,
                           const QModelIndex &index) const override;
     void setEditorData(QWidget *editor, const QModelIndex &index) const override;
diff --git a/examples/widgets/itemviews/spreadsheet/spreadsheetitem.cpp b/examples/widgets/itemviews/spreadsheet/spreadsheetitem.cpp
index 4c18fa8251..62d3a6fdcd 100644
--- a/examples/widgets/itemviews/spreadsheet/spreadsheetitem.cpp
+++ b/examples/widgets/itemviews/spreadsheet/spreadsheetitem.cpp
@@ -50,19 +50,9 @@
 
 #include "spreadsheetitem.h"
 
-SpreadSheetItem::SpreadSheetItem()
-        : QTableWidgetItem(), isResolving(false)
-{
-}
-
-SpreadSheetItem::SpreadSheetItem(const QString &text)
-        : QTableWidgetItem(text), isResolving(false)
-{
-}
-
 QTableWidgetItem *SpreadSheetItem::clone() const
 {
-    SpreadSheetItem *item = new SpreadSheetItem();
+    SpreadSheetItem *item = new SpreadSheetItem;
     *item = *this;
     return item;
 }
@@ -75,21 +65,20 @@ QVariant SpreadSheetItem::data(int role) const
     if (role == Qt::DisplayRole)
         return display();
 
-    QString t = display().toString();
-    bool isNumber = false;
-    int number = t.toInt(&isNumber);
+    const QString t = display().toString();
 
-    if (role == Qt::TextColorRole) {
-        if (!isNumber)
-            return QVariant::fromValue(QColor(Qt::black));
-        else if (number < 0)
-            return QVariant::fromValue(QColor(Qt::red));
-        return QVariant::fromValue(QColor(Qt::blue));
+    if (role == Qt::ForegroundRole) {
+        bool isNumber = false;
+        const int number = t.toInt(&isNumber);
+        QColor color = Qt::black;
+        if (isNumber)
+            color = (number < 0) ? Qt::red : Qt::blue;
+        return QVariant::fromValue(color);
     }
 
-     if (role == Qt::TextAlignmentRole)
-         if (!t.isEmpty() && (t.at(0).isNumber() || t.at(0) == '-'))
-             return (int)(Qt::AlignRight | Qt::AlignVCenter);
+    if (role == Qt::TextAlignmentRole)
+        if (!t.isEmpty() && (t.at(0).isNumber() || t.at(0) == '-'))
+            return int(Qt::AlignRight | Qt::AlignVCenter);
 
      return QTableWidgetItem::data(role);
  }
diff --git a/examples/widgets/itemviews/spreadsheet/spreadsheetitem.h b/examples/widgets/itemviews/spreadsheet/spreadsheetitem.h
index 46460df527..159f4a7eea 100644
--- a/examples/widgets/itemviews/spreadsheet/spreadsheetitem.h
+++ b/examples/widgets/itemviews/spreadsheet/spreadsheetitem.h
@@ -58,8 +58,7 @@
 class SpreadSheetItem : public QTableWidgetItem
 {
 public:
-    SpreadSheetItem();
-    SpreadSheetItem(const QString &text);
+    using QTableWidgetItem::QTableWidgetItem;
 
     QTableWidgetItem *clone() const override;
 
@@ -74,10 +73,10 @@ public:
 
     static QVariant computeFormula(const QString &formula,
                                    const QTableWidget *widget,
-                                   const QTableWidgetItem *self = 0);
+                                   const QTableWidgetItem *self = nullptr);
 
 private:
-    mutable bool isResolving;
+    mutable bool isResolving = false;
 };
 
 #endif // SPREADSHEETITEM_H
diff --git a/examples/widgets/itemviews/stardelegate/main.cpp b/examples/widgets/itemviews/stardelegate/main.cpp
index 51ca30c73a..452976bba0 100644
--- a/examples/widgets/itemviews/stardelegate/main.cpp
+++ b/examples/widgets/itemviews/stardelegate/main.cpp
@@ -101,10 +101,7 @@ int main(int argc, char *argv[])
     tableWidget.setEditTriggers(QAbstractItemView::DoubleClicked
                                 | QAbstractItemView::SelectedClicked);
     tableWidget.setSelectionBehavior(QAbstractItemView::SelectRows);
-
-    QStringList headerLabels;
-    headerLabels << "Title" << "Genre" << "Artist" << "Rating";
-    tableWidget.setHorizontalHeaderLabels(headerLabels);
+    tableWidget.setHorizontalHeaderLabels({"Title", "Genre", "Artist", "Rating"});
 
     populateTableWidget(&tableWidget);
 
diff --git a/examples/widgets/itemviews/stardelegate/stardelegate.cpp b/examples/widgets/itemviews/stardelegate/stardelegate.cpp
index da5902a160..41ae5a920f 100644
--- a/examples/widgets/itemviews/stardelegate/stardelegate.cpp
+++ b/examples/widgets/itemviews/stardelegate/stardelegate.cpp
@@ -65,7 +65,7 @@ void StarDelegate::paint(QPainter *painter, const QStyleOptionViewItem &option,
             painter->fillRect(option.rect, option.palette.highlight());
 
         starRating.paint(painter, option.rect, option.palette,
-                         StarRating::ReadOnly);
+                         StarRating::EditMode::ReadOnly);
     } else {
         QStyledItemDelegate::paint(painter, option, index);
     }
@@ -79,9 +79,8 @@ QSize StarDelegate::sizeHint(const QStyleOptionViewItem &option,
     if (index.data().canConvert<StarRating>()) {
         StarRating starRating = qvariant_cast<StarRating>(index.data());
         return starRating.sizeHint();
-    } else {
-        return QStyledItemDelegate::sizeHint(option, index);
     }
+    return QStyledItemDelegate::sizeHint(option, index);
 }
 //! [1]
 
@@ -96,9 +95,8 @@ QWidget *StarDelegate::createEditor(QWidget *parent,
         connect(editor, &StarEditor::editingFinished,
                 this, &StarDelegate::commitAndCloseEditor);
         return editor;
-    } else {
-        return QStyledItemDelegate::createEditor(parent, option, index);
     }
+    return QStyledItemDelegate::createEditor(parent, option, index);
 }
 //! [2]
 
diff --git a/examples/widgets/itemviews/stardelegate/stardelegate.h b/examples/widgets/itemviews/stardelegate/stardelegate.h
index ffc65fbedd..1fc31f8ee8 100644
--- a/examples/widgets/itemviews/stardelegate/stardelegate.h
+++ b/examples/widgets/itemviews/stardelegate/stardelegate.h
@@ -57,9 +57,8 @@
 class StarDelegate : public QStyledItemDelegate
 {
     Q_OBJECT
-
 public:
-    StarDelegate(QWidget *parent = 0) : QStyledItemDelegate(parent) {}
+    using QStyledItemDelegate::QStyledItemDelegate;
 
     void paint(QPainter *painter, const QStyleOptionViewItem &option,
                const QModelIndex &index) const override;
diff --git a/examples/widgets/itemviews/stardelegate/stareditor.cpp b/examples/widgets/itemviews/stardelegate/stareditor.cpp
index 19a4b54d9e..43706eeae0 100644
--- a/examples/widgets/itemviews/stardelegate/stareditor.cpp
+++ b/examples/widgets/itemviews/stardelegate/stareditor.cpp
@@ -48,11 +48,11 @@
 **
 ****************************************************************************/
 
-#include <QtWidgets>
-
 #include "stareditor.h"
 #include "starrating.h"
 
+#include <QtWidgets>
+
 //! [0]
 StarEditor::StarEditor(QWidget *parent)
     : QWidget(parent)
@@ -71,35 +71,37 @@ QSize StarEditor::sizeHint() const
 void StarEditor::paintEvent(QPaintEvent *)
 {
     QPainter painter(this);
-    myStarRating.paint(&painter, rect(), this->palette(),
-                       StarRating::Editable);
+    myStarRating.paint(&painter, rect(), palette(),
+                       StarRating::EditMode::Editable);
 }
 //! [1]
 
 //! [2]
 void StarEditor::mouseMoveEvent(QMouseEvent *event)
 {
-    int star = starAtPosition(event->x());
+    const int star = starAtPosition(event->x());
 
     if (star != myStarRating.starCount() && star != -1) {
         myStarRating.setStarCount(star);
         update();
     }
+    QWidget::mouseMoveEvent(event);
 }
 //! [2]
 
 //! [3]
-void StarEditor::mouseReleaseEvent(QMouseEvent * /* event */)
+void StarEditor::mouseReleaseEvent(QMouseEvent *event)
 {
     emit editingFinished();
+    QWidget::mouseReleaseEvent(event);
 }
 //! [3]
 
 //! [4]
-int StarEditor::starAtPosition(int x)
+int StarEditor::starAtPosition(int x) const
 {
-    int star = (x / (myStarRating.sizeHint().width()
-                     / myStarRating.maxStarCount())) + 1;
+    const int star = (x / (myStarRating.sizeHint().width()
+                           / myStarRating.maxStarCount())) + 1;
     if (star <= 0 || star > myStarRating.maxStarCount())
         return -1;
 
diff --git a/examples/widgets/itemviews/stardelegate/stareditor.h b/examples/widgets/itemviews/stardelegate/stareditor.h
index 4a4c3a4954..8b1bf2efed 100644
--- a/examples/widgets/itemviews/stardelegate/stareditor.h
+++ b/examples/widgets/itemviews/stardelegate/stareditor.h
@@ -59,9 +59,8 @@
 class StarEditor : public QWidget
 {
     Q_OBJECT
-
 public:
-    StarEditor(QWidget *parent = 0);
+    StarEditor(QWidget *parent = nullptr);
 
     QSize sizeHint() const override;
     void setStarRating(const StarRating &starRating) {
@@ -78,7 +77,7 @@ protected:
     void mouseReleaseEvent(QMouseEvent *event) override;
 
 private:
-    int starAtPosition(int x);
+    int starAtPosition(int x) const;
 
     StarRating myStarRating;
 };
diff --git a/examples/widgets/itemviews/stardelegate/starrating.cpp b/examples/widgets/itemviews/stardelegate/starrating.cpp
index 845e474de9..75f0bd9cf7 100644
--- a/examples/widgets/itemviews/stardelegate/starrating.cpp
+++ b/examples/widgets/itemviews/stardelegate/starrating.cpp
@@ -48,19 +48,18 @@
 **
 ****************************************************************************/
 
+#include "starrating.h"
+
 #include <QtWidgets>
 #include <cmath>
 
-#include "starrating.h"
-
-const int PaintingScaleFactor = 20;
+constexpr int PaintingScaleFactor = 20;
 
 //! [0]
 StarRating::StarRating(int starCount, int maxStarCount)
+    : myStarCount(starCount),
+      myMaxStarCount(maxStarCount)
 {
-    myStarCount = starCount;
-    myMaxStarCount = maxStarCount;
-
     starPolygon << QPointF(1.0, 0.5);
     for (int i = 1; i < 5; ++i)
         starPolygon << QPointF(0.5 + 0.5 * std::cos(0.8 * i * 3.14),
@@ -87,23 +86,19 @@ void StarRating::paint(QPainter *painter, const QRect &rect,
 
     painter->setRenderHint(QPainter::Antialiasing, true);
     painter->setPen(Qt::NoPen);
+    painter->setBrush(mode == EditMode::Editable ?
+                          palette.highlight() :
+                          palette.windowText());
 
-    if (mode == Editable) {
-        painter->setBrush(palette.highlight());
-    } else {
-        painter->setBrush(palette.foreground());
-    }
-
-    int yOffset = (rect.height() - PaintingScaleFactor) / 2;
+    const int yOffset = (rect.height() - PaintingScaleFactor) / 2;
     painter->translate(rect.x(), rect.y() + yOffset);
     painter->scale(PaintingScaleFactor, PaintingScaleFactor);
 
     for (int i = 0; i < myMaxStarCount; ++i) {
-        if (i < myStarCount) {
+        if (i < myStarCount)
             painter->drawPolygon(starPolygon, Qt::WindingFill);
-        } else if (mode == Editable) {
+        else if (mode == EditMode::Editable)
             painter->drawPolygon(diamondPolygon, Qt::WindingFill);
-        }
         painter->translate(1.0, 0.0);
     }
 
diff --git a/examples/widgets/itemviews/stardelegate/starrating.h b/examples/widgets/itemviews/stardelegate/starrating.h
index fa77311914..fc3028db58 100644
--- a/examples/widgets/itemviews/stardelegate/starrating.h
+++ b/examples/widgets/itemviews/stardelegate/starrating.h
@@ -51,15 +51,15 @@
 #ifndef STARRATING_H
 #define STARRATING_H
 
-#include <QMetaType>
-#include <QPointF>
-#include <QVector>
+#include <QPainter>
+#include <QPolygonF>
+#include <QSize>
 
 //! [0]
 class StarRating
 {
 public:
-    enum EditMode { Editable, ReadOnly };
+    enum class EditMode { Editable, ReadOnly };
 
     explicit StarRating(int starCount = 1, int maxStarCount = 5);
 
diff --git a/examples/widgets/itemviews/storageview/main.cpp b/examples/widgets/itemviews/storageview/main.cpp
index f349e58fad..8f23a4820a 100644
--- a/examples/widgets/itemviews/storageview/main.cpp
+++ b/examples/widgets/itemviews/storageview/main.cpp
@@ -49,10 +49,9 @@
 **
 ****************************************************************************/
 
-#include <QtWidgets/QApplication>
-#include <QtWidgets/QHeaderView>
-#include <QtWidgets/QShortcut>
-#include <QtWidgets/QTreeView>
+#include <QApplication>
+#include <QShortcut>
+#include <QTreeView>
 
 #include "storagemodel.h"
 
diff --git a/examples/widgets/itemviews/storageview/storagemodel.cpp b/examples/widgets/itemviews/storageview/storagemodel.cpp
index 063f126d86..b98fc8445c 100644
--- a/examples/widgets/itemviews/storageview/storagemodel.cpp
+++ b/examples/widgets/itemviews/storageview/storagemodel.cpp
@@ -53,14 +53,6 @@
 
 #include <QDir>
 #include <QLocale>
-#include <qmath.h>
-#include <algorithm>
-#include <cmath>
-
-StorageModel::StorageModel(QObject *parent) :
-    QAbstractTableModel(parent)
-{
-}
 
 void StorageModel::refresh()
 {
diff --git a/examples/widgets/itemviews/storageview/storagemodel.h b/examples/widgets/itemviews/storageview/storagemodel.h
index 787b2f04de..597218c220 100644
--- a/examples/widgets/itemviews/storageview/storagemodel.h
+++ b/examples/widgets/itemviews/storageview/storagemodel.h
@@ -74,7 +74,7 @@ public:
         ColumnCount
     };
 
-    explicit StorageModel(QObject *parent = nullptr);
+    using QAbstractTableModel::QAbstractTableModel;
 
     int columnCount(const QModelIndex &parent) const override;
     int rowCount(const QModelIndex &parent) const override;
diff --git a/examples/widgets/layouts/basiclayouts/dialog.cpp b/examples/widgets/layouts/basiclayouts/dialog.cpp
index 7acbc50eb7..8376820545 100644
--- a/examples/widgets/layouts/basiclayouts/dialog.cpp
+++ b/examples/widgets/layouts/basiclayouts/dialog.cpp
@@ -69,8 +69,8 @@ Dialog::Dialog()
     buttonBox = new QDialogButtonBox(QDialogButtonBox::Ok
                                      | QDialogButtonBox::Cancel);
 
-    connect(buttonBox, SIGNAL(accepted()), this, SLOT(accept()));
-    connect(buttonBox, SIGNAL(rejected()), this, SLOT(reject()));
+    connect(buttonBox, &QDialogButtonBox::accepted, this, &QDialog::accept);
+    connect(buttonBox, &QDialogButtonBox::rejected, this, &QDialog::reject);
 //! [1]
 
 //! [2]
@@ -99,7 +99,7 @@ void Dialog::createMenu()
     exitAction = fileMenu->addAction(tr("E&xit"));
     menuBar->addMenu(fileMenu);
 
-    connect(exitAction, SIGNAL(triggered()), this, SLOT(accept()));
+    connect(exitAction, &QAction::triggered, this, &QDialog::accept);
 }
 //! [6]
 
diff --git a/examples/widgets/layouts/borderlayout/borderlayout.cpp b/examples/widgets/layouts/borderlayout/borderlayout.cpp
index 9b142584c9..b8ddd3af83 100644
--- a/examples/widgets/layouts/borderlayout/borderlayout.cpp
+++ b/examples/widgets/layouts/borderlayout/borderlayout.cpp
@@ -50,10 +50,10 @@
 
 #include "borderlayout.h"
 
-BorderLayout::BorderLayout(QWidget *parent, int margin, int spacing)
+BorderLayout::BorderLayout(QWidget *parent, const QMargins &margins, int spacing)
     : QLayout(parent)
 {
-    setMargin(margin);
+    setContentsMargins(margins);
     setSpacing(spacing);
 }
 
@@ -98,10 +98,7 @@ int BorderLayout::count() const
 QLayoutItem *BorderLayout::itemAt(int index) const
 {
     ItemWrapper *wrapper = list.value(index);
-    if (wrapper)
-        return wrapper->item;
-    else
-        return 0;
+    return wrapper ? wrapper->item : nullptr;
 }
 
 QSize BorderLayout::minimumSize() const
@@ -111,7 +108,7 @@ QSize BorderLayout::minimumSize() const
 
 void BorderLayout::setGeometry(const QRect &rect)
 {
-    ItemWrapper *center = 0;
+    ItemWrapper *center = nullptr;
     int eastWidth = 0;
     int westWidth = 0;
     int northHeight = 0;
@@ -189,7 +186,7 @@ QLayoutItem *BorderLayout::takeAt(int index)
         ItemWrapper *layoutStruct = list.takeAt(index);
         return layoutStruct->item;
     }
-    return 0;
+    return nullptr;
 }
 
 void BorderLayout::add(QLayoutItem *item, Position position)
diff --git a/examples/widgets/layouts/borderlayout/borderlayout.h b/examples/widgets/layouts/borderlayout/borderlayout.h
index 4c0c01f90b..58d1aa394d 100644
--- a/examples/widgets/layouts/borderlayout/borderlayout.h
+++ b/examples/widgets/layouts/borderlayout/borderlayout.h
@@ -59,7 +59,7 @@ class BorderLayout : public QLayout
 public:
     enum Position { West, North, South, East, Center };
 
-    explicit BorderLayout(QWidget *parent, int margin = 0, int spacing = -1);
+    explicit BorderLayout(QWidget *parent, const QMargins &margins = QMargins(), int spacing = -1);
     BorderLayout(int spacing = -1);
     ~BorderLayout();
 
diff --git a/examples/widgets/layouts/dynamiclayouts/dialog.cpp b/examples/widgets/layouts/dynamiclayouts/dialog.cpp
index f46053372a..baf3b4cf1e 100644
--- a/examples/widgets/layouts/dynamiclayouts/dialog.cpp
+++ b/examples/widgets/layouts/dynamiclayouts/dialog.cpp
@@ -104,7 +104,7 @@ void Dialog::rotateWidgets()
 {
     Q_ASSERT(rotatableWidgets.count() % 2 == 0);
 
-    foreach (QWidget *widget, rotatableWidgets)
+    for (QWidget *widget : qAsConst(rotatableWidgets))
         rotatableLayout->removeWidget(widget);
 
     rotatableWidgets.enqueue(rotatableWidgets.dequeue());
diff --git a/examples/widgets/layouts/flowlayout/flowlayout.cpp b/examples/widgets/layouts/flowlayout/flowlayout.cpp
index 9203da0ba1..5c59ae025c 100644
--- a/examples/widgets/layouts/flowlayout/flowlayout.cpp
+++ b/examples/widgets/layouts/flowlayout/flowlayout.cpp
@@ -116,8 +116,7 @@ QLayoutItem *FlowLayout::takeAt(int index)
 {
     if (index >= 0 && index < itemList.size())
         return itemList.takeAt(index);
-    else
-        return 0;
+    return nullptr;
 }
 //! [5]
 
@@ -156,11 +155,11 @@ QSize FlowLayout::sizeHint() const
 QSize FlowLayout::minimumSize() const
 {
     QSize size;
-    QLayoutItem *item;
-    foreach (item, itemList)
+    for (const QLayoutItem *item : qAsConst(itemList))
         size = size.expandedTo(item->minimumSize());
 
-    size += QSize(2*margin(), 2*margin());
+    const QMargins margins = contentsMargins();
+    size += QSize(margins.left() + margins.right(), margins.top() + margins.bottom());
     return size;
 }
 //! [8]
@@ -177,9 +176,8 @@ int FlowLayout::doLayout(const QRect &rect, bool testOnly) const
 //! [9]
 
 //! [10]
-    QLayoutItem *item;
-    foreach (item, itemList) {
-        QWidget *wid = item->widget();
+    for (QLayoutItem *item : qAsConst(itemList)) {
+        const QWidget *wid = item->widget();
         int spaceX = horizontalSpacing();
         if (spaceX == -1)
             spaceX = wid->style()->layoutSpacing(
@@ -215,7 +213,7 @@ int FlowLayout::smartSpacing(QStyle::PixelMetric pm) const
         return -1;
     } else if (parent->isWidgetType()) {
         QWidget *pw = static_cast<QWidget *>(parent);
-        return pw->style()->pixelMetric(pm, 0, pw);
+        return pw->style()->pixelMetric(pm, nullptr, pw);
     } else {
         return static_cast<QLayout *>(parent)->spacing();
     }
diff --git a/examples/widgets/mainwindows/application/images/save.png b/examples/widgets/mainwindows/application/images/save.png
index daba865faf..e65a29d5f1 100644
--- a/examples/widgets/mainwindows/application/images/save.png
+++ b/examples/widgets/mainwindows/application/images/save.png
diff --git a/examples/widgets/mainwindows/application/mainwindow.cpp b/examples/widgets/mainwindows/application/mainwindow.cpp
index dc93fe4eb2..4b639ead18 100644
--- a/examples/widgets/mainwindows/application/mainwindow.cpp
+++ b/examples/widgets/mainwindows/application/mainwindow.cpp
@@ -337,11 +337,11 @@ void MainWindow::loadFile(const QString &fileName)
 
     QTextStream in(&file);
 #ifndef QT_NO_CURSOR
-    QApplication::setOverrideCursor(Qt::WaitCursor);
+    QGuiApplication::setOverrideCursor(Qt::WaitCursor);
 #endif
     textEdit->setPlainText(in.readAll());
 #ifndef QT_NO_CURSOR
-    QApplication::restoreOverrideCursor();
+    QGuiApplication::restoreOverrideCursor();
 #endif
 
     setCurrentFile(fileName);
@@ -364,11 +364,11 @@ bool MainWindow::saveFile(const QString &fileName)
 
     QTextStream out(&file);
 #ifndef QT_NO_CURSOR
-    QApplication::setOverrideCursor(Qt::WaitCursor);
+    QGuiApplication::setOverrideCursor(Qt::WaitCursor);
 #endif
     out << textEdit->toPlainText();
 #ifndef QT_NO_CURSOR
-    QApplication::restoreOverrideCursor();
+    QGuiApplication::restoreOverrideCursor();
 #endif
 
     setCurrentFile(fileName);
diff --git a/examples/widgets/mainwindows/dockwidgets/mainwindow.cpp b/examples/widgets/mainwindows/dockwidgets/mainwindow.cpp
index 47a6e78265..a62765cdab 100644
--- a/examples/widgets/mainwindows/dockwidgets/mainwindow.cpp
+++ b/examples/widgets/mainwindows/dockwidgets/mainwindow.cpp
@@ -161,9 +161,9 @@ void MainWindow::save()
     }
 
     QTextStream out(&file);
-    QApplication::setOverrideCursor(Qt::WaitCursor);
+    QGuiApplication::setOverrideCursor(Qt::WaitCursor);
     out << textEdit->toHtml();
-    QApplication::restoreOverrideCursor();
+    QGuiApplication::restoreOverrideCursor();
 
     statusBar()->showMessage(tr("Saved '%1'").arg(fileName), 2000);
 }
diff --git a/examples/widgets/mainwindows/mainwindow/colorswatch.cpp b/examples/widgets/mainwindows/mainwindow/colorswatch.cpp
index 720f9a2085..5662518ddc 100644
--- a/examples/widgets/mainwindows/mainwindow/colorswatch.cpp
+++ b/examples/widgets/mainwindows/mainwindow/colorswatch.cpp
@@ -86,7 +86,7 @@ QColor bgColorForName(const QString &name)
         return QColor("#D8D8F1");
     if (name == "Yellow")
         return QColor("#F1F0D8");
-    return QColor(name).light(110);
+    return QColor(name).lighter(110);
 }
 
 QColor fgColorForName(const QString &name)
@@ -454,8 +454,8 @@ void ColorSwatch::updateContextMenu()
     tabMenu->clear();
     splitHMenu->clear();
     splitVMenu->clear();
-    QList<ColorSwatch*> dock_list = mainWindow->findChildren<ColorSwatch*>();
-    foreach (ColorSwatch *dock, dock_list) {
+    const QList<ColorSwatch *> dockList = mainWindow->findChildren<ColorSwatch*>();
+    for (const ColorSwatch *dock : dockList) {
         tabMenu->addAction(dock->objectName());
         splitHMenu->addAction(dock->objectName());
         splitVMenu->addAction(dock->objectName());
@@ -464,7 +464,8 @@ void ColorSwatch::updateContextMenu()
 
 static ColorSwatch *findByName(const QMainWindow *mainWindow, const QString &name)
 {
-    foreach (ColorSwatch *dock, mainWindow->findChildren<ColorSwatch*>()) {
+    const QList<ColorSwatch *> dockList = mainWindow->findChildren<ColorSwatch*>();
+    for (ColorSwatch *dock : dockList) {
         if (name == dock->objectName())
             return dock;
     }
@@ -584,7 +585,7 @@ void ColorSwatch::changeVerticalTitleBar(bool on)
 QSize BlueTitleBar::minimumSizeHint() const
 {
     QDockWidget *dw = qobject_cast<QDockWidget*>(parentWidget());
-    Q_ASSERT(dw != 0);
+    Q_ASSERT(dw);
     QSize result(leftPm.width() + rightPm.width(), centerPm.height());
     if (dw->features() & QDockWidget::DockWidgetVerticalTitleBar)
         result.transpose();
@@ -605,7 +606,7 @@ void BlueTitleBar::paintEvent(QPaintEvent*)
     QRect rect = this->rect();
 
     QDockWidget *dw = qobject_cast<QDockWidget*>(parentWidget());
-    Q_ASSERT(dw != 0);
+    Q_ASSERT(dw);
 
     if (dw->features() & QDockWidget::DockWidgetVerticalTitleBar) {
         QSize s = rect.size();
@@ -632,7 +633,7 @@ void BlueTitleBar::mouseReleaseEvent(QMouseEvent *event)
     QRect rect = this->rect();
 
     QDockWidget *dw = qobject_cast<QDockWidget*>(parentWidget());
-    Q_ASSERT(dw != 0);
+    Q_ASSERT(dw);
 
     if (dw->features() & QDockWidget::DockWidgetVerticalTitleBar) {
         QPoint p = pos;
@@ -676,7 +677,7 @@ void BlueTitleBar::mouseReleaseEvent(QMouseEvent *event)
 void BlueTitleBar::updateMask()
 {
     QDockWidget *dw = qobject_cast<QDockWidget*>(parent());
-    Q_ASSERT(dw != 0);
+    Q_ASSERT(dw);
 
     QRect rect = dw->rect();
     QPixmap bitmap(dw->size());
diff --git a/examples/widgets/mainwindows/mainwindow/toolbar.cpp b/examples/widgets/mainwindows/mainwindow/toolbar.cpp
index 7c96f5b1be..36d4108b1e 100644
--- a/examples/widgets/mainwindows/mainwindow/toolbar.cpp
+++ b/examples/widgets/mainwindows/mainwindow/toolbar.cpp
@@ -208,7 +208,7 @@ ToolBar::ToolBar(const QString &title, QWidget *parent)
 void ToolBar::updateMenu()
 {
     QMainWindow *mainWindow = qobject_cast<QMainWindow *>(parentWidget());
-    Q_ASSERT(mainWindow != 0);
+    Q_ASSERT(mainWindow);
 
     const Qt::ToolBarArea area = mainWindow->toolBarArea(this);
     const Qt::ToolBarAreas areas = allowedAreas();
@@ -244,7 +244,8 @@ void ToolBar::order()
 {
     QList<QAction *> ordered;
     QList<QAction *> actions1 = actions();
-    foreach (QAction *action, findChildren<QAction *>()) {
+    const QList<QAction *> childActions = findChildren<QAction *>();
+    for (QAction *action : childActions) {
         if (!actions1.contains(action))
             continue;
         actions1.removeAll(action);
@@ -313,7 +314,7 @@ void ToolBar::place(Qt::ToolBarArea area, bool p)
         return;
 
     QMainWindow *mainWindow = qobject_cast<QMainWindow *>(parentWidget());
-    Q_ASSERT(mainWindow != 0);
+    Q_ASSERT(mainWindow);
 
     mainWindow->addToolBar(area, this);
 
@@ -355,7 +356,7 @@ void ToolBar::placeBottom(bool p)
 void ToolBar::insertToolBarBreak()
 {
     QMainWindow *mainWindow = qobject_cast<QMainWindow *>(parentWidget());
-    Q_ASSERT(mainWindow != 0);
+    Q_ASSERT(mainWindow);
 
     mainWindow->insertToolBarBreak(this);
 }
diff --git a/examples/widgets/mainwindows/mdi/images/save.png b/examples/widgets/mainwindows/mdi/images/save.png
index daba865faf..e65a29d5f1 100644
--- a/examples/widgets/mainwindows/mdi/images/save.png
+++ b/examples/widgets/mainwindows/mdi/images/save.png
diff --git a/examples/widgets/mainwindows/mdi/main.cpp b/examples/widgets/mainwindows/mdi/main.cpp
index e23f5f6e60..950244ad53 100644
--- a/examples/widgets/mainwindows/mdi/main.cpp
+++ b/examples/widgets/mainwindows/mdi/main.cpp
@@ -70,7 +70,8 @@ int main(int argc, char *argv[])
     parser.process(app);
 
     MainWindow mainWin;
-    foreach (const QString &fileName, parser.positionalArguments())
+    const QStringList posArgs = parser.positionalArguments();
+    for (const QString &fileName : posArgs)
         mainWin.openFile(fileName);
     mainWin.show();
     return app.exec();
diff --git a/examples/widgets/mainwindows/mdi/mainwindow.cpp b/examples/widgets/mainwindows/mdi/mainwindow.cpp
index 188de1893e..b952d19e2e 100644
--- a/examples/widgets/mainwindows/mdi/mainwindow.cpp
+++ b/examples/widgets/mainwindows/mdi/mainwindow.cpp
@@ -242,7 +242,7 @@ void MainWindow::about()
 
 void MainWindow::updateMenus()
 {
-    bool hasMdiChild = (activeMdiChild() != 0);
+    bool hasMdiChild = (activeMdiChild() != nullptr);
     saveAct->setEnabled(hasMdiChild);
     saveAsAct->setEnabled(hasMdiChild);
 #ifndef QT_NO_CLIPBOARD
@@ -483,19 +483,20 @@ MdiChild *MainWindow::activeMdiChild() const
 {
     if (QMdiSubWindow *activeSubWindow = mdiArea->activeSubWindow())
         return qobject_cast<MdiChild *>(activeSubWindow->widget());
-    return 0;
+    return nullptr;
 }
 
 QMdiSubWindow *MainWindow::findMdiChild(const QString &fileName) const
 {
     QString canonicalFilePath = QFileInfo(fileName).canonicalFilePath();
 
-    foreach (QMdiSubWindow *window, mdiArea->subWindowList()) {
+    const QList<QMdiSubWindow *> subWindows = mdiArea->subWindowList();
+    for (QMdiSubWindow *window : subWindows) {
         MdiChild *mdiChild = qobject_cast<MdiChild *>(window->widget());
         if (mdiChild->currentFile() == canonicalFilePath)
             return window;
     }
-    return 0;
+    return nullptr;
 }
 
 void MainWindow::switchLayoutDirection()
diff --git a/examples/widgets/mainwindows/mdi/mdichild.cpp b/examples/widgets/mainwindows/mdi/mdichild.cpp
index 006c84574a..16f2040de0 100644
--- a/examples/widgets/mainwindows/mdi/mdichild.cpp
+++ b/examples/widgets/mainwindows/mdi/mdichild.cpp
@@ -82,9 +82,9 @@ bool MdiChild::loadFile(const QString &fileName)
     }
 
     QTextStream in(&file);
-    QApplication::setOverrideCursor(Qt::WaitCursor);
+    QGuiApplication::setOverrideCursor(Qt::WaitCursor);
     setPlainText(in.readAll());
-    QApplication::restoreOverrideCursor();
+    QGuiApplication::restoreOverrideCursor();
 
     setCurrentFile(fileName);
 
@@ -124,9 +124,9 @@ bool MdiChild::saveFile(const QString &fileName)
     }
 
     QTextStream out(&file);
-    QApplication::setOverrideCursor(Qt::WaitCursor);
+    QGuiApplication::setOverrideCursor(Qt::WaitCursor);
     out << toPlainText();
-    QApplication::restoreOverrideCursor();
+    QGuiApplication::restoreOverrideCursor();
 
     setCurrentFile(fileName);
     return true;
diff --git a/examples/widgets/mainwindows/menus/mainwindow.cpp b/examples/widgets/mainwindows/menus/mainwindow.cpp
index 600b04fdb2..c6aba8be83 100644
--- a/examples/widgets/mainwindows/menus/mainwindow.cpp
+++ b/examples/widgets/mainwindows/menus/mainwindow.cpp
@@ -72,7 +72,7 @@ MainWindow::MainWindow()
     bottomFiller->setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Expanding);
 
     QVBoxLayout *layout = new QVBoxLayout;
-    layout->setMargin(5);
+    layout->setContentsMargins(5, 5, 5, 5);
     layout->addWidget(topFiller);
     layout->addWidget(infoLabel);
     layout->addWidget(bottomFiller);
diff --git a/examples/widgets/mainwindows/sdi/images/save.png b/examples/widgets/mainwindows/sdi/images/save.png
index daba865faf..e65a29d5f1 100644
--- a/examples/widgets/mainwindows/sdi/images/save.png
+++ b/examples/widgets/mainwindows/sdi/images/save.png
diff --git a/examples/widgets/mainwindows/sdi/main.cpp b/examples/widgets/mainwindows/sdi/main.cpp
index 6e29fafd6f..7a18c0c39c 100644
--- a/examples/widgets/mainwindows/sdi/main.cpp
+++ b/examples/widgets/mainwindows/sdi/main.cpp
@@ -68,7 +68,8 @@ int main(int argc, char *argv[])
     parser.process(app);
 
     MainWindow *mainWin = nullptr;
-    foreach (const QString &file, parser.positionalArguments()) {
+    const QStringList posArgs = parser.positionalArguments();
+    for (const QString &file : posArgs) {
         MainWindow *newWin = new MainWindow(file);
         newWin->tile(mainWin);
         newWin->show();
diff --git a/examples/widgets/mainwindows/sdi/mainwindow.cpp b/examples/widgets/mainwindows/sdi/mainwindow.cpp
index 301c85c144..62a74b26e6 100644
--- a/examples/widgets/mainwindows/sdi/mainwindow.cpp
+++ b/examples/widgets/mainwindows/sdi/mainwindow.cpp
@@ -338,9 +338,9 @@ void MainWindow::loadFile(const QString &fileName)
     }
 
     QTextStream in(&file);
-    QApplication::setOverrideCursor(Qt::WaitCursor);
+    QGuiApplication::setOverrideCursor(Qt::WaitCursor);
     textEdit->setPlainText(in.readAll());
-    QApplication::restoreOverrideCursor();
+    QGuiApplication::restoreOverrideCursor();
 
     setCurrentFile(fileName);
     statusBar()->showMessage(tr("File loaded"), 2000);
@@ -434,9 +434,9 @@ bool MainWindow::saveFile(const QString &fileName)
     }
 
     QTextStream out(&file);
-    QApplication::setOverrideCursor(Qt::WaitCursor);
+    QGuiApplication::setOverrideCursor(Qt::WaitCursor);
     out << textEdit->toPlainText();
-    QApplication::restoreOverrideCursor();
+    QGuiApplication::restoreOverrideCursor();
 
     setCurrentFile(fileName);
     statusBar()->showMessage(tr("File saved"), 2000);
@@ -472,11 +472,12 @@ MainWindow *MainWindow::findMainWindow(const QString &fileName) const
 {
     QString canonicalFilePath = QFileInfo(fileName).canonicalFilePath();
 
-    foreach (QWidget *widget, QApplication::topLevelWidgets()) {
+    const QList<QWidget *> topLevelWidgets = QApplication::topLevelWidgets();
+    for (QWidget *widget : topLevelWidgets) {
         MainWindow *mainWin = qobject_cast<MainWindow *>(widget);
         if (mainWin && mainWin->curFile == canonicalFilePath)
             return mainWin;
     }
 
-    return 0;
+    return nullptr;
 }
diff --git a/examples/widgets/painting/affine/affine.pro b/examples/widgets/painting/affine/affine.pro
index 0ad869183c..0af18b82ca 100644
--- a/examples/widgets/painting/affine/affine.pro
+++ b/examples/widgets/painting/affine/affine.pro
@@ -1,10 +1,6 @@
 SOURCES += main.cpp xform.cpp
 HEADERS += xform.h
 
-qtHaveModule(opengl) {
-	DEFINES += QT_OPENGL_SUPPORT
-	QT += opengl
-}
 QT += widgets
 
 SHARED_FOLDER = ../shared
diff --git a/examples/widgets/painting/affine/main.cpp b/examples/widgets/painting/affine/main.cpp
index a820c784f0..6ce8efe482 100644
--- a/examples/widgets/painting/affine/main.cpp
+++ b/examples/widgets/painting/affine/main.cpp
@@ -58,12 +58,12 @@ int main(int argc, char **argv)
 
     QApplication app(argc, argv);
 
-    XFormWidget xformWidget(0);
-    QStyle *arthurStyle = new ArthurStyle();
+    XFormWidget xformWidget(nullptr);
+    QStyle *arthurStyle = new ArthurStyle;
     xformWidget.setStyle(arthurStyle);
 
-    QList<QWidget *> widgets = xformWidget.findChildren<QWidget *>();
-    foreach (QWidget *w, widgets) {
+    const QList<QWidget *> widgets = xformWidget.findChildren<QWidget *>();
+    for (QWidget *w : widgets) {
         w->setStyle(arthurStyle);
         w->setAttribute(Qt::WA_AcceptTouchEvents);
     }
diff --git a/examples/widgets/painting/affine/xform.cpp b/examples/widgets/painting/affine/xform.cpp
index 20f6eb3c6d..482e0f3268 100644
--- a/examples/widgets/painting/affine/xform.cpp
+++ b/examples/widgets/painting/affine/xform.cpp
@@ -160,10 +160,7 @@ void XFormView::updateCtrlPoints(const QPolygonF &points)
     ctrlPoints = points;
 
     QLineF line(ctrlPoints.at(0), ctrlPoints.at(1));
-    m_rotation = line.angle(QLineF(0, 0, 1, 0));
-    if (line.dy() < 0)
-        m_rotation = 360 - m_rotation;
-
+    m_rotation = 360 - QLineF(0, 0, 1, 0).angleTo(line);
     if (trans.isNull())
         emit rotationChanged(int(m_rotation*10));
 }
@@ -830,13 +827,11 @@ XFormWidget::XFormWidget(QWidget *parent)
 
     QPushButton *showSourceButton = new QPushButton(mainGroup);
     showSourceButton->setText(tr("Show Source"));
-#ifdef QT_OPENGL_SUPPORT
+#if QT_CONFIG(opengl)
     QPushButton *enableOpenGLButton = new QPushButton(mainGroup);
     enableOpenGLButton->setText(tr("Use OpenGL"));
     enableOpenGLButton->setCheckable(true);
     enableOpenGLButton->setChecked(view->usesOpenGL());
-    if (!QGLFormat::hasOpenGL())
-        enableOpenGLButton->hide();
 #endif
     QPushButton *whatsThisButton = new QPushButton(mainGroup);
     whatsThisButton->setText(tr("What's This?"));
@@ -871,7 +866,7 @@ XFormWidget::XFormWidget(QWidget *parent)
     mainGroupLayout->addWidget(resetButton);
     mainGroupLayout->addWidget(animateButton);
     mainGroupLayout->addWidget(showSourceButton);
-#ifdef QT_OPENGL_SUPPORT
+#if QT_CONFIG(opengl)
     mainGroupLayout->addWidget(enableOpenGLButton);
 #endif
     mainGroupLayout->addWidget(whatsThisButton);
@@ -897,7 +892,7 @@ XFormWidget::XFormWidget(QWidget *parent)
     connect(view, &XFormView::descriptionEnabledChanged, view->hoverPoints(), &HoverPoints::setDisabled);
     connect(view, &XFormView::descriptionEnabledChanged, whatsThisButton, &QPushButton::setChecked);
     connect(showSourceButton, &QPushButton::clicked, view, &XFormView::showSource);
-#ifdef QT_OPENGL_SUPPORT
+#if QT_CONFIG(opengl)
     connect(enableOpenGLButton, &QPushButton::clicked, view, &XFormView::enableOpenGL);
 #endif
     view->loadSourceFile(":res/affine/xform.cpp");
diff --git a/examples/widgets/painting/basicdrawing/window.cpp b/examples/widgets/painting/basicdrawing/window.cpp
index c80237e914..65f6971d13 100644
--- a/examples/widgets/painting/basicdrawing/window.cpp
+++ b/examples/widgets/painting/basicdrawing/window.cpp
@@ -157,22 +157,22 @@ Window::Window()
 //! [7]
 
 //! [8]
-    connect(shapeComboBox, SIGNAL(activated(int)),
-            this, SLOT(shapeChanged()));
-    connect(penWidthSpinBox, SIGNAL(valueChanged(int)),
-            this, SLOT(penChanged()));
-    connect(penStyleComboBox, SIGNAL(activated(int)),
-            this, SLOT(penChanged()));
-    connect(penCapComboBox, SIGNAL(activated(int)),
-            this, SLOT(penChanged()));
-    connect(penJoinComboBox, SIGNAL(activated(int)),
-            this, SLOT(penChanged()));
-    connect(brushStyleComboBox, SIGNAL(activated(int)),
-            this, SLOT(brushChanged()));
-    connect(antialiasingCheckBox, SIGNAL(toggled(bool)),
-            renderArea, SLOT(setAntialiased(bool)));
-    connect(transformationsCheckBox, SIGNAL(toggled(bool)),
-            renderArea, SLOT(setTransformed(bool)));
+    connect(shapeComboBox, QOverload<int>::of(&QComboBox::activated),
+            this, &Window::shapeChanged);
+    connect(penWidthSpinBox, QOverload<int>::of(&QSpinBox::valueChanged),
+            this, &Window::penChanged);
+    connect(penStyleComboBox, QOverload<int>::of(&QComboBox::activated),
+            this, &Window::penChanged);
+    connect(penCapComboBox, QOverload<int>::of(&QComboBox::activated),
+            this, &Window::penChanged);
+    connect(penJoinComboBox, QOverload<int>::of(&QComboBox::activated),
+            this, &Window::penChanged);
+    connect(brushStyleComboBox, QOverload<int>::of(&QComboBox::activated),
+            this, &Window::brushChanged);
+    connect(antialiasingCheckBox, &QAbstractButton::toggled,
+            renderArea, &RenderArea::setAntialiased);
+    connect(transformationsCheckBox, &QAbstractButton::toggled,
+            renderArea, &RenderArea::setTransformed);
 //! [8]
 
 //! [9]
diff --git a/examples/widgets/painting/composition/composition.cpp b/examples/widgets/painting/composition/composition.cpp
index 0b57d3c7d3..9bd71735a0 100644
--- a/examples/widgets/painting/composition/composition.cpp
+++ b/examples/widgets/painting/composition/composition.cpp
@@ -57,6 +57,11 @@
 #include <QMouseEvent>
 #include <qmath.h>
 
+#if QT_CONFIG(opengl)
+#include <QOpenGLFunctions>
+#include <QOpenGLWindow>
+#endif
+
 const int animationInterval = 15; // update every 16 ms = ~60FPS
 
 CompositionWidget::CompositionWidget(QWidget *parent)
@@ -71,79 +76,76 @@ CompositionWidget::CompositionWidget(QWidget *parent)
     modesGroup->setTitle(tr("Mode"));
 
     rbClear = new QRadioButton(tr("Clear"), modesGroup);
-    connect(rbClear, SIGNAL(clicked()), view, SLOT(setClearMode()));
+    connect(rbClear, &QAbstractButton::clicked, view, &CompositionRenderer::setClearMode);
     rbSource = new QRadioButton(tr("Source"), modesGroup);
-    connect(rbSource, SIGNAL(clicked()), view, SLOT(setSourceMode()));
+    connect(rbSource, &QAbstractButton::clicked, view, &CompositionRenderer::setSourceMode);
     rbDest = new QRadioButton(tr("Destination"), modesGroup);
-    connect(rbDest, SIGNAL(clicked()), view, SLOT(setDestMode()));
+    connect(rbDest, &QAbstractButton::clicked, view, &CompositionRenderer::setDestMode);
     rbSourceOver = new QRadioButton(tr("Source Over"), modesGroup);
-    connect(rbSourceOver, SIGNAL(clicked()), view, SLOT(setSourceOverMode()));
+    connect(rbSourceOver, &QAbstractButton::clicked, view, &CompositionRenderer::setSourceOverMode);
     rbDestOver = new QRadioButton(tr("Destination Over"), modesGroup);
-    connect(rbDestOver, SIGNAL(clicked()), view, SLOT(setDestOverMode()));
+    connect(rbDestOver, &QAbstractButton::clicked, view, &CompositionRenderer::setDestOverMode);
     rbSourceIn = new QRadioButton(tr("Source In"), modesGroup);
-    connect(rbSourceIn, SIGNAL(clicked()), view, SLOT(setSourceInMode()));
+    connect(rbSourceIn, &QAbstractButton::clicked, view, &CompositionRenderer::setSourceInMode);
     rbDestIn = new QRadioButton(tr("Dest In"), modesGroup);
-    connect(rbDestIn, SIGNAL(clicked()), view, SLOT(setDestInMode()));
+    connect(rbDestIn, &QAbstractButton::clicked, view, &CompositionRenderer::setDestInMode);
     rbSourceOut = new QRadioButton(tr("Source Out"), modesGroup);
-    connect(rbSourceOut, SIGNAL(clicked()), view, SLOT(setSourceOutMode()));
+    connect(rbSourceOut, &QAbstractButton::clicked, view, &CompositionRenderer::setSourceOutMode);
     rbDestOut = new QRadioButton(tr("Dest Out"), modesGroup);
-    connect(rbDestOut, SIGNAL(clicked()), view, SLOT(setDestOutMode()));
+    connect(rbDestOut, &QAbstractButton::clicked, view, &CompositionRenderer::setDestOutMode);
     rbSourceAtop = new QRadioButton(tr("Source Atop"), modesGroup);
-    connect(rbSourceAtop, SIGNAL(clicked()), view, SLOT(setSourceAtopMode()));
+    connect(rbSourceAtop, &QAbstractButton::clicked, view, &CompositionRenderer::setSourceAtopMode);
     rbDestAtop = new QRadioButton(tr("Dest Atop"), modesGroup);
-    connect(rbDestAtop, SIGNAL(clicked()), view, SLOT(setDestAtopMode()));
+    connect(rbDestAtop, &QAbstractButton::clicked, view, &CompositionRenderer::setDestAtopMode);
     rbXor = new QRadioButton(tr("Xor"), modesGroup);
-    connect(rbXor, SIGNAL(clicked()), view, SLOT(setXorMode()));
+    connect(rbXor, &QAbstractButton::clicked, view, &CompositionRenderer::setXorMode);
 
     rbPlus = new QRadioButton(tr("Plus"), modesGroup);
-    connect(rbPlus, SIGNAL(clicked()), view, SLOT(setPlusMode()));
+    connect(rbPlus, &QAbstractButton::clicked, view, &CompositionRenderer::setPlusMode);
     rbMultiply = new QRadioButton(tr("Multiply"), modesGroup);
-    connect(rbMultiply, SIGNAL(clicked()), view, SLOT(setMultiplyMode()));
+    connect(rbMultiply, &QAbstractButton::clicked, view, &CompositionRenderer::setMultiplyMode);
     rbScreen = new QRadioButton(tr("Screen"), modesGroup);
-    connect(rbScreen, SIGNAL(clicked()), view, SLOT(setScreenMode()));
+    connect(rbScreen, &QAbstractButton::clicked, view, &CompositionRenderer::setScreenMode);
     rbOverlay = new QRadioButton(tr("Overlay"), modesGroup);
-    connect(rbOverlay, SIGNAL(clicked()), view, SLOT(setOverlayMode()));
+    connect(rbOverlay, &QAbstractButton::clicked, view, &CompositionRenderer::setOverlayMode);
     rbDarken = new QRadioButton(tr("Darken"), modesGroup);
-    connect(rbDarken, SIGNAL(clicked()), view, SLOT(setDarkenMode()));
+    connect(rbDarken, &QAbstractButton::clicked, view, &CompositionRenderer::setDarkenMode);
     rbLighten = new QRadioButton(tr("Lighten"), modesGroup);
-    connect(rbLighten, SIGNAL(clicked()), view, SLOT(setLightenMode()));
+    connect(rbLighten, &QAbstractButton::clicked, view, &CompositionRenderer::setLightenMode);
     rbColorDodge = new QRadioButton(tr("Color Dodge"), modesGroup);
-    connect(rbColorDodge, SIGNAL(clicked()), view, SLOT(setColorDodgeMode()));
+    connect(rbColorDodge, &QAbstractButton::clicked, view, &CompositionRenderer::setColorDodgeMode);
     rbColorBurn = new QRadioButton(tr("Color Burn"), modesGroup);
-    connect(rbColorBurn, SIGNAL(clicked()), view, SLOT(setColorBurnMode()));
+    connect(rbColorBurn, &QAbstractButton::clicked, view, &CompositionRenderer::setColorBurnMode);
     rbHardLight = new QRadioButton(tr("Hard Light"), modesGroup);
-    connect(rbHardLight, SIGNAL(clicked()), view, SLOT(setHardLightMode()));
+    connect(rbHardLight, &QAbstractButton::clicked, view, &CompositionRenderer::setHardLightMode);
     rbSoftLight = new QRadioButton(tr("Soft Light"), modesGroup);
-    connect(rbSoftLight, SIGNAL(clicked()), view, SLOT(setSoftLightMode()));
+    connect(rbSoftLight, &QAbstractButton::clicked, view, &CompositionRenderer::setSoftLightMode);
     rbDifference = new QRadioButton(tr("Difference"), modesGroup);
-    connect(rbDifference, SIGNAL(clicked()), view, SLOT(setDifferenceMode()));
+    connect(rbDifference, &QAbstractButton::clicked, view, &CompositionRenderer::setDifferenceMode);
     rbExclusion = new QRadioButton(tr("Exclusion"), modesGroup);
-    connect(rbExclusion, SIGNAL(clicked()), view, SLOT(setExclusionMode()));
+    connect(rbExclusion, &QAbstractButton::clicked, view, &CompositionRenderer::setExclusionMode);
 
     QGroupBox *circleColorGroup = new QGroupBox(mainGroup);
     circleColorGroup->setTitle(tr("Circle color"));
     QSlider *circleColorSlider = new QSlider(Qt::Horizontal, circleColorGroup);
     circleColorSlider->setRange(0, 359);
     circleColorSlider->setSizePolicy(QSizePolicy::Preferred, QSizePolicy::Fixed);
-    connect(circleColorSlider, SIGNAL(valueChanged(int)), view, SLOT(setCircleColor(int)));
+    connect(circleColorSlider, &QAbstractSlider::valueChanged, view, &CompositionRenderer::setCircleColor);
 
     QGroupBox *circleAlphaGroup = new QGroupBox(mainGroup);
     circleAlphaGroup->setTitle(tr("Circle alpha"));
     QSlider *circleAlphaSlider = new QSlider(Qt::Horizontal, circleAlphaGroup);
     circleAlphaSlider->setRange(0, 255);
     circleAlphaSlider->setSizePolicy(QSizePolicy::Preferred, QSizePolicy::Fixed);
-    connect(circleAlphaSlider, SIGNAL(valueChanged(int)), view, SLOT(setCircleAlpha(int)));
+    connect(circleAlphaSlider, &QAbstractSlider::valueChanged, view, &CompositionRenderer::setCircleAlpha);
 
     QPushButton *showSourceButton = new QPushButton(mainGroup);
     showSourceButton->setText(tr("Show Source"));
-#if defined(USE_OPENGL) && !defined(QT_OPENGL_ES)
+#if QT_CONFIG(opengl)
     QPushButton *enableOpenGLButton = new QPushButton(mainGroup);
     enableOpenGLButton->setText(tr("Use OpenGL"));
     enableOpenGLButton->setCheckable(true);
     enableOpenGLButton->setChecked(view->usesOpenGL());
-
-    if (!QGLFormat::hasOpenGL() || !QGLPixelBuffer::hasOpenGLPbuffers())
-        enableOpenGLButton->hide();
 #endif
     QPushButton *whatsThisButton = new QPushButton(mainGroup);
     whatsThisButton->setText(tr("What's This?"));
@@ -166,7 +168,7 @@ CompositionWidget::CompositionWidget(QWidget *parent)
     mainGroupLayout->addWidget(animateButton);
     mainGroupLayout->addWidget(whatsThisButton);
     mainGroupLayout->addWidget(showSourceButton);
-#if defined(USE_OPENGL) && !defined(QT_OPENGL_ES)
+#if QT_CONFIG(opengl)
     mainGroupLayout->addWidget(enableOpenGLButton);
 #endif
 
@@ -207,13 +209,13 @@ CompositionWidget::CompositionWidget(QWidget *parent)
     view->loadDescription(":res/composition/composition.html");
     view->loadSourceFile(":res/composition/composition.cpp");
 
-    connect(whatsThisButton, SIGNAL(clicked(bool)), view, SLOT(setDescriptionEnabled(bool)));
-    connect(view, SIGNAL(descriptionEnabledChanged(bool)), whatsThisButton, SLOT(setChecked(bool)));
-    connect(showSourceButton, SIGNAL(clicked()), view, SLOT(showSource()));
-#if defined(USE_OPENGL) && !defined(QT_OPENGL_ES)
-    connect(enableOpenGLButton, SIGNAL(clicked(bool)), view, SLOT(enableOpenGL(bool)));
+    connect(whatsThisButton, &QAbstractButton::clicked, view, &ArthurFrame::setDescriptionEnabled);
+    connect(view, &ArthurFrame::descriptionEnabledChanged, whatsThisButton, &QAbstractButton::setChecked);
+    connect(showSourceButton, &QAbstractButton::clicked, view, &ArthurFrame::showSource);
+#if QT_CONFIG(opengl)
+    connect(enableOpenGLButton, &QAbstractButton::clicked, view, &ArthurFrame::enableOpenGL);
 #endif
-    connect(animateButton, SIGNAL(toggled(bool)), view, SLOT(setAnimationEnabled(bool)));
+    connect(animateButton, &QAbstractButton::toggled, view, &CompositionRenderer::setAnimationEnabled);
 
     circleColorSlider->setValue(270);
     circleAlphaSlider->setValue(200);
@@ -258,8 +260,7 @@ CompositionRenderer::CompositionRenderer(QWidget *parent)
     m_circle_pos = QPoint(200, 100);
 
     setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Expanding);
-#ifdef USE_OPENGL
-    m_pbuffer = 0;
+#if QT_CONFIG(opengl)
     m_pbuffer_size = 1024;
 #endif
 }
@@ -340,9 +341,9 @@ void CompositionRenderer::drawSource(QPainter &p)
     QRectF circle_rect = rectangle_around(m_circle_pos);
     QColor color = QColor::fromHsvF(m_circle_hue / 360.0, 1, 1, m_circle_alpha / 255.0);
     QLinearGradient circle_gradient(circle_rect.topLeft(), circle_rect.bottomRight());
-    circle_gradient.setColorAt(0, color.light());
+    circle_gradient.setColorAt(0, color.lighter());
     circle_gradient.setColorAt(0.5, color);
-    circle_gradient.setColorAt(1, color.dark());
+    circle_gradient.setColorAt(1, color.darker());
     p.setBrush(circle_gradient);
 
     p.drawEllipse(circle_rect);
@@ -350,105 +351,62 @@ void CompositionRenderer::drawSource(QPainter &p)
 
 void CompositionRenderer::paint(QPainter *painter)
 {
-#if defined(USE_OPENGL) && !defined(QT_OPENGL_ES)
-    if (usesOpenGL()) {
+#if QT_CONFIG(opengl)
+    if (usesOpenGL() && glWindow()->isValid()) {
+
+        if (!m_blitter.isCreated())
+            m_blitter.create();
 
         int new_pbuf_size = m_pbuffer_size;
-        if (size().width() > m_pbuffer_size || size().height() > m_pbuffer_size)
+        while (size().width() > new_pbuf_size || size().height() > new_pbuf_size)
             new_pbuf_size *= 2;
 
-        if (size().width() < m_pbuffer_size/2 && size().height() < m_pbuffer_size/2)
+        while (size().width() < new_pbuf_size/2 && size().height() < new_pbuf_size/2)
             new_pbuf_size /= 2;
 
-        if (!m_pbuffer || new_pbuf_size != m_pbuffer_size) {
-            if (m_pbuffer) {
-                m_pbuffer->deleteTexture(m_base_tex);
-                m_pbuffer->deleteTexture(m_compositing_tex);
-                delete m_pbuffer;
-            }
-
-            m_pbuffer = new QGLPixelBuffer(QSize(new_pbuf_size, new_pbuf_size), QGLFormat::defaultFormat(), glWidget());
-            m_pbuffer->makeCurrent();
-            m_base_tex = m_pbuffer->generateDynamicTexture();
-            m_compositing_tex = m_pbuffer->generateDynamicTexture();
+        if (!m_fbo || new_pbuf_size != m_pbuffer_size) {
+            m_fbo.reset(new QFboPaintDevice(QSize(new_pbuf_size, new_pbuf_size), false, false));
             m_pbuffer_size = new_pbuf_size;
         }
 
         if (size() != m_previous_size) {
             m_previous_size = size();
-            QPainter p(m_pbuffer);
+            QPainter p(m_fbo.data());
             p.setCompositionMode(QPainter::CompositionMode_Source);
-            p.fillRect(QRect(0, 0, m_pbuffer->width(), m_pbuffer->height()), Qt::transparent);
+            p.fillRect(QRect(QPoint(0, 0), size()), Qt::transparent);
+            p.setCompositionMode(QPainter::CompositionMode_SourceOver);
             drawBase(p);
             p.end();
-            m_pbuffer->updateDynamicTexture(m_base_tex);
+            m_base_tex = m_fbo->takeTexture();
         }
 
-        qreal x_fraction = width()/float(m_pbuffer->width());
-        qreal y_fraction = height()/float(m_pbuffer->height());
-
+        painter->beginNativePainting();
         {
-            QPainter p(m_pbuffer);
-            p.setCompositionMode(QPainter::CompositionMode_Source);
-            p.fillRect(QRect(0, 0, m_pbuffer->width(), m_pbuffer->height()), Qt::transparent);
-
-            p.save(); // Needed when using the GL1 engine
-            p.beginNativePainting(); // Needed when using the GL2 engine
-
-            glBindTexture(GL_TEXTURE_2D, m_base_tex);
-            glEnable(GL_TEXTURE_2D);
-            glColor4f(1.,1.,1.,1.);
-
-            glBegin(GL_QUADS);
-            {
-                glTexCoord2f(0, 1.0);
-                glVertex2f(0, 0);
-
-                glTexCoord2f(x_fraction, 1.0);
-                glVertex2f(width(), 0);
-
-                glTexCoord2f(x_fraction, 1.0-y_fraction);
-                glVertex2f(width(), height());
-
-                glTexCoord2f(0, 1.0-y_fraction);
-                glVertex2f(0, height());
-            }
-            glEnd();
-
-            glDisable(GL_TEXTURE_2D);
-
-            p.endNativePainting(); // Needed when using the GL2 engine
-            p.restore(); // Needed when using the GL1 engine
-
+            QPainter p(m_fbo.data());
+            p.beginNativePainting();
+            m_blitter.bind();
+            const QRect targetRect(QPoint(0, 0), m_fbo->size());
+            const QMatrix4x4 target = QOpenGLTextureBlitter::targetTransform(targetRect, QRect(QPoint(0, 0), m_fbo->size()));
+            m_blitter.blit(m_base_tex, target, QOpenGLTextureBlitter::OriginBottomLeft);
+            m_blitter.release();
+            p.endNativePainting();
             drawSource(p);
             p.end();
-            m_pbuffer->updateDynamicTexture(m_compositing_tex);
-        }
-
-        painter->beginNativePainting(); // Needed when using the GL2 engine
-        glWidget()->makeCurrent(); // Needed when using the GL1 engine
-        glBindTexture(GL_TEXTURE_2D, m_compositing_tex);
-        glEnable(GL_TEXTURE_2D);
-        glEnable(GL_BLEND);
-        glBlendFunc(GL_ONE, GL_ONE_MINUS_SRC_ALPHA);
-        glColor4f(1.,1.,1.,1.);
-        glBegin(GL_QUADS);
-        {
-            glTexCoord2f(0, 1.0);
-            glVertex2f(0, 0);
-
-            glTexCoord2f(x_fraction, 1.0);
-            glVertex2f(width(), 0);
-
-            glTexCoord2f(x_fraction, 1.0-y_fraction);
-            glVertex2f(width(), height());
-
-            glTexCoord2f(0, 1.0-y_fraction);
-            glVertex2f(0, height());
+            m_compositing_tex = m_fbo->takeTexture();
         }
-        glEnd();
-        glDisable(GL_TEXTURE_2D);
-        painter->endNativePainting(); // Needed when using the GL2 engine
+        painter->endNativePainting();
+
+        painter->beginNativePainting();
+        auto *funcs = QOpenGLContext::currentContext()->functions();
+        funcs->glEnable(GL_BLEND);
+        funcs->glBlendEquation(GL_FUNC_ADD);
+        funcs->glBlendFunc(GL_ONE, GL_ONE_MINUS_SRC_ALPHA);
+        m_blitter.bind();
+        const QRect targetRect(QPoint(0, 0), m_fbo->size());
+        const QMatrix4x4 target = QOpenGLTextureBlitter::targetTransform(targetRect, QRect(QPoint(0, 0), size()));
+        m_blitter.blit(m_compositing_tex, target, QOpenGLTextureBlitter::OriginBottomLeft);
+        m_blitter.release();
+        painter->endNativePainting();
     } else
 #endif
     {
@@ -520,7 +478,7 @@ void CompositionRenderer::setCirclePos(const QPointF &pos)
     const QRect oldRect = rectangle_around(m_circle_pos).toAlignedRect();
     m_circle_pos = pos;
     const QRect newRect = rectangle_around(m_circle_pos).toAlignedRect();
-#if defined(USE_OPENGL) && !defined(QT_OPENGL_ES)
+#if QT_CONFIG(opengl)
     if (usesOpenGL()) {
         update();
         return;
diff --git a/examples/widgets/painting/composition/composition.h b/examples/widgets/painting/composition/composition.h
index 49853f503b..19150e2024 100644
--- a/examples/widgets/painting/composition/composition.h
+++ b/examples/widgets/painting/composition/composition.h
@@ -53,6 +53,11 @@
 
 #include "arthurwidgets.h"
 
+#if QT_CONFIG(opengl)
+#include "fbopaintdevice.h"
+#include <QOpenGLTextureBlitter>
+#endif
+
 #include <QPainter>
 #include <QEvent>
 
@@ -61,10 +66,6 @@ class QPushButton;
 class QRadioButton;
 QT_END_NAMESPACE
 
-#ifdef QT_OPENGL_SUPPORT
-#include <QtOpenGL>
-#endif
-
 class CompositionWidget : public QWidget
 {
     Q_OBJECT
@@ -186,12 +187,13 @@ private:
     bool m_animation_enabled;
     int m_animationTimer;
 
-#ifdef QT_OPENGL_SUPPORT
-    QGLPixelBuffer *m_pbuffer;
-    GLuint m_base_tex;
-    GLuint m_compositing_tex;
+#if QT_CONFIG(opengl)
+    QScopedPointer<QFboPaintDevice> m_fbo;
     int m_pbuffer_size; // width==height==size of pbuffer
+    uint m_base_tex;
+    uint m_compositing_tex;
     QSize m_previous_size;
+    QOpenGLTextureBlitter m_blitter;
 #endif
 };
 
diff --git a/examples/widgets/painting/composition/composition.pro b/examples/widgets/painting/composition/composition.pro
index 5fdbe4a5a2..15d8c6e67b 100644
--- a/examples/widgets/painting/composition/composition.pro
+++ b/examples/widgets/painting/composition/composition.pro
@@ -6,10 +6,6 @@ SHARED_FOLDER = ../shared
 include($$SHARED_FOLDER/shared.pri)
 
 RESOURCES += composition.qrc
-qtHaveModule(opengl):!qtConfig(dynamicgl) {
-    DEFINES += USE_OPENGL
-    QT += opengl
-}
 QT += widgets
 
 # install
diff --git a/examples/widgets/painting/composition/main.cpp b/examples/widgets/painting/composition/main.cpp
index 1a5dfd3e5e..2eaeaba2c5 100644
--- a/examples/widgets/painting/composition/main.cpp
+++ b/examples/widgets/painting/composition/main.cpp
@@ -51,22 +51,17 @@
 #include "composition.h"
 
 #include <QApplication>
-#ifdef QT_OPENGL_SUPPORT
-#include <QtOpenGL>
-#endif
 
 int main(int argc, char *argv[])
 {
- //   Q_INIT_RESOURCE(deform);
-
     QApplication app(argc, argv);
 
-    CompositionWidget compWidget(0);
+    CompositionWidget compWidget(nullptr);
     QStyle *arthurStyle = new ArthurStyle();
     compWidget.setStyle(arthurStyle);
 
-    QList<QWidget *> widgets = compWidget.findChildren<QWidget *>();
-    foreach (QWidget *w, widgets)
+    const QList<QWidget *> widgets = compWidget.findChildren<QWidget *>();
+    for (QWidget *w : widgets)
         w->setStyle(arthurStyle);
     compWidget.show();
 
diff --git a/examples/widgets/painting/concentriccircles/window.cpp b/examples/widgets/painting/concentriccircles/window.cpp
index 0f65dc2285..45258e0bc4 100644
--- a/examples/widgets/painting/concentriccircles/window.cpp
+++ b/examples/widgets/painting/concentriccircles/window.cpp
@@ -77,8 +77,8 @@ Window::Window()
             circleWidgets[i][j]->setAntialiased(j != 0);
             circleWidgets[i][j]->setFloatBased(i != 0);
 
-            connect(timer, SIGNAL(timeout()),
-                    circleWidgets[i][j], SLOT(nextAnimationFrame()));
+            connect(timer, &QTimer::timeout,
+                    circleWidgets[i][j], &CircleWidget::nextAnimationFrame);
 
             layout->addWidget(circleWidgets[i][j], i + 1, j + 1);
         }
diff --git a/examples/widgets/painting/deform/deform.pro b/examples/widgets/painting/deform/deform.pro
index 6409aaed96..498ec57686 100644
--- a/examples/widgets/painting/deform/deform.pro
+++ b/examples/widgets/painting/deform/deform.pro
@@ -7,10 +7,6 @@ include($$SHARED_FOLDER/shared.pri)
 
 RESOURCES += deform.qrc
 
-qtHaveModule(opengl) {
-	DEFINES += QT_OPENGL_SUPPORT
-	QT += opengl
-}
 QT += widgets
 
 # install
diff --git a/examples/widgets/painting/deform/main.cpp b/examples/widgets/painting/deform/main.cpp
index 85e83207c0..28e3d6823d 100644
--- a/examples/widgets/painting/deform/main.cpp
+++ b/examples/widgets/painting/deform/main.cpp
@@ -60,12 +60,12 @@ int main(int argc, char **argv)
 
     bool smallScreen = QApplication::arguments().contains("-small-screen");
 
-    PathDeformWidget deformWidget(0, smallScreen);
+    PathDeformWidget deformWidget(nullptr, smallScreen);
 
-    QStyle *arthurStyle = new ArthurStyle();
+    QStyle *arthurStyle = new ArthurStyle;
     deformWidget.setStyle(arthurStyle);
-    QList<QWidget *> widgets = deformWidget.findChildren<QWidget *>();
-    foreach (QWidget *w, widgets)
+    const QList<QWidget *> widgets = deformWidget.findChildren<QWidget *>();
+    for (QWidget *w : widgets)
         w->setStyle(arthurStyle);
 
     if (smallScreen)
diff --git a/examples/widgets/painting/deform/pathdeform.cpp b/examples/widgets/painting/deform/pathdeform.cpp
index 805804716f..64e81f8cab 100644
--- a/examples/widgets/painting/deform/pathdeform.cpp
+++ b/examples/widgets/painting/deform/pathdeform.cpp
@@ -109,13 +109,11 @@ void PathDeformControls::layoutForDesktop()
     QPushButton *showSourceButton = new QPushButton(mainGroup);
     showSourceButton->setText(tr("Show Source"));
 
-#ifdef QT_OPENGL_SUPPORT
+#if QT_CONFIG(opengl)
     QPushButton *enableOpenGLButton = new QPushButton(mainGroup);
     enableOpenGLButton->setText(tr("Use OpenGL"));
     enableOpenGLButton->setCheckable(true);
     enableOpenGLButton->setChecked(m_renderer->usesOpenGL());
-    if (!QGLFormat::hasOpenGL())
-        enableOpenGLButton->hide();
 #endif
 
     QPushButton *whatsThisButton = new QPushButton(mainGroup);
@@ -132,7 +130,7 @@ void PathDeformControls::layoutForDesktop()
     mainGroupLayout->addWidget(textGroup);
     mainGroupLayout->addWidget(animateButton);
     mainGroupLayout->addStretch(1);
-#ifdef QT_OPENGL_SUPPORT
+#if QT_CONFIG(opengl)
     mainGroupLayout->addWidget(enableOpenGLButton);
 #endif
     mainGroupLayout->addWidget(showSourceButton);
@@ -152,21 +150,21 @@ void PathDeformControls::layoutForDesktop()
 
     QVBoxLayout * mainLayout = new QVBoxLayout(this);
     mainLayout->addWidget(mainGroup);
-    mainLayout->setMargin(0);
-
-    connect(radiusSlider, SIGNAL(valueChanged(int)), m_renderer, SLOT(setRadius(int)));
-    connect(deformSlider, SIGNAL(valueChanged(int)), m_renderer, SLOT(setIntensity(int)));
-    connect(fontSizeSlider, SIGNAL(valueChanged(int)), m_renderer, SLOT(setFontSize(int)));
-    connect(animateButton, SIGNAL(clicked(bool)), m_renderer, SLOT(setAnimated(bool)));
-#ifdef QT_OPENGL_SUPPORT
-    connect(enableOpenGLButton, SIGNAL(clicked(bool)), m_renderer, SLOT(enableOpenGL(bool)));
+    mainLayout->setContentsMargins(QMargins());
+
+    connect(radiusSlider, &QAbstractSlider::valueChanged, m_renderer, &PathDeformRenderer::setRadius);
+    connect(deformSlider, &QAbstractSlider::valueChanged, m_renderer, &PathDeformRenderer::setIntensity);
+    connect(fontSizeSlider, &QAbstractSlider::valueChanged, m_renderer, &PathDeformRenderer::setFontSize);
+    connect(animateButton, &QAbstractButton::clicked, m_renderer, &PathDeformRenderer::setAnimated);
+#if QT_CONFIG(opengl)
+    connect(enableOpenGLButton, &QAbstractButton::clicked, m_renderer, &ArthurFrame::enableOpenGL);
 #endif
 
-    connect(textInput, SIGNAL(textChanged(QString)), m_renderer, SLOT(setText(QString)));
-    connect(m_renderer, SIGNAL(descriptionEnabledChanged(bool)),
-            whatsThisButton, SLOT(setChecked(bool)));
-    connect(whatsThisButton, SIGNAL(clicked(bool)), m_renderer, SLOT(setDescriptionEnabled(bool)));
-    connect(showSourceButton, SIGNAL(clicked()), m_renderer, SLOT(showSource()));
+    connect(textInput, &QLineEdit::textChanged, m_renderer, &PathDeformRenderer::setText);
+    connect(m_renderer, &ArthurFrame::descriptionEnabledChanged,
+            whatsThisButton, &QAbstractButton::setChecked);
+    connect(whatsThisButton, &QAbstractButton::clicked, m_renderer, &ArthurFrame::setDescriptionEnabled);
+    connect(showSourceButton, &QAbstractButton::clicked, m_renderer, &ArthurFrame::showSource);
 
     animateButton->animateClick();
     deformSlider->setValue(80);
@@ -201,13 +199,11 @@ void PathDeformControls::layoutForSmallScreen()
     QPushButton *animateButton = new QPushButton(tr("Animated"), mainGroup);
     animateButton->setCheckable(true);
 
-#ifdef QT_OPENGL_SUPPORT
+#if QT_CONFIG(opengl)
     QPushButton *enableOpenGLButton = new QPushButton(mainGroup);
     enableOpenGLButton->setText(tr("Use OpenGL"));
     enableOpenGLButton->setCheckable(mainGroup);
     enableOpenGLButton->setChecked(m_renderer->usesOpenGL());
-    if (!QGLFormat::hasOpenGL())
-        enableOpenGLButton->hide();
 #endif
 
     QPushButton *quitButton = new QPushButton(tr("Quit"), mainGroup);
@@ -215,7 +211,7 @@ void PathDeformControls::layoutForSmallScreen()
 
 
     QGridLayout *mainGroupLayout = new QGridLayout(mainGroup);
-    mainGroupLayout->setMargin(0);
+    mainGroupLayout->setContentsMargins(QMargins());
     mainGroupLayout->addWidget(radiusLabel, 0, 0, Qt::AlignRight);
     mainGroupLayout->addWidget(radiusSlider, 0, 1);
     mainGroupLayout->addWidget(deformLabel, 1, 0, Qt::AlignRight);
@@ -223,7 +219,7 @@ void PathDeformControls::layoutForSmallScreen()
     mainGroupLayout->addWidget(fontSizeLabel, 2, 0, Qt::AlignRight);
     mainGroupLayout->addWidget(fontSizeSlider, 2, 1);
     mainGroupLayout->addWidget(animateButton, 3,0, 1,2);
-#ifdef QT_OPENGL_SUPPORT
+#if QT_CONFIG(opengl)
     mainGroupLayout->addWidget(enableOpenGLButton, 4,0, 1,2);
 #endif
 
@@ -233,14 +229,14 @@ void PathDeformControls::layoutForSmallScreen()
     mainLayout->addWidget(okButton);
     mainLayout->addWidget(quitButton);
 
-    connect(quitButton, SIGNAL(clicked()), this, SIGNAL(quitPressed()));
-    connect(okButton, SIGNAL(clicked()), this, SIGNAL(okPressed()));
-    connect(radiusSlider, SIGNAL(valueChanged(int)), m_renderer, SLOT(setRadius(int)));
-    connect(deformSlider, SIGNAL(valueChanged(int)), m_renderer, SLOT(setIntensity(int)));
-    connect(fontSizeSlider, SIGNAL(valueChanged(int)), m_renderer, SLOT(setFontSize(int)));
-    connect(animateButton, SIGNAL(clicked(bool)), m_renderer, SLOT(setAnimated(bool)));
-#ifdef QT_OPENGL_SUPPORT
-    connect(enableOpenGLButton, SIGNAL(clicked(bool)), m_renderer, SLOT(enableOpenGL(bool)));
+    connect(quitButton, &QAbstractButton::clicked, this, &PathDeformControls::quitPressed);
+    connect(okButton, &QAbstractButton::clicked, this, &PathDeformControls::okPressed);
+    connect(radiusSlider, &QAbstractSlider::valueChanged, m_renderer, &PathDeformRenderer::setRadius);
+    connect(deformSlider, &QAbstractSlider::valueChanged, m_renderer, &PathDeformRenderer::setIntensity);
+    connect(fontSizeSlider, &QAbstractSlider::valueChanged, m_renderer, &PathDeformRenderer::setFontSize);
+    connect(animateButton, &QAbstractButton::clicked, m_renderer, &PathDeformRenderer::setAnimated);
+#if QT_CONFIG(opengl)
+    connect(enableOpenGLButton, &QAbstractButton::clicked, m_renderer, &ArthurFrame::enableOpenGL);
 #endif
 
 
@@ -276,9 +272,12 @@ PathDeformWidget::PathDeformWidget(QWidget *parent, bool smallScreen)
     m_renderer->loadDescription(":res/deform/pathdeform.html");
     m_renderer->setDescriptionEnabled(false);
 
-    connect(m_renderer, SIGNAL(clicked()), this, SLOT(showControls()));
-    connect(m_controls, SIGNAL(okPressed()), this, SLOT(hideControls()));
-    connect(m_controls, SIGNAL(quitPressed()), QCoreApplication::instance(), SLOT(quit()));
+    connect(m_renderer, &PathDeformRenderer::clicked,
+            this, &PathDeformWidget::showControls);
+    connect(m_controls, &PathDeformControls::okPressed,
+            this, &PathDeformWidget::hideControls);
+    connect(m_controls, &PathDeformControls::quitPressed,
+            qApp, &QCoreApplication::quit);
 }
 
 
@@ -292,16 +291,16 @@ void PathDeformWidget::hideControls()
     m_controls->hide();
 }
 
-void PathDeformWidget::setStyle( QStyle * style )
+void PathDeformWidget::setStyle(QStyle *style)
 {
     QWidget::setStyle(style);
-    if (m_controls == 0)
+    if (!m_controls)
         return;
 
     m_controls->setStyle(style);
 
-    QList<QWidget *> widgets = m_controls->findChildren<QWidget *>();
-    foreach (QWidget *w, widgets)
+    const QList<QWidget *> widgets = m_controls->findChildren<QWidget *>();
+    for (QWidget *w : widgets)
         w->setStyle(style);
 }
 
@@ -463,7 +462,7 @@ void PathDeformRenderer::timerEvent(QTimerEvent *e)
             m_pos.setY(height() - m_radius);
         }
 
-#ifdef QT_OPENGL_SUPPORT
+#if QT_CONFIG(opengl)
         if (usesOpenGL()) {
             update();
         } else
@@ -527,7 +526,7 @@ void PathDeformRenderer::mouseMoveEvent(QMouseEvent *e)
             m_direction = (m_direction + dir) / 2;
         }
         m_pos = e->pos() + m_offset;
-#ifdef QT_OPENGL_SUPPORT
+#if QT_CONFIG(opengl)
         if (usesOpenGL()) {
             update();
         } else
@@ -620,7 +619,7 @@ void PathDeformRenderer::setRadius(int radius)
     m_radius = radius;
     generateLensPixmap();
     if (!m_animated || m_radius < max) {
-#ifdef QT_OPENGL_SUPPORT
+#if QT_CONFIG(opengl)
         if (usesOpenGL()){
             update();
             return;
@@ -634,7 +633,7 @@ void PathDeformRenderer::setIntensity(int intensity)
 {
     m_intensity = intensity;
     if (!m_animated) {
-#ifdef QT_OPENGL_SUPPORT
+#if QT_CONFIG(opengl)
         if (usesOpenGL()) {
             update();
             return;
diff --git a/examples/widgets/painting/deform/pathdeform.h b/examples/widgets/painting/deform/pathdeform.h
index 68908045b9..b7c7386e2a 100644
--- a/examples/widgets/painting/deform/pathdeform.h
+++ b/examples/widgets/painting/deform/pathdeform.h
@@ -135,7 +135,7 @@ signals:
     void okPressed();
     void quitPressed();
 private:
-    PathDeformRenderer* m_renderer;
+    PathDeformRenderer *m_renderer;
     void layoutForDesktop();
     void layoutForSmallScreen();
 };
@@ -145,7 +145,7 @@ class PathDeformWidget : public QWidget
     Q_OBJECT
 public:
     PathDeformWidget(QWidget *parent, bool smallScreen);
-    void setStyle (QStyle * style );
+    void setStyle(QStyle *style);
 
 private:
     PathDeformRenderer *m_renderer;
diff --git a/examples/widgets/painting/fontsampler/mainwindow.cpp b/examples/widgets/painting/fontsampler/mainwindow.cpp
index bd15438df9..b3304b4b6d 100644
--- a/examples/widgets/painting/fontsampler/mainwindow.cpp
+++ b/examples/widgets/painting/fontsampler/mainwindow.cpp
@@ -71,13 +71,14 @@ MainWindow::MainWindow(QWidget *parent)
     markedCount = 0;
     setupFontTree();
 
-    connect(quitAction, SIGNAL(triggered()), qApp, SLOT(quit()));
-    connect(fontTree, SIGNAL(currentItemChanged(QTreeWidgetItem*,QTreeWidgetItem*)),
-            this, SLOT(showFont(QTreeWidgetItem*)));
-    connect(fontTree, SIGNAL(itemChanged(QTreeWidgetItem*,int)),
-            this, SLOT(updateStyles(QTreeWidgetItem*,int)));
-
-    fontTree->setItemSelected(fontTree->topLevelItem(0), true);
+    connect(quitAction, &QAction::triggered,
+            qApp, &QApplication::quit);
+    connect(fontTree, &QTreeWidget::currentItemChanged,
+            this, &MainWindow::showFont);
+    connect(fontTree, &QTreeWidget::itemChanged,
+            this, &MainWindow::updateStyles);
+
+    fontTree->topLevelItem(0)->setSelected(true);
     showFont(fontTree->topLevelItem(0));
 }
 
@@ -85,9 +86,10 @@ void MainWindow::setupFontTree()
 {
     QFontDatabase database;
     fontTree->setColumnCount(1);
-    fontTree->setHeaderLabels(QStringList() << tr("Font"));
+    fontTree->setHeaderLabels({ tr("Font") });
 
-    foreach (QString family, database.families()) {
+    const QStringList fontFamilies = database.families();
+    for (const QString &family : fontFamilies) {
         const QStringList styles = database.styles(family);
         if (styles.isEmpty())
             continue;
@@ -97,7 +99,7 @@ void MainWindow::setupFontTree()
         familyItem->setCheckState(0, Qt::Unchecked);
         familyItem->setFlags(familyItem->flags() | Qt::ItemIsAutoTristate);
 
-        foreach (QString style, styles) {
+        for (const QString &style : styles) {
             QTreeWidgetItem *styleItem = new QTreeWidgetItem(familyItem);
             styleItem->setText(0, style);
             styleItem->setCheckState(0, Qt::Unchecked);
@@ -109,10 +111,10 @@ void MainWindow::setupFontTree()
 
 void MainWindow::on_clearAction_triggered()
 {
-    QTreeWidgetItem *currentItem = fontTree->currentItem();
-    foreach (QTreeWidgetItem *item, fontTree->selectedItems())
-        fontTree->setItemSelected(item, false);
-    fontTree->setItemSelected(currentItem, true);
+    const QList<QTreeWidgetItem *> items = fontTree->selectedItems();
+    for (QTreeWidgetItem *item : items)
+        item->setSelected(false);
+    fontTree->currentItem()->setSelected(true);
 }
 
 void MainWindow::on_markAction_triggered()
@@ -127,8 +129,8 @@ void MainWindow::on_unmarkAction_triggered()
 
 void MainWindow::markUnmarkFonts(Qt::CheckState state)
 {
-    QList<QTreeWidgetItem *> items = fontTree->selectedItems();
-    foreach (QTreeWidgetItem *item, items) {
+    const QList<QTreeWidgetItem *> items = fontTree->selectedItems();
+    for (QTreeWidgetItem *item : items) {
         if (item->checkState(0) != state)
             item->setCheckState(0, state);
     }
@@ -285,8 +287,8 @@ void MainWindow::on_printPreviewAction_triggered()
 
     QPrinter printer(QPrinter::HighResolution);
     QPrintPreviewDialog preview(&printer, this);
-    connect(&preview, SIGNAL(paintRequested(QPrinter*)),
-            this, SLOT(printDocument(QPrinter*)));
+    connect(&preview, &QPrintPreviewDialog::paintRequested,
+            this, &MainWindow::printDocument);
     preview.exec();
 #endif
 }
@@ -294,19 +296,19 @@ void MainWindow::on_printPreviewAction_triggered()
 void MainWindow::printPage(int index, QPainter *painter, QPrinter *printer)
 {
 #if defined(QT_PRINTSUPPORT_LIB) && QT_CONFIG(printdialog)
-    QString family = pageMap.keys()[index];
-    StyleItems items = pageMap[family];
+    const QString family = (pageMap.begin() + index).key();
+    const StyleItems items = pageMap.value(family);
 
     // Find the dimensions of the text on each page.
     qreal width = 0.0;
     qreal height = 0.0;
-    foreach (QTreeWidgetItem *item, items) {
+    for (const QTreeWidgetItem *item : items) {
         QString style = item->text(0);
         int weight = item->data(0, Qt::UserRole).toInt();
         bool italic = item->data(0, Qt::UserRole + 1).toBool();
 
         // Calculate the maximum width and total height of the text.
-        foreach (int size, sampleSizes) {
+        for (int size : qAsConst(sampleSizes)) {
             QFont font(family, size, weight, italic);
             font.setStyleName(style);
             font = QFont(font, painter->device());
@@ -334,13 +336,13 @@ void MainWindow::printPage(int index, QPainter *painter, QPrinter *printer)
     qreal x = -width / 2.0;
     qreal y = -height / 2.0 - remainingHeight / 4.0 + spaceHeight;
 
-    foreach (QTreeWidgetItem *item, items) {
+    for (const QTreeWidgetItem *item : items) {
         QString style = item->text(0);
         int weight = item->data(0, Qt::UserRole).toInt();
         bool italic = item->data(0, Qt::UserRole + 1).toBool();
 
         // Draw each line of text.
-        foreach (int size, sampleSizes) {
+        for (int size : qAsConst(sampleSizes)) {
             QFont font(family, size, weight, italic);
             font.setStyleName(style);
             font = QFont(font, painter->device());
diff --git a/examples/widgets/painting/gradients/gradients.cpp b/examples/widgets/painting/gradients/gradients.cpp
index 6d9f514a8d..8df45be8d9 100644
--- a/examples/widgets/painting/gradients/gradients.cpp
+++ b/examples/widgets/painting/gradients/gradients.cpp
@@ -180,7 +180,7 @@ GradientEditor::GradientEditor(QWidget *parent)
 {
     QVBoxLayout *vbox = new QVBoxLayout(this);
     vbox->setSpacing(1);
-    vbox->setMargin(1);
+    vbox->setContentsMargins(1, 1, 1, 1);
 
     m_red_shade = new ShadeWidget(ShadeWidget::RedShade, this);
     m_green_shade = new ShadeWidget(ShadeWidget::GreenShade, this);
@@ -317,13 +317,11 @@ GradientWidget::GradientWidget(QWidget *parent)
 
     QPushButton *showSourceButton = new QPushButton(mainGroup);
     showSourceButton->setText(tr("Show Source"));
-#ifdef QT_OPENGL_SUPPORT
+#if QT_CONFIG(opengl)
     QPushButton *enableOpenGLButton = new QPushButton(mainGroup);
     enableOpenGLButton->setText(tr("Use OpenGL"));
     enableOpenGLButton->setCheckable(true);
     enableOpenGLButton->setChecked(m_renderer->usesOpenGL());
-    if (!QGLFormat::hasOpenGL())
-        enableOpenGLButton->hide();
 #endif
     QPushButton *whatsThisButton = new QPushButton(mainGroup);
     whatsThisButton->setText(tr("What's This?"));
@@ -343,7 +341,7 @@ GradientWidget::GradientWidget(QWidget *parent)
     mainGroupLayout->addWidget(defaultsGroup);
     mainGroupLayout->addStretch(1);
     mainGroupLayout->addWidget(showSourceButton);
-#ifdef QT_OPENGL_SUPPORT
+#if QT_CONFIG(opengl)
     mainGroupLayout->addWidget(enableOpenGLButton);
 #endif
     mainGroupLayout->addWidget(whatsThisButton);
@@ -406,7 +404,7 @@ GradientWidget::GradientWidget(QWidget *parent)
 
     connect(showSourceButton, &QPushButton::clicked,
             m_renderer, &GradientRenderer::showSource);
-#ifdef QT_OPENGL_SUPPORT
+#if QT_CONFIG(opengl)
     connect(enableOpenGLButton, QOverload<bool>::of(&QPushButton::clicked),
             m_renderer, &ArthurFrame::enableOpenGL);
 #endif
@@ -423,7 +421,7 @@ GradientWidget::GradientWidget(QWidget *parent)
     m_renderer->loadSourceFile(":res/gradients/gradients.cpp");
     m_renderer->loadDescription(":res/gradients/gradients.html");
 
-    QTimer::singleShot(50, this, SLOT(setDefault1()));
+    QTimer::singleShot(50, this, &GradientWidget::setDefault1);
 }
 
 void GradientWidget::setDefault(int config)
@@ -566,9 +564,7 @@ void GradientRenderer::paint(QPainter *p)
 
     } else {
         QLineF l(pts.at(0), pts.at(1));
-        qreal angle = l.angle(QLineF(0, 0, 1, 0));
-        if (l.dy() > 0)
-            angle = 360 - angle;
+        qreal angle = QLineF(0, 0, 1, 0).angleTo(l);
         g = QConicalGradient(pts.at(0), angle);
     }
 
diff --git a/examples/widgets/painting/gradients/gradients.pro b/examples/widgets/painting/gradients/gradients.pro
index 73f3974c62..14eccb6500 100644
--- a/examples/widgets/painting/gradients/gradients.pro
+++ b/examples/widgets/painting/gradients/gradients.pro
@@ -6,10 +6,6 @@ SHARED_FOLDER = ../shared
 include($$SHARED_FOLDER/shared.pri)
 
 RESOURCES += gradients.qrc
-qtHaveModule(opengl) {
-	DEFINES += QT_OPENGL_SUPPORT
-	QT += opengl
-}
 QT += widgets
 
 # install
diff --git a/examples/widgets/painting/gradients/main.cpp b/examples/widgets/painting/gradients/main.cpp
index 6c5261fe6b..539d67e40e 100644
--- a/examples/widgets/painting/gradients/main.cpp
+++ b/examples/widgets/painting/gradients/main.cpp
@@ -61,8 +61,8 @@ int main(int argc, char *argv[])
     GradientWidget gradientWidget(0);
     QStyle *arthurStyle = new ArthurStyle();
     gradientWidget.setStyle(arthurStyle);
-    QList<QWidget *> widgets = gradientWidget.findChildren<QWidget *>();
-    foreach (QWidget *w, widgets) {
+    const QList<QWidget *> widgets = gradientWidget.findChildren<QWidget *>();
+    for (QWidget *w : widgets) {
         w->setStyle(arthurStyle);
         w->setAttribute(Qt::WA_AcceptTouchEvents);
     }
diff --git a/examples/widgets/painting/imagecomposition/imagecomposer.cpp b/examples/widgets/painting/imagecomposition/imagecomposer.cpp
index d53017b955..ffdc8f433c 100644
--- a/examples/widgets/painting/imagecomposition/imagecomposer.cpp
+++ b/examples/widgets/painting/imagecomposition/imagecomposer.cpp
@@ -100,9 +100,12 @@ ImageComposer::ImageComposer()
 //! [2]
 
 //! [3]
-    connect(sourceButton, SIGNAL(clicked()), this, SLOT(chooseSource()));
-    connect(operatorComboBox, SIGNAL(activated(int)), this, SLOT(recalculateResult()));
-    connect(destinationButton, SIGNAL(clicked()), this, SLOT(chooseDestination()));
+    connect(sourceButton, &QAbstractButton::clicked,
+            this, &ImageComposer::chooseSource);
+    connect(operatorComboBox, QOverload<int>::of(&QComboBox::activated),
+            this, &ImageComposer::recalculateResult);
+    connect(destinationButton, &QAbstractButton::clicked,
+            this, &ImageComposer::chooseDestination);
 //! [3]
 
 //! [4]
diff --git a/examples/widgets/painting/painterpaths/window.cpp b/examples/widgets/painting/painterpaths/window.cpp
index a987937b39..6fb3218313 100644
--- a/examples/widgets/painting/painterpaths/window.cpp
+++ b/examples/widgets/painting/painterpaths/window.cpp
@@ -194,22 +194,30 @@ Window::Window()
 //! [12]
 
 //! [16]
-    connect(fillRuleComboBox, SIGNAL(activated(int)), this, SLOT(fillRuleChanged()));
-    connect(fillColor1ComboBox, SIGNAL(activated(int)), this, SLOT(fillGradientChanged()));
-    connect(fillColor2ComboBox, SIGNAL(activated(int)), this, SLOT(fillGradientChanged()));
-    connect(penColorComboBox, SIGNAL(activated(int)), this, SLOT(penColorChanged()));
-
-    for(QList<RenderArea*>::iterator it = renderAreas.begin(); it != renderAreas.end(); it++) {
-        connect(penWidthSpinBox, SIGNAL(valueChanged(int)), *it, SLOT(setPenWidth(int)));
-        connect(rotationAngleSpinBox, SIGNAL(valueChanged(int)), *it, SLOT(setRotationAngle(int)));
+    connect(fillRuleComboBox, QOverload<int>::of(&QComboBox::activated),
+            this, &Window::fillRuleChanged);
+    connect(fillColor1ComboBox, QOverload<int>::of(&QComboBox::activated),
+            this, &Window::fillGradientChanged);
+    connect(fillColor2ComboBox, QOverload<int>::of(&QComboBox::activated),
+            this, &Window::fillGradientChanged);
+    connect(penColorComboBox, QOverload<int>::of(&QComboBox::activated),
+            this, &Window::penColorChanged);
+
+    for (RenderArea *area : qAsConst(renderAreas)) {
+        connect(penWidthSpinBox, QOverload<int>::of(&QSpinBox::valueChanged),
+                area, &RenderArea::setPenWidth);
+        connect(rotationAngleSpinBox, QOverload<int>::of(&QSpinBox::valueChanged),
+                area, &RenderArea::setRotationAngle);
     }
 
 //! [16] //! [17]
     QGridLayout *topLayout = new QGridLayout;
 
-    int i=0;
-    for(QList<RenderArea*>::iterator it = renderAreas.begin(); it != renderAreas.end(); it++, i++)
-        topLayout->addWidget(*it, i / 3, i % 3);
+    int i = 0;
+    for (RenderArea *area : qAsConst(renderAreas)) {
+        topLayout->addWidget(area, i / 3, i % 3);
+        ++i;
+    }
 
     QGridLayout *mainLayout = new QGridLayout;
     mainLayout->addLayout(topLayout, 0, 0, 1, 4);
@@ -243,8 +251,8 @@ void Window::fillRuleChanged()
 {
     Qt::FillRule rule = (Qt::FillRule)currentItemData(fillRuleComboBox).toInt();
 
-    for (QList<RenderArea*>::iterator it = renderAreas.begin(); it != renderAreas.end(); ++it)
-        (*it)->setFillRule(rule);
+    for (RenderArea *area : qAsConst(renderAreas))
+        area->setFillRule(rule);
 }
 //! [19]
 
@@ -254,8 +262,8 @@ void Window::fillGradientChanged()
     QColor color1 = qvariant_cast<QColor>(currentItemData(fillColor1ComboBox));
     QColor color2 = qvariant_cast<QColor>(currentItemData(fillColor2ComboBox));
 
-    for (QList<RenderArea*>::iterator it = renderAreas.begin(); it != renderAreas.end(); ++it)
-        (*it)->setFillGradient(color1, color2);
+    for (RenderArea *area : qAsConst(renderAreas))
+        area->setFillGradient(color1, color2);
 }
 //! [20]
 
@@ -264,16 +272,16 @@ void Window::penColorChanged()
 {
     QColor color = qvariant_cast<QColor>(currentItemData(penColorComboBox));
 
-    for (QList<RenderArea*>::iterator it = renderAreas.begin(); it != renderAreas.end(); ++it)
-        (*it)->setPenColor(color);
+    for (RenderArea *area : qAsConst(renderAreas))
+        area->setPenColor(color);
 }
 //! [21]
 
 //! [22]
 void Window::populateWithColors(QComboBox *comboBox)
 {
-    QStringList colorNames = QColor::colorNames();
-    foreach (QString name, colorNames)
+    const QStringList colorNames = QColor::colorNames();
+    for (const QString &name : colorNames)
         comboBox->addItem(name, QColor(name));
 }
 //! [22]
diff --git a/examples/widgets/painting/pathstroke/main.cpp b/examples/widgets/painting/pathstroke/main.cpp
index 3a63203118..57c85d73a3 100644
--- a/examples/widgets/painting/pathstroke/main.cpp
+++ b/examples/widgets/painting/pathstroke/main.cpp
@@ -63,8 +63,8 @@ int main(int argc, char **argv)
     PathStrokeWidget pathStrokeWidget(smallScreen);
     QStyle *arthurStyle = new ArthurStyle();
     pathStrokeWidget.setStyle(arthurStyle);
-    QList<QWidget *> widgets = pathStrokeWidget.findChildren<QWidget *>();
-    foreach (QWidget *w, widgets) {
+    const QList<QWidget *> widgets = pathStrokeWidget.findChildren<QWidget *>();
+    for (QWidget *w : widgets) {
         w->setStyle(arthurStyle);
         w->setAttribute(Qt::WA_AcceptTouchEvents);
     }
diff --git a/examples/widgets/painting/pathstroke/pathstroke.cpp b/examples/widgets/painting/pathstroke/pathstroke.cpp
index 5a7b8fd9fe..03e55bb2a2 100644
--- a/examples/widgets/painting/pathstroke/pathstroke.cpp
+++ b/examples/widgets/painting/pathstroke/pathstroke.cpp
@@ -164,24 +164,24 @@ void PathStrokeControls::createCommonControls(QWidget* parent)
 
 
     // Connections
-    connect(flatCap, SIGNAL(clicked()), m_renderer, SLOT(setFlatCap()));
-    connect(squareCap, SIGNAL(clicked()), m_renderer, SLOT(setSquareCap()));
-    connect(roundCap, SIGNAL(clicked()), m_renderer, SLOT(setRoundCap()));
+    connect(flatCap, &QAbstractButton::clicked, m_renderer, &PathStrokeRenderer::setFlatCap);
+    connect(squareCap, &QAbstractButton::clicked, m_renderer, &PathStrokeRenderer::setSquareCap);
+    connect(roundCap, &QAbstractButton::clicked, m_renderer, &PathStrokeRenderer::setRoundCap);
 
-    connect(bevelJoin, SIGNAL(clicked()), m_renderer, SLOT(setBevelJoin()));
-    connect(miterJoin, SIGNAL(clicked()), m_renderer, SLOT(setMiterJoin()));
-    connect(svgMiterJoin, SIGNAL(clicked()), m_renderer, SLOT(setSvgMiterJoin()));
-    connect(roundJoin, SIGNAL(clicked()), m_renderer, SLOT(setRoundJoin()));
+    connect(bevelJoin, &QAbstractButton::clicked, m_renderer, &PathStrokeRenderer::setBevelJoin);
+    connect(miterJoin, &QAbstractButton::clicked, m_renderer, &PathStrokeRenderer::setMiterJoin);
+    connect(svgMiterJoin, &QAbstractButton::clicked, m_renderer, &PathStrokeRenderer::setSvgMiterJoin);
+    connect(roundJoin, &QAbstractButton::clicked, m_renderer, &PathStrokeRenderer::setRoundJoin);
 
-    connect(curveMode, SIGNAL(clicked()), m_renderer, SLOT(setCurveMode()));
-    connect(lineMode, SIGNAL(clicked()), m_renderer, SLOT(setLineMode()));
+    connect(curveMode, &QAbstractButton::clicked, m_renderer, &PathStrokeRenderer::setCurveMode);
+    connect(lineMode, &QAbstractButton::clicked, m_renderer, &PathStrokeRenderer::setLineMode);
 
-    connect(solidLine, SIGNAL(clicked()), m_renderer, SLOT(setSolidLine()));
-    connect(dashLine, SIGNAL(clicked()), m_renderer, SLOT(setDashLine()));
-    connect(dotLine, SIGNAL(clicked()), m_renderer, SLOT(setDotLine()));
-    connect(dashDotLine, SIGNAL(clicked()), m_renderer, SLOT(setDashDotLine()));
-    connect(dashDotDotLine, SIGNAL(clicked()), m_renderer, SLOT(setDashDotDotLine()));
-    connect(customDashLine, SIGNAL(clicked()), m_renderer, SLOT(setCustomDashLine()));
+    connect(solidLine, &QAbstractButton::clicked, m_renderer, &PathStrokeRenderer::setSolidLine);
+    connect(dashLine, &QAbstractButton::clicked, m_renderer, &PathStrokeRenderer::setDashLine);
+    connect(dotLine, &QAbstractButton::clicked, m_renderer, &PathStrokeRenderer::setDotLine);
+    connect(dashDotLine, &QAbstractButton::clicked, m_renderer, &PathStrokeRenderer::setDashDotLine);
+    connect(dashDotDotLine, &QAbstractButton::clicked, m_renderer, &PathStrokeRenderer::setDashDotDotLine);
+    connect(customDashLine, &QAbstractButton::clicked, m_renderer, &PathStrokeRenderer::setCustomDashLine);
 
     // Set the defaults:
     flatCap->setChecked(true);
@@ -211,13 +211,11 @@ void PathStrokeControls::layoutForDesktop()
 
     QPushButton *showSourceButton = new QPushButton(mainGroup);
     showSourceButton->setText(tr("Show Source"));
-#ifdef QT_OPENGL_SUPPORT
+#if QT_CONFIG(opengl)
     QPushButton *enableOpenGLButton = new QPushButton(mainGroup);
     enableOpenGLButton->setText(tr("Use OpenGL"));
     enableOpenGLButton->setCheckable(true);
     enableOpenGLButton->setChecked(m_renderer->usesOpenGL());
-    if (!QGLFormat::hasOpenGL())
-        enableOpenGLButton->hide();
 #endif
     QPushButton *whatsThisButton = new QPushButton(mainGroup);
     whatsThisButton->setText(tr("What's This?"));
@@ -229,11 +227,11 @@ void PathStrokeControls::layoutForDesktop()
     penWidthLayout->addWidget(penWidth);
 
     QVBoxLayout * mainLayout = new QVBoxLayout(this);
-    mainLayout->setMargin(0);
+    mainLayout->setContentsMargins(QMargins());
     mainLayout->addWidget(mainGroup);
 
     QVBoxLayout *mainGroupLayout = new QVBoxLayout(mainGroup);
-    mainGroupLayout->setMargin(3);
+    mainGroupLayout->setContentsMargins(3, 3, 3, 3);
     mainGroupLayout->addWidget(m_capGroup);
     mainGroupLayout->addWidget(m_joinGroup);
     mainGroupLayout->addWidget(m_styleGroup);
@@ -242,24 +240,24 @@ void PathStrokeControls::layoutForDesktop()
     mainGroupLayout->addWidget(animated);
     mainGroupLayout->addStretch(1);
     mainGroupLayout->addWidget(showSourceButton);
-#ifdef QT_OPENGL_SUPPORT
+#if QT_CONFIG(opengl)
     mainGroupLayout->addWidget(enableOpenGLButton);
 #endif
     mainGroupLayout->addWidget(whatsThisButton);
 
 
     // Set up connections
-    connect(animated, SIGNAL(toggled(bool)), m_renderer, SLOT(setAnimation(bool)));
+    connect(animated, &QAbstractButton::toggled, m_renderer, &PathStrokeRenderer::setAnimation);
 
-    connect(penWidth, SIGNAL(valueChanged(int)), m_renderer, SLOT(setPenWidth(int)));
+    connect(penWidth, &QAbstractSlider::valueChanged, m_renderer, &PathStrokeRenderer::setPenWidth);
 
-    connect(showSourceButton, SIGNAL(clicked()), m_renderer, SLOT(showSource()));
-#ifdef QT_OPENGL_SUPPORT
-    connect(enableOpenGLButton, SIGNAL(clicked(bool)), m_renderer, SLOT(enableOpenGL(bool)));
+    connect(showSourceButton, &QAbstractButton::clicked, m_renderer, &ArthurFrame::showSource);
+#if QT_CONFIG(opengl)
+    connect(enableOpenGLButton, &QAbstractButton::clicked, m_renderer, &ArthurFrame::enableOpenGL);
 #endif
-    connect(whatsThisButton, SIGNAL(clicked(bool)), m_renderer, SLOT(setDescriptionEnabled(bool)));
-    connect(m_renderer, SIGNAL(descriptionEnabledChanged(bool)),
-            whatsThisButton, SLOT(setChecked(bool)));
+    connect(whatsThisButton, &QAbstractButton::clicked, m_renderer, &ArthurFrame::setDescriptionEnabled);
+    connect(m_renderer, &ArthurFrame::descriptionEnabledChanged,
+            whatsThisButton, &QAbstractButton::setChecked);
 
 
     // Set the defaults
@@ -272,10 +270,10 @@ void PathStrokeControls::layoutForSmallScreens()
 {
     createCommonControls(this);
 
-    m_capGroup->layout()->setMargin(0);
-    m_joinGroup->layout()->setMargin(0);
-    m_styleGroup->layout()->setMargin(0);
-    m_pathModeGroup->layout()->setMargin(0);
+    m_capGroup->layout()->setContentsMargins(QMargins());
+    m_joinGroup->layout()->setContentsMargins(QMargins());
+    m_styleGroup->layout()->setContentsMargins(QMargins());
+    m_pathModeGroup->layout()->setContentsMargins(QMargins());
 
     QPushButton* okBtn = new QPushButton(tr("OK"), this);
     okBtn->setSizePolicy(QSizePolicy::Fixed, QSizePolicy::Fixed);
@@ -290,13 +288,11 @@ void PathStrokeControls::layoutForSmallScreens()
     penWidth->setSizePolicy(QSizePolicy::Preferred, QSizePolicy::Fixed);
     penWidth->setRange(0, 500);
 
-#ifdef QT_OPENGL_SUPPORT
+#if QT_CONFIG(opengl)
     QPushButton *enableOpenGLButton = new QPushButton(this);
     enableOpenGLButton->setText(tr("Use OpenGL"));
     enableOpenGLButton->setCheckable(true);
     enableOpenGLButton->setChecked(m_renderer->usesOpenGL());
-    if (!QGLFormat::hasOpenGL())
-        enableOpenGLButton->hide();
 #endif
 
     // Layouts:
@@ -307,7 +303,7 @@ void PathStrokeControls::layoutForSmallScreens()
     QVBoxLayout *leftLayout = new QVBoxLayout(0);
     leftLayout->addWidget(m_capGroup);
     leftLayout->addWidget(m_joinGroup);
-#ifdef QT_OPENGL_SUPPORT
+#if QT_CONFIG(opengl)
     leftLayout->addWidget(enableOpenGLButton);
 #endif
     leftLayout->addLayout(penWidthLayout);
@@ -317,7 +313,7 @@ void PathStrokeControls::layoutForSmallScreens()
     rightLayout->addWidget(m_pathModeGroup);
 
     QGridLayout *mainLayout = new QGridLayout(this);
-    mainLayout->setMargin(0);
+    mainLayout->setContentsMargins(QMargins());
 
     // Add spacers around the form items so we don't look stupid at higher resolutions
     mainLayout->addItem(new QSpacerItem(0,0), 0, 0, 1, 4);
@@ -330,13 +326,13 @@ void PathStrokeControls::layoutForSmallScreens()
     mainLayout->addWidget(quitBtn, 2, 1, Qt::AlignHCenter | Qt::AlignTop);
     mainLayout->addWidget(okBtn, 2, 2, Qt::AlignHCenter | Qt::AlignTop);
 
-#ifdef QT_OPENGL_SUPPORT
-    connect(enableOpenGLButton, SIGNAL(clicked(bool)), m_renderer, SLOT(enableOpenGL(bool)));
+#if QT_CONFIG(opengl)
+    connect(enableOpenGLButton, &QAbstractButton::clicked, m_renderer, &ArthurFrame::enableOpenGL);
 #endif
 
-    connect(penWidth, SIGNAL(valueChanged(int)), m_renderer, SLOT(setPenWidth(int)));
-    connect(quitBtn, SIGNAL(clicked()), this, SLOT(emitQuitSignal()));
-    connect(okBtn, SIGNAL(clicked()), this, SLOT(emitOkSignal()));
+    connect(penWidth, &QAbstractSlider::valueChanged, m_renderer, &PathStrokeRenderer::setPenWidth);
+    connect(quitBtn, &QAbstractButton::clicked, this, &PathStrokeControls::emitQuitSignal);
+    connect(okBtn, &QAbstractButton::clicked, this, &PathStrokeControls::emitOkSignal);
 
     m_renderer->setAnimation(true);
     penWidth->setValue(50);
@@ -372,8 +368,8 @@ PathStrokeWidget::PathStrokeWidget(bool smallScreen)
     m_renderer->loadSourceFile(":res/pathstroke/pathstroke.cpp");
     m_renderer->loadDescription(":res/pathstroke/pathstroke.html");
 
-    connect(m_renderer, SIGNAL(clicked()), this, SLOT(showControls()));
-    connect(m_controls, SIGNAL(okPressed()), this, SLOT(hideControls()));
+    connect(m_renderer, &PathStrokeRenderer::clicked, this, &PathStrokeWidget::showControls);
+    connect(m_controls, &PathStrokeControls::okPressed, this, &PathStrokeWidget::hideControls);
     connect(m_controls, SIGNAL(quitPressed()), QApplication::instance(), SLOT(quit()));
 }
 
@@ -394,8 +390,8 @@ void PathStrokeWidget::setStyle( QStyle * style )
     {
         m_controls->setStyle(style);
 
-        QList<QWidget *> widgets = m_controls->findChildren<QWidget *>();
-        foreach (QWidget *w, widgets)
+        const QList<QWidget *> widgets = m_controls->findChildren<QWidget *>();
+        for (QWidget *w : widgets)
             w->setStyle(style);
     }
 }
@@ -609,7 +605,7 @@ bool PathStrokeRenderer::event(QEvent *e)
     {
         const QTouchEvent *const event = static_cast<const QTouchEvent*>(e);
         const QList<QTouchEvent::TouchPoint> points = event->touchPoints();
-        foreach (const QTouchEvent::TouchPoint &touchPoint, points) {
+        for (const QTouchEvent::TouchPoint &touchPoint : points) {
             const int id = touchPoint.id();
             switch (touchPoint.state()) {
             case Qt::TouchPointPressed:
diff --git a/examples/widgets/painting/pathstroke/pathstroke.pro b/examples/widgets/painting/pathstroke/pathstroke.pro
index 8ab3cb9244..3e71b2db56 100644
--- a/examples/widgets/painting/pathstroke/pathstroke.pro
+++ b/examples/widgets/painting/pathstroke/pathstroke.pro
@@ -7,10 +7,6 @@ include($$SHARED_FOLDER/shared.pri)
 
 RESOURCES += pathstroke.qrc
 
-qtHaveModule(opengl) {
-	DEFINES += QT_OPENGL_SUPPORT
-	QT += opengl
-}
 QT += widgets
 
 # install
diff --git a/examples/widgets/painting/shared/arthurstyle.cpp b/examples/widgets/painting/shared/arthurstyle.cpp
index f4fc76bda6..3fc461bbd2 100644
--- a/examples/widgets/painting/shared/arthurstyle.cpp
+++ b/examples/widgets/painting/shared/arthurstyle.cpp
@@ -61,10 +61,10 @@
 
 QPixmap cached(const QString &img)
 {
-    if (QPixmap *p = QPixmapCache::find(img))
-        return *p;
-
     QPixmap pm;
+    if (QPixmapCache::find(img, &pm))
+        return pm;
+
     pm = QPixmap::fromImage(QImage(img), Qt::OrderedDither | Qt::OrderedAlphaDither);
     if (pm.isNull())
         return QPixmap();
@@ -443,9 +443,9 @@ void ArthurStyle::polish(QWidget *widget)
     if (widget->layout() && qobject_cast<QGroupBox *>(widget)) {
         if (widget->findChildren<QGroupBox *>().size() == 0) {
             widget->layout()->setSpacing(0);
-            widget->layout()->setMargin(12);
+            widget->layout()->setContentsMargins(12, 12, 12, 12);
         } else {
-            widget->layout()->setMargin(13);
+            widget->layout()->setContentsMargins(13, 13, 13, 13);
         }
     }
 
diff --git a/examples/widgets/painting/shared/arthurwidgets.cpp b/examples/widgets/painting/shared/arthurwidgets.cpp
index 965660a3a3..bdac5de13c 100644
--- a/examples/widgets/painting/shared/arthurwidgets.cpp
+++ b/examples/widgets/painting/shared/arthurwidgets.cpp
@@ -60,6 +60,10 @@
 #include <QTextBrowser>
 #include <QBoxLayout>
 #include <QRegularExpression>
+#include <QOffscreenSurface>
+#include <QOpenGLContext>
+#include <QOpenGLPaintDevice>
+#include <QOpenGLWindow>
 
 extern QPixmap cached(const QString &img);
 
@@ -67,17 +71,12 @@ ArthurFrame::ArthurFrame(QWidget *parent)
     : QWidget(parent)
     , m_prefer_image(false)
 {
-#ifdef QT_OPENGL_SUPPORT
-    glw = 0;
+#if QT_CONFIG(opengl)
+    m_glWindow = nullptr;
+    m_glWidget = nullptr;
     m_use_opengl = false;
-    QGLFormat f = QGLFormat::defaultFormat();
-    f.setSampleBuffers(true);
-    f.setStencil(true);
-    f.setAlpha(true);
-    f.setAlphaBufferSize(8);
-    QGLFormat::setDefaultFormat(f);
 #endif
-    m_document = 0;
+    m_document = nullptr;
     m_show_doc = false;
 
     m_tile = QPixmap(128, 128);
@@ -94,37 +93,55 @@ ArthurFrame::ArthurFrame(QWidget *parent)
 }
 
 
-#ifdef QT_OPENGL_SUPPORT
+#if QT_CONFIG(opengl)
 void ArthurFrame::enableOpenGL(bool use_opengl)
 {
     if (m_use_opengl == use_opengl)
         return;
 
-    if (!glw && use_opengl) {
-        glw = new GLWidget(this);
-        glw->setAutoFillBackground(false);
-        glw->disableAutoBufferSwap();
+    m_use_opengl = use_opengl;
+
+    if (!m_glWindow && use_opengl) {
+        createGlWindow();
         QApplication::postEvent(this, new QResizeEvent(size(), size()));
     }
 
-    m_use_opengl = use_opengl;
     if (use_opengl) {
-        glw->show();
+        m_glWidget->show();
     } else {
-        if (glw)
-            glw->hide();
+        if (m_glWidget)
+            m_glWidget->hide();
     }
 
     update();
 }
+
+void ArthurFrame::createGlWindow()
+{
+    Q_ASSERT(m_use_opengl);
+
+    m_glWindow = new QOpenGLWindow();
+    QSurfaceFormat f = QSurfaceFormat::defaultFormat();
+    f.setSamples(4);
+    f.setAlphaBufferSize(8);
+    f.setStencilBufferSize(8);
+    m_glWindow->setFormat(f);
+    m_glWindow->setFlags(Qt::WindowTransparentForInput);
+    m_glWindow->resize(width() - 1, height() - 1);
+    m_glWindow->create();
+    m_glWidget = QWidget::createWindowContainer(m_glWindow, this);
+}
 #endif
 
+
 void ArthurFrame::paintEvent(QPaintEvent *e)
 {
     static QImage *static_image = 0;
+
     QPainter painter;
+
     if (preferImage()
-#ifdef QT_OPENGL_SUPPORT
+#if QT_CONFIG(opengl)
         && !m_use_opengl
 #endif
         ) {
@@ -142,10 +159,12 @@ void ArthurFrame::paintEvent(QPaintEvent *e)
         painter.fillRect(0, height() - o, o, o, bg);
         painter.fillRect(width() - o, height() - o, o, o, bg);
     } else {
-#ifdef QT_OPENGL_SUPPORT
-        if (m_use_opengl) {
-            painter.begin(glw);
-            painter.fillRect(QRectF(0, 0, glw->width(), glw->height()), palette().color(backgroundRole()));
+#if QT_CONFIG(opengl)
+        if (m_use_opengl && m_glWindow->isValid()) {
+            m_glWindow->makeCurrent();
+
+            painter.begin(m_glWindow);
+            painter.fillRect(QRectF(0, 0, m_glWindow->width(), m_glWindow->height()), palette().color(backgroundRole()));
         } else {
             painter.begin(this);
         }
@@ -196,7 +215,7 @@ void ArthurFrame::paintEvent(QPaintEvent *e)
     painter.drawPath(clipPath);
 
     if (preferImage()
-#ifdef QT_OPENGL_SUPPORT
+#if QT_CONFIG(opengl)
         && !m_use_opengl
 #endif
         ) {
@@ -204,18 +223,17 @@ void ArthurFrame::paintEvent(QPaintEvent *e)
         painter.begin(this);
         painter.drawImage(e->rect(), *static_image, e->rect());
     }
-
-#ifdef QT_OPENGL_SUPPORT
-    if (m_use_opengl && (inherits("PathDeformRenderer") || inherits("PathStrokeRenderer") || inherits("CompositionRenderer") || m_show_doc))
-        glw->swapBuffers();
+#if QT_CONFIG(opengl)
+    if (m_use_opengl)
+        m_glWindow->update();
 #endif
 }
 
 void ArthurFrame::resizeEvent(QResizeEvent *e)
 {
-#ifdef QT_OPENGL_SUPPORT
-    if (glw)
-        glw->setGeometry(0, 0, e->size().width()-1, e->size().height()-1);
+#if QT_CONFIG(opengl)
+    if (m_glWidget)
+        m_glWidget->setGeometry(0, 0, e->size().width()-1, e->size().height()-1);
 #endif
     QWidget::resizeEvent(e);
 }
@@ -312,32 +330,40 @@ void ArthurFrame::showSource()
 
     QString contents;
     if (m_sourceFileName.isEmpty()) {
-        contents = QString("No source for widget: '%1'").arg(objectName());
+        contents = tr("No source for widget: '%1'").arg(objectName());
     } else {
         QFile f(m_sourceFileName);
         if (!f.open(QFile::ReadOnly))
-            contents = QString("Could not open file: '%1'").arg(m_sourceFileName);
+            contents = tr("Could not open file: '%1'").arg(m_sourceFileName);
         else
             contents = f.readAll();
     }
 
-    contents.replace('&', "&amp;");
-    contents.replace('<', "&lt;");
-    contents.replace('>', "&gt;");
-
-    QStringList keywords;
-    keywords << "for " << "if " << "switch " << " int " << "#include " << "const"
-             << "void " << "uint " << "case " << "double " << "#define " << "static"
-             << "new" << "this";
-
-    foreach (QString keyword, keywords)
+    contents.replace(QLatin1Char('&'), QStringLiteral("&amp;"));
+    contents.replace(QLatin1Char('<'), QStringLiteral("&lt;"));
+    contents.replace(QLatin1Char('>'), QStringLiteral("&gt;"));
+
+    static const QString keywords[] = {
+        QStringLiteral("for "),      QStringLiteral("if "),
+        QStringLiteral("switch "),   QStringLiteral(" int "),
+        QStringLiteral("#include "), QStringLiteral("const"),
+        QStringLiteral("void "),     QStringLiteral("uint "),
+        QStringLiteral("case "),     QStringLiteral("double "),
+        QStringLiteral("#define "),  QStringLiteral("static"),
+        QStringLiteral("new"),       QStringLiteral("this")
+    };
+
+    for (const QString &keyword : keywords)
         contents.replace(keyword, QLatin1String("<font color=olive>") + keyword + QLatin1String("</font>"));
-    contents.replace("(int ", "(<font color=olive><b>int </b></font>");
+    contents.replace(QStringLiteral("(int "), QStringLiteral("(<font color=olive><b>int </b></font>"));
 
-    QStringList ppKeywords;
-    ppKeywords << "#ifdef" << "#ifndef" << "#if" << "#endif" << "#else";
+    static const QString ppKeywords[] = {
+        QStringLiteral("#ifdef"), QStringLiteral("#ifndef"),
+        QStringLiteral("#if"),    QStringLiteral("#endif"),
+        QStringLiteral("#else")
+    };
 
-    foreach (QString keyword, ppKeywords)
+    for (const QString &keyword : ppKeywords)
         contents.replace(keyword, QLatin1String("<font color=navy>") + keyword + QLatin1String("</font>"));
 
     contents.replace(QRegularExpression("(\\d\\d?)"), QLatin1String("<font color=navy>\\1</font>"));
@@ -348,12 +374,10 @@ void ArthurFrame::showSource()
     QRegularExpression stringLiteralRe("(\".+?\")");
     contents.replace(stringLiteralRe, QLatin1String("<font color=green>\\1</font>"));
 
-    QString html = contents;
-    html.prepend("<html><pre>");
-    html.append("</pre></html>");
+    const QString html = QStringLiteral("<html><pre>") + contents + QStringLiteral("</pre></html>");
 
     QTextBrowser *sourceViewer = new QTextBrowser(0);
-    sourceViewer->setWindowTitle("Source: " + m_sourceFileName.mid(5));
+    sourceViewer->setWindowTitle(tr("Source: %1").arg(m_sourceFileName.midRef(5)));
     sourceViewer->setParent(this, Qt::Dialog);
     sourceViewer->setAttribute(Qt::WA_DeleteOnClose);
     sourceViewer->setLineWrapMode(QTextEdit::NoWrap);
diff --git a/examples/widgets/painting/shared/arthurwidgets.h b/examples/widgets/painting/shared/arthurwidgets.h
index d6e1e44b3a..73e1310c0e 100644
--- a/examples/widgets/painting/shared/arthurwidgets.h
+++ b/examples/widgets/painting/shared/arthurwidgets.h
@@ -56,42 +56,13 @@
 #include <QPushButton>
 #include <QGroupBox>
 
-#if defined(QT_OPENGL_SUPPORT)
-#include <QGLWidget>
-#include <QEvent>
-class GLWidget : public QGLWidget
-{
-public:
-    GLWidget(QWidget *parent)
-        : QGLWidget(QGLFormat(QGL::SampleBuffers), parent)
-    {
-        setAttribute(Qt::WA_AcceptTouchEvents);
-    }
-    void disableAutoBufferSwap() { setAutoBufferSwap(false); }
-    void paintEvent(QPaintEvent *) override { parentWidget()->update(); }
-protected:
-    bool event(QEvent *event) override
-    {
-        switch (event->type()) {
-        case QEvent::TouchBegin:
-        case QEvent::TouchUpdate:
-        case QEvent::TouchEnd:
-            event->ignore();
-            return false;
-            break;
-        default:
-            break;
-        }
-        return QGLWidget::event(event);
-    }
-};
-#endif
-
+QT_FORWARD_DECLARE_CLASS(QOpenGLWindow)
 QT_FORWARD_DECLARE_CLASS(QTextDocument)
 QT_FORWARD_DECLARE_CLASS(QTextEdit)
 QT_FORWARD_DECLARE_CLASS(QVBoxLayout)
 
 class ArthurFrame : public QWidget
+
 {
     Q_OBJECT
 public:
@@ -107,9 +78,8 @@ public:
     void loadSourceFile(const QString &fileName);
 
     bool preferImage() const { return m_prefer_image; }
-
-#if defined(QT_OPENGL_SUPPORT)
-    QGLWidget *glWidget() const { return glw; }
+#if QT_CONFIG(opengl)
+    QOpenGLWindow *glWindow() const { return m_glWindow; }
 #endif
 
 public slots:
@@ -117,7 +87,7 @@ public slots:
     void setDescriptionEnabled(bool enabled);
     void showSource();
 
-#if defined(QT_OPENGL_SUPPORT)
+#if QT_CONFIG(opengl)
     void enableOpenGL(bool use_opengl);
     bool usesOpenGL() { return m_use_opengl; }
 #endif
@@ -129,8 +99,10 @@ protected:
     void paintEvent(QPaintEvent *) override;
     void resizeEvent(QResizeEvent *) override;
 
-#if defined(QT_OPENGL_SUPPORT)
-    GLWidget *glw;
+#if QT_CONFIG(opengl)
+    virtual void createGlWindow();
+    QOpenGLWindow *m_glWindow;
+    QWidget *m_glWidget;
     bool m_use_opengl;
 #endif
     QPixmap m_tile;
diff --git a/examples/widgets/painting/shared/fbopaintdevice.cpp b/examples/widgets/painting/shared/fbopaintdevice.cpp
new file mode 100644
index 0000000000..8207090cc8
--- /dev/null
+++ b/examples/widgets/painting/shared/fbopaintdevice.cpp
@@ -0,0 +1,113 @@
+/****************************************************************************
+**
+** Copyright (C) 2018 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the demonstration applications of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:BSD$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** BSD License Usage
+** Alternatively, you may use this file under the terms of the BSD license
+** as follows:
+**
+** "Redistribution and use in source and binary forms, with or without
+** modification, are permitted provided that the following conditions are
+** met:
+**   * Redistributions of source code must retain the above copyright
+**     notice, this list of conditions and the following disclaimer.
+**   * Redistributions in binary form must reproduce the above copyright
+**     notice, this list of conditions and the following disclaimer in
+**     the documentation and/or other materials provided with the
+**     distribution.
+**   * Neither the name of The Qt Company Ltd nor the names of its
+**     contributors may be used to endorse or promote products derived
+**     from this software without specific prior written permission.
+**
+**
+** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "fbopaintdevice.h"
+
+#include <QOffscreenSurface>
+#include <QOpenGLFunctions>
+
+QFboPaintDevice::QFboPaintDevice(const QSize& size, bool flipped, bool clearOnInit,
+                                 QOpenGLFramebufferObject::Attachment attachment)
+        : QOpenGLPaintDevice(size)
+{
+    QOpenGLFramebufferObjectFormat format;
+    format.setAttachment(attachment);
+    format.setSamples(4);
+    m_framebufferObject = new QOpenGLFramebufferObject(size, format);
+    QOffscreenSurface *surface = new QOffscreenSurface();
+    surface->create();
+    m_surface = surface;
+    setPaintFlipped(flipped);
+    if (clearOnInit) {
+        m_framebufferObject->bind();
+
+        context()->functions()->glClearColor(0, 0, 0, 0);
+        context()->functions()->glClear(GL_COLOR_BUFFER_BIT);
+    }
+}
+
+QFboPaintDevice::~QFboPaintDevice()
+{
+    delete m_framebufferObject;
+    delete m_surface;
+}
+
+void QFboPaintDevice::ensureActiveTarget()
+{
+    if (QOpenGLContext::currentContext() != context())
+        context()->makeCurrent(m_surface);
+
+    m_framebufferObject->bind();
+}
+
+GLuint QFboPaintDevice::takeTexture()
+{
+    // We have multisamples so we can't just forward takeTexture().
+    QOpenGLFramebufferObject resolvedFbo(m_framebufferObject->size(), m_framebufferObject->attachment());
+    QOpenGLFramebufferObject::blitFramebuffer(&resolvedFbo, m_framebufferObject);
+    return resolvedFbo.takeTexture();
+}
+
+QImage QFboPaintDevice::toImage() const
+{
+    QOpenGLContext* currentContext = QOpenGLContext::currentContext();
+    QSurface* currentSurface = currentContext ? currentContext->surface() : 0;
+
+    context()->makeCurrent(m_surface);
+
+    QImage image = m_framebufferObject->toImage(!paintFlipped());
+
+    if (currentContext)
+        currentContext->makeCurrent(currentSurface);
+    else
+        context()->doneCurrent();
+
+    return image;
+}
diff --git a/examples/widgets/painting/shared/fbopaintdevice.h b/examples/widgets/painting/shared/fbopaintdevice.h
new file mode 100644
index 0000000000..78451af895
--- /dev/null
+++ b/examples/widgets/painting/shared/fbopaintdevice.h
@@ -0,0 +1,91 @@
+/****************************************************************************
+**
+** Copyright (C) 2018 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the demonstration applications of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:BSD$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** BSD License Usage
+** Alternatively, you may use this file under the terms of the BSD license
+** as follows:
+**
+** "Redistribution and use in source and binary forms, with or without
+** modification, are permitted provided that the following conditions are
+** met:
+**   * Redistributions of source code must retain the above copyright
+**     notice, this list of conditions and the following disclaimer.
+**   * Redistributions in binary form must reproduce the above copyright
+**     notice, this list of conditions and the following disclaimer in
+**     the documentation and/or other materials provided with the
+**     distribution.
+**   * Neither the name of The Qt Company Ltd nor the names of its
+**     contributors may be used to endorse or promote products derived
+**     from this software without specific prior written permission.
+**
+**
+** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef QFBOPAINTDEVICE_H
+#define QFBOPAINTDEVICE_H
+
+#ifndef QT_NO_OPENGL
+
+#include <QImage>
+#include <QOpenGLFramebufferObject>
+#include <QOpenGLPaintDevice>
+#include <QSurface>
+
+class QFboPaintDevice : public QOpenGLPaintDevice {
+public:
+    QFboPaintDevice(const QSize&, bool flipped = false, bool clearOnInit = true,
+        QOpenGLFramebufferObject::Attachment = QOpenGLFramebufferObject::CombinedDepthStencil);
+    ~QFboPaintDevice();
+
+    // QOpenGLPaintDevice:
+    void ensureActiveTarget() override;
+
+    bool isValid() const { return m_framebufferObject->isValid(); }
+    GLuint handle() const { return m_framebufferObject->handle(); }
+    GLuint takeTexture();
+    QImage toImage() const;
+
+    bool bind() { return m_framebufferObject->bind(); }
+    bool release() { return m_framebufferObject->release(); }
+    QSize size() const { return m_framebufferObject->size(); }
+
+    QOpenGLFramebufferObject* framebufferObject() { return m_framebufferObject; }
+    const QOpenGLFramebufferObject* framebufferObject() const { return m_framebufferObject; }
+
+    static bool isSupported() { return QOpenGLFramebufferObject::hasOpenGLFramebufferObjects(); }
+
+private:
+    QOpenGLFramebufferObject *m_framebufferObject;
+    QSurface* m_surface;
+};
+
+#endif // QT_NO_OPENGL
+
+#endif // QFBOPAINTDEVICE_H
diff --git a/examples/widgets/painting/shared/hoverpoints.cpp b/examples/widgets/painting/shared/hoverpoints.cpp
index c735c83f6a..74c78088ad 100644
--- a/examples/widgets/painting/shared/hoverpoints.cpp
+++ b/examples/widgets/painting/shared/hoverpoints.cpp
@@ -48,10 +48,6 @@
 **
 ****************************************************************************/
 
-#ifdef QT_OPENGL_SUPPORT
-#include <QGLWidget>
-#endif
-
 #include "arthurwidgets.h"
 #include "hoverpoints.h"
 
@@ -77,8 +73,8 @@ HoverPoints::HoverPoints(QWidget *widget, PointShape shape)
     m_editable = true;
     m_enabled = true;
 
-    connect(this, SIGNAL(pointsChanged(QPolygonF)),
-            m_widget, SLOT(update()));
+    connect(this, &HoverPoints::pointsChanged,
+            m_widget, QOverload<>::of(&QWidget::update));
 }
 
 
@@ -178,7 +174,7 @@ bool HoverPoints::eventFilter(QObject *object, QEvent *event)
                 const QTouchEvent *const touchEvent = static_cast<const QTouchEvent*>(event);
                 const QList<QTouchEvent::TouchPoint> points = touchEvent->touchPoints();
                 const qreal pointSize = qMax(m_pointSize.width(), m_pointSize.height());
-                foreach (const QTouchEvent::TouchPoint &touchPoint, points) {
+                for (const QTouchEvent::TouchPoint &touchPoint : points) {
                     const int id = touchPoint.id();
                     switch (touchPoint.state()) {
                     case Qt::TouchPointPressed:
@@ -269,11 +265,6 @@ bool HoverPoints::eventFilter(QObject *object, QEvent *event)
             QApplication::sendEvent(object, event);
             m_widget = that_widget;
             paintPoints();
-#ifdef QT_OPENGL_SUPPORT
-            ArthurFrame *af = qobject_cast<ArthurFrame *>(that_widget);
-            if (af && af->usesOpenGL())
-                af->glWidget()->swapBuffers();
-#endif
             return true;
         }
         default:
@@ -288,12 +279,14 @@ bool HoverPoints::eventFilter(QObject *object, QEvent *event)
 void HoverPoints::paintPoints()
 {
     QPainter p;
-#ifdef QT_OPENGL_SUPPORT
+#if QT_CONFIG(opengl)
     ArthurFrame *af = qobject_cast<ArthurFrame *>(m_widget);
-    if (af && af->usesOpenGL())
-        p.begin(af->glWidget());
-    else
+    if (af && af->usesOpenGL() && af->glWindow()->isValid()) {
+        af->glWindow()->makeCurrent();
+        p.begin(af->glWindow());
+    } else {
         p.begin(m_widget);
+    }
 #else
     p.begin(m_widget);
 #endif
diff --git a/examples/widgets/painting/shared/shared.pri b/examples/widgets/painting/shared/shared.pri
index 362cc6819c..cb08b00348 100644
--- a/examples/widgets/painting/shared/shared.pri
+++ b/examples/widgets/painting/shared/shared.pri
@@ -1,8 +1,8 @@
 INCLUDEPATH += $$PWD
 
-qtHaveModule(opengl)|qtConfig(opengles2)  {
-    DEFINES += QT_OPENGL_SUPPORT
-    QT += opengl widgets
+qtConfig(opengl) {
+    SOURCES += $$PWD/fbopaintdevice.cpp
+    HEADERS += $$PWD/fbopaintdevice.h
 }
 
 SOURCES += \
diff --git a/examples/widgets/painting/transformations/window.cpp b/examples/widgets/painting/transformations/window.cpp
index d8babb2e00..8261c4e12e 100644
--- a/examples/widgets/painting/transformations/window.cpp
+++ b/examples/widgets/painting/transformations/window.cpp
@@ -79,8 +79,8 @@ Window::Window()
         operationComboBoxes[i]->addItem(tr("Scale to 75%"));
         operationComboBoxes[i]->addItem(tr("Translate by (50, 50)"));
 
-        connect(operationComboBoxes[i], SIGNAL(activated(int)),
-                this, SLOT(operationChanged()));
+        connect(operationComboBoxes[i], QOverload<int>::of(&QComboBox::activated),
+                this, &Window::operationChanged);
 
         layout->addWidget(transformedRenderAreas[i], 0, i + 1);
         layout->addWidget(operationComboBoxes[i], 1, i + 1);
@@ -159,7 +159,8 @@ void Window::setupShapes()
     shapes.append(text);
     shapes.append(truck);
 
-    connect(shapeComboBox, SIGNAL(activated(int)), this, SLOT(shapeSelected(int)));
+    connect(shapeComboBox, QOverload<int>::of(&QComboBox::activated),
+            this, &Window::shapeSelected);
 }
 //! [7]
 
diff --git a/examples/widgets/richtext/calendar/mainwindow.cpp b/examples/widgets/richtext/calendar/mainwindow.cpp
index 38dc0e2849..3ddb1cf7ad 100644
--- a/examples/widgets/richtext/calendar/mainwindow.cpp
+++ b/examples/widgets/richtext/calendar/mainwindow.cpp
@@ -86,10 +86,12 @@ MainWindow::MainWindow()
 //! [2]
 
 //! [3]
-    connect(monthCombo, SIGNAL(activated(int)), this, SLOT(setMonth(int)));
-    connect(yearEdit, SIGNAL(dateChanged(QDate)), this, SLOT(setYear(QDate)));
-    connect(fontSizeSpinBox, SIGNAL(valueChanged(int)),
-            this, SLOT(setFontSize(int)));
+    connect(monthCombo, QOverload<int>::of(&QComboBox::activated),
+            this, &MainWindow::setMonth);
+    connect(yearEdit, &QDateTimeEdit::dateChanged,
+            this, &MainWindow::setYear);
+    connect(fontSizeSpinBox, QOverload<int>::of(&QSpinBox::valueChanged),
+            this, &MainWindow::setFontSize);
 //! [3]
 
     fontSizeSpinBox->setValue(10);
diff --git a/examples/widgets/richtext/orderform/mainwindow.cpp b/examples/widgets/richtext/orderform/mainwindow.cpp
index b207ee4dbc..0b6a2cac6c 100644
--- a/examples/widgets/richtext/orderform/mainwindow.cpp
+++ b/examples/widgets/richtext/orderform/mainwindow.cpp
@@ -66,7 +66,7 @@ MainWindow::MainWindow()
     QMenu *fileMenu = new QMenu(tr("&File"), this);
     QAction *newAction = fileMenu->addAction(tr("&New..."));
     newAction->setShortcuts(QKeySequence::New);
-    printAction = fileMenu->addAction(tr("&Print..."), this, SLOT(printFile()));
+    printAction = fileMenu->addAction(tr("&Print..."), this, &MainWindow::printFile);
     printAction->setShortcuts(QKeySequence::Print);
     printAction->setEnabled(false);
     QAction *quitAction = fileMenu->addAction(tr("E&xit"));
@@ -126,8 +126,8 @@ void MainWindow::createLetter(const QString &name, const QString &address,
     cursor.setPosition(topFrame->lastPosition());
 
     cursor.insertText(name, textFormat);
-    QString line;
-    foreach (line, address.split("\n")) {
+    const QStringList lines = address.split('\n');
+    for (const QString &line : lines) {
         cursor.insertBlock();
         cursor.insertText(line);
     }
diff --git a/examples/widgets/richtext/syntaxhighlighter/highlighter.cpp b/examples/widgets/richtext/syntaxhighlighter/highlighter.cpp
index 6c420c328a..0c10eed6cf 100644
--- a/examples/widgets/richtext/syntaxhighlighter/highlighter.cpp
+++ b/examples/widgets/richtext/syntaxhighlighter/highlighter.cpp
@@ -58,18 +58,19 @@ Highlighter::Highlighter(QTextDocument *parent)
 
     keywordFormat.setForeground(Qt::darkBlue);
     keywordFormat.setFontWeight(QFont::Bold);
-    QStringList keywordPatterns;
-    keywordPatterns << "\\bchar\\b" << "\\bclass\\b" << "\\bconst\\b"
-                    << "\\bdouble\\b" << "\\benum\\b" << "\\bexplicit\\b"
-                    << "\\bfriend\\b" << "\\binline\\b" << "\\bint\\b"
-                    << "\\blong\\b" << "\\bnamespace\\b" << "\\boperator\\b"
-                    << "\\bprivate\\b" << "\\bprotected\\b" << "\\bpublic\\b"
-                    << "\\bshort\\b" << "\\bsignals\\b" << "\\bsigned\\b"
-                    << "\\bslots\\b" << "\\bstatic\\b" << "\\bstruct\\b"
-                    << "\\btemplate\\b" << "\\btypedef\\b" << "\\btypename\\b"
-                    << "\\bunion\\b" << "\\bunsigned\\b" << "\\bvirtual\\b"
-                    << "\\bvoid\\b" << "\\bvolatile\\b" << "\\bbool\\b";
-    foreach (const QString &pattern, keywordPatterns) {
+    const QString keywordPatterns[] = {
+        QStringLiteral("\\bchar\\b"), QStringLiteral("\\bclass\\b"), QStringLiteral("\\bconst\\b"),
+        QStringLiteral("\\bdouble\\b"), QStringLiteral("\\benum\\b"), QStringLiteral("\\bexplicit\\b"),
+        QStringLiteral("\\bfriend\\b"), QStringLiteral("\\binline\\b"), QStringLiteral("\\bint\\b"),
+        QStringLiteral("\\blong\\b"), QStringLiteral("\\bnamespace\\b"), QStringLiteral("\\boperator\\b"),
+        QStringLiteral("\\bprivate\\b"), QStringLiteral("\\bprotected\\b"), QStringLiteral("\\bpublic\\b"),
+        QStringLiteral("\\bshort\\b"), QStringLiteral("\\bsignals\\b"), QStringLiteral("\\bsigned\\b"),
+        QStringLiteral("\\bslots\\b"), QStringLiteral("\\bstatic\\b"), QStringLiteral("\\bstruct\\b"),
+        QStringLiteral("\\btemplate\\b"), QStringLiteral("\\btypedef\\b"), QStringLiteral("\\btypename\\b"),
+        QStringLiteral("\\bunion\\b"), QStringLiteral("\\bunsigned\\b"), QStringLiteral("\\bvirtual\\b"),
+        QStringLiteral("\\bvoid\\b"), QStringLiteral("\\bvolatile\\b"), QStringLiteral("\\bbool\\b")
+    };
+    for (const QString &pattern : keywordPatterns) {
         rule.pattern = QRegularExpression(pattern);
         rule.format = keywordFormat;
         highlightingRules.append(rule);
@@ -80,14 +81,14 @@ Highlighter::Highlighter(QTextDocument *parent)
 //! [2]
     classFormat.setFontWeight(QFont::Bold);
     classFormat.setForeground(Qt::darkMagenta);
-    rule.pattern = QRegularExpression("\\bQ[A-Za-z]+\\b");
+    rule.pattern = QRegularExpression(QStringLiteral("\\bQ[A-Za-z]+\\b"));
     rule.format = classFormat;
     highlightingRules.append(rule);
 //! [2]
 
 //! [3]
     singleLineCommentFormat.setForeground(Qt::red);
-    rule.pattern = QRegularExpression("//[^\n]*");
+    rule.pattern = QRegularExpression(QStringLiteral("//[^\n]*"));
     rule.format = singleLineCommentFormat;
     highlightingRules.append(rule);
 
@@ -96,7 +97,7 @@ Highlighter::Highlighter(QTextDocument *parent)
 
 //! [4]
     quotationFormat.setForeground(Qt::darkGreen);
-    rule.pattern = QRegularExpression("\".*\"");
+    rule.pattern = QRegularExpression(QStringLiteral("\".*\""));
     rule.format = quotationFormat;
     highlightingRules.append(rule);
 //! [4]
@@ -104,21 +105,21 @@ Highlighter::Highlighter(QTextDocument *parent)
 //! [5]
     functionFormat.setFontItalic(true);
     functionFormat.setForeground(Qt::blue);
-    rule.pattern = QRegularExpression("\\b[A-Za-z0-9_]+(?=\\()");
+    rule.pattern = QRegularExpression(QStringLiteral("\\b[A-Za-z0-9_]+(?=\\()"));
     rule.format = functionFormat;
     highlightingRules.append(rule);
 //! [5]
 
 //! [6]
-    commentStartExpression = QRegularExpression("/\\*");
-    commentEndExpression = QRegularExpression("\\*/");
+    commentStartExpression = QRegularExpression(QStringLiteral("/\\*"));
+    commentEndExpression = QRegularExpression(QStringLiteral("\\*/"));
 }
 //! [6]
 
 //! [7]
 void Highlighter::highlightBlock(const QString &text)
 {
-    foreach (const HighlightingRule &rule, highlightingRules) {
+    for (const HighlightingRule &rule : qAsConst(highlightingRules)) {
         QRegularExpressionMatchIterator matchIterator = rule.pattern.globalMatch(text);
         while (matchIterator.hasNext()) {
             QRegularExpressionMatch match = matchIterator.next();
diff --git a/examples/widgets/richtext/syntaxhighlighter/mainwindow.cpp b/examples/widgets/richtext/syntaxhighlighter/mainwindow.cpp
index dd58f1f45b..2dba0ba73e 100644
--- a/examples/widgets/richtext/syntaxhighlighter/mainwindow.cpp
+++ b/examples/widgets/richtext/syntaxhighlighter/mainwindow.cpp
@@ -117,9 +117,12 @@ void MainWindow::setupFileMenu()
     QMenu *fileMenu = new QMenu(tr("&File"), this);
     menuBar()->addMenu(fileMenu);
 
-    fileMenu->addAction(tr("&New"), this, SLOT(newFile()), QKeySequence::New);
-    fileMenu->addAction(tr("&Open..."), this, SLOT(openFile()), QKeySequence::Open);
-    fileMenu->addAction(tr("E&xit"), qApp, SLOT(quit()), QKeySequence::Quit);
+    fileMenu->addAction(tr("&New"), this,
+                        &MainWindow::newFile, QKeySequence::New);
+    fileMenu->addAction(tr("&Open..."),
+                        this, [this](){ openFile(); }, QKeySequence::Open);
+    fileMenu->addAction(tr("E&xit"), qApp,
+                        &QApplication::quit, QKeySequence::Quit);
 }
 
 void MainWindow::setupHelpMenu()
@@ -127,6 +130,6 @@ void MainWindow::setupHelpMenu()
     QMenu *helpMenu = new QMenu(tr("&Help"), this);
     menuBar()->addMenu(helpMenu);
 
-    helpMenu->addAction(tr("&About"), this, SLOT(about()));
-    helpMenu->addAction(tr("About &Qt"), qApp, SLOT(aboutQt()));
+    helpMenu->addAction(tr("&About"), this, &MainWindow::about);
+    helpMenu->addAction(tr("About &Qt"), qApp, &QApplication::aboutQt);
 }
diff --git a/examples/widgets/richtext/textedit/images/mac/exportpdf.png b/examples/widgets/richtext/textedit/images/mac/exportpdf.png
index ebb44e6b88..9e199407af 100644
--- a/examples/widgets/richtext/textedit/images/mac/exportpdf.png
+++ b/examples/widgets/richtext/textedit/images/mac/exportpdf.png
diff --git a/examples/widgets/richtext/textedit/images/mac/filesave.png b/examples/widgets/richtext/textedit/images/mac/filesave.png
index b41ecf5319..e65a29d5f1 100644
--- a/examples/widgets/richtext/textedit/images/mac/filesave.png
+++ b/examples/widgets/richtext/textedit/images/mac/filesave.png
diff --git a/examples/widgets/richtext/textedit/images/win/exportpdf.png b/examples/widgets/richtext/textedit/images/win/exportpdf.png
index eef5132928..ebb44e6b88 100644
--- a/examples/widgets/richtext/textedit/images/win/exportpdf.png
+++ b/examples/widgets/richtext/textedit/images/win/exportpdf.png
diff --git a/examples/widgets/richtext/textedit/textedit.cpp b/examples/widgets/richtext/textedit/textedit.cpp
index 0d51ce61ad..3ad9f48b67 100644
--- a/examples/widgets/richtext/textedit/textedit.cpp
+++ b/examples/widgets/richtext/textedit/textedit.cpp
@@ -369,7 +369,7 @@ void TextEdit::setupTextActions()
 
     comboFont = new QFontComboBox(tb);
     tb->addWidget(comboFont);
-    connect(comboFont, QOverload<const QString &>::of(&QComboBox::activated), this, &TextEdit::textFamily);
+    connect(comboFont, &QComboBox::textActivated, this, &TextEdit::textFamily);
 
     comboSize = new QComboBox(tb);
     comboSize->setObjectName("comboSize");
@@ -377,11 +377,11 @@ void TextEdit::setupTextActions()
     comboSize->setEditable(true);
 
     const QList<int> standardSizes = QFontDatabase::standardSizes();
-    foreach (int size, standardSizes)
+    for (int size : standardSizes)
         comboSize->addItem(QString::number(size));
     comboSize->setCurrentIndex(standardSizes.indexOf(QApplication::font().pointSize()));
 
-    connect(comboSize, QOverload<const QString &>::of(&QComboBox::activated), this, &TextEdit::textSize);
+    connect(comboSize, &QComboBox::textActivated, this, &TextEdit::textSize);
 }
 
 bool TextEdit::load(const QString &f)
diff --git a/examples/widgets/scroller/graphicsview/main.cpp b/examples/widgets/scroller/graphicsview/main.cpp
index c33a3091ed..d6b2956d50 100644
--- a/examples/widgets/scroller/graphicsview/main.cpp
+++ b/examples/widgets/scroller/graphicsview/main.cpp
@@ -117,7 +117,8 @@ public:
     QRectF boundingRect() const override
     {
         QRectF rect;
-        foreach (QGraphicsItem *item, childItems())
+        const auto items = childItems();
+        for (const QGraphicsItem *item : items)
             rect |= item->boundingRect().translated(item->pos());
         return rect;
     }
diff --git a/examples/widgets/statemachine/factorial/factorial.pro b/examples/widgets/statemachine/factorial/factorial.pro
index f200c738ba..bf285acf4d 100644
--- a/examples/widgets/statemachine/factorial/factorial.pro
+++ b/examples/widgets/statemachine/factorial/factorial.pro
@@ -1,6 +1,5 @@
 QT = core
-win32: CONFIG += console
-mac:CONFIG -= app_bundle
+CONFIG += cmdline
 
 SOURCES += main.cpp
 
diff --git a/examples/widgets/statemachine/factorial/main.cpp b/examples/widgets/statemachine/factorial/main.cpp
index f100aa0110..e9431596fe 100644
--- a/examples/widgets/statemachine/factorial/main.cpp
+++ b/examples/widgets/statemachine/factorial/main.cpp
@@ -49,7 +49,6 @@
 ****************************************************************************/
 
 #include <QtCore>
-#include <stdio.h>
 
 //! [0]
 class Factorial : public QObject
@@ -100,7 +99,7 @@ class FactorialLoopTransition : public QSignalTransition
 {
 public:
     FactorialLoopTransition(Factorial *fact)
-        : QSignalTransition(fact, SIGNAL(xChanged(int))), m_fact(fact)
+        : QSignalTransition(fact, &Factorial::xChanged), m_fact(fact)
     {}
 
     bool eventTest(QEvent *e) override
@@ -130,7 +129,7 @@ class FactorialDoneTransition : public QSignalTransition
 {
 public:
     FactorialDoneTransition(Factorial *fact)
-        : QSignalTransition(fact, SIGNAL(xChanged(int))), m_fact(fact)
+        : QSignalTransition(fact, &Factorial::xChanged), m_fact(fact)
     {}
 
     bool eventTest(QEvent *e) override
@@ -143,7 +142,7 @@ public:
 
     void onTransition(QEvent *) override
     {
-        fprintf(stdout, "%d\n", m_fact->property("fac").toInt());
+        qInfo() << m_fact->property("fac").toInt();
     }
 
 private:
diff --git a/examples/widgets/statemachine/pingpong/pingpong.pro b/examples/widgets/statemachine/pingpong/pingpong.pro
index 7cc27a13f5..18dee0400d 100644
--- a/examples/widgets/statemachine/pingpong/pingpong.pro
+++ b/examples/widgets/statemachine/pingpong/pingpong.pro
@@ -1,6 +1,5 @@
 QT = core
-win32: CONFIG += console
-mac:CONFIG -= app_bundle
+CONFIG += cmdline
 
 SOURCES = main.cpp
 
diff --git a/examples/widgets/statemachine/rogue/window.cpp b/examples/widgets/statemachine/rogue/window.cpp
index 059fbf1003..a5363e2758 100644
--- a/examples/widgets/statemachine/rogue/window.cpp
+++ b/examples/widgets/statemachine/rogue/window.cpp
@@ -66,7 +66,8 @@ Window::Window()
         font = QFont("Monospace");
     }
     else {
-        foreach (QString family, database.families()) {
+        const QStringList fontFamilies = database.families();
+        for (const QString &family : fontFamilies ) {
             if (database.isFixedPitch(family)) {
                 font = QFont(family);
                 break;
@@ -217,7 +218,8 @@ void Window::buildMachine()
 //![5]
     machine->setInitialState(inputState);
 
-    connect(machine, SIGNAL(finished()), qApp, SLOT(quit()));
+    connect(machine, &QStateMachine::finished,
+            qApp, &QApplication::quit);
 
     machine->start();
 }
diff --git a/examples/widgets/statemachine/trafficlight/main.cpp b/examples/widgets/statemachine/trafficlight/main.cpp
index 21df91d8b0..1a7050c28d 100644
--- a/examples/widgets/statemachine/trafficlight/main.cpp
+++ b/examples/widgets/statemachine/trafficlight/main.cpp
@@ -132,11 +132,11 @@ QState *createLightState(LightWidget *light, int duration, QState *parent = 0)
     timer->setInterval(duration);
     timer->setSingleShot(true);
     QState *timing = new QState(lightState);
-    QObject::connect(timing, SIGNAL(entered()), light, SLOT(turnOn()));
-    QObject::connect(timing, SIGNAL(entered()), timer, SLOT(start()));
-    QObject::connect(timing, SIGNAL(exited()), light, SLOT(turnOff()));
+    QObject::connect(timing, &QAbstractState::entered, light, &LightWidget::turnOn);
+    QObject::connect(timing, &QAbstractState::entered, timer, QOverload<>::of(&QTimer::start));
+    QObject::connect(timing, &QAbstractState::exited, light, &LightWidget::turnOff);
     QFinalState *done = new QFinalState(lightState);
-    timing->addTransition(timer, SIGNAL(timeout()), done);
+    timing->addTransition(timer, &QTimer::timeout, done);
     lightState->setInitialState(timing);
     return lightState;
 }
@@ -146,27 +146,27 @@ QState *createLightState(LightWidget *light, int duration, QState *parent = 0)
 class TrafficLight : public QWidget
 {
 public:
-    TrafficLight(QWidget *parent = 0)
+    TrafficLight(QWidget *parent = nullptr)
         : QWidget(parent)
     {
         QVBoxLayout *vbox = new QVBoxLayout(this);
-        TrafficLightWidget *widget = new TrafficLightWidget();
+        TrafficLightWidget *widget = new TrafficLightWidget;
         vbox->addWidget(widget);
-        vbox->setMargin(0);
+        vbox->setContentsMargins(QMargins());
 
         QStateMachine *machine = new QStateMachine(this);
         QState *redGoingYellow = createLightState(widget->redLight(), 3000);
         redGoingYellow->setObjectName("redGoingYellow");
         QState *yellowGoingGreen = createLightState(widget->yellowLight(), 1000);
         yellowGoingGreen->setObjectName("yellowGoingGreen");
-        redGoingYellow->addTransition(redGoingYellow, SIGNAL(finished()), yellowGoingGreen);
+        redGoingYellow->addTransition(redGoingYellow, &QState::finished, yellowGoingGreen);
         QState *greenGoingYellow = createLightState(widget->greenLight(), 3000);
         greenGoingYellow->setObjectName("greenGoingYellow");
-        yellowGoingGreen->addTransition(yellowGoingGreen, SIGNAL(finished()), greenGoingYellow);
+        yellowGoingGreen->addTransition(yellowGoingGreen, &QState::finished, greenGoingYellow);
         QState *yellowGoingRed = createLightState(widget->yellowLight(), 1000);
         yellowGoingRed->setObjectName("yellowGoingRed");
-        greenGoingYellow->addTransition(greenGoingYellow, SIGNAL(finished()), yellowGoingRed);
-        yellowGoingRed->addTransition(yellowGoingRed, SIGNAL(finished()), redGoingYellow);
+        greenGoingYellow->addTransition(greenGoingYellow, &QState::finished, yellowGoingRed);
+        yellowGoingRed->addTransition(yellowGoingRed, &QState::finished, redGoingYellow);
 
         machine->addState(redGoingYellow);
         machine->addState(yellowGoingGreen);
diff --git a/examples/widgets/statemachine/twowaybutton/main.cpp b/examples/widgets/statemachine/twowaybutton/main.cpp
index 5c778aba70..3d4fef3bbe 100644
--- a/examples/widgets/statemachine/twowaybutton/main.cpp
+++ b/examples/widgets/statemachine/twowaybutton/main.cpp
@@ -69,8 +69,8 @@ int main(int argc, char **argv)
 //! [1]
 
 //! [2]
-    off->addTransition(&button, SIGNAL(clicked()), on);
-    on->addTransition(&button, SIGNAL(clicked()), off);
+    off->addTransition(&button, &QAbstractButton::clicked, on);
+    on->addTransition(&button, &QAbstractButton::clicked, off);
 //! [2]
 
 //! [3]
diff --git a/examples/widgets/tools/codecs/CMakeLists.txt b/examples/widgets/tools/codecs/CMakeLists.txt
index fbf2e4e1a0..703aa3fb47 100644
--- a/examples/widgets/tools/codecs/CMakeLists.txt
+++ b/examples/widgets/tools/codecs/CMakeLists.txt
@@ -9,12 +9,18 @@ add_qt_executable(codecs
     OUTPUT_DIRECTORY "${INSTALL_EXAMPLESDIR}/widgets/tools/codecs"
     INSTALL_DIRECTORY "${INSTALL_EXAMPLESDIR}/widgets/tools/codecs"
     SOURCES
+        encodingdialog.cpp encodingdialog.h
         main.cpp
         mainwindow.cpp mainwindow.h
         previewform.cpp previewform.h
-    LIBRARIES
+    PUBLIC_LIBRARIES
         Qt::Widgets
 )
 
-#### Keys ignored in scope 1:.:codecs.pro:<NONE>:
+# Resources:
+add_qt_resource(codecs "codecs" PREFIX "/" FILES
+    images/editcopy.png)
+
+
+#### Keys ignored in scope 1:.:.:codecs.pro:<TRUE>:
 # EXAMPLE_FILES = "encodedfiles"
diff --git a/examples/widgets/tools/codecs/codecs.pro b/examples/widgets/tools/codecs/codecs.pro
index 13daa79237..6f4b0742a9 100644
--- a/examples/widgets/tools/codecs/codecs.pro
+++ b/examples/widgets/tools/codecs/codecs.pro
@@ -2,10 +2,15 @@ QT += widgets
 requires(qtConfig(filedialog))
 
 HEADERS      += mainwindow.h \
-                previewform.h
+                previewform.h \
+                encodingdialog.h
+
 SOURCES      += main.cpp \
                 mainwindow.cpp \
-                previewform.cpp
+                previewform.cpp \
+                encodingdialog.cpp
+
+RESOURCES    += codecs.qrc
 
 EXAMPLE_FILES = encodedfiles
 
diff --git a/examples/widgets/tools/codecs/codecs.qrc b/examples/widgets/tools/codecs/codecs.qrc
new file mode 100644
index 0000000000..65fa1aa64d
--- /dev/null
+++ b/examples/widgets/tools/codecs/codecs.qrc
@@ -0,0 +1,5 @@
+<RCC>
+    <qresource prefix="/" >
+        <file>images/editcopy.png</file>
+    </qresource>
+</RCC>
diff --git a/examples/widgets/tools/codecs/encodingdialog.cpp b/examples/widgets/tools/codecs/encodingdialog.cpp
new file mode 100644
index 0000000000..ca4b56db9e
--- /dev/null
+++ b/examples/widgets/tools/codecs/encodingdialog.cpp
@@ -0,0 +1,333 @@
+/****************************************************************************
+**
+** Copyright (C) 2018 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the examples of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:BSD$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** BSD License Usage
+** Alternatively, you may use this file under the terms of the BSD license
+** as follows:
+**
+** "Redistribution and use in source and binary forms, with or without
+** modification, are permitted provided that the following conditions are
+** met:
+**   * Redistributions of source code must retain the above copyright
+**     notice, this list of conditions and the following disclaimer.
+**   * Redistributions in binary form must reproduce the above copyright
+**     notice, this list of conditions and the following disclaimer in
+**     the documentation and/or other materials provided with the
+**     distribution.
+**   * Neither the name of The Qt Company Ltd nor the names of its
+**     contributors may be used to endorse or promote products derived
+**     from this software without specific prior written permission.
+**
+**
+** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "encodingdialog.h"
+
+#if QT_CONFIG(action)
+#  include <QAction>
+#endif
+#include <QDialogButtonBox>
+#include <QFormLayout>
+#include <QLabel>
+#include <QLineEdit>
+#include <QVBoxLayout>
+
+#if QT_CONFIG(clipboard)
+#  include <QGuiApplication>
+#  include <QClipboard>
+#endif
+
+#include <QTextStream>
+
+// Helpers for formatting character sequences
+
+// Format a special character like '\x0a'
+template <class Int>
+static void formatEscapedNumber(QTextStream &str, Int value, int base,
+                                int width = 0,char prefix = 0)
+{
+    str << '\\';
+    if (prefix)
+        str << prefix;
+    const auto oldPadChar = str.padChar();
+    const auto oldFieldWidth = str.fieldWidth();
+    const auto oldFieldAlignment = str.fieldAlignment();
+    const auto oldIntegerBase = str.integerBase();
+    str.setPadChar(QLatin1Char('0'));
+    str.setFieldWidth(width);
+    str.setFieldAlignment(QTextStream::AlignRight);
+    str.setIntegerBase(base);
+    str << value;
+    str.setIntegerBase(oldIntegerBase);
+    str.setFieldAlignment(oldFieldAlignment);
+    str.setFieldWidth(oldFieldWidth);
+    str.setPadChar(oldPadChar);
+}
+
+template <class Int>
+static bool formatSpecialCharacter(QTextStream &str, Int value)
+{
+    bool result = true;
+    switch (value) {
+    case '\\':
+        str << "\\\\";
+        break;
+    case '\"':
+        str << "\\\"";
+        break;
+    case '\n':
+        str << "\\n";
+        break;
+    default:
+        result = false;
+        break;
+    }
+    return result;
+}
+
+// Format a sequence of characters (QChar, ushort (UTF-16), uint (UTF-32)
+// or just char (Latin1, Utf-8)) with the help of traits specifying
+// how to obtain the code for checking the printable-ness and how to
+// stream out the plain ASCII values.
+
+template <EncodingDialog::Encoding>
+struct FormattingTraits
+{
+};
+
+template <>
+struct FormattingTraits<EncodingDialog::Unicode>
+{
+    static ushort code(QChar c) { return c.unicode(); }
+    static char toAscii(QChar c) { return c.toLatin1(); }
+};
+
+template <>
+struct FormattingTraits<EncodingDialog::Utf8>
+{
+    static ushort code(char c) { return uchar(c); }
+    static char toAscii(char c) { return c; }
+};
+
+template <>
+struct FormattingTraits<EncodingDialog::Utf16>
+{
+    static ushort code(ushort c) { return c; }
+    static char toAscii(ushort c) { return char(c); }
+};
+
+template <>
+struct FormattingTraits<EncodingDialog::Utf32>
+{
+    static uint code(uint c) { return c; }
+    static char toAscii(uint c) { return char(c); }
+};
+
+template <>
+struct FormattingTraits<EncodingDialog::Latin1>
+{
+    static uchar code(char c) { return uchar(c); }
+    static char toAscii(char  c) { return c; }
+};
+
+static bool isHexDigit(char c)
+{
+    return (c >= '0' && c <= '9') || (c >= 'a' && c <= 'f')
+        || (c >= 'A' && c <= 'F');
+}
+
+template <EncodingDialog::Encoding encoding, class Iterator>
+static void formatStringSequence(QTextStream &str, Iterator i1, Iterator i2,
+                                 int escapeIntegerBase, int escapeWidth,
+                                 char escapePrefix = 0)
+{
+    str << '"';
+    bool separateHexEscape = false;
+    for (; i1 != i2; ++i1) {
+        const auto code = FormattingTraits<encoding>::code(*i1);
+        if (code >= 0x80) {
+            formatEscapedNumber(str, code, escapeIntegerBase, escapeWidth, escapePrefix);
+            separateHexEscape = escapeIntegerBase == 16 && escapeWidth == 0;
+        } else {
+            if (!formatSpecialCharacter(str, code)) {
+                const char c = FormattingTraits<encoding>::toAscii(*i1);
+                // For variable width/hex: Terminate the literal to stop digit parsing
+                // ("\x12" "34...").
+                if (separateHexEscape && isHexDigit(c))
+                    str << "\" \"";
+                str << c;
+            }
+            separateHexEscape = false;
+        }
+    }
+    str << '"';
+}
+
+static QString encodedString(const QString &value, EncodingDialog::Encoding e)
+{
+    QString result;
+    QTextStream str(&result);
+    switch (e) {
+    case EncodingDialog::Unicode:
+        formatStringSequence<EncodingDialog::Unicode>(str, value.cbegin(), value.cend(),
+                                                      16, 4, 'u');
+        break;
+    case EncodingDialog::Utf8: {
+        const QByteArray utf8 = value.toUtf8();
+        str << "u8";
+        formatStringSequence<EncodingDialog::Utf8>(str, utf8.cbegin(), utf8.cend(),
+                                                   8, 3);
+    }
+        break;
+    case EncodingDialog::Utf16: {
+        auto utf16 = value.utf16();
+        auto utf16End = utf16 + value.size();
+        str << 'u';
+        formatStringSequence<EncodingDialog::Utf16>(str, utf16, utf16End,
+                                                    16, 0, 'x');
+    }
+        break;
+    case EncodingDialog::Utf32: {
+        auto utf32 = value.toUcs4();
+        str << 'U';
+        formatStringSequence<EncodingDialog::Utf32>(str, utf32.cbegin(), utf32.cend(),
+                                                    16, 0, 'x');
+    }
+        break;
+    case EncodingDialog::Latin1: {
+        const QByteArray latin1 = value.toLatin1();
+        formatStringSequence<EncodingDialog::Latin1>(str, latin1.cbegin(), latin1.cend(),
+                                                     16, 0, 'x');
+    }
+        break;
+    case EncodingDialog::EncodingCount:
+        break;
+    }
+    return result;
+}
+
+// Dialog helpers
+
+static const char *encodingLabels[]
+{
+    QT_TRANSLATE_NOOP("EncodingDialog", "Unicode:"),
+    QT_TRANSLATE_NOOP("EncodingDialog", "UTF-8:"),
+    QT_TRANSLATE_NOOP("EncodingDialog", "UTF-16:"),
+    QT_TRANSLATE_NOOP("EncodingDialog", "UTF-32:"),
+    QT_TRANSLATE_NOOP("EncodingDialog", "Latin1:")
+};
+
+static const char *encodingToolTips[]
+{
+    QT_TRANSLATE_NOOP("EncodingDialog", "Unicode points for use with any encoding (C++, Python)"),
+    QT_TRANSLATE_NOOP("EncodingDialog", "QString::fromUtf8()"),
+    QT_TRANSLATE_NOOP("EncodingDialog", "QStringViewLiteral(), wchar_t on Windows"),
+    QT_TRANSLATE_NOOP("EncodingDialog", "wchar_t on Unix (Ucs4)"),
+    QT_TRANSLATE_NOOP("EncodingDialog", "QLatin1String")
+};
+
+// A read-only line edit with a tool button to copy the contents
+class DisplayLineEdit : public QLineEdit
+{
+    Q_OBJECT
+public:
+    explicit DisplayLineEdit(const QIcon &icon, QWidget *parent = nullptr);
+
+public slots:
+    void copyAll();
+};
+
+DisplayLineEdit::DisplayLineEdit(const QIcon &icon, QWidget *parent) :
+    QLineEdit(parent)
+{
+    setReadOnly(true);
+#if QT_CONFIG(clipboard) && QT_CONFIG(action)
+    auto copyAction = addAction(icon, QLineEdit::TrailingPosition);
+    connect(copyAction, &QAction::triggered, this, &DisplayLineEdit::copyAll);
+#endif
+}
+
+void DisplayLineEdit::copyAll()
+{
+#if QT_CONFIG(clipboard)
+    QGuiApplication::clipboard()->setText(text());
+#endif
+}
+
+static void addFormLayoutRow(QFormLayout *formLayout, const QString &text,
+                             QWidget *w, const QString &toolTip)
+{
+    auto label = new QLabel(text);
+    label->setToolTip(toolTip);
+    w->setToolTip(toolTip);
+    label->setBuddy(w);
+    formLayout->addRow(label, w);
+}
+
+EncodingDialog::EncodingDialog(QWidget *parent) :
+    QDialog(parent)
+{
+    setWindowFlags(windowFlags() & ~Qt::WindowContextHelpButtonHint);
+    setWindowTitle(tr("Encodings"));
+
+    auto formLayout = new QFormLayout;
+    auto sourceLineEdit = new QLineEdit(this);
+    sourceLineEdit->setClearButtonEnabled(true);
+    connect(sourceLineEdit, &QLineEdit::textChanged, this, &EncodingDialog::textChanged);
+
+    addFormLayoutRow(formLayout, tr("&Source:"), sourceLineEdit, tr("Enter text"));
+
+    const auto copyIcon = QIcon::fromTheme(QLatin1String("edit-copy"),
+                                           QIcon(QLatin1String(":/images/editcopy")));
+    for (int i = 0; i < EncodingCount; ++i) {
+        m_lineEdits[i] = new DisplayLineEdit(copyIcon, this);
+        addFormLayoutRow(formLayout, tr(encodingLabels[i]),
+                         m_lineEdits[i], tr(encodingToolTips[i]));
+    }
+
+    auto mainLayout = new QVBoxLayout(this);
+    mainLayout->addLayout(formLayout);
+    auto buttonBox = new QDialogButtonBox(QDialogButtonBox::Close);
+    connect(buttonBox, &QDialogButtonBox::rejected, this, &QDialog::reject);
+    mainLayout->addWidget(buttonBox);
+}
+
+void EncodingDialog::textChanged(const QString &t)
+{
+    if (t.isEmpty()) {
+        for (auto lineEdit : m_lineEdits)
+            lineEdit->clear();
+    } else {
+         for (int i = 0; i < EncodingCount; ++i)
+             m_lineEdits[i]->setText(encodedString(t, static_cast<Encoding>(i)));
+    }
+}
+
+#include "encodingdialog.moc"
diff --git a/examples/widgets/tools/codecs/encodingdialog.h b/examples/widgets/tools/codecs/encodingdialog.h
new file mode 100644
index 0000000000..3f82da84af
--- /dev/null
+++ b/examples/widgets/tools/codecs/encodingdialog.h
@@ -0,0 +1,73 @@
+/****************************************************************************
+**
+** Copyright (C) 2018 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the examples of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:BSD$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** BSD License Usage
+** Alternatively, you may use this file under the terms of the BSD license
+** as follows:
+**
+** "Redistribution and use in source and binary forms, with or without
+** modification, are permitted provided that the following conditions are
+** met:
+**   * Redistributions of source code must retain the above copyright
+**     notice, this list of conditions and the following disclaimer.
+**   * Redistributions in binary form must reproduce the above copyright
+**     notice, this list of conditions and the following disclaimer in
+**     the documentation and/or other materials provided with the
+**     distribution.
+**   * Neither the name of The Qt Company Ltd nor the names of its
+**     contributors may be used to endorse or promote products derived
+**     from this software without specific prior written permission.
+**
+**
+** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef ENCODINGDIALOG_H
+#define ENCODINGDIALOG_H
+
+#include <QDialog>
+
+QT_FORWARD_DECLARE_CLASS(QLineEdit)
+
+class EncodingDialog : public QDialog
+{
+    Q_OBJECT
+public:
+    explicit EncodingDialog(QWidget *parent = nullptr);
+
+    enum Encoding { Unicode, Utf8, Utf16, Utf32, Latin1, EncodingCount };
+
+private slots:
+    void textChanged(const QString &t);
+
+private:
+    QLineEdit *m_lineEdits[EncodingCount];
+};
+
+#endif // ENCODINGDIALOG_H
diff --git a/examples/widgets/tools/codecs/images/editcopy.png b/examples/widgets/tools/codecs/images/editcopy.png
new file mode 100644
index 0000000000..1121b47d8b
--- /dev/null
+++ b/examples/widgets/tools/codecs/images/editcopy.png
diff --git a/examples/widgets/tools/codecs/mainwindow.cpp b/examples/widgets/tools/codecs/mainwindow.cpp
index 28f904d1a7..53db9fe61f 100644
--- a/examples/widgets/tools/codecs/mainwindow.cpp
+++ b/examples/widgets/tools/codecs/mainwindow.cpp
@@ -51,6 +51,7 @@
 #include <QtWidgets>
 
 #include "mainwindow.h"
+#include "encodingdialog.h"
 #include "previewform.h"
 
 MainWindow::MainWindow()
@@ -126,11 +127,10 @@ void MainWindow::about()
 
 void MainWindow::aboutToShowSaveAsMenu()
 {
-    QString currentText = textEdit->toPlainText();
-
-    foreach (QAction *action, saveAsActs) {
-        QByteArray codecName = action->data().toByteArray();
-        QTextCodec *codec = QTextCodec::codecForName(codecName);
+    const QString currentText = textEdit->toPlainText();
+    for (QAction *action : qAsConst(saveAsActs)) {
+        const QByteArray codecName = action->data().toByteArray();
+        const QTextCodec *codec = QTextCodec::codecForName(codecName);
         action->setVisible(codec && codec->canEncode(currentText));
     }
 }
@@ -141,7 +141,8 @@ void MainWindow::findCodecs()
     QRegularExpression iso8859RegExp("^ISO[- ]8859-([0-9]+).*$");
     QRegularExpressionMatch match;
 
-    foreach (int mib, QTextCodec::availableMibs()) {
+    const QList<int> mibs = QTextCodec::availableMibs();
+    for (int mib : mibs) {
         QTextCodec *codec = QTextCodec::codecForMib(mib);
 
         QString sortKey = codec->name().toUpper();
@@ -176,7 +177,7 @@ void MainWindow::createMenus()
     QMenu *saveAsMenu = fileMenu->addMenu(tr("&Save As"));
     connect(saveAsMenu, &QMenu::aboutToShow,
             this, &MainWindow::aboutToShowSaveAsMenu);
-    foreach (const QTextCodec *codec, codecs) {
+    for (const QTextCodec *codec : qAsConst(codecs)) {
         const QByteArray name = codec->name();
         QAction *action = saveAsMenu->addAction(tr("%1...").arg(QLatin1String(name)));
         action->setData(QVariant(name));
@@ -188,9 +189,27 @@ void MainWindow::createMenus()
     QAction *exitAct = fileMenu->addAction(tr("E&xit"), this, &QWidget::close);
     exitAct->setShortcuts(QKeySequence::Quit);
 
+    auto toolMenu =  menuBar()->addMenu(tr("&Tools"));
+    auto encodingAction = toolMenu->addAction(tr("Encodings"), this, &MainWindow::encodingDialog);
+    encodingAction->setShortcut(Qt::CTRL + Qt::Key_E);
+    encodingAction->setToolTip(tr("Shows a dialog allowing to convert to common encoding in programming languages."));
+
+
     menuBar()->addSeparator();
 
     QMenu *helpMenu = menuBar()->addMenu(tr("&Help"));
     helpMenu->addAction(tr("&About"), this, &MainWindow::about);
     helpMenu->addAction(tr("About &Qt"), qApp, &QApplication::aboutQt);
 }
+
+void MainWindow::encodingDialog()
+{
+    if (!m_encodingDialog) {
+        m_encodingDialog = new EncodingDialog(this);
+        const QRect screenGeometry = QApplication::desktop()->screenGeometry(this);
+        m_encodingDialog->setMinimumWidth(screenGeometry.width() / 4);
+    }
+    m_encodingDialog->show();
+    m_encodingDialog->raise();
+
+}
diff --git a/examples/widgets/tools/codecs/mainwindow.h b/examples/widgets/tools/codecs/mainwindow.h
index 7121c0b122..64494d1960 100644
--- a/examples/widgets/tools/codecs/mainwindow.h
+++ b/examples/widgets/tools/codecs/mainwindow.h
@@ -59,6 +59,8 @@ class QAction;
 class QTextCodec;
 class QPlainTextEdit;
 QT_END_NAMESPACE
+
+class EncodingDialog;
 class PreviewForm;
 
 class MainWindow : public QMainWindow
@@ -73,6 +75,7 @@ private slots:
     void save();
     void about();
     void aboutToShowSaveAsMenu();
+    void encodingDialog();
 
 private:
     void findCodecs();
@@ -82,6 +85,7 @@ private:
     QPlainTextEdit *textEdit;
     PreviewForm *previewForm;
     QList<QTextCodec *> codecs;
+    EncodingDialog *m_encodingDialog = nullptr;
 };
 
 #endif
diff --git a/examples/widgets/tools/codecs/previewform.cpp b/examples/widgets/tools/codecs/previewform.cpp
index d19b9c0833..206b5757cd 100644
--- a/examples/widgets/tools/codecs/previewform.cpp
+++ b/examples/widgets/tools/codecs/previewform.cpp
@@ -182,7 +182,7 @@ PreviewForm::PreviewForm(QWidget *parent)
 void PreviewForm::setCodecList(const QList<QTextCodec *> &list)
 {
     encodingComboBox->clear();
-    foreach (const QTextCodec *codec, list) {
+    for (const QTextCodec *codec : list) {
         encodingComboBox->addItem(QLatin1String(codec->name()),
                                   QVariant(codec->mibEnum()));
     }
diff --git a/examples/widgets/tools/completer/mainwindow.cpp b/examples/widgets/tools/completer/mainwindow.cpp
index d63d523548..114ff0fd7c 100644
--- a/examples/widgets/tools/completer/mainwindow.cpp
+++ b/examples/widgets/tools/completer/mainwindow.cpp
@@ -102,10 +102,14 @@ MainWindow::MainWindow(QWidget *parent)
     contentsLabel = new QLabel;
     contentsLabel->setSizePolicy(QSizePolicy::Fixed, QSizePolicy::Fixed);
 
-    connect(modelCombo, SIGNAL(activated(int)), this, SLOT(changeModel()));
-    connect(modeCombo, SIGNAL(activated(int)), this, SLOT(changeMode(int)));
-    connect(caseCombo, SIGNAL(activated(int)), this, SLOT(changeCase(int)));
-    connect(maxVisibleSpinBox, SIGNAL(valueChanged(int)), this, SLOT(changeMaxVisible(int)));
+    connect(modelCombo, QOverload<int>::of(&QComboBox::activated),
+            this, &MainWindow::changeModel);
+    connect(modeCombo, QOverload<int>::of(&QComboBox::activated),
+            this, &MainWindow::changeMode);
+    connect(caseCombo, QOverload<int>::of(&QComboBox::activated),
+            this, &MainWindow::changeCase);
+    connect(maxVisibleSpinBox, QOverload<int>::of(&QSpinBox::valueChanged),
+            this, &MainWindow::changeMaxVisible);
 //! [2]
 
 //! [3]
@@ -136,9 +140,9 @@ void MainWindow::createMenu()
     QAction *aboutAct = new QAction(tr("About"), this);
     QAction *aboutQtAct = new QAction(tr("About Qt"), this);
 
-    connect(exitAction, SIGNAL(triggered()), qApp, SLOT(quit()));
-    connect(aboutAct, SIGNAL(triggered()), this, SLOT(about()));
-    connect(aboutQtAct, SIGNAL(triggered()), qApp, SLOT(aboutQt()));
+    connect(exitAction, &QAction::triggered, qApp, &QApplication::quit);
+    connect(aboutAct, &QAction::triggered, this, &MainWindow::about);
+    connect(aboutQtAct, &QAction::triggered, qApp, &QApplication::aboutQt);
 
     QMenu* fileMenu = menuBar()->addMenu(tr("File"));
     fileMenu->addAction(exitAction);
@@ -159,7 +163,7 @@ QAbstractItemModel *MainWindow::modelFromFile(const QString& fileName)
 
 //! [6]
 #ifndef QT_NO_CURSOR
-    QApplication::setOverrideCursor(QCursor(Qt::WaitCursor));
+    QGuiApplication::setOverrideCursor(QCursor(Qt::WaitCursor));
 #endif
     QStringList words;
 
@@ -170,7 +174,7 @@ QAbstractItemModel *MainWindow::modelFromFile(const QString& fileName)
     }
 
 #ifndef QT_NO_CURSOR
-    QApplication::restoreOverrideCursor();
+    QGuiApplication::restoreOverrideCursor();
 #endif
 //! [6]
 
@@ -271,7 +275,7 @@ void MainWindow::changeModel()
     changeCase(caseCombo->currentIndex());
     completer->setWrapAround(wrapCheckBox->isChecked());
     lineEdit->setCompleter(completer);
-    connect(wrapCheckBox, SIGNAL(clicked(bool)), completer, SLOT(setWrapAround(bool)));
+    connect(wrapCheckBox, &QAbstractButton::clicked, completer, &QCompleter::setWrapAround);
 }
 //! [14]
 
diff --git a/examples/widgets/tools/customcompleter/mainwindow.cpp b/examples/widgets/tools/customcompleter/mainwindow.cpp
index 26948d0c8e..39f5f39617 100644
--- a/examples/widgets/tools/customcompleter/mainwindow.cpp
+++ b/examples/widgets/tools/customcompleter/mainwindow.cpp
@@ -79,9 +79,9 @@ void MainWindow::createMenu()
     QAction *aboutAct = new QAction(tr("About"), this);
     QAction *aboutQtAct = new QAction(tr("About Qt"), this);
 
-    connect(exitAction, SIGNAL(triggered()), qApp, SLOT(quit()));
-    connect(aboutAct, SIGNAL(triggered()), this, SLOT(about()));
-    connect(aboutQtAct, SIGNAL(triggered()), qApp, SLOT(aboutQt()));
+    connect(exitAction, &QAction::triggered, qApp, &QApplication::quit);
+    connect(aboutAct, &QAction::triggered, this, &MainWindow::about);
+    connect(aboutQtAct, &QAction::triggered, qApp, &QApplication::aboutQt);
 
     QMenu* fileMenu = menuBar()->addMenu(tr("File"));
     fileMenu->addAction(exitAction);
@@ -100,7 +100,7 @@ QAbstractItemModel *MainWindow::modelFromFile(const QString& fileName)
         return new QStringListModel(completer);
 
 #ifndef QT_NO_CURSOR
-    QApplication::setOverrideCursor(QCursor(Qt::WaitCursor));
+    QGuiApplication::setOverrideCursor(QCursor(Qt::WaitCursor));
 #endif
     QStringList words;
 
@@ -111,7 +111,7 @@ QAbstractItemModel *MainWindow::modelFromFile(const QString& fileName)
     }
 
 #ifndef QT_NO_CURSOR
-    QApplication::restoreOverrideCursor();
+    QGuiApplication::restoreOverrideCursor();
 #endif
     return new QStringListModel(words, completer);
 }
diff --git a/examples/widgets/tools/customcompleter/textedit.cpp b/examples/widgets/tools/customcompleter/textedit.cpp
index 5512e72843..d42f7b38bb 100644
--- a/examples/widgets/tools/customcompleter/textedit.cpp
+++ b/examples/widgets/tools/customcompleter/textedit.cpp
@@ -88,8 +88,8 @@ void TextEdit::setCompleter(QCompleter *completer)
     c->setWidget(this);
     c->setCompletionMode(QCompleter::PopupCompletion);
     c->setCaseSensitivity(Qt::CaseInsensitive);
-    QObject::connect(c, SIGNAL(activated(QString)),
-                     this, SLOT(insertCompletion(QString)));
+    QObject::connect(c, QOverload<const QString &>::of(&QCompleter::activated),
+                     this, &TextEdit::insertCompletion);
 }
 //! [2]
 
diff --git a/examples/widgets/tools/echoplugin/echowindow/echowindow.cpp b/examples/widgets/tools/echoplugin/echowindow/echowindow.cpp
index 64b59d506e..6886a4cd88 100644
--- a/examples/widgets/tools/echoplugin/echowindow/echowindow.cpp
+++ b/examples/widgets/tools/echoplugin/echowindow/echowindow.cpp
@@ -113,7 +113,8 @@ bool EchoWindow::loadPlugin()
     }
 #endif
     pluginsDir.cd("plugins");
-    foreach (QString fileName, pluginsDir.entryList(QDir::Files)) {
+    const QStringList entries = pluginsDir.entryList(QDir::Files);
+    for (const QString &fileName : entries) {
         QPluginLoader pluginLoader(pluginsDir.absoluteFilePath(fileName));
         QObject *plugin = pluginLoader.instance();
         if (plugin) {
diff --git a/examples/widgets/tools/i18n/languagechooser.cpp b/examples/widgets/tools/i18n/languagechooser.cpp
index 58cf9d4047..f07d0ddee3 100644
--- a/examples/widgets/tools/i18n/languagechooser.cpp
+++ b/examples/widgets/tools/i18n/languagechooser.cpp
@@ -148,14 +148,14 @@ void LanguageChooser::checkBoxToggled()
 
 void LanguageChooser::showAll()
 {
-    foreach (QCheckBox *checkBox, qmFileForCheckBoxMap.keys())
-        checkBox->setChecked(true);
+    for (auto it = qmFileForCheckBoxMap.keyBegin(); it != qmFileForCheckBoxMap.keyEnd(); ++it)
+        (*it)->setChecked(true);
 }
 
 void LanguageChooser::hideAll()
 {
-    foreach (QCheckBox *checkBox, qmFileForCheckBoxMap.keys())
-        checkBox->setChecked(false);
+    for (auto it = qmFileForCheckBoxMap.keyBegin(); it != qmFileForCheckBoxMap.keyEnd(); ++it)
+        (*it)->setChecked(false);
 }
 
 QStringList LanguageChooser::findQmFiles()
diff --git a/examples/widgets/tools/plugandpaint/app/plugindialog.cpp b/examples/widgets/tools/plugandpaint/app/plugindialog.cpp
index af5828f67e..84bd364b41 100644
--- a/examples/widgets/tools/plugandpaint/app/plugindialog.cpp
+++ b/examples/widgets/tools/plugandpaint/app/plugindialog.cpp
@@ -125,7 +125,7 @@ void PluginDialog::populateTreeWidget(QObject *plugin, const QString &text)
 {
     auto pluginItem = new QTreeWidgetItem(treeWidget);
     pluginItem->setText(0, text);
-    treeWidget->setItemExpanded(pluginItem, true);
+    pluginItem->setExpanded(true);
 
     QFont boldFont = pluginItem->font(0);
     boldFont.setBold(true);
diff --git a/examples/widgets/tools/regexp/regexpdialog.cpp b/examples/widgets/tools/regexp/regexpdialog.cpp
index 7b3fee5794..bf61d09974 100644
--- a/examples/widgets/tools/regexp/regexpdialog.cpp
+++ b/examples/widgets/tools/regexp/regexpdialog.cpp
@@ -135,15 +135,15 @@ RegExpDialog::RegExpDialog(QWidget *parent)
     }
     setLayout(mainLayout);
 
-    connect(patternComboBox, SIGNAL(editTextChanged(QString)),
-            this, SLOT(refresh()));
-    connect(textComboBox, SIGNAL(editTextChanged(QString)),
-            this, SLOT(refresh()));
-    connect(caseSensitiveCheckBox, SIGNAL(toggled(bool)),
-            this, SLOT(refresh()));
-    connect(minimalCheckBox, SIGNAL(toggled(bool)), this, SLOT(refresh()));
-    connect(syntaxComboBox, SIGNAL(currentIndexChanged(int)),
-            this, SLOT(refresh()));
+    connect(patternComboBox, &QComboBox::editTextChanged,
+            this, &RegExpDialog::refresh);
+    connect(textComboBox, &QComboBox::editTextChanged,
+            this, &RegExpDialog::refresh);
+    connect(caseSensitiveCheckBox, &QAbstractButton::toggled,
+            this, &RegExpDialog::refresh);
+    connect(minimalCheckBox, &QAbstractButton::toggled, this, &RegExpDialog::refresh);
+    connect(syntaxComboBox, QOverload<int>::of(&QComboBox::currentIndexChanged),
+            this, &RegExpDialog::refresh);
 
     patternComboBox->addItem(tr("[A-Za-z_]+([A-Za-z_0-9]*)"));
     textComboBox->addItem(tr("(10 + delta4) * 32"));
diff --git a/examples/widgets/tools/regularexpression/regularexpressiondialog.cpp b/examples/widgets/tools/regularexpression/regularexpressiondialog.cpp
index 8fbf143cbd..ea3cb00a02 100644
--- a/examples/widgets/tools/regularexpression/regularexpressiondialog.cpp
+++ b/examples/widgets/tools/regularexpression/regularexpressiondialog.cpp
@@ -376,7 +376,7 @@ QWidget *RegularExpressionDialog::setupLeftUi()
 
     QFormLayout *layout = new QFormLayout(container);
     layout->setFieldGrowthPolicy(QFormLayout::AllNonFixedFieldsGrow);
-    layout->setMargin(0);
+    layout->setContentsMargins(QMargins());
 
     QLabel *regexpAndSubjectLabel = new QLabel(tr("<h3>Regular expression and text input</h3>"));
     layout->addRow(regexpAndSubjectLabel);
@@ -448,7 +448,7 @@ QWidget *RegularExpressionDialog::setupRightUi()
 
     QFormLayout *layout = new QFormLayout(container);
     layout->setFieldGrowthPolicy(QFormLayout::AllNonFixedFieldsGrow);
-    layout->setMargin(0);
+    layout->setContentsMargins(QMargins());
 
     QLabel *matchInfoLabel = new QLabel(tr("<h3>Match information</h3>"));
     layout->addRow(matchInfoLabel);
diff --git a/examples/widgets/tools/settingseditor/settingstree.cpp b/examples/widgets/tools/settingseditor/settingstree.cpp
index 4ca843784e..8585792787 100644
--- a/examples/widgets/tools/settingseditor/settingstree.cpp
+++ b/examples/widgets/tools/settingseditor/settingstree.cpp
@@ -170,7 +170,8 @@ void SettingsTree::updateChildItems(QTreeWidgetItem *parent)
 {
     int dividerIndex = 0;
 
-    foreach (QString group, settings->childGroups()) {
+    const QStringList childGroups = settings->childGroups();
+    for (const QString &group : childGroups) {
         QTreeWidgetItem *child;
         int childIndex = findChild(parent, group, dividerIndex);
         if (childIndex != -1) {
@@ -190,7 +191,8 @@ void SettingsTree::updateChildItems(QTreeWidgetItem *parent)
         settings->endGroup();
     }
 
-    foreach (const QString &key, settings->childKeys()) {
+    const QStringList childKeys = settings->childKeys();
+    for (const QString &key : childKeys) {
         QTreeWidgetItem *child;
         int childIndex = findChild(parent, key, 0);
 
diff --git a/examples/widgets/tools/treemodelcompleter/mainwindow.cpp b/examples/widgets/tools/treemodelcompleter/mainwindow.cpp
index a8b51c7aa0..dec3cb0496 100644
--- a/examples/widgets/tools/treemodelcompleter/mainwindow.cpp
+++ b/examples/widgets/tools/treemodelcompleter/mainwindow.cpp
@@ -61,8 +61,8 @@ MainWindow::MainWindow(QWidget *parent)
     completer = new TreeModelCompleter(this);
     completer->setModel(modelFromFile(":/resources/treemodel.txt"));
     completer->setSeparator(QLatin1String("."));
-    QObject::connect(completer, SIGNAL(highlighted(QModelIndex)),
-                     this, SLOT(highlight(QModelIndex)));
+    QObject::connect(completer, QOverload<const QModelIndex &>::of(&TreeModelCompleter::highlighted),
+                     this, &MainWindow::highlight);
 
     QWidget *centralWidget = new QWidget;
 
@@ -91,18 +91,18 @@ MainWindow::MainWindow(QWidget *parent)
 
     QLineEdit *separatorLineEdit = new QLineEdit;
     separatorLineEdit->setText(completer->separator());
-    connect(separatorLineEdit, SIGNAL(textChanged(QString)),
-            completer, SLOT(setSeparator(QString)));
+    connect(separatorLineEdit, &QLineEdit::textChanged,
+            completer, &TreeModelCompleter::setSeparator);
 
     QCheckBox *wrapCheckBox = new QCheckBox;
     wrapCheckBox->setText(tr("Wrap around completions"));
     wrapCheckBox->setChecked(completer->wrapAround());
-    connect(wrapCheckBox, SIGNAL(clicked(bool)), completer, SLOT(setWrapAround(bool)));
+    connect(wrapCheckBox, &QAbstractButton::clicked, completer, &QCompleter::setWrapAround);
 
     contentsLabel = new QLabel;
     contentsLabel->setSizePolicy(QSizePolicy::Fixed, QSizePolicy::Fixed);
-    connect(separatorLineEdit, SIGNAL(textChanged(QString)),
-            this, SLOT(updateContentsLabel(QString)));
+    connect(separatorLineEdit, &QLineEdit::textChanged,
+            this, &MainWindow::updateContentsLabel);
 
     treeView = new QTreeView;
     treeView->setModel(completer->model());
@@ -111,8 +111,10 @@ MainWindow::MainWindow(QWidget *parent)
 //! [1]
 
 //! [2]
-    connect(modeCombo, SIGNAL(activated(int)), this, SLOT(changeMode(int)));
-    connect(caseCombo, SIGNAL(activated(int)), this, SLOT(changeCase(int)));
+    connect(modeCombo, QOverload<int>::of(&QComboBox::activated),
+            this, &MainWindow::changeMode);
+    connect(caseCombo, QOverload<int>::of(&QComboBox::activated),
+            this, &MainWindow::changeMode);
 
     lineEdit = new QLineEdit;
     lineEdit->setCompleter(completer);
@@ -145,9 +147,9 @@ void MainWindow::createMenu()
     QAction *aboutAct = new QAction(tr("About"), this);
     QAction *aboutQtAct = new QAction(tr("About Qt"), this);
 
-    connect(exitAction, SIGNAL(triggered()), qApp, SLOT(quit()));
-    connect(aboutAct, SIGNAL(triggered()), this, SLOT(about()));
-    connect(aboutQtAct, SIGNAL(triggered()), qApp, SLOT(aboutQt()));
+    connect(exitAction, &QAction::triggered, qApp, &QApplication::quit);
+    connect(aboutAct, &QAction::triggered, this, &MainWindow::about);
+    connect(aboutQtAct, &QAction::triggered, qApp, &QApplication::aboutQt);
 
     QMenu* fileMenu = menuBar()->addMenu(tr("File"));
     fileMenu->addAction(exitAction);
@@ -180,7 +182,7 @@ QAbstractItemModel *MainWindow::modelFromFile(const QString& fileName)
         return new QStringListModel(completer);
 
 #ifndef QT_NO_CURSOR
-    QApplication::setOverrideCursor(QCursor(Qt::WaitCursor));
+    QGuiApplication::setOverrideCursor(QCursor(Qt::WaitCursor));
 #endif
     QStringList words;
 
@@ -218,7 +220,7 @@ QAbstractItemModel *MainWindow::modelFromFile(const QString& fileName)
     }
 
 #ifndef QT_NO_CURSOR
-    QApplication::restoreOverrideCursor();
+    QGuiApplication::restoreOverrideCursor();
 #endif
 
     return model;
diff --git a/examples/widgets/tools/undo/document.cpp b/examples/widgets/tools/undo/document.cpp
index 212656721e..8935f98a7a 100644
--- a/examples/widgets/tools/undo/document.cpp
+++ b/examples/widgets/tools/undo/document.cpp
@@ -338,9 +338,9 @@ static QGradient gradient(const QColor &color, const QRect &rect)
     QColor c = color;
     c.setAlpha(160);
     QLinearGradient result(rect.topLeft(), rect.bottomRight());
-    result.setColorAt(0, c.dark(150));
-    result.setColorAt(0.5, c.light(200));
-    result.setColorAt(1, c.dark(150));
+    result.setColorAt(0, c.darker(150));
+    result.setColorAt(0.5, c.lighter(200));
+    result.setColorAt(1, c.darker(150));
     return result;
 }
 
diff --git a/examples/widgets/tools/undo/mainwindow.cpp b/examples/widgets/tools/undo/mainwindow.cpp
index 5976163f3f..118d604742 100644
--- a/examples/widgets/tools/undo/mainwindow.cpp
+++ b/examples/widgets/tools/undo/mainwindow.cpp
@@ -68,25 +68,25 @@ MainWindow::MainWindow(QWidget *parent)
     documentTabs->removeTab(0);
     delete w;
 
-    connect(actionOpen, SIGNAL(triggered()), this, SLOT(openDocument()));
-    connect(actionClose, SIGNAL(triggered()), this, SLOT(closeDocument()));
-    connect(actionNew, SIGNAL(triggered()), this, SLOT(newDocument()));
-    connect(actionSave, SIGNAL(triggered()), this, SLOT(saveDocument()));
-    connect(actionExit, SIGNAL(triggered()), this, SLOT(close()));
-    connect(actionRed, SIGNAL(triggered()), this, SLOT(setShapeColor()));
-    connect(actionGreen, SIGNAL(triggered()), this, SLOT(setShapeColor()));
-    connect(actionBlue, SIGNAL(triggered()), this, SLOT(setShapeColor()));
-    connect(actionAddCircle, SIGNAL(triggered()), this, SLOT(addShape()));
-    connect(actionAddRectangle, SIGNAL(triggered()), this, SLOT(addShape()));
-    connect(actionAddTriangle, SIGNAL(triggered()), this, SLOT(addShape()));
-    connect(actionRemoveShape, SIGNAL(triggered()), this, SLOT(removeShape()));
-    connect(actionAddRobot, SIGNAL(triggered()), this, SLOT(addRobot()));
-    connect(actionAddSnowman, SIGNAL(triggered()), this, SLOT(addSnowman()));
-    connect(actionAbout, SIGNAL(triggered()), this, SLOT(about()));
-    connect(actionAboutQt, SIGNAL(triggered()), this, SLOT(aboutQt()));
-
-    connect(undoLimit, SIGNAL(valueChanged(int)), this, SLOT(updateActions()));
-    connect(documentTabs, SIGNAL(currentChanged(int)), this, SLOT(updateActions()));
+    connect(actionOpen, &QAction::triggered, this, &MainWindow::openDocument);
+    connect(actionClose, &QAction::triggered, this, &MainWindow::closeDocument);
+    connect(actionNew, &QAction::triggered, this, &MainWindow::newDocument);
+    connect(actionSave, &QAction::triggered, this, &MainWindow::saveDocument);
+    connect(actionExit, &QAction::triggered, this, &QWidget::close);
+    connect(actionRed, &QAction::triggered, this, &MainWindow::setShapeColor);
+    connect(actionGreen, &QAction::triggered, this, &MainWindow::setShapeColor);
+    connect(actionBlue, &QAction::triggered, this, &MainWindow::setShapeColor);
+    connect(actionAddCircle, &QAction::triggered, this, &MainWindow::addShape);
+    connect(actionAddRectangle, &QAction::triggered, this, &MainWindow::addShape);
+    connect(actionAddTriangle, &QAction::triggered, this, &MainWindow::addShape);
+    connect(actionRemoveShape, &QAction::triggered, this, &MainWindow::removeShape);
+    connect(actionAddRobot, &QAction::triggered, this, &MainWindow::addRobot);
+    connect(actionAddSnowman, &QAction::triggered, this, &MainWindow::addSnowman);
+    connect(actionAbout, &QAction::triggered, this, &MainWindow::about);
+    connect(actionAboutQt, &QAction::triggered, this, &MainWindow::aboutQt);
+
+    connect(undoLimit, QOverload<int>::of(&QSpinBox::valueChanged), this, &MainWindow::updateActions);
+    connect(documentTabs, &QTabWidget::currentChanged, this, &MainWindow::updateActions);
 
     actionOpen->setShortcut(QString("Ctrl+O"));
     actionClose->setShortcut(QString("Ctrl+W"));
@@ -226,9 +226,9 @@ void MainWindow::addDocument(Document *doc)
         return;
     m_undoGroup->addStack(doc->undoStack());
     documentTabs->addTab(doc, fixedWindowTitle(doc));
-    connect(doc, SIGNAL(currentShapeChanged(QString)), this, SLOT(updateActions()));
-    connect(doc->undoStack(), SIGNAL(indexChanged(int)), this, SLOT(updateActions()));
-    connect(doc->undoStack(), SIGNAL(cleanChanged(bool)), this, SLOT(updateActions()));
+    connect(doc, &Document::currentShapeChanged, this, &MainWindow::updateActions);
+    connect(doc->undoStack(), &QUndoStack::indexChanged, this, &MainWindow::updateActions);
+    connect(doc->undoStack(), &QUndoStack::cleanChanged, this, &MainWindow::updateActions);
 
     setCurrentDocument(doc);
 }
@@ -251,9 +251,9 @@ void MainWindow::removeDocument(Document *doc)
 
     documentTabs->removeTab(index);
     m_undoGroup->removeStack(doc->undoStack());
-    disconnect(doc, SIGNAL(currentShapeChanged(QString)), this, SLOT(updateActions()));
-    disconnect(doc->undoStack(), SIGNAL(indexChanged(int)), this, SLOT(updateActions()));
-    disconnect(doc->undoStack(), SIGNAL(cleanChanged(bool)), this, SLOT(updateActions()));
+    disconnect(doc, &Document::currentShapeChanged, this, &MainWindow::updateActions);
+    disconnect(doc->undoStack(), &QUndoStack::indexChanged, this, &MainWindow::updateActions);
+    disconnect(doc->undoStack(), &QUndoStack::cleanChanged, this, &MainWindow::updateActions);
 
     if (documentTabs->count() == 0) {
         newDocument();
diff --git a/examples/widgets/tools/undoframework/mainwindow.cpp b/examples/widgets/tools/undoframework/mainwindow.cpp
index b2f5405b73..e95d50d164 100644
--- a/examples/widgets/tools/undoframework/mainwindow.cpp
+++ b/examples/widgets/tools/undoframework/mainwindow.cpp
@@ -70,8 +70,8 @@ MainWindow::MainWindow()
     diagramScene->setBackgroundBrush(pixmapBrush);
     diagramScene->setSceneRect(QRect(0, 0, 500, 500));
 
-    connect(diagramScene, SIGNAL(itemMoved(DiagramItem*,QPointF)),
-            this, SLOT(itemMoved(DiagramItem*,QPointF)));
+    connect(diagramScene, &DiagramScene::itemMoved,
+            this, &MainWindow::itemMoved);
 
     setWindowTitle("Undo Framework");
     QGraphicsView *view = new QGraphicsView(diagramScene);
@@ -95,18 +95,18 @@ void MainWindow::createActions()
 {
     deleteAction = new QAction(tr("&Delete Item"), this);
     deleteAction->setShortcut(tr("Del"));
-    connect(deleteAction, SIGNAL(triggered()), this, SLOT(deleteItem()));
+    connect(deleteAction, &QAction::triggered, this, &MainWindow::deleteItem);
 //! [2] //! [3]
 
 //! [3] //! [4]
     addBoxAction = new QAction(tr("Add &Box"), this);
 //! [4]
     addBoxAction->setShortcut(tr("Ctrl+O"));
-    connect(addBoxAction, SIGNAL(triggered()), this, SLOT(addBox()));
+    connect(addBoxAction, &QAction::triggered, this, &MainWindow::addBox);
 
     addTriangleAction = new QAction(tr("Add &Triangle"), this);
     addTriangleAction->setShortcut(tr("Ctrl+T"));
-    connect(addTriangleAction, SIGNAL(triggered()), this, SLOT(addTriangle()));
+    connect(addTriangleAction, &QAction::triggered, this, &MainWindow::addTriangle);
 
 //! [5]
     undoAction = undoStack->createUndoAction(this, tr("&Undo"));
@@ -118,13 +118,13 @@ void MainWindow::createActions()
 
     exitAction = new QAction(tr("E&xit"), this);
     exitAction->setShortcuts(QKeySequence::Quit);
-    connect(exitAction, SIGNAL(triggered()), this, SLOT(close()));
+    connect(exitAction, &QAction::triggered, this, &QWidget::close);
 
     aboutAction = new QAction(tr("&About"), this);
     QList<QKeySequence> aboutShortcuts;
     aboutShortcuts << tr("Ctrl+A") << tr("Ctrl+B");
     aboutAction->setShortcuts(aboutShortcuts);
-    connect(aboutAction, SIGNAL(triggered()), this, SLOT(about()));
+    connect(aboutAction, &QAction::triggered, this, &MainWindow::about);
 }
 
 //! [6]
@@ -140,10 +140,10 @@ void MainWindow::createMenus()
     editMenu->addAction(redoAction);
     editMenu->addSeparator();
     editMenu->addAction(deleteAction);
-    connect(editMenu, SIGNAL(aboutToShow()),
-            this, SLOT(itemMenuAboutToShow()));
-    connect(editMenu, SIGNAL(aboutToHide()),
-            this, SLOT(itemMenuAboutToHide()));
+    connect(editMenu, &QMenu::aboutToShow,
+            this, &MainWindow::itemMenuAboutToShow);
+    connect(editMenu, &QMenu::aboutToHide,
+            this, &MainWindow::itemMenuAboutToHide);
 
 //! [7]
     itemMenu = menuBar()->addMenu(tr("&Item"));
diff --git a/examples/widgets/touch/dials/main.cpp b/examples/widgets/touch/dials/main.cpp
index 071f485de3..059dfdc716 100644
--- a/examples/widgets/touch/dials/main.cpp
+++ b/examples/widgets/touch/dials/main.cpp
@@ -60,8 +60,8 @@ int main(int argc, char **argv)
     QWidget window;
     Ui::Dials dialsUi;
     dialsUi.setupUi(&window);
-    QList<QAbstractSlider *> sliders = window.findChildren<QAbstractSlider *>();
-    foreach (QAbstractSlider *slider, sliders)
+    const QList<QAbstractSlider *> sliders = window.findChildren<QAbstractSlider *>();
+    for (QAbstractSlider *slider : sliders)
         slider->setAttribute(Qt::WA_AcceptTouchEvents);
     window.showMaximized();
     return app.exec();
diff --git a/examples/widgets/touch/fingerpaint/mainwindow.cpp b/examples/widgets/touch/fingerpaint/mainwindow.cpp
index 0e45eea240..2f7ec38d1a 100644
--- a/examples/widgets/touch/fingerpaint/mainwindow.cpp
+++ b/examples/widgets/touch/fingerpaint/mainwindow.cpp
@@ -127,34 +127,35 @@ void MainWindow::createActions()
 {
     openAct = new QAction(tr("&Open..."), this);
     openAct->setShortcut(tr("Ctrl+O"));
-    connect(openAct, SIGNAL(triggered()), this, SLOT(open()));
+    connect(openAct, &QAction::triggered, this, &MainWindow::open);
 
-    foreach (QByteArray format, QImageWriter::supportedImageFormats()) {
+    const QList<QByteArray> imageFormats = QImageWriter::supportedImageFormats();
+    for (const QByteArray &format : imageFormats) {
         QString text = tr("%1...").arg(QString(format).toUpper());
 
         QAction *action = new QAction(text, this);
         action->setData(format);
-        connect(action, SIGNAL(triggered()), this, SLOT(save()));
+        connect(action, &QAction::triggered, this, &MainWindow::save);
         saveAsActs.append(action);
     }
 
     printAct = new QAction(tr("&Print..."), this);
-    connect(printAct, SIGNAL(triggered()), scribbleArea, SLOT(print()));
+    connect(printAct, &QAction::triggered, scribbleArea, &ScribbleArea::print);
 
     exitAct = new QAction(tr("E&xit"), this);
     exitAct->setShortcut(tr("Ctrl+Q"));
-    connect(exitAct, SIGNAL(triggered()), this, SLOT(close()));
+    connect(exitAct, &QAction::triggered, this, &QWidget::close);
 
     clearScreenAct = new QAction(tr("&Clear Screen"), this);
     clearScreenAct->setShortcut(tr("Ctrl+L"));
-    connect(clearScreenAct, SIGNAL(triggered()),
-            scribbleArea, SLOT(clearImage()));
+    connect(clearScreenAct, &QAction::triggered,
+            scribbleArea, &ScribbleArea::clearImage);
 
     aboutAct = new QAction(tr("&About"), this);
-    connect(aboutAct, SIGNAL(triggered()), this, SLOT(about()));
+    connect(aboutAct, &QAction::triggered, this, &MainWindow::about);
 
     aboutQtAct = new QAction(tr("About &Qt"), this);
-    connect(aboutQtAct, SIGNAL(triggered()), qApp, SLOT(aboutQt()));
+    connect(aboutQtAct, &QAction::triggered, qApp, &QApplication::aboutQt);
 }
 //! [14]
 
@@ -163,8 +164,7 @@ void MainWindow::createMenus()
 //! [15] //! [16]
 {
     saveAsMenu = new QMenu(tr("&Save As"), this);
-    foreach (QAction *action, saveAsActs)
-        saveAsMenu->addAction(action);
+    saveAsMenu->addActions(saveAsActs);
 
     fileMenu = new QMenu(tr("&File"), this);
     fileMenu->addAction(openAct);
diff --git a/examples/widgets/touch/fingerpaint/scribblearea.cpp b/examples/widgets/touch/fingerpaint/scribblearea.cpp
index aa4e60c934..0b0c4476d9 100644
--- a/examples/widgets/touch/fingerpaint/scribblearea.cpp
+++ b/examples/widgets/touch/fingerpaint/scribblearea.cpp
@@ -195,9 +195,9 @@ bool ScribbleArea::event(QEvent *event)
     case QEvent::TouchUpdate:
     case QEvent::TouchEnd:
     {
-        QTouchEvent *touch = static_cast<QTouchEvent *>(event);
-        QList<QTouchEvent::TouchPoint> touchPoints = static_cast<QTouchEvent *>(event)->touchPoints();
-        foreach (const QTouchEvent::TouchPoint &touchPoint, touchPoints) {
+        const QTouchEvent *touch = static_cast<QTouchEvent *>(event);
+        const QList<QTouchEvent::TouchPoint> touchPoints = static_cast<QTouchEvent *>(event)->touchPoints();
+        for (const QTouchEvent::TouchPoint &touchPoint : touchPoints) {
             switch (touchPoint.state()) {
             case Qt::TouchPointStationary:
             case Qt::TouchPointReleased:
diff --git a/examples/widgets/touch/pinchzoom/mouse.cpp b/examples/widgets/touch/pinchzoom/mouse.cpp
index 1e6814be13..1dfd7d749c 100644
--- a/examples/widgets/touch/pinchzoom/mouse.cpp
+++ b/examples/widgets/touch/pinchzoom/mouse.cpp
@@ -163,7 +163,7 @@ void Mouse::timerEvent(QTimerEvent *)
                                                        << mapToScene(0, 0)
                                                        << mapToScene(-30, -50)
                                                        << mapToScene(30, -50));
-    foreach (QGraphicsItem *item, dangerMice) {
+    for (QGraphicsItem *item : dangerMice) {
         if (item == this)
             continue;
 
diff --git a/examples/widgets/tutorials/addressbook/part2/addressbook.cpp b/examples/widgets/tutorials/addressbook/part2/addressbook.cpp
index 34fa5d2060..d5ee394abd 100644
--- a/examples/widgets/tutorials/addressbook/part2/addressbook.cpp
+++ b/examples/widgets/tutorials/addressbook/part2/addressbook.cpp
@@ -74,9 +74,12 @@ AddressBook::AddressBook(QWidget *parent)
     cancelButton->hide();
 //! [pushbutton declaration]
 //! [connecting signals and slots]
-    connect(addButton, SIGNAL(clicked()), this, SLOT(addContact()));
-    connect(submitButton, SIGNAL(clicked()), this, SLOT(submitContact()));
-    connect(cancelButton, SIGNAL(clicked()), this, SLOT(cancel()));
+    connect(addButton, &QPushButton::clicked,
+            this, &AddressBook::addContact);
+    connect(submitButton, &QPushButton::clicked,
+            this, &AddressBook::submitContact);
+    connect(cancelButton, &QPushButton::clicked,
+            this, &AddressBook::cancel);
 //! [connecting signals and slots]
 //! [vertical layout]
     QVBoxLayout *buttonLayout1 = new QVBoxLayout;
diff --git a/examples/widgets/tutorials/addressbook/part3/addressbook.cpp b/examples/widgets/tutorials/addressbook/part3/addressbook.cpp
index caef83970a..b6d48f7a0d 100644
--- a/examples/widgets/tutorials/addressbook/part3/addressbook.cpp
+++ b/examples/widgets/tutorials/addressbook/part3/addressbook.cpp
@@ -74,13 +74,17 @@ AddressBook::AddressBook(QWidget *parent)
     previousButton = new QPushButton(tr("&Previous"));
     previousButton->setEnabled(false);
 //! [navigation pushbuttons]
-
-    connect(addButton, SIGNAL(clicked()), this, SLOT(addContact()));
-    connect(submitButton, SIGNAL(clicked()), this, SLOT(submitContact()));
-    connect(cancelButton, SIGNAL(clicked()), this, SLOT(cancel()));
+    connect(addButton, &QPushButton::clicked,
+            this, &AddressBook::addContact);
+    connect(submitButton, &QPushButton::clicked,
+            this, &AddressBook::submitContact);
+    connect(cancelButton, &QPushButton::clicked,
+            this, &AddressBook::cancel);
 //! [connecting navigation signals]
-    connect(nextButton, SIGNAL(clicked()), this, SLOT(next()));
-    connect(previousButton, SIGNAL(clicked()), this, SLOT(previous()));
+    connect(nextButton, &QPushButton::clicked,
+            this, &AddressBook::next);
+    connect(previousButton, &QPushButton::clicked,
+            this, &AddressBook::previous);
 //! [connecting navigation signals]
 
     QVBoxLayout *buttonLayout1 = new QVBoxLayout;
diff --git a/examples/widgets/tutorials/addressbook/part4/addressbook.cpp b/examples/widgets/tutorials/addressbook/part4/addressbook.cpp
index 92f0776727..77ce216c07 100644
--- a/examples/widgets/tutorials/addressbook/part4/addressbook.cpp
+++ b/examples/widgets/tutorials/addressbook/part4/addressbook.cpp
@@ -79,15 +79,22 @@ AddressBook::AddressBook(QWidget *parent)
     previousButton = new QPushButton(tr("&Previous"));
     previousButton->setEnabled(false);
 
-    connect(addButton, SIGNAL(clicked()), this, SLOT(addContact()));
-    connect(submitButton, SIGNAL(clicked()), this, SLOT(submitContact()));
+    connect(addButton, &QPushButton::clicked,
+            this, &AddressBook::addContact);
+    connect(submitButton, &QPushButton::clicked,
+            this, &AddressBook::submitContact);
 //! [connecting edit and remove]
-    connect(editButton, SIGNAL(clicked()), this, SLOT(editContact()));
-    connect(removeButton, SIGNAL(clicked()), this, SLOT(removeContact()));
+    connect(editButton, &QPushButton::clicked,
+            this, &AddressBook::editContact);
+    connect(removeButton, &QPushButton::clicked,
+            this, &AddressBook::removeContact);
 //! [connecting edit and remove]
-    connect(cancelButton, SIGNAL(clicked()), this, SLOT(cancel()));
-    connect(nextButton, SIGNAL(clicked()), this, SLOT(next()));
-    connect(previousButton, SIGNAL(clicked()), this, SLOT(previous()));
+    connect(cancelButton, &QPushButton::clicked,
+            this, &AddressBook::cancel);
+    connect(nextButton, &QPushButton::clicked,
+            this, &AddressBook::next);
+    connect(previousButton, &QPushButton::clicked,
+            this, &AddressBook::previous);
 
     QVBoxLayout *buttonLayout1 = new QVBoxLayout;
     buttonLayout1->addWidget(addButton);
diff --git a/examples/widgets/tutorials/addressbook/part5/addressbook.cpp b/examples/widgets/tutorials/addressbook/part5/addressbook.cpp
index 6e09ec287d..5505a0e35c 100644
--- a/examples/widgets/tutorials/addressbook/part5/addressbook.cpp
+++ b/examples/widgets/tutorials/addressbook/part5/addressbook.cpp
@@ -86,16 +86,24 @@ AddressBook::AddressBook(QWidget *parent)
     dialog = new FindDialog(this);
 //! [instantiating FindDialog]
 
-    connect(addButton, SIGNAL(clicked()), this, SLOT(addContact()));
-    connect(submitButton, SIGNAL(clicked()), this, SLOT(submitContact()));
-    connect(editButton, SIGNAL(clicked()), this, SLOT(editContact()));
-    connect(cancelButton, SIGNAL(clicked()), this, SLOT(cancel()));
-    connect(removeButton, SIGNAL(clicked()), this, SLOT(removeContact()));
+    connect(addButton, &QPushButton::clicked,
+            this, &AddressBook::addContact);
+    connect(submitButton, &QPushButton::clicked,
+            this, &AddressBook::submitContact);
+    connect(editButton, &QPushButton::clicked,
+            this, &AddressBook::editContact);
+    connect(removeButton, &QPushButton::clicked,
+            this, &AddressBook::removeContact);
+    connect(cancelButton, &QPushButton::clicked,
+            this, &AddressBook::cancel);
 //! [signals and slots for find]
-    connect(findButton, SIGNAL(clicked()), this, SLOT(findContact()));
+    connect(findButton, &QPushButton::clicked,
+            this, &AddressBook::findContact);
 //! [signals and slots for find]
-    connect(nextButton, SIGNAL(clicked()), this, SLOT(next()));
-    connect(previousButton, SIGNAL(clicked()), this, SLOT(previous()));
+    connect(nextButton, &QPushButton::clicked,
+            this, &AddressBook::next);
+    connect(previousButton, &QPushButton::clicked,
+            this, &AddressBook::previous);
 
     QVBoxLayout *buttonLayout1 = new QVBoxLayout;
     buttonLayout1->addWidget(addButton);
diff --git a/examples/widgets/tutorials/addressbook/part5/finddialog.cpp b/examples/widgets/tutorials/addressbook/part5/finddialog.cpp
index b0d9a5e6e3..615b39d42f 100644
--- a/examples/widgets/tutorials/addressbook/part5/finddialog.cpp
+++ b/examples/widgets/tutorials/addressbook/part5/finddialog.cpp
@@ -68,8 +68,10 @@ FindDialog::FindDialog(QWidget *parent)
 
     setLayout(layout);
     setWindowTitle(tr("Find a Contact"));
-    connect(findButton, SIGNAL(clicked()), this, SLOT(findClicked()));
-    connect(findButton, SIGNAL(clicked()), this, SLOT(accept()));
+    connect(findButton, &QPushButton::clicked,
+            this, &FindDialog::findClicked);
+    connect(findButton, &QPushButton::clicked,
+            this, &FindDialog::accept);
 }
 //! [constructor]
 //! [findClicked() function]
diff --git a/examples/widgets/tutorials/addressbook/part6/addressbook.cpp b/examples/widgets/tutorials/addressbook/part6/addressbook.cpp
index b2e361a45e..8e740cfffc 100644
--- a/examples/widgets/tutorials/addressbook/part6/addressbook.cpp
+++ b/examples/widgets/tutorials/addressbook/part6/addressbook.cpp
@@ -92,16 +92,26 @@ AddressBook::AddressBook(QWidget *parent)
 
     dialog = new FindDialog(this);
 
-    connect(addButton, SIGNAL(clicked()), this, SLOT(addContact()));
-    connect(submitButton, SIGNAL(clicked()), this, SLOT(submitContact()));
-    connect(editButton, SIGNAL(clicked()), this, SLOT(editContact()));
-    connect(cancelButton, SIGNAL(clicked()), this, SLOT(cancel()));
-    connect(removeButton, SIGNAL(clicked()), this, SLOT(removeContact()));
-    connect(findButton, SIGNAL(clicked()), this, SLOT(findContact()));
-    connect(nextButton, SIGNAL(clicked()), this, SLOT(next()));
-    connect(previousButton, SIGNAL(clicked()), this, SLOT(previous()));
-    connect(loadButton, SIGNAL(clicked()), this, SLOT(loadFromFile()));
-    connect(saveButton, SIGNAL(clicked()), this, SLOT(saveToFile()));
+    connect(addButton, &QPushButton::clicked,
+            this, &AddressBook::addContact);
+    connect(submitButton, &QPushButton::clicked,
+            this, &AddressBook::submitContact);
+    connect(editButton, &QPushButton::clicked,
+            this, &AddressBook::editContact);
+    connect(removeButton, &QPushButton::clicked,
+            this, &AddressBook::removeContact);
+    connect(cancelButton, &QPushButton::clicked,
+            this, &AddressBook::cancel);
+    connect(findButton, &QPushButton::clicked,
+            this, &AddressBook::findContact);
+    connect(nextButton, &QPushButton::clicked,
+            this, &AddressBook::next);
+    connect(previousButton, &QPushButton::clicked,
+            this, &AddressBook::previous);
+    connect(loadButton, &QPushButton::clicked,
+            this, &AddressBook::loadFromFile);
+    connect(saveButton, &QPushButton::clicked,
+            this, &AddressBook::saveToFile);
 
     QVBoxLayout *buttonLayout1 = new QVBoxLayout;
     buttonLayout1->addWidget(addButton);
diff --git a/examples/widgets/tutorials/addressbook/part6/finddialog.cpp b/examples/widgets/tutorials/addressbook/part6/finddialog.cpp
index 6a1e6b116f..c25cccd552 100644
--- a/examples/widgets/tutorials/addressbook/part6/finddialog.cpp
+++ b/examples/widgets/tutorials/addressbook/part6/finddialog.cpp
@@ -67,8 +67,10 @@ FindDialog::FindDialog(QWidget *parent)
 
     setLayout(layout);
     setWindowTitle(tr("Find a Contact"));
-    connect(findButton, SIGNAL(clicked()), this, SLOT(findClicked()));
-    connect(findButton, SIGNAL(clicked()), this, SLOT(accept()));
+    connect(findButton, &QPushButton::clicked,
+            this, &FindDialog::findClicked);
+    connect(findButton, &QPushButton::clicked,
+            this, &FindDialog::accept);
 }
 
 void FindDialog::findClicked()
diff --git a/examples/widgets/tutorials/addressbook/part7/addressbook.cpp b/examples/widgets/tutorials/addressbook/part7/addressbook.cpp
index e946c873e3..717d0882af 100644
--- a/examples/widgets/tutorials/addressbook/part7/addressbook.cpp
+++ b/examples/widgets/tutorials/addressbook/part7/addressbook.cpp
@@ -92,17 +92,28 @@ AddressBook::AddressBook(QWidget *parent)
 
     dialog = new FindDialog(this);
 
-    connect(addButton, SIGNAL(clicked()), this, SLOT(addContact()));
-    connect(submitButton, SIGNAL(clicked()), this, SLOT(submitContact()));
-    connect(editButton, SIGNAL(clicked()), this, SLOT(editContact()));
-    connect(cancelButton, SIGNAL(clicked()), this, SLOT(cancel()));
-    connect(removeButton, SIGNAL(clicked()), this, SLOT(removeContact()));
-    connect(findButton, SIGNAL(clicked()), this, SLOT(findContact()));
-    connect(nextButton, SIGNAL(clicked()), this, SLOT(next()));
-    connect(previousButton, SIGNAL(clicked()), this, SLOT(previous()));
-    connect(loadButton, SIGNAL(clicked()), this, SLOT(loadFromFile()));
-    connect(saveButton, SIGNAL(clicked()), this, SLOT(saveToFile()));
-    connect(exportButton, SIGNAL(clicked()), this, SLOT(exportAsVCard()));
+    connect(addButton, &QPushButton::clicked,
+            this, &AddressBook::addContact);
+    connect(submitButton, &QPushButton::clicked,
+            this, &AddressBook::submitContact);
+    connect(editButton, &QPushButton::clicked,
+            this, &AddressBook::editContact);
+    connect(removeButton, &QPushButton::clicked,
+            this, &AddressBook::removeContact);
+    connect(cancelButton, &QPushButton::clicked,
+            this, &AddressBook::cancel);
+    connect(findButton, &QPushButton::clicked,
+            this, &AddressBook::findContact);
+    connect(nextButton, &QPushButton::clicked,
+            this, &AddressBook::next);
+    connect(previousButton, &QPushButton::clicked,
+            this, &AddressBook::previous);
+    connect(loadButton, &QPushButton::clicked,
+            this, &AddressBook::loadFromFile);
+    connect(saveButton, &QPushButton::clicked,
+            this, &AddressBook::saveToFile);
+    connect(exportButton, &QPushButton::clicked,
+            this, &AddressBook::exportAsVCard);
 
     QVBoxLayout *buttonLayout1 = new QVBoxLayout;
     buttonLayout1->addWidget(addButton);
diff --git a/examples/widgets/tutorials/addressbook/part7/finddialog.cpp b/examples/widgets/tutorials/addressbook/part7/finddialog.cpp
index 6a1e6b116f..c25cccd552 100644
--- a/examples/widgets/tutorials/addressbook/part7/finddialog.cpp
+++ b/examples/widgets/tutorials/addressbook/part7/finddialog.cpp
@@ -67,8 +67,10 @@ FindDialog::FindDialog(QWidget *parent)
 
     setLayout(layout);
     setWindowTitle(tr("Find a Contact"));
-    connect(findButton, SIGNAL(clicked()), this, SLOT(findClicked()));
-    connect(findButton, SIGNAL(clicked()), this, SLOT(accept()));
+    connect(findButton, &QPushButton::clicked,
+            this, &FindDialog::findClicked);
+    connect(findButton, &QPushButton::clicked,
+            this, &FindDialog::accept);
 }
 
 void FindDialog::findClicked()
diff --git a/examples/widgets/tutorials/gettingStarted/gsQt/part2/main.cpp b/examples/widgets/tutorials/gettingStarted/gsQt/part2/main.cpp
index 90f5f1a6b3..8bf83859a0 100644
--- a/examples/widgets/tutorials/gettingStarted/gsQt/part2/main.cpp
+++ b/examples/widgets/tutorials/gettingStarted/gsQt/part2/main.cpp
@@ -57,7 +57,8 @@ int main(int argc, char *argv[])
     QTextEdit *textEdit = new QTextEdit;
     QPushButton *quitButton = new QPushButton("&Quit");
 
-    QObject::connect(quitButton, SIGNAL(clicked()), qApp, SLOT(quit()));
+    QObject::connect(quitButton, &QPushButton::clicked,
+                     qApp, &QApplication::quit);
 
     QVBoxLayout *layout = new QVBoxLayout;
     layout->addWidget(textEdit);
diff --git a/examples/widgets/tutorials/gettingStarted/gsQt/part3/main.cpp b/examples/widgets/tutorials/gettingStarted/gsQt/part3/main.cpp
index 0a60c1cf16..d4b43eb034 100644
--- a/examples/widgets/tutorials/gettingStarted/gsQt/part3/main.cpp
+++ b/examples/widgets/tutorials/gettingStarted/gsQt/part3/main.cpp
@@ -71,7 +71,8 @@ Notepad::Notepad()
     textEdit = new QTextEdit;
     quitButton = new QPushButton(tr("Quit"));
 
-    connect(quitButton, SIGNAL(clicked()), this, SLOT(quit()));
+    connect(quitButton, &QPushButton::clicked,
+            this, &Notepad::quit);
 
     QVBoxLayout *layout = new QVBoxLayout;
     layout->addWidget(textEdit);
diff --git a/examples/widgets/tutorials/gettingStarted/gsQt/part4/main.cpp b/examples/widgets/tutorials/gettingStarted/gsQt/part4/main.cpp
index 6d9e96a3d4..8c5fbc70ca 100644
--- a/examples/widgets/tutorials/gettingStarted/gsQt/part4/main.cpp
+++ b/examples/widgets/tutorials/gettingStarted/gsQt/part4/main.cpp
@@ -73,14 +73,16 @@ private:
 
 Notepad::Notepad()
 {
-
     loadAction = new QAction(tr("&Load"), this);
     saveAction = new QAction(tr("&Save"), this);
     exitAction = new QAction(tr("E&xit"), this);
 
-    connect(loadAction, SIGNAL(triggered()), this, SLOT(load()));
-    connect(saveAction, SIGNAL(triggered()), this, SLOT(save()));
-    connect(exitAction, SIGNAL(triggered()), qApp, SLOT(quit()));
+    connect(loadAction, &QAction::triggered,
+            this, &Notepad::load);
+    connect(saveAction, &QAction::triggered,
+            this, &Notepad::save);
+    connect(exitAction, &QAction::triggered,
+            qApp, &QApplication::quit);
 
     fileMenu = menuBar()->addMenu(tr("&File"));
     fileMenu->addAction(loadAction);
diff --git a/examples/widgets/tutorials/gettingStarted/gsQt/part5/main.cpp b/examples/widgets/tutorials/gettingStarted/gsQt/part5/main.cpp
index b2b4a73874..cc3e1a261c 100644
--- a/examples/widgets/tutorials/gettingStarted/gsQt/part5/main.cpp
+++ b/examples/widgets/tutorials/gettingStarted/gsQt/part5/main.cpp
@@ -73,14 +73,16 @@ private:
 
 Notepad::Notepad()
 {
-
     openAction = new QAction(tr("&Load"), this);
     saveAction = new QAction(tr("&Save"), this);
     exitAction = new QAction(tr("E&xit"), this);
 
-    connect(openAction, SIGNAL(triggered()), this, SLOT(open()));
-    connect(saveAction, SIGNAL(triggered()), this, SLOT(save()));
-    connect(exitAction, SIGNAL(triggered()), qApp, SLOT(quit()));
+    connect(openAction, &QAction::triggered,
+            this, &Notepad::open);
+    connect(saveAction, &QAction::triggered,
+            this, &Notepad::save);
+    connect(exitAction, &QAction::triggered,
+            qApp, &QApplication::quit);
 
     fileMenu = menuBar()->addMenu(tr("&File"));
     fileMenu->addAction(openAction);
diff --git a/examples/widgets/tutorials/gettingstartedqt.qdoc b/examples/widgets/tutorials/gettingstartedqt.qdoc
index bbe1dd1a8d..32e8845c05 100644
--- a/examples/widgets/tutorials/gettingstartedqt.qdoc
+++ b/examples/widgets/tutorials/gettingstartedqt.qdoc
@@ -390,10 +390,10 @@
     action concerned. When the QAction has been dragged to the toolbar,
     clicking the icon will launch the associated slot.
 
-    Complete the method \c on_actionNew_triggered():
+    Complete the method \c newDocument():
 
     \quotefromfile tutorials/notepad/notepad.cpp
-    \skipto on_actionNew_triggered()
+    \skipto newDocument()
     \printuntil }
 
     \c current_file is a global variable containing the file presently
@@ -411,10 +411,10 @@
     In \c notepad.ui, right click on \c actionOpen and select \c {Go to
     slot}
 
-    Complete method \c on_actionOpen_triggered().
+    Complete method \c open().
 
     \quotefromfile tutorials/notepad/notepad.cpp
-    \skipto on_actionOpen_triggered()
+    \skipto open()
     \printuntil file.close
     \printuntil }
 
@@ -436,7 +436,7 @@
     \l {Opening a file}, by right clicking on \c actionSave, and
     selecting \c {Go to Slot}.
 
-    \skipto Notepad::on_actionSave_triggered
+    \skipto Notepad::save
     \printuntil file.close
     \printuntil }
 
@@ -449,7 +449,7 @@
 
     \section2 Saving a file with \c {Save as}
 
-    \skipto Notepad::on_actionSave_as_triggered
+    \skipto Notepad::saveAs
     \printuntil file.close
     \printuntil }
 
@@ -475,7 +475,7 @@
 
     \section2 Select a Font
 
-    \skipto Notepad::on_actionFont_triggered
+    \skipto Notepad::selectFont
     \printuntil ui->textEdit->setFont
     \printline }
 
diff --git a/examples/widgets/tutorials/modelview/1_readonly/main.cpp b/examples/widgets/tutorials/modelview/1_readonly/main.cpp
index 80383f8c94..ea571d3699 100644
--- a/examples/widgets/tutorials/modelview/1_readonly/main.cpp
+++ b/examples/widgets/tutorials/modelview/1_readonly/main.cpp
@@ -50,16 +50,16 @@
 
 //! [Quoting ModelView Tutorial]
 // main.cpp
-#include <QtWidgets/QApplication>
-#include <QtWidgets/QTableView>
+#include <QApplication>
+#include <QTableView>
 #include "mymodel.h"
 
 int main(int argc, char *argv[])
 {
     QApplication a(argc, argv);
     QTableView tableView;
-    MyModel myModel(0);
-    tableView.setModel( &myModel );
+    MyModel myModel;
+    tableView.setModel(&myModel);
     tableView.show();
     return a.exec();
 }
diff --git a/examples/widgets/tutorials/modelview/1_readonly/mymodel.cpp b/examples/widgets/tutorials/modelview/1_readonly/mymodel.cpp
index 82ec53c665..2b36565bc6 100644
--- a/examples/widgets/tutorials/modelview/1_readonly/mymodel.cpp
+++ b/examples/widgets/tutorials/modelview/1_readonly/mymodel.cpp
@@ -53,7 +53,7 @@
 #include "mymodel.h"
 
 MyModel::MyModel(QObject *parent)
-    :QAbstractTableModel(parent)
+    : QAbstractTableModel(parent)
 {
 }
 
@@ -70,11 +70,10 @@ int MyModel::columnCount(const QModelIndex & /*parent*/) const
 QVariant MyModel::data(const QModelIndex &index, int role) const
 {
     if (role == Qt::DisplayRole)
-    {
        return QString("Row%1, Column%2")
                    .arg(index.row() + 1)
                    .arg(index.column() +1);
-    }
+
     return QVariant();
 }
 //! [Quoting ModelView Tutorial]
diff --git a/examples/widgets/tutorials/modelview/1_readonly/mymodel.h b/examples/widgets/tutorials/modelview/1_readonly/mymodel.h
index e675cc6bc2..8761322896 100644
--- a/examples/widgets/tutorials/modelview/1_readonly/mymodel.h
+++ b/examples/widgets/tutorials/modelview/1_readonly/mymodel.h
@@ -59,8 +59,8 @@ class MyModel : public QAbstractTableModel
 {
     Q_OBJECT
 public:
-    MyModel(QObject *parent);
-    int rowCount(const QModelIndex &parent = QModelIndex()) const override ;
+    MyModel(QObject *parent = nullptr);
+    int rowCount(const QModelIndex &parent = QModelIndex()) const override;
     int columnCount(const QModelIndex &parent = QModelIndex()) const override;
     QVariant data(const QModelIndex &index, int role = Qt::DisplayRole) const override;
 };
diff --git a/examples/widgets/tutorials/modelview/2_formatting/main.cpp b/examples/widgets/tutorials/modelview/2_formatting/main.cpp
index 80383f8c94..ea571d3699 100644
--- a/examples/widgets/tutorials/modelview/2_formatting/main.cpp
+++ b/examples/widgets/tutorials/modelview/2_formatting/main.cpp
@@ -50,16 +50,16 @@
 
 //! [Quoting ModelView Tutorial]
 // main.cpp
-#include <QtWidgets/QApplication>
-#include <QtWidgets/QTableView>
+#include <QApplication>
+#include <QTableView>
 #include "mymodel.h"
 
 int main(int argc, char *argv[])
 {
     QApplication a(argc, argv);
     QTableView tableView;
-    MyModel myModel(0);
-    tableView.setModel( &myModel );
+    MyModel myModel;
+    tableView.setModel(&myModel);
     tableView.show();
     return a.exec();
 }
diff --git a/examples/widgets/tutorials/modelview/2_formatting/mymodel.cpp b/examples/widgets/tutorials/modelview/2_formatting/mymodel.cpp
index 9511648392..938597a34e 100644
--- a/examples/widgets/tutorials/modelview/2_formatting/mymodel.cpp
+++ b/examples/widgets/tutorials/modelview/2_formatting/mymodel.cpp
@@ -48,13 +48,14 @@
 **
 ****************************************************************************/
 
+#include "mymodel.h"
+
 #include <QFont>
 #include <QBrush>
-#include "mymodel.h"
 #include <QDebug>
 
 MyModel::MyModel(QObject *parent)
-    :QAbstractTableModel(parent)
+    : QAbstractTableModel(parent)
 {
 }
 
@@ -78,7 +79,7 @@ QVariant MyModel::data(const QModelIndex &index, int role) const
     qDebug() << QString("row %1, col%2, role %3")
             .arg(row).arg(col).arg(role);
 
-    switch(role){
+    switch (role) {
     case Qt::DisplayRole:
         if (row == 0 && col == 1) return QString("<--left");
         if (row == 1 && col == 1) return QString("right-->");
@@ -86,36 +87,25 @@ QVariant MyModel::data(const QModelIndex &index, int role) const
         return QString("Row%1, Column%2")
                 .arg(row + 1)
                 .arg(col +1);
-        break;
     case Qt::FontRole:
-        if (row == 0 && col == 0) //change font only for cell(0,0)
-        {
+        if (row == 0 && col == 0) { //change font only for cell(0,0)
             QFont boldFont;
             boldFont.setBold(true);
             return boldFont;
         }
         break;
     case Qt::BackgroundRole:
-
         if (row == 1 && col == 2)  //change background only for cell(1,2)
-        {
-            QBrush redBackground(Qt::red);
-            return redBackground;
-        }
+            return QBrush(Qt::red);
         break;
     case Qt::TextAlignmentRole:
-
         if (row == 1 && col == 1) //change text alignment only for cell(1,1)
-        {
             return Qt::AlignRight + Qt::AlignVCenter;
-        }
         break;
     case Qt::CheckStateRole:
-
         if (row == 1 && col == 0) //add a checkbox to cell(1,0)
-        {
             return Qt::Checked;
-        }
+        break;
     }
     return QVariant();
 }
diff --git a/examples/widgets/tutorials/modelview/2_formatting/mymodel.h b/examples/widgets/tutorials/modelview/2_formatting/mymodel.h
index 9c12f98ba9..e8ae673f62 100644
--- a/examples/widgets/tutorials/modelview/2_formatting/mymodel.h
+++ b/examples/widgets/tutorials/modelview/2_formatting/mymodel.h
@@ -57,8 +57,8 @@ class MyModel : public QAbstractTableModel
 {
     Q_OBJECT
 public:
-    MyModel(QObject *parent);
-    int rowCount(const QModelIndex &parent = QModelIndex()) const override ;
+    MyModel(QObject *parent = nullptr);
+    int rowCount(const QModelIndex &parent = QModelIndex()) const override;
     int columnCount(const QModelIndex &parent = QModelIndex()) const override;
     QVariant data(const QModelIndex &index, int role = Qt::DisplayRole) const override;
 };
diff --git a/examples/widgets/tutorials/modelview/3_changingmodel/main.cpp b/examples/widgets/tutorials/modelview/3_changingmodel/main.cpp
index c03019a910..2330019f93 100644
--- a/examples/widgets/tutorials/modelview/3_changingmodel/main.cpp
+++ b/examples/widgets/tutorials/modelview/3_changingmodel/main.cpp
@@ -48,8 +48,8 @@
 **
 ****************************************************************************/
 
-#include <QtWidgets/QApplication>
-#include <QtWidgets/QTableView>
+#include <QApplication>
+#include <QTableView>
 #include "mymodel.h"
 
 int main(int argc, char *argv[])
@@ -57,7 +57,7 @@ int main(int argc, char *argv[])
     QApplication a(argc, argv);
     QTableView tableView;
     MyModel myModel(0);
-    tableView.setModel( &myModel );
+    tableView.setModel(&myModel);
     tableView.show();
     return a.exec();
 }
diff --git a/examples/widgets/tutorials/modelview/3_changingmodel/mymodel.cpp b/examples/widgets/tutorials/modelview/3_changingmodel/mymodel.cpp
index e4580a0e01..f289d9abda 100644
--- a/examples/widgets/tutorials/modelview/3_changingmodel/mymodel.cpp
+++ b/examples/widgets/tutorials/modelview/3_changingmodel/mymodel.cpp
@@ -48,18 +48,17 @@
 **
 ****************************************************************************/
 
-#include <QBrush>
-#include <QTime>
 #include "mymodel.h"
 
+#include <QTime>
+
 //! [quoting mymodel_a]
 MyModel::MyModel(QObject *parent)
-    :QAbstractTableModel(parent)
+    : QAbstractTableModel(parent)
+    , timer(new QTimer(this))
 {
-//    selectedCell = 0;
-    timer = new QTimer(this);
     timer->setInterval(1000);
-    connect(timer, SIGNAL(timeout()) , this, SLOT(timerHit()));
+    connect(timer, &QTimer::timeout , this, &MyModel::timerHit);
     timer->start();
 }
 //! [quoting mymodel_a]
@@ -82,13 +81,9 @@ QVariant MyModel::data(const QModelIndex &index, int role) const
     int row = index.row();
     int col = index.column();
 
-    if (role == Qt::DisplayRole)
-    {
-        if (row == 0 && col == 0)
-        {
-            return QTime::currentTime().toString();
-        }
-    }
+    if (role == Qt::DisplayRole && row == 0 && col == 0)
+        return QTime::currentTime().toString();
+
     return QVariant();
 }
 //! [quoting mymodel_QVariant ]
@@ -99,6 +94,6 @@ void MyModel::timerHit()
     //we identify the top left cell
     QModelIndex topLeft = createIndex(0,0);
     //emit a signal to make the view reread identified data
-    emit dataChanged(topLeft, topLeft);
+    emit dataChanged(topLeft, topLeft, {Qt::DisplayRole});
 }
 //! [quoting mymodel_b ]
diff --git a/examples/widgets/tutorials/modelview/3_changingmodel/mymodel.h b/examples/widgets/tutorials/modelview/3_changingmodel/mymodel.h
index dfcf0f6239..2ef0e480c2 100644
--- a/examples/widgets/tutorials/modelview/3_changingmodel/mymodel.h
+++ b/examples/widgets/tutorials/modelview/3_changingmodel/mymodel.h
@@ -58,13 +58,12 @@ class MyModel : public QAbstractTableModel
 {
     Q_OBJECT
 public:
-    MyModel(QObject *parent);
-    int rowCount(const QModelIndex &parent = QModelIndex()) const override ;
+    MyModel(QObject *parent = nullptr);
+    int rowCount(const QModelIndex &parent = QModelIndex()) const override;
     int columnCount(const QModelIndex &parent = QModelIndex()) const override;
     QVariant data(const QModelIndex &index, int role = Qt::DisplayRole) const override;
-    QTimer *timer;
 private:
-    int selectedCell;
+    QTimer *timer;
 private slots:
     void timerHit();
 };
diff --git a/examples/widgets/tutorials/modelview/4_headers/main.cpp b/examples/widgets/tutorials/modelview/4_headers/main.cpp
index 82d493345d..90a8c6e894 100644
--- a/examples/widgets/tutorials/modelview/4_headers/main.cpp
+++ b/examples/widgets/tutorials/modelview/4_headers/main.cpp
@@ -48,16 +48,16 @@
 **
 ****************************************************************************/
 
-#include <QtWidgets/QApplication>
-#include <QtWidgets/QTableView>
+#include <QApplication>
+#include <QTableView>
 #include "mymodel.h"
 
 int main(int argc, char *argv[])
 {
     QApplication a(argc, argv);
     QTableView tableView;
-    MyModel myModel(0);
-    tableView.setModel( &myModel );
+    MyModel myModel;
+    tableView.setModel(&myModel);
     tableView.show();
     return a.exec();
-}
-\ No newline at end of file
+}
diff --git a/examples/widgets/tutorials/modelview/4_headers/mymodel.cpp b/examples/widgets/tutorials/modelview/4_headers/mymodel.cpp
index 35e3463b7f..0084475374 100644
--- a/examples/widgets/tutorials/modelview/4_headers/mymodel.cpp
+++ b/examples/widgets/tutorials/modelview/4_headers/mymodel.cpp
@@ -51,7 +51,7 @@
 #include "mymodel.h"
 
 MyModel::MyModel(QObject *parent)
-    :QAbstractTableModel(parent)
+    : QAbstractTableModel(parent)
 {
 }
 
@@ -70,8 +70,7 @@ int MyModel::columnCount(const QModelIndex & /*parent*/) const
 //-------------------------------------------------------
 QVariant MyModel::data(const QModelIndex &index, int role) const
 {
-    if (role == Qt::DisplayRole)
-    {
+    if (role == Qt::DisplayRole) {
         return QString("Row%1, Column%2")
                 .arg(index.row() + 1)
                 .arg(index.column() +1);
@@ -82,18 +81,14 @@ QVariant MyModel::data(const QModelIndex &index, int role) const
 //! [quoting mymodel_c]
 QVariant MyModel::headerData(int section, Qt::Orientation orientation, int role) const
 {
-    if (role == Qt::DisplayRole)
-    {
-        if (orientation == Qt::Horizontal) {
-            switch (section)
-            {
-            case 0:
-                return QString("first");
-            case 1:
-                return QString("second");
-            case 2:
-                return QString("third");
-            }
+    if (role == Qt::DisplayRole && orientation == Qt::Horizontal) {
+        switch (section) {
+        case 0:
+            return QString("first");
+        case 1:
+            return QString("second");
+        case 2:
+            return QString("third");
         }
     }
     return QVariant();
diff --git a/examples/widgets/tutorials/modelview/4_headers/mymodel.h b/examples/widgets/tutorials/modelview/4_headers/mymodel.h
index fb2d7aa940..6d8477dae2 100644
--- a/examples/widgets/tutorials/modelview/4_headers/mymodel.h
+++ b/examples/widgets/tutorials/modelview/4_headers/mymodel.h
@@ -57,8 +57,8 @@ class MyModel : public QAbstractTableModel
 {
     Q_OBJECT
 public:
-    MyModel(QObject *parent);
-    int rowCount(const QModelIndex &parent = QModelIndex()) const override ;
+    MyModel(QObject *parent = nullptr);
+    int rowCount(const QModelIndex &parent = QModelIndex()) const override;
     int columnCount(const QModelIndex &parent = QModelIndex()) const override;
     QVariant data(const QModelIndex &index, int role = Qt::DisplayRole) const override;
     QVariant headerData(int section, Qt::Orientation orientation, int role) const override;
diff --git a/examples/widgets/tutorials/modelview/5_edit/main.cpp b/examples/widgets/tutorials/modelview/5_edit/main.cpp
index e1b46339b1..315875a627 100644
--- a/examples/widgets/tutorials/modelview/5_edit/main.cpp
+++ b/examples/widgets/tutorials/modelview/5_edit/main.cpp
@@ -48,7 +48,7 @@
 **
 ****************************************************************************/
 
-#include <QtWidgets/QApplication>
+#include <QApplication>
 #include "mainwindow.h"
 
 int main(int argc, char *argv[])
diff --git a/examples/widgets/tutorials/modelview/5_edit/mainwindow.cpp b/examples/widgets/tutorials/modelview/5_edit/mainwindow.cpp
index e0b6ea7b1f..d8dfc33212 100644
--- a/examples/widgets/tutorials/modelview/5_edit/mainwindow.cpp
+++ b/examples/widgets/tutorials/modelview/5_edit/mainwindow.cpp
@@ -48,23 +48,25 @@
 **
 ****************************************************************************/
 
-#include <QTableView>
 #include "mainwindow.h"
 #include "mymodel.h"
 
+#include <QTableView>
+
 MainWindow::MainWindow(QWidget *parent)
     : QMainWindow(parent)
+    , tableView(new QTableView(this))
 {
-    tableView = new QTableView(this);
     setCentralWidget(tableView);
-    QAbstractTableModel *myModel = new MyModel(this);
+    MyModel *myModel = new MyModel(this);
     tableView->setModel(myModel);
 
     //transfer changes to the model to the window title
-    connect(myModel, SIGNAL(editCompleted(const QString &)), this, SLOT(setWindowTitle(const QString &)));
+    connect(myModel, &MyModel::editCompleted,
+            this, &MainWindow::showWindowTitle);
 }
 
-void MainWindow::showWindowTitle(const QString & title)
+void MainWindow::showWindowTitle(const QString &title)
 {
-setWindowTitle(title);
+    setWindowTitle(title);
 }
diff --git a/examples/widgets/tutorials/modelview/5_edit/mainwindow.h b/examples/widgets/tutorials/modelview/5_edit/mainwindow.h
index 7915b29cdf..104f06f82e 100644
--- a/examples/widgets/tutorials/modelview/5_edit/mainwindow.h
+++ b/examples/widgets/tutorials/modelview/5_edit/mainwindow.h
@@ -51,9 +51,9 @@
 #ifndef MAINWINDOW_H
 #define MAINWINDOW_H
 
-#include <QtWidgets/QMainWindow>
+#include <QMainWindow>
 
-QT_BEGIN_NAMESPACE // QT_BEGIN_NAMESPACE / QT_END_NAMESPACE are not needed in Qt user code
+QT_BEGIN_NAMESPACE
 class QTableView; //forward declaration
 QT_END_NAMESPACE
 
@@ -64,9 +64,9 @@ class MainWindow : public QMainWindow
 private:
     QTableView *tableView;
 public:
-    MainWindow(QWidget *parent = 0);
+    MainWindow(QWidget *parent = nullptr);
 public slots:
-    void showWindowTitle(const QString & title);
+    void showWindowTitle(const QString &title);
 };
 
 #endif // MAINWINDOW_H
diff --git a/examples/widgets/tutorials/modelview/5_edit/mymodel.cpp b/examples/widgets/tutorials/modelview/5_edit/mymodel.cpp
index fb2954baf2..eeca2ce0a0 100644
--- a/examples/widgets/tutorials/modelview/5_edit/mymodel.cpp
+++ b/examples/widgets/tutorials/modelview/5_edit/mymodel.cpp
@@ -48,12 +48,10 @@
 **
 ****************************************************************************/
 
-
 #include "mymodel.h"
 
-
 MyModel::MyModel(QObject *parent)
-    :QAbstractTableModel(parent)
+    : QAbstractTableModel(parent)
 {
 }
 
@@ -72,33 +70,31 @@ int MyModel::columnCount(const QModelIndex & /*parent*/) const
 //-----------------------------------------------------------------
 QVariant MyModel::data(const QModelIndex &index, int role) const
 {
-    if (role == Qt::DisplayRole)
-    {
-        return m_gridData[index.row()][index.column()];
-    }
+    if (role == Qt::DisplayRole && checkIndex(index))
+            return m_gridData[index.row()][index.column()];
+
     return QVariant();
 }
 
 //-----------------------------------------------------------------
 //! [quoting mymodel_e]
-bool MyModel::setData(const QModelIndex & index, const QVariant & value, int role)
+bool MyModel::setData(const QModelIndex &index, const QVariant &value, int role)
 {
-    if (role == Qt::EditRole)
-    {
+    if (role == Qt::EditRole) {
+        if (!checkIndex(index))
+            return false;
         //save value from editor to member m_gridData
         m_gridData[index.row()][index.column()] = value.toString();
         //for presentation purposes only: build and emit a joined string
         QString result;
-        for (int row= 0; row < ROWS; row++)
-        {
-            for(int col= 0; col < COLS; col++)
-            {
+        for (int row = 0; row < ROWS; row++) {
+            for (int col= 0; col < COLS; col++)
                 result += m_gridData[row][col] + ' ';
-            }
         }
-        emit editCompleted( result );
+        emit editCompleted(result);
+        return true;
     }
-    return true;
+    return false;
 }
 //! [quoting mymodel_e]
 
diff --git a/examples/widgets/tutorials/modelview/5_edit/mymodel.h b/examples/widgets/tutorials/modelview/5_edit/mymodel.h
index dd0d4f5066..ce462351af 100644
--- a/examples/widgets/tutorials/modelview/5_edit/mymodel.h
+++ b/examples/widgets/tutorials/modelview/5_edit/mymodel.h
@@ -64,12 +64,12 @@ class MyModel : public QAbstractTableModel
 {
     Q_OBJECT
 public:
-    MyModel(QObject *parent);
-    int rowCount(const QModelIndex &parent = QModelIndex()) const override ;
+    MyModel(QObject *parent = nullptr);
+    int rowCount(const QModelIndex &parent = QModelIndex()) const override;
     int columnCount(const QModelIndex &parent = QModelIndex()) const override;
     QVariant data(const QModelIndex &index, int role = Qt::DisplayRole) const override;
-    bool setData(const QModelIndex & index, const QVariant & value, int role = Qt::EditRole) override;
-    Qt::ItemFlags flags(const QModelIndex & index) const override ;
+    bool setData(const QModelIndex &index, const QVariant &value, int role = Qt::EditRole) override;
+    Qt::ItemFlags flags(const QModelIndex &index) const override;
 private:
     QString m_gridData[ROWS][COLS];  //holds text entered into QTableView
 signals:
diff --git a/examples/widgets/tutorials/modelview/6_treeview/main.cpp b/examples/widgets/tutorials/modelview/6_treeview/main.cpp
index e1b46339b1..315875a627 100644
--- a/examples/widgets/tutorials/modelview/6_treeview/main.cpp
+++ b/examples/widgets/tutorials/modelview/6_treeview/main.cpp
@@ -48,7 +48,7 @@
 **
 ****************************************************************************/
 
-#include <QtWidgets/QApplication>
+#include <QApplication>
 #include "mainwindow.h"
 
 int main(int argc, char *argv[])
diff --git a/examples/widgets/tutorials/modelview/6_treeview/mainwindow.cpp b/examples/widgets/tutorials/modelview/6_treeview/mainwindow.cpp
index 1016afba07..ae4a343680 100644
--- a/examples/widgets/tutorials/modelview/6_treeview/mainwindow.cpp
+++ b/examples/widgets/tutorials/modelview/6_treeview/mainwindow.cpp
@@ -50,24 +50,25 @@
 
 //! [Quoting ModelView Tutorial]
 // modelview.cpp
+#include "mainwindow.h"
+
 #include <QTreeView>
 #include <QStandardItemModel>
 #include <QStandardItem>
-#include "mainwindow.h"
 
 MainWindow::MainWindow(QWidget *parent)
     : QMainWindow(parent)
+    , treeView(new QTreeView(this))
+    , standardModel(new QStandardItemModel(this))
 {
-    treeView = new QTreeView(this);
     setCentralWidget(treeView);
-    standardModel = new QStandardItemModel ;
 
-    QList<QStandardItem *> preparedRow =prepareRow("first", "second", "third");
+    QList<QStandardItem *> preparedRow = prepareRow("first", "second", "third");
     QStandardItem *item = standardModel->invisibleRootItem();
     // adding a row to the invisible root item produces a root element
     item->appendRow(preparedRow);
 
-    QList<QStandardItem *> secondRow =prepareRow("111", "222", "333");
+    QList<QStandardItem *> secondRow = prepareRow("111", "222", "333");
     // adding a row to an item starts a subtree
     preparedRow.first()->appendRow(secondRow);
 
@@ -76,13 +77,11 @@ MainWindow::MainWindow(QWidget *parent)
 }
 
 QList<QStandardItem *> MainWindow::prepareRow(const QString &first,
-                                                const QString &second,
-                                                const QString &third)
+                                              const QString &second,
+                                              const QString &third) const
 {
-    QList<QStandardItem *> rowItems;
-    rowItems << new QStandardItem(first);
-    rowItems << new QStandardItem(second);
-    rowItems << new QStandardItem(third);
-    return rowItems;
+    return {new QStandardItem(first),
+            new QStandardItem(second),
+            new QStandardItem(third)};
 }
 //! [Quoting ModelView Tutorial]
diff --git a/examples/widgets/tutorials/modelview/6_treeview/mainwindow.h b/examples/widgets/tutorials/modelview/6_treeview/mainwindow.h
index d625d5991d..65d9c18658 100644
--- a/examples/widgets/tutorials/modelview/6_treeview/mainwindow.h
+++ b/examples/widgets/tutorials/modelview/6_treeview/mainwindow.h
@@ -51,9 +51,9 @@
 #ifndef MAINWINDOW_H
 #define MAINWINDOW_H
 
-#include <QtWidgets/QMainWindow>
+#include <QMainWindow>
 
-QT_BEGIN_NAMESPACE // QT_BEGIN_NAMESPACE / QT_END_NAMESPACE are not needed in Qt user code
+QT_BEGIN_NAMESPACE
 class QTreeView; //forward declarations
 class QStandardItemModel;
 class QStandardItem;
@@ -66,11 +66,11 @@ class MainWindow : public QMainWindow
 private:
     QTreeView *treeView;
     QStandardItemModel *standardModel;
-    QList<QStandardItem *> prepareRow( const QString &first,
-                                       const QString &second,
-                                       const QString &third );
+    QList<QStandardItem *> prepareRow(const QString &first,
+                                      const QString &second,
+                                      const QString &third) const;
 public:
-    MainWindow(QWidget *parent = 0);
+    MainWindow(QWidget *parent = nullptr);
 };
 
 #endif // MAINWINDOW_H
diff --git a/examples/widgets/tutorials/modelview/7_selections/main.cpp b/examples/widgets/tutorials/modelview/7_selections/main.cpp
index e1b46339b1..315875a627 100644
--- a/examples/widgets/tutorials/modelview/7_selections/main.cpp
+++ b/examples/widgets/tutorials/modelview/7_selections/main.cpp
@@ -48,7 +48,7 @@
 **
 ****************************************************************************/
 
-#include <QtWidgets/QApplication>
+#include <QApplication>
 #include "mainwindow.h"
 
 int main(int argc, char *argv[])
diff --git a/examples/widgets/tutorials/modelview/7_selections/mainwindow.cpp b/examples/widgets/tutorials/modelview/7_selections/mainwindow.cpp
index 200751ee6d..2b10071a68 100644
--- a/examples/widgets/tutorials/modelview/7_selections/mainwindow.cpp
+++ b/examples/widgets/tutorials/modelview/7_selections/mainwindow.cpp
@@ -49,17 +49,18 @@
 ****************************************************************************/
 
 //! [quoting modelview_a]
+#include "mainwindow.h"
+
 #include <QTreeView>
 #include <QStandardItemModel>
 #include <QItemSelectionModel>
-#include "mainwindow.h"
 
 MainWindow::MainWindow(QWidget *parent)
     : QMainWindow(parent)
+    , treeView(new QTreeView(this))
+    , standardModel(new QStandardItemModel(this))
 {
-    treeView = new QTreeView(this);
     setCentralWidget(treeView);
-    standardModel = new QStandardItemModel ;
     QStandardItem *rootNode = standardModel->invisibleRootItem();
 
 
@@ -88,9 +89,9 @@ MainWindow::MainWindow(QWidget *parent)
     treeView->expandAll();
 
     //selection changes shall trigger a slot
-    QItemSelectionModel *selectionModel= treeView->selectionModel();
-    connect(selectionModel, SIGNAL(selectionChanged (const QItemSelection &, const QItemSelection &)),
-            this, SLOT(selectionChangedSlot(const QItemSelection &, const QItemSelection &)));
+    QItemSelectionModel *selectionModel = treeView->selectionModel();
+    connect(selectionModel, &QItemSelectionModel::selectionChanged,
+            this, &MainWindow::selectionChangedSlot);
 }
 //! [quoting modelview_a]
 
@@ -103,10 +104,9 @@ void MainWindow::selectionChangedSlot(const QItemSelection & /*newSelection*/, c
     const QModelIndex index = treeView->selectionModel()->currentIndex();
     QString selectedText = index.data(Qt::DisplayRole).toString();
     //find out the hierarchy level of the selected item
-    int hierarchyLevel=1;
+    int hierarchyLevel = 1;
     QModelIndex seekRoot = index;
-    while(seekRoot.parent() != QModelIndex())
-    {
+    while (seekRoot.parent() != QModelIndex()) {
         seekRoot = seekRoot.parent();
         hierarchyLevel++;
     }
diff --git a/examples/widgets/tutorials/modelview/7_selections/mainwindow.h b/examples/widgets/tutorials/modelview/7_selections/mainwindow.h
index 13ca7dbc30..c9761dd3d9 100644
--- a/examples/widgets/tutorials/modelview/7_selections/mainwindow.h
+++ b/examples/widgets/tutorials/modelview/7_selections/mainwindow.h
@@ -51,9 +51,9 @@
 #ifndef MAINWINDOW_H
 #define MAINWINDOW_H
 
-#include <QtWidgets/QMainWindow>
+#include <QMainWindow>
 
-QT_BEGIN_NAMESPACE // QT_BEGIN_NAMESPACE / QT_END_NAMESPACE are not needed in Qt user code
+QT_BEGIN_NAMESPACE
 class QTreeView; //forward declarations
 class QStandardItemModel;
 class QItemSelection;
@@ -67,7 +67,7 @@ private:
     QTreeView *treeView;
     QStandardItemModel *standardModel;
 private slots:
-    void selectionChangedSlot(const QItemSelection & newSelection, const QItemSelection & oldSelection);
+    void selectionChangedSlot(const QItemSelection &newSelection, const QItemSelection &oldSelection);
 public:
     MainWindow(QWidget *parent = 0);
 };
diff --git a/examples/widgets/tutorials/notepad/notepad.cpp b/examples/widgets/tutorials/notepad/notepad.cpp
index d0e600e852..2ccd6501a1 100644
--- a/examples/widgets/tutorials/notepad/notepad.cpp
+++ b/examples/widgets/tutorials/notepad/notepad.cpp
@@ -74,6 +74,23 @@ Notepad::Notepad(QWidget *parent) :
     ui->setupUi(this);
     this->setCentralWidget(ui->textEdit);
 
+    connect(ui->actionNew, &QAction::triggered, this, &Notepad::newDocument);
+    connect(ui->actionOpen, &QAction::triggered, this, &Notepad::open);
+    connect(ui->actionSave, &QAction::triggered, this, &Notepad::save);
+    connect(ui->actionSave_as, &QAction::triggered, this, &Notepad::saveAs);
+    connect(ui->actionPrint, &QAction::triggered, this, &Notepad::print);
+    connect(ui->actionExit, &QAction::triggered, this, &Notepad::exit);
+    connect(ui->actionCopy, &QAction::triggered, this, &Notepad::copy);
+    connect(ui->actionCut, &QAction::triggered, this, &Notepad::cut);
+    connect(ui->actionPaste, &QAction::triggered, this, &Notepad::paste);
+    connect(ui->actionUndo, &QAction::triggered, this, &Notepad::undo);
+    connect(ui->actionRedo, &QAction::triggered, this, &Notepad::redo);
+    connect(ui->actionFont, &QAction::triggered, this, &Notepad::selectFont);
+    connect(ui->actionBold, &QAction::triggered, this, &Notepad::setFontBold);
+    connect(ui->actionUnderline, &QAction::triggered, this, &Notepad::setFontUnderline);
+    connect(ui->actionItalic, &QAction::triggered, this, &Notepad::setFontItalic);
+    connect(ui->actionAbout, &QAction::triggered, this, &Notepad::about);
+
 // Disable menu actions for unavailable features
 #if !QT_CONFIG(printer)
     ui->actionPrint->setEnabled(false);
@@ -91,13 +108,13 @@ Notepad::~Notepad()
     delete ui;
 }
 
-void Notepad::on_actionNew_triggered()
+void Notepad::newDocument()
 {
     currentFile.clear();
     ui->textEdit->setText(QString());
 }
 
-void Notepad::on_actionOpen_triggered()
+void Notepad::open()
 {
     QString fileName = QFileDialog::getOpenFileName(this, "Open the file");
     QFile file(fileName);
@@ -113,7 +130,7 @@ void Notepad::on_actionOpen_triggered()
     file.close();
 }
 
-void Notepad::on_actionSave_triggered()
+void Notepad::save()
 {
     QString fileName;
     // If we don't have a filename from before, get one.
@@ -135,7 +152,7 @@ void Notepad::on_actionSave_triggered()
     file.close();
 }
 
-void Notepad::on_actionSave_as_triggered()
+void Notepad::saveAs()
 {
     QString fileName = QFileDialog::getSaveFileName(this, "Save as");
     QFile file(fileName);
@@ -152,7 +169,7 @@ void Notepad::on_actionSave_as_triggered()
     file.close();
 }
 
-void Notepad::on_actionPrint_triggered()
+void Notepad::print()
 {
 #if QT_CONFIG(printer)
     QPrinter printDev;
@@ -165,43 +182,43 @@ void Notepad::on_actionPrint_triggered()
 #endif // QT_CONFIG(printer)
 }
 
-void Notepad::on_actionExit_triggered()
+void Notepad::exit()
 {
     QCoreApplication::quit();
 }
 
-void Notepad::on_actionCopy_triggered()
+void Notepad::copy()
 {
 #if QT_CONFIG(clipboard)
     ui->textEdit->copy();
 #endif
 }
 
-void Notepad::on_actionCut_triggered()
+void Notepad::cut()
 {
 #if QT_CONFIG(clipboard)
     ui->textEdit->cut();
 #endif
 }
 
-void Notepad::on_actionPaste_triggered()
+void Notepad::paste()
 {
 #if QT_CONFIG(clipboard)
     ui->textEdit->paste();
 #endif
 }
 
-void Notepad::on_actionUndo_triggered()
+void Notepad::undo()
 {
      ui->textEdit->undo();
 }
 
-void Notepad::on_actionRedo_triggered()
+void Notepad::redo()
 {
     ui->textEdit->redo();
 }
 
-void Notepad::on_actionFont_triggered()
+void Notepad::selectFont()
 {
     bool fontSelected;
     QFont font = QFontDialog::getFont(&fontSelected, this);
@@ -209,23 +226,23 @@ void Notepad::on_actionFont_triggered()
         ui->textEdit->setFont(font);
 }
 
-void Notepad::on_actionUnderline_triggered()
+void Notepad::setFontUnderline(bool underline)
 {
-    ui->textEdit->setFontUnderline(ui->actionUnderline->isChecked());
+    ui->textEdit->setFontUnderline(underline);
 }
 
-void Notepad::on_actionItalic_triggered()
+void Notepad::setFontItalic(bool italic)
 {
-    ui->textEdit->setFontItalic(ui->actionItalic->isChecked());
+    ui->textEdit->setFontItalic(italic);
 }
 
-void Notepad::on_actionBold_triggered()
+void Notepad::setFontBold(bool bold)
 {
-    ui->actionBold->isChecked() ? ui->textEdit->setFontWeight(QFont::Bold) :
-                                  ui->textEdit->setFontWeight(QFont::Normal);
+    bold ? ui->textEdit->setFontWeight(QFont::Bold) :
+           ui->textEdit->setFontWeight(QFont::Normal);
 }
 
-void Notepad::on_actionAbout_triggered()
+void Notepad::about()
 {
    QMessageBox::about(this, tr("About MDI"),
                 tr("The <b>Notepad</b> example demonstrates how to code a basic "
diff --git a/examples/widgets/tutorials/notepad/notepad.h b/examples/widgets/tutorials/notepad/notepad.h
index 288ab4e373..9580ab8071 100644
--- a/examples/widgets/tutorials/notepad/notepad.h
+++ b/examples/widgets/tutorials/notepad/notepad.h
@@ -79,37 +79,37 @@ public:
 //! [5]
 
 private slots:
-    void on_actionNew_triggered();
+    void newDocument();
 
-    void on_actionOpen_triggered();
+    void open();
 
-    void on_actionSave_triggered();
+    void save();
 
-    void on_actionSave_as_triggered();
+    void saveAs();
 
-    void on_actionPrint_triggered();
+    void print();
 
-    void on_actionExit_triggered();
+    void exit();
 
-    void on_actionCopy_triggered();
+    void copy();
 
-    void on_actionCut_triggered();
+    void cut();
 
-    void on_actionPaste_triggered();
+    void paste();
 
-    void on_actionUndo_triggered();
+    void undo();
 
-    void on_actionRedo_triggered();
+    void redo();
 
-    void on_actionFont_triggered();
+    void selectFont();
 
-    void on_actionBold_triggered();
+    void setFontBold(bool bold);
 
-    void on_actionUnderline_triggered();
+    void setFontUnderline(bool underline);
 
-    void on_actionItalic_triggered();
+    void setFontItalic(bool italic);
 
-    void on_actionAbout_triggered();
+    void about();
 
 //! [6]
 private:
diff --git a/examples/widgets/tutorials/widgets/nestedlayouts/main.cpp b/examples/widgets/tutorials/widgets/nestedlayouts/main.cpp
index 9acc74b469..8880dbe3d0 100644
--- a/examples/widgets/tutorials/widgets/nestedlayouts/main.cpp
+++ b/examples/widgets/tutorials/widgets/nestedlayouts/main.cpp
@@ -76,25 +76,26 @@ int main(int argc, char *argv[])
 
 //! [set up the model]
     QStandardItemModel model;
-    model.setHorizontalHeaderLabels(
-        QStringList() << QApplication::translate("nestedlayouts", "Name")
-                      << QApplication::translate("nestedlayouts", "Office"));
+    model.setHorizontalHeaderLabels({ QApplication::translate("nestedlayouts", "Name"),
+                                      QApplication::translate("nestedlayouts", "Office") });
 
-    QList<QStringList> rows = QList<QStringList>()
-        << (QStringList() << "Verne Nilsen" << "123")
-        << (QStringList() << "Carlos Tang" << "77")
-        << (QStringList() << "Bronwyn Hawcroft" << "119")
-        << (QStringList() << "Alessandro Hanssen" << "32")
-        << (QStringList() << "Andrew John Bakken" << "54")
-        << (QStringList() << "Vanessa Weatherley" << "85")
-        << (QStringList() << "Rebecca Dickens" << "17")
-        << (QStringList() << "David Bradley" << "42")
-        << (QStringList() << "Knut Walters" << "25")
-        << (QStringList() << "Andrea Jones" << "34");
+    const QStringList rows[] = {
+        QStringList{ QStringLiteral("Verne Nilsen"), QStringLiteral("123") },
+        QStringList{ QStringLiteral("Carlos Tang"), QStringLiteral("77") },
+        QStringList{ QStringLiteral("Bronwyn Hawcroft"), QStringLiteral("119") },
+        QStringList{ QStringLiteral("Alessandro Hanssen"), QStringLiteral("32") },
+        QStringList{ QStringLiteral("Andrew John Bakken"), QStringLiteral("54") },
+        QStringList{ QStringLiteral("Vanessa Weatherley"), QStringLiteral("85") },
+        QStringList{ QStringLiteral("Rebecca Dickens"), QStringLiteral("17") },
+        QStringList{ QStringLiteral("David Bradley"), QStringLiteral("42") },
+        QStringList{ QStringLiteral("Knut Walters"), QStringLiteral("25") },
+        QStringList{ QStringLiteral("Andrea Jones"), QStringLiteral("34") }
+    };
 
-    foreach (QStringList row, rows) {
-        QList<QStandardItem *> items;
-        foreach (QString text, row)
+    QList<QStandardItem *> items;
+    for (const QStringList &row : rows) {
+        items.clear();
+        for (const QString &text : row)
             items.append(new QStandardItem(text));
         model.appendRow(items);
     }
diff --git a/examples/widgets/widgets.pro b/examples/widgets/widgets.pro
index 8bd85bfe6b..d975ea8307 100644
--- a/examples/widgets/widgets.pro
+++ b/examples/widgets/widgets.pro
@@ -28,4 +28,5 @@ qtHaveModule(gui):qtConfig(opengl): \
 
 contains(DEFINES, QT_NO_CURSOR): SUBDIRS -= mainwindows
 !qtConfig(draganddrop): SUBDIRS -= draganddrop
+!qtConfig(animation): SUBDIRS -= animation
 mac:SUBDIRS += mac
diff --git a/examples/widgets/widgets/analogclock/analogclock.cpp b/examples/widgets/widgets/analogclock/analogclock.cpp
index 0dc2fbc708..c7b3f66cca 100644
--- a/examples/widgets/widgets/analogclock/analogclock.cpp
+++ b/examples/widgets/widgets/analogclock/analogclock.cpp
@@ -48,10 +48,10 @@
 **
 ****************************************************************************/
 
-#include <QtWidgets>
-
 #include "analogclock.h"
 
+#include <QtWidgets>
+
 //! [0] //! [1]
 AnalogClock::AnalogClock(QWidget *parent)
 //! [0] //! [2]
@@ -61,7 +61,7 @@ AnalogClock::AnalogClock(QWidget *parent)
 //! [3] //! [4]
     QTimer *timer = new QTimer(this);
 //! [4] //! [5]
-    connect(timer, SIGNAL(timeout()), this, SLOT(update()));
+    connect(timer, &QTimer::timeout, this, QOverload<>::of(&AnalogClock::update));
 //! [5] //! [6]
     timer->start(1000);
 //! [6]
diff --git a/examples/widgets/widgets/analogclock/analogclock.h b/examples/widgets/widgets/analogclock/analogclock.h
index 19e580d1ac..e2486a915f 100644
--- a/examples/widgets/widgets/analogclock/analogclock.h
+++ b/examples/widgets/widgets/analogclock/analogclock.h
@@ -59,7 +59,7 @@ class AnalogClock : public QWidget
     Q_OBJECT
 
 public:
-    AnalogClock(QWidget *parent = 0);
+    AnalogClock(QWidget *parent = nullptr);
 
 protected:
     void paintEvent(QPaintEvent *event) override;
diff --git a/examples/widgets/widgets/calculator/button.cpp b/examples/widgets/widgets/calculator/button.cpp
index 0d622b1781..a1ce0bf428 100644
--- a/examples/widgets/widgets/calculator/button.cpp
+++ b/examples/widgets/widgets/calculator/button.cpp
@@ -48,10 +48,10 @@
 **
 ****************************************************************************/
 
-#include <QtWidgets>
-
 #include "button.h"
 
+#include <QtWidgets>
+
 //! [0]
 Button::Button(const QString &text, QWidget *parent)
     : QToolButton(parent)
diff --git a/examples/widgets/widgets/calculator/button.h b/examples/widgets/widgets/calculator/button.h
index 057640700f..7c6f26867f 100644
--- a/examples/widgets/widgets/calculator/button.h
+++ b/examples/widgets/widgets/calculator/button.h
@@ -59,7 +59,7 @@ class Button : public QToolButton
     Q_OBJECT
 
 public:
-    explicit Button(const QString &text, QWidget *parent = 0);
+    explicit Button(const QString &text, QWidget *parent = nullptr);
 
     QSize sizeHint() const override;
 };
diff --git a/examples/widgets/widgets/calculator/calculator.cpp b/examples/widgets/widgets/calculator/calculator.cpp
index cbcc29b2a8..dd908cf40a 100644
--- a/examples/widgets/widgets/calculator/calculator.cpp
+++ b/examples/widgets/widgets/calculator/calculator.cpp
@@ -48,13 +48,13 @@
 **
 ****************************************************************************/
 
+#include "button.h"
+#include "calculator.h"
+
 #include <QtWidgets>
 
 #include <cmath>
 
-#include "button.h"
-#include "calculator.h"
-
 //! [0]
 Calculator::Calculator(QWidget *parent)
     : QWidget(parent)
diff --git a/examples/widgets/widgets/calculator/calculator.h b/examples/widgets/widgets/calculator/calculator.h
index 6d7e336347..937de185e7 100644
--- a/examples/widgets/widgets/calculator/calculator.h
+++ b/examples/widgets/widgets/calculator/calculator.h
@@ -64,7 +64,7 @@ class Calculator : public QWidget
     Q_OBJECT
 
 public:
-    Calculator(QWidget *parent = 0);
+    Calculator(QWidget *parent = nullptr);
 
 private slots:
     void digitClicked();
diff --git a/examples/widgets/widgets/calendarwidget/window.cpp b/examples/widgets/widgets/calendarwidget/window.cpp
index c3a0e1e3f7..64047aaac9 100644
--- a/examples/widgets/widgets/calendarwidget/window.cpp
+++ b/examples/widgets/widgets/calendarwidget/window.cpp
@@ -53,7 +53,8 @@
 #include "window.h"
 
 //! [0]
-Window::Window()
+Window::Window(QWidget *parent)
+    : QWidget(parent)
 {
     createPreviewGroupBox();
     createGeneralOptionsGroupBox();
@@ -220,8 +221,8 @@ void Window::createPreviewGroupBox()
     calendar->setMaximumDate(QDate(3000, 1, 1));
     calendar->setGridVisible(true);
 
-    connect(calendar, SIGNAL(currentPageChanged(int,int)),
-            this, SLOT(reformatCalendarPage()));
+    connect(calendar, &QCalendarWidget::currentPageChanged,
+            this, &Window::reformatCalendarPage);
 
     previewLayout = new QGridLayout;
     previewLayout->addWidget(calendar, 0, 0, Qt::AlignCenter);
@@ -305,20 +306,20 @@ void Window::createGeneralOptionsGroupBox()
     verticalHeaderLabel->setBuddy(verticalHeaderCombo);
 
 //! [11]
-    connect(localeCombo, SIGNAL(currentIndexChanged(int)),
-            this, SLOT(localeChanged(int)));
-    connect(firstDayCombo, SIGNAL(currentIndexChanged(int)),
-            this, SLOT(firstDayChanged(int)));
-    connect(selectionModeCombo, SIGNAL(currentIndexChanged(int)),
-            this, SLOT(selectionModeChanged(int)));
-    connect(gridCheckBox, SIGNAL(toggled(bool)),
-            calendar, SLOT(setGridVisible(bool)));
-    connect(navigationCheckBox, SIGNAL(toggled(bool)),
-            calendar, SLOT(setNavigationBarVisible(bool)));
-    connect(horizontalHeaderCombo, SIGNAL(currentIndexChanged(int)),
-            this, SLOT(horizontalHeaderChanged(int)));
-    connect(verticalHeaderCombo, SIGNAL(currentIndexChanged(int)),
-            this, SLOT(verticalHeaderChanged(int)));
+    connect(localeCombo, QOverload<int>::of(&QComboBox::currentIndexChanged),
+            this, &Window::localeChanged);
+    connect(firstDayCombo, QOverload<int>::of(&QComboBox::currentIndexChanged),
+            this, &Window::firstDayChanged);
+    connect(selectionModeCombo, QOverload<int>::of(&QComboBox::currentIndexChanged),
+            this, &Window::selectionModeChanged);
+    connect(gridCheckBox, &QCheckBox::toggled,
+            calendar, &QCalendarWidget::setGridVisible);
+    connect(navigationCheckBox, &QCheckBox::toggled,
+            calendar, &QCalendarWidget::setNavigationBarVisible);
+    connect(horizontalHeaderCombo, QOverload<int>::of(&QComboBox::currentIndexChanged),
+            this, &Window::horizontalHeaderChanged);
+    connect(verticalHeaderCombo, QOverload<int>::of(&QComboBox::currentIndexChanged),
+            this, &Window::verticalHeaderChanged);
 //! [11]
 
     QHBoxLayout *checkBoxLayout = new QHBoxLayout;
@@ -381,14 +382,14 @@ void Window::createDatesGroupBox()
     maximumDateLabel->setBuddy(maximumDateEdit);
 
 //! [13] //! [14]
-    connect(currentDateEdit, SIGNAL(dateChanged(QDate)),
-            calendar, SLOT(setSelectedDate(QDate)));
-    connect(calendar, SIGNAL(selectionChanged()),
-            this, SLOT(selectedDateChanged()));
-    connect(minimumDateEdit, SIGNAL(dateChanged(QDate)),
-            this, SLOT(minimumDateChanged(QDate)));
-    connect(maximumDateEdit, SIGNAL(dateChanged(QDate)),
-            this, SLOT(maximumDateChanged(QDate)));
+    connect(currentDateEdit, &QDateEdit::dateChanged,
+            calendar, &QCalendarWidget::setSelectedDate);
+    connect(calendar, &QCalendarWidget::selectionChanged,
+            this, &Window::selectedDateChanged);
+    connect(minimumDateEdit, &QDateEdit::dateChanged,
+            this, &Window::minimumDateChanged);
+    connect(maximumDateEdit, &QDateEdit::dateChanged,
+            this, &Window::maximumDateChanged);
 
 //! [14]
     QGridLayout *dateBoxLayout = new QGridLayout;
@@ -438,20 +439,20 @@ void Window::createTextFormatsGroupBox()
     mayFirstCheckBox = new QCheckBox(tr("May &1 in red"));
 
 //! [17] //! [18]
-    connect(weekdayColorCombo, SIGNAL(currentIndexChanged(int)),
-            this, SLOT(weekdayFormatChanged()));
-    connect(weekdayColorCombo, SIGNAL(currentIndexChanged(int)),
-            this, SLOT(reformatCalendarPage()));
-    connect(weekendColorCombo, SIGNAL(currentIndexChanged(int)),
-            this, SLOT(weekendFormatChanged()));
-    connect(weekendColorCombo, SIGNAL(currentIndexChanged(int)),
-            this, SLOT(reformatCalendarPage()));
-    connect(headerTextFormatCombo, SIGNAL(currentIndexChanged(QString)),
-            this, SLOT(reformatHeaders()));
-    connect(firstFridayCheckBox, SIGNAL(toggled(bool)),
-            this, SLOT(reformatCalendarPage()));
-    connect(mayFirstCheckBox, SIGNAL(toggled(bool)),
-            this, SLOT(reformatCalendarPage()));
+    connect(weekdayColorCombo, QOverload<int>::of(&QComboBox::currentIndexChanged),
+            this, &Window::weekdayFormatChanged);
+    connect(weekdayColorCombo, QOverload<int>::of(&QComboBox::currentIndexChanged),
+            this, &Window::reformatCalendarPage);
+    connect(weekendColorCombo, QOverload<int>::of(&QComboBox::currentIndexChanged),
+            this, &Window::weekendFormatChanged);
+    connect(weekendColorCombo, QOverload<int>::of(&QComboBox::currentIndexChanged),
+            this, &Window::reformatCalendarPage);
+    connect(headerTextFormatCombo, QOverload<int>::of(&QComboBox::currentIndexChanged),
+            this, &Window::reformatHeaders);
+    connect(firstFridayCheckBox, &QCheckBox::toggled,
+            this, &Window::reformatCalendarPage);
+    connect(mayFirstCheckBox, &QCheckBox::toggled,
+            this, &Window::reformatCalendarPage);
 
 //! [18]
     QHBoxLayout *checkBoxLayout = new QHBoxLayout;
diff --git a/examples/widgets/widgets/calendarwidget/window.h b/examples/widgets/widgets/calendarwidget/window.h
index fa01fc4db6..83ea494fc2 100644
--- a/examples/widgets/widgets/calendarwidget/window.h
+++ b/examples/widgets/widgets/calendarwidget/window.h
@@ -70,7 +70,7 @@ class Window : public QWidget
     Q_OBJECT
 
 public:
-    Window();
+    Window(QWidget *parent = nullptr);
 
 private slots:
     void localeChanged(int index);
diff --git a/examples/widgets/widgets/charactermap/characterwidget.cpp b/examples/widgets/widgets/charactermap/characterwidget.cpp
index 5bab921516..061c0164b0 100644
--- a/examples/widgets/widgets/charactermap/characterwidget.cpp
+++ b/examples/widgets/widgets/charactermap/characterwidget.cpp
@@ -48,10 +48,10 @@
 **
 ****************************************************************************/
 
-#include <QtWidgets>
-
 #include "characterwidget.h"
 
+#include <QtWidgets>
+
 //! [0]
 CharacterWidget::CharacterWidget(QWidget *parent)
     : QWidget(parent), columns(16), lastKey(-1)
diff --git a/examples/widgets/widgets/charactermap/characterwidget.h b/examples/widgets/widgets/charactermap/characterwidget.h
index 53add51e6f..d12a46aa15 100644
--- a/examples/widgets/widgets/charactermap/characterwidget.h
+++ b/examples/widgets/widgets/charactermap/characterwidget.h
@@ -52,7 +52,6 @@
 #define CHARACTERWIDGET_H
 
 #include <QFont>
-#include <QPoint>
 #include <QSize>
 #include <QString>
 #include <QWidget>
@@ -68,7 +67,7 @@ class CharacterWidget : public QWidget
     Q_OBJECT
 
 public:
-    CharacterWidget(QWidget *parent = 0);
+    CharacterWidget(QWidget *parent = nullptr);
     QSize sizeHint() const override;
 
 public slots:
diff --git a/examples/widgets/widgets/charactermap/mainwindow.cpp b/examples/widgets/widgets/charactermap/mainwindow.cpp
index d3ac55483c..77aad145e7 100644
--- a/examples/widgets/widgets/charactermap/mainwindow.cpp
+++ b/examples/widgets/widgets/charactermap/mainwindow.cpp
@@ -57,7 +57,8 @@
 
 Q_DECLARE_METATYPE(QFontComboBox::FontFilter)
 
-MainWindow::MainWindow()
+MainWindow::MainWindow(QWidget *parent)
+    : QMainWindow(parent)
 {
     QMenu *fileMenu = menuBar()->addMenu(tr("File"));
     fileMenu->addAction(tr("Quit"), this, &QWidget::close);
@@ -113,9 +114,9 @@ MainWindow::MainWindow()
             this, &MainWindow::findSizes);
     connect(fontCombo, &QFontComboBox::currentFontChanged,
             characterWidget, &CharacterWidget::updateFont);
-    connect(sizeCombo, QOverload<const QString &>::of(&QComboBox::currentIndexChanged),
+    connect(sizeCombo, &QComboBox::currentTextChanged,
             characterWidget, &CharacterWidget::updateSize);
-    connect(styleCombo, QOverload<const QString &>::of(&QComboBox::currentIndexChanged),
+    connect(styleCombo, &QComboBox::currentTextChanged,
             characterWidget, &CharacterWidget::updateStyle);
 //! [4] //! [5]
     connect(characterWidget, &CharacterWidget::characterSelected,
@@ -169,8 +170,8 @@ void MainWindow::findStyles(const QFont &font)
 //! [7]
 
 //! [8]
-    QString style;
-    foreach (style, fontDatabase.styles(font.family()))
+    const QStringList styles = fontDatabase.styles(font.family());
+    for (const QString &style : styles)
         styleCombo->addItem(style);
 
     int styleIndex = styleCombo->findText(currentItem);
@@ -187,7 +188,7 @@ void MainWindow::filterChanged(int f)
     const QFontComboBox::FontFilter filter =
         filterCombo->itemData(f).value<QFontComboBox::FontFilter>();
     fontCombo->setFontFilters(filter);
-    statusBar()->showMessage(tr("%n font(s) found", 0, fontCombo->count()));
+    statusBar()->showMessage(tr("%n font(s) found", nullptr, fontCombo->count()));
 }
 
 void MainWindow::findSizes(const QFont &font)
@@ -200,15 +201,16 @@ void MainWindow::findSizes(const QFont &font)
         // sizeCombo signals are now blocked until end of scope
         sizeCombo->clear();
 
-        int size;
         if (fontDatabase.isSmoothlyScalable(font.family(), fontDatabase.styleString(font))) {
-            foreach (size, QFontDatabase::standardSizes()) {
+            const QList<int> sizes = QFontDatabase::standardSizes();
+            for (const int size : sizes) {
                 sizeCombo->addItem(QVariant(size).toString());
                 sizeCombo->setEditable(true);
             }
 
         } else {
-            foreach (size, fontDatabase.smoothSizes(font.family(), fontDatabase.styleString(font))) {
+            const QList<int> sizes = fontDatabase.smoothSizes(font.family(), fontDatabase.styleString(font));
+            for (const int size : sizes ) {
                 sizeCombo->addItem(QVariant(size).toString());
                 sizeCombo->setEditable(false);
             }
diff --git a/examples/widgets/widgets/charactermap/mainwindow.h b/examples/widgets/widgets/charactermap/mainwindow.h
index eac16b35fa..79fe9f9cc8 100644
--- a/examples/widgets/widgets/charactermap/mainwindow.h
+++ b/examples/widgets/widgets/charactermap/mainwindow.h
@@ -70,7 +70,7 @@ class MainWindow : public QMainWindow
     Q_OBJECT
 
 public:
-    MainWindow();
+    MainWindow(QWidget *parent = nullptr);
 
 public slots:
     void filterChanged(int);
diff --git a/examples/widgets/widgets/codeeditor/codeeditor.cpp b/examples/widgets/widgets/codeeditor/codeeditor.cpp
index 7e56a75294..8e29860669 100644
--- a/examples/widgets/widgets/codeeditor/codeeditor.cpp
+++ b/examples/widgets/widgets/codeeditor/codeeditor.cpp
@@ -58,9 +58,9 @@ CodeEditor::CodeEditor(QWidget *parent) : QPlainTextEdit(parent)
 {
     lineNumberArea = new LineNumberArea(this);
 
-    connect(this, SIGNAL(blockCountChanged(int)), this, SLOT(updateLineNumberAreaWidth(int)));
-    connect(this, SIGNAL(updateRequest(QRect,int)), this, SLOT(updateLineNumberArea(QRect,int)));
-    connect(this, SIGNAL(cursorPositionChanged()), this, SLOT(highlightCurrentLine()));
+    connect(this, &CodeEditor::blockCountChanged, this, &CodeEditor::updateLineNumberAreaWidth);
+    connect(this, &CodeEditor::updateRequest, this, &CodeEditor::updateLineNumberArea);
+    connect(this, &CodeEditor::cursorPositionChanged, this, &CodeEditor::highlightCurrentLine);
 
     updateLineNumberAreaWidth(0);
     highlightCurrentLine();
diff --git a/examples/widgets/widgets/codeeditor/codeeditor.h b/examples/widgets/widgets/codeeditor/codeeditor.h
index 65be76d81d..5a48abafc4 100644
--- a/examples/widgets/widgets/codeeditor/codeeditor.h
+++ b/examples/widgets/widgets/codeeditor/codeeditor.h
@@ -52,7 +52,6 @@
 #define CODEEDITOR_H
 
 #include <QPlainTextEdit>
-#include <QObject>
 
 QT_BEGIN_NAMESPACE
 class QPaintEvent;
@@ -70,7 +69,7 @@ class CodeEditor : public QPlainTextEdit
     Q_OBJECT
 
 public:
-    CodeEditor(QWidget *parent = 0);
+    CodeEditor(QWidget *parent = nullptr);
 
     void lineNumberAreaPaintEvent(QPaintEvent *event);
     int lineNumberAreaWidth();
diff --git a/examples/widgets/widgets/digitalclock/digitalclock.cpp b/examples/widgets/widgets/digitalclock/digitalclock.cpp
index dec7e64fc3..000334f33b 100644
--- a/examples/widgets/widgets/digitalclock/digitalclock.cpp
+++ b/examples/widgets/widgets/digitalclock/digitalclock.cpp
@@ -48,10 +48,10 @@
 **
 ****************************************************************************/
 
-#include <QtWidgets>
-
 #include "digitalclock.h"
 
+#include <QtWidgets>
+
 //! [0]
 DigitalClock::DigitalClock(QWidget *parent)
     : QLCDNumber(parent)
diff --git a/examples/widgets/widgets/digitalclock/digitalclock.h b/examples/widgets/widgets/digitalclock/digitalclock.h
index 4365b965bf..31c12f39ab 100644
--- a/examples/widgets/widgets/digitalclock/digitalclock.h
+++ b/examples/widgets/widgets/digitalclock/digitalclock.h
@@ -59,7 +59,7 @@ class DigitalClock : public QLCDNumber
     Q_OBJECT
 
 public:
-    DigitalClock(QWidget *parent = 0);
+    DigitalClock(QWidget *parent = nullptr);
 
 private slots:
     void showTime();
diff --git a/examples/widgets/widgets/elidedlabel/elidedlabel.cpp b/examples/widgets/widgets/elidedlabel/elidedlabel.cpp
index b12bf118f6..e80f7a9894 100644
--- a/examples/widgets/widgets/elidedlabel/elidedlabel.cpp
+++ b/examples/widgets/widgets/elidedlabel/elidedlabel.cpp
@@ -51,8 +51,8 @@
 #include "elidedlabel.h"
 
 #include <QPainter>
+#include <QSizePolicy>
 #include <QTextLayout>
-#include <QDebug>
 
 //! [0]
 ElidedLabel::ElidedLabel(const QString &text, QWidget *parent)
diff --git a/examples/widgets/widgets/elidedlabel/elidedlabel.h b/examples/widgets/widgets/elidedlabel/elidedlabel.h
index 8a2a40f49a..0c8d96834e 100644
--- a/examples/widgets/widgets/elidedlabel/elidedlabel.h
+++ b/examples/widgets/widgets/elidedlabel/elidedlabel.h
@@ -51,11 +51,8 @@
 #ifndef ELIDEDLABEL_H
 #define ELIDEDLABEL_H
 
-#include <QtWidgets/QFrame>
-#include <QtCore/QRect>
-#include <QtGui/QResizeEvent>
-#include <QtCore/QString>
-#include <QtWidgets/QWidget>
+#include <QFrame>
+#include <QString>
 
 //! [0]
 class ElidedLabel : public QFrame
@@ -65,7 +62,7 @@ class ElidedLabel : public QFrame
     Q_PROPERTY(bool isElided READ isElided)
 
 public:
-    explicit ElidedLabel(const QString &text, QWidget *parent = 0);
+    explicit ElidedLabel(const QString &text, QWidget *parent = nullptr);
 
     void setText(const QString &text);
     const QString & text() const { return content; }
diff --git a/examples/widgets/widgets/elidedlabel/main.cpp b/examples/widgets/widgets/elidedlabel/main.cpp
index f692db0efc..1c620c1d41 100644
--- a/examples/widgets/widgets/elidedlabel/main.cpp
+++ b/examples/widgets/widgets/elidedlabel/main.cpp
@@ -50,7 +50,7 @@
 
 #include "testwidget.h"
 
-#include <QtWidgets/QApplication>
+#include <QApplication>
 
 //! [0]
 int main( int argc, char *argv[] )
diff --git a/examples/widgets/widgets/elidedlabel/testwidget.cpp b/examples/widgets/widgets/elidedlabel/testwidget.cpp
index 6392a4b4fa..4e013cc5de 100644
--- a/examples/widgets/widgets/elidedlabel/testwidget.cpp
+++ b/examples/widgets/widgets/elidedlabel/testwidget.cpp
@@ -51,14 +51,13 @@
 #include "testwidget.h"
 #include "elidedlabel.h"
 
-#include <QtWidgets/QLabel>
-#include <QtWidgets/QPushButton>
-#include <QtWidgets/QSizePolicy>
-#include <QtWidgets/QGridLayout>
+#include <QGridLayout>
+#include <QLabel>
+#include <QPushButton>
 
 //! [0]
-TestWidget::TestWidget(QWidget *parent):
-    QWidget(parent)
+TestWidget::TestWidget(QWidget *parent)
+    : QWidget(parent)
 {
     const QString romeo = tr(
         "But soft, what light through yonder window breaks? / "
@@ -116,7 +115,7 @@ TestWidget::TestWidget(QWidget *parent):
     //! [3]
 
     //! [4]
-    QGridLayout *layout = new QGridLayout();
+    QGridLayout *layout = new QGridLayout;
     layout->addWidget(label, 0, 1, Qt::AlignCenter);
     layout->addWidget(switchButton, 0, 2);
     layout->addWidget(exitButton, 0, 3);
diff --git a/examples/widgets/widgets/elidedlabel/testwidget.h b/examples/widgets/widgets/elidedlabel/testwidget.h
index 840bc98b40..bcb2f33044 100644
--- a/examples/widgets/widgets/elidedlabel/testwidget.h
+++ b/examples/widgets/widgets/elidedlabel/testwidget.h
@@ -51,10 +51,9 @@
 #ifndef TESTWIDGET_H
 #define TESTWIDGET_H
 
-#include <QtWidgets/QWidget>
-#include <QtCore/QStringList>
-#include <QtWidgets/QSlider>
-#include <QtWidgets/QComboBox>
+#include <QSlider>
+#include <QStringList>
+#include <QWidget>
 
 class ElidedLabel;
 
@@ -64,7 +63,7 @@ class TestWidget : public QWidget
     Q_OBJECT
 
 public:
-    TestWidget(QWidget *parent = 0);
+    TestWidget(QWidget *parent = nullptr);
 
 protected:
     void resizeEvent(QResizeEvent *event) override;
diff --git a/examples/widgets/widgets/groupbox/window.h b/examples/widgets/widgets/groupbox/window.h
index 566fafa151..1f041fd003 100644
--- a/examples/widgets/widgets/groupbox/window.h
+++ b/examples/widgets/widgets/groupbox/window.h
@@ -63,7 +63,7 @@ class Window : public QWidget
     Q_OBJECT
 
 public:
-    Window(QWidget *parent = 0);
+    Window(QWidget *parent = nullptr);
 
 private:
     QGroupBox *createFirstExclusiveGroup();
diff --git a/examples/widgets/widgets/icons/iconpreviewarea.cpp b/examples/widgets/widgets/icons/iconpreviewarea.cpp
index 9cb54c47f6..1a2f514ba8 100644
--- a/examples/widgets/widgets/icons/iconpreviewarea.cpp
+++ b/examples/widgets/widgets/icons/iconpreviewarea.cpp
@@ -48,10 +48,10 @@
 **
 ****************************************************************************/
 
-#include <QtWidgets>
-
 #include "iconpreviewarea.h"
 
+#include <QtWidgets>
+
 //! [0]
 IconPreviewArea::IconPreviewArea(QWidget *parent)
     : QWidget(parent)
diff --git a/examples/widgets/widgets/icons/iconsizespinbox.cpp b/examples/widgets/widgets/icons/iconsizespinbox.cpp
index 4c6a850858..e94d943993 100644
--- a/examples/widgets/widgets/icons/iconsizespinbox.cpp
+++ b/examples/widgets/widgets/icons/iconsizespinbox.cpp
@@ -48,10 +48,10 @@
 **
 ****************************************************************************/
 
-#include <QtWidgets>
-
 #include "iconsizespinbox.h"
 
+#include <QtWidgets>
+
 //! [0]
 IconSizeSpinBox::IconSizeSpinBox(QWidget *parent)
     : QSpinBox(parent)
diff --git a/examples/widgets/widgets/icons/imagedelegate.cpp b/examples/widgets/widgets/icons/imagedelegate.cpp
index 3c873f1e24..786194bae7 100644
--- a/examples/widgets/widgets/icons/imagedelegate.cpp
+++ b/examples/widgets/widgets/icons/imagedelegate.cpp
@@ -48,11 +48,11 @@
 **
 ****************************************************************************/
 
-#include <QtWidgets>
-
 #include "imagedelegate.h"
 #include "iconpreviewarea.h"
 
+#include <QtWidgets>
+
 //! [0]
 ImageDelegate::ImageDelegate(QObject *parent)
     : QItemDelegate(parent)
diff --git a/examples/widgets/widgets/icons/mainwindow.cpp b/examples/widgets/widgets/icons/mainwindow.cpp
index f704b8306f..0cf11c978d 100644
--- a/examples/widgets/widgets/icons/mainwindow.cpp
+++ b/examples/widgets/widgets/icons/mainwindow.cpp
@@ -60,7 +60,8 @@ enum { OtherSize = QStyle::PM_CustomBase };
 //! [40]
 
 //! [0]
-MainWindow::MainWindow()
+MainWindow::MainWindow(QWidget *parent)
+    : QMainWindow(parent)
 {
     QWidget *centralWidget = new QWidget(this);
     setCentralWidget(centralWidget);
@@ -121,7 +122,8 @@ void MainWindow::changeStyle(bool checked)
     Q_ASSERT(style);
     QApplication::setStyle(style);
 
-    foreach (QAbstractButton *button, sizeButtonGroup->buttons()) {
+    const QList<QAbstractButton*> buttons = sizeButtonGroup->buttons();
+    for (QAbstractButton *button : buttons) {
         const QStyle::PixelMetric metric = static_cast<QStyle::PixelMetric>(sizeButtonGroup->id(button));
         const int value = style->pixelMetric(metric);
         switch (metric) {
@@ -229,7 +231,8 @@ void MainWindow::addImages(const QString &directory)
 {
     QFileDialog fileDialog(this, tr("Open Images"), directory);
     QStringList mimeTypeFilters;
-    foreach (const QByteArray &mimeTypeName, QImageReader::supportedMimeTypes())
+    const QList<QByteArray> mimeTypes = QImageReader::supportedMimeTypes();
+    for (const QByteArray &mimeTypeName : mimeTypes)
         mimeTypeFilters.append(mimeTypeName);
     mimeTypeFilters.sort();
     fileDialog.setMimeTypeFilters(mimeTypeFilters);
@@ -245,7 +248,7 @@ void MainWindow::addImages(const QString &directory)
 
 void MainWindow::loadImages(const QStringList &fileNames)
 {
-    foreach (const QString &fileName, fileNames) {
+    for (const QString &fileName : fileNames) {
         const int row = imagesTable->rowCount();
         imagesTable->setRowCount(row + 1);
 //! [13]
@@ -468,7 +471,8 @@ void MainWindow::createActions()
     QMenu *viewMenu = menuBar()->addMenu(tr("&View"));
 
     styleActionGroup = new QActionGroup(this);
-    foreach (const QString &styleName, QStyleFactory::keys()) {
+    const QStringList styleKeys = QStyleFactory::keys();
+    for (const QString &styleName : styleKeys) {
         QAction *action = new QAction(tr("%1 Style").arg(styleName), styleActionGroup);
         action->setData(styleName);
         action->setCheckable(true);
@@ -507,8 +511,9 @@ void MainWindow::createContextMenu()
 //! [31]
 void MainWindow::checkCurrentStyle()
 {
-    foreach (QAction *action, styleActionGroup->actions()) {
-        QString styleName = action->data().toString();
+    const QList<QAction *> actions = styleActionGroup->actions();
+    for (QAction *action : actions) {
+        const QString styleName = action->data().toString();
         QScopedPointer<QStyle> candidate(QStyleFactory::create(styleName));
         Q_ASSERT(!candidate.isNull());
         if (candidate->metaObject()->className()
diff --git a/examples/widgets/widgets/icons/mainwindow.h b/examples/widgets/widgets/icons/mainwindow.h
index e3888e5fb1..c67d828cab 100644
--- a/examples/widgets/widgets/icons/mainwindow.h
+++ b/examples/widgets/widgets/icons/mainwindow.h
@@ -60,8 +60,6 @@ QT_BEGIN_NAMESPACE
 class QAction;
 class QActionGroup;
 class QLabel;
-class QMenu;
-class QRadioButton;
 class QButtonGroup;
 class QTableWidget;
 QT_END_NAMESPACE
@@ -74,7 +72,7 @@ class MainWindow : public QMainWindow
     Q_OBJECT
 
 public:
-    MainWindow();
+    MainWindow(QWidget *parent = nullptr);
 
     void loadImages(const QStringList &fileNames);
 
diff --git a/examples/widgets/widgets/imageviewer/imageviewer.cpp b/examples/widgets/widgets/imageviewer/imageviewer.cpp
index 327abf7e43..2fc8ff63de 100644
--- a/examples/widgets/widgets/imageviewer/imageviewer.cpp
+++ b/examples/widgets/widgets/imageviewer/imageviewer.cpp
@@ -48,6 +48,8 @@
 **
 ****************************************************************************/
 
+#include "imageviewer.h"
+
 #include <QtWidgets>
 #if defined(QT_PRINTSUPPORT_LIB)
 #include <QtPrintSupport/qtprintsupportglobal.h>
@@ -56,13 +58,10 @@
 #endif
 #endif
 
-#include "imageviewer.h"
-
 //! [0]
-ImageViewer::ImageViewer()
-   : imageLabel(new QLabel)
-   , scrollArea(new QScrollArea)
-   , scaleFactor(1)
+ImageViewer::ImageViewer(QWidget *parent)
+   : QMainWindow(parent), imageLabel(new QLabel),
+     scrollArea(new QScrollArea), scaleFactor(1)
 {
     imageLabel->setBackgroundRole(QPalette::Base);
     imageLabel->setSizePolicy(QSizePolicy::Ignored, QSizePolicy::Ignored);
@@ -107,6 +106,8 @@ bool ImageViewer::loadFile(const QString &fileName)
 void ImageViewer::setImage(const QImage &newImage)
 {
     image = newImage;
+    if (image.colorSpace().isValid())
+        image.convertToColorSpace(QColorSpace::SRgb);
     imageLabel->setPixmap(QPixmap::fromImage(image));
 //! [4]
     scaleFactor = 1.0;
@@ -152,7 +153,7 @@ static void initializeImageFileDialog(QFileDialog &dialog, QFileDialog::AcceptMo
     QStringList mimeTypeFilters;
     const QByteArrayList supportedMimeTypes = acceptMode == QFileDialog::AcceptOpen
         ? QImageReader::supportedMimeTypes() : QImageWriter::supportedMimeTypes();
-    foreach (const QByteArray &mimeTypeName, supportedMimeTypes)
+    for (const QByteArray &mimeTypeName : supportedMimeTypes)
         mimeTypeFilters.append(mimeTypeName);
     mimeTypeFilters.sort();
     dialog.setMimeTypeFilters(mimeTypeFilters);
diff --git a/examples/widgets/widgets/imageviewer/imageviewer.h b/examples/widgets/widgets/imageviewer/imageviewer.h
index f4a62cafe9..7e53105b33 100644
--- a/examples/widgets/widgets/imageviewer/imageviewer.h
+++ b/examples/widgets/widgets/imageviewer/imageviewer.h
@@ -71,7 +71,7 @@ class ImageViewer : public QMainWindow
     Q_OBJECT
 
 public:
-    ImageViewer();
+    ImageViewer(QWidget *parent = nullptr);
     bool loadFile(const QString &);
 
 private slots:
diff --git a/examples/widgets/widgets/lineedits/window.cpp b/examples/widgets/widgets/lineedits/window.cpp
index ffb1edc5ce..33f09d544d 100644
--- a/examples/widgets/widgets/lineedits/window.cpp
+++ b/examples/widgets/widgets/lineedits/window.cpp
@@ -53,7 +53,8 @@
 #include "window.h"
 
 //! [0]
-Window::Window()
+Window::Window(QWidget *parent)
+    : QWidget(parent)
 {
     QGroupBox *echoGroup = new QGroupBox(tr("Echo"));
 
@@ -122,16 +123,16 @@ Window::Window()
 //! [4]
 
 //! [5]
-    connect(echoComboBox, SIGNAL(activated(int)),
-            this, SLOT(echoChanged(int)));
-    connect(validatorComboBox, SIGNAL(activated(int)),
-            this, SLOT(validatorChanged(int)));
-    connect(alignmentComboBox, SIGNAL(activated(int)),
-            this, SLOT(alignmentChanged(int)));
-    connect(inputMaskComboBox, SIGNAL(activated(int)),
-            this, SLOT(inputMaskChanged(int)));
-    connect(accessComboBox, SIGNAL(activated(int)),
-            this, SLOT(accessChanged(int)));
+    connect(echoComboBox, QOverload<int>::of(&QComboBox::activated),
+            this, &Window::echoChanged);
+    connect(validatorComboBox, QOverload<int>::of(&QComboBox::activated),
+            this, &Window::validatorChanged);
+    connect(alignmentComboBox, QOverload<int>::of(&QComboBox::activated),
+            this, &Window::alignmentChanged);
+    connect(inputMaskComboBox, QOverload<int>::of(&QComboBox::activated),
+            this, &Window::inputMaskChanged);
+    connect(accessComboBox, QOverload<int>::of(&QComboBox::activated),
+            this, &Window::accessChanged);
 //! [5]
 
 //! [6]
@@ -205,7 +206,7 @@ void Window::validatorChanged(int index)
 {
     switch (index) {
     case 0:
-        validatorLineEdit->setValidator(0);
+        validatorLineEdit->setValidator(nullptr);
         break;
     case 1:
         validatorLineEdit->setValidator(new QIntValidator(
diff --git a/examples/widgets/widgets/lineedits/window.h b/examples/widgets/widgets/lineedits/window.h
index 2070b3b84c..a31634f3a3 100644
--- a/examples/widgets/widgets/lineedits/window.h
+++ b/examples/widgets/widgets/lineedits/window.h
@@ -54,7 +54,6 @@
 #include <QWidget>
 
 QT_BEGIN_NAMESPACE
-class QComboBox;
 class QLineEdit;
 QT_END_NAMESPACE
 
@@ -64,7 +63,7 @@ class Window : public QWidget
     Q_OBJECT
 
 public:
-    Window();
+    Window(QWidget *parent = nullptr);
 
 public slots:
     void echoChanged(int);
diff --git a/examples/widgets/widgets/mousebuttons/buttontester.h b/examples/widgets/widgets/mousebuttons/buttontester.h
index d99dcceb18..231733bd44 100644
--- a/examples/widgets/widgets/mousebuttons/buttontester.h
+++ b/examples/widgets/widgets/mousebuttons/buttontester.h
@@ -59,13 +59,14 @@
 class ButtonTester : public QTextEdit
 {
     Q_OBJECT
-
+public:
+    using QTextEdit::QTextEdit;
 protected:
     void    mousePressEvent(QMouseEvent *event) override;
     void    mouseReleaseEvent(QMouseEvent *event) override;
     void    mouseDoubleClickEvent(QMouseEvent *event) override;
 #if QT_CONFIG(wheelevent)
-    void    wheelEvent(QWheelEvent * event) override;
+    void    wheelEvent(QWheelEvent *event) override;
 #endif
     int     buttonByNumber(const Qt::MouseButton button);
     QString enumNameFromValue(const Qt::MouseButton button);
diff --git a/examples/widgets/widgets/mousebuttons/main.cpp b/examples/widgets/widgets/mousebuttons/main.cpp
index 28be0ffddf..e35a442181 100644
--- a/examples/widgets/widgets/mousebuttons/main.cpp
+++ b/examples/widgets/widgets/mousebuttons/main.cpp
@@ -68,7 +68,7 @@ int main(int argv, char **args)
     testArea->setText("To test your mouse with Qt, press buttons in this area.\nYou may also scroll or tilt your mouse wheel.");
     QPushButton *quitButton = new QPushButton("Quit");
 
-    QObject::connect(quitButton, SIGNAL(clicked()), qApp, SLOT(quit()));
+    QObject::connect(quitButton, &QPushButton::clicked, qApp, &QCoreApplication::quit);
 
     QVBoxLayout *layout = new QVBoxLayout;
     layout->addWidget(testArea);
diff --git a/examples/widgets/widgets/movie/movieplayer.cpp b/examples/widgets/widgets/movie/movieplayer.cpp
index 61e85537a3..182b258a82 100644
--- a/examples/widgets/widgets/movie/movieplayer.cpp
+++ b/examples/widgets/widgets/movie/movieplayer.cpp
@@ -48,10 +48,10 @@
 **
 ****************************************************************************/
 
-#include <QtWidgets>
-
 #include "movieplayer.h"
 
+#include <QtWidgets>
+
 MoviePlayer::MoviePlayer(QWidget *parent)
     : QWidget(parent)
 {
@@ -69,13 +69,12 @@ MoviePlayer::MoviePlayer(QWidget *parent)
     createControls();
     createButtons();
 
-    connect(movie, SIGNAL(frameChanged(int)), this, SLOT(updateFrameSlider()));
-    connect(movie, SIGNAL(stateChanged(QMovie::MovieState)),
-            this, SLOT(updateButtons()));
-    connect(fitCheckBox, SIGNAL(clicked()), this, SLOT(fitToWindow()));
-    connect(frameSlider, SIGNAL(valueChanged(int)), this, SLOT(goToFrame(int)));
-    connect(speedSpinBox, SIGNAL(valueChanged(int)),
-            movie, SLOT(setSpeed(int)));
+    connect(movie, &QMovie::frameChanged, this, &MoviePlayer::updateFrameSlider);
+    connect(movie, &QMovie::stateChanged, this, &MoviePlayer::updateButtons);
+    connect(fitCheckBox, &QCheckBox::clicked, this, &MoviePlayer::fitToWindow);
+    connect(frameSlider, &QSlider::valueChanged, this, &MoviePlayer::goToFrame);
+    connect(speedSpinBox, QOverload<int>::of(&QSpinBox::valueChanged),
+            movie, &QMovie::setSpeed);
 
     mainLayout = new QVBoxLayout;
     mainLayout->addWidget(movieLabel);
@@ -182,32 +181,32 @@ void MoviePlayer::createButtons()
     openButton->setIcon(style()->standardIcon(QStyle::SP_DialogOpenButton));
     openButton->setIconSize(iconSize);
     openButton->setToolTip(tr("Open File"));
-    connect(openButton, SIGNAL(clicked()), this, SLOT(open()));
+    connect(openButton, &QToolButton::clicked, this, &MoviePlayer::open);
 
     playButton = new QToolButton;
     playButton->setIcon(style()->standardIcon(QStyle::SP_MediaPlay));
     playButton->setIconSize(iconSize);
     playButton->setToolTip(tr("Play"));
-    connect(playButton, SIGNAL(clicked()), movie, SLOT(start()));
+    connect(playButton, &QToolButton::clicked, movie, &QMovie::start);
 
     pauseButton = new QToolButton;
     pauseButton->setCheckable(true);
     pauseButton->setIcon(style()->standardIcon(QStyle::SP_MediaPause));
     pauseButton->setIconSize(iconSize);
     pauseButton->setToolTip(tr("Pause"));
-    connect(pauseButton, SIGNAL(clicked(bool)), movie, SLOT(setPaused(bool)));
+    connect(pauseButton, &QToolButton::clicked, movie, &QMovie::setPaused);
 
     stopButton = new QToolButton;
     stopButton->setIcon(style()->standardIcon(QStyle::SP_MediaStop));
     stopButton->setIconSize(iconSize);
     stopButton->setToolTip(tr("Stop"));
-    connect(stopButton, SIGNAL(clicked()), movie, SLOT(stop()));
+    connect(stopButton, &QToolButton::clicked, movie, &QMovie::stop);
 
     quitButton = new QToolButton;
     quitButton->setIcon(style()->standardIcon(QStyle::SP_DialogCloseButton));
     quitButton->setIconSize(iconSize);
     quitButton->setToolTip(tr("Quit"));
-    connect(quitButton, SIGNAL(clicked()), this, SLOT(close()));
+    connect(quitButton, &QToolButton::clicked, this, &MoviePlayer::close);
 
     buttonsLayout = new QHBoxLayout;
     buttonsLayout->addStretch();
diff --git a/examples/widgets/widgets/movie/movieplayer.h b/examples/widgets/widgets/movie/movieplayer.h
index 9fa9604025..7d143bd37c 100644
--- a/examples/widgets/widgets/movie/movieplayer.h
+++ b/examples/widgets/widgets/movie/movieplayer.h
@@ -70,7 +70,7 @@ class MoviePlayer : public QWidget
     Q_OBJECT
 
 public:
-    MoviePlayer(QWidget *parent = 0);
+    MoviePlayer(QWidget *parent = nullptr);
     void openFile(const QString &fileName);
 
 private slots:
diff --git a/examples/widgets/widgets/scribble/mainwindow.cpp b/examples/widgets/widgets/scribble/mainwindow.cpp
index d54e5ce0f9..44afa64b94 100644
--- a/examples/widgets/widgets/scribble/mainwindow.cpp
+++ b/examples/widgets/widgets/scribble/mainwindow.cpp
@@ -54,9 +54,9 @@
 #include "scribblearea.h"
 
 //! [0]
-MainWindow::MainWindow()
+MainWindow::MainWindow(QWidget *parent)
+    : QMainWindow(parent), scribbleArea(new ScribbleArea(this))
 {
-    scribbleArea = new ScribbleArea;
     setCentralWidget(scribbleArea);
 
     createActions();
@@ -151,40 +151,41 @@ void MainWindow::createActions()
 {
     openAct = new QAction(tr("&Open..."), this);
     openAct->setShortcuts(QKeySequence::Open);
-    connect(openAct, SIGNAL(triggered()), this, SLOT(open()));
+    connect(openAct, &QAction::triggered, this, &MainWindow::open);
 
-    foreach (QByteArray format, QImageWriter::supportedImageFormats()) {
-        QString text = tr("%1...").arg(QString(format).toUpper());
+    const QList<QByteArray> imageFormats = QImageWriter::supportedImageFormats();
+    for (const QByteArray &format : imageFormats) {
+        QString text = tr("%1...").arg(QString::fromLatin1(format).toUpper());
 
         QAction *action = new QAction(text, this);
         action->setData(format);
-        connect(action, SIGNAL(triggered()), this, SLOT(save()));
+        connect(action, &QAction::triggered, this, &MainWindow::save);
         saveAsActs.append(action);
     }
 
     printAct = new QAction(tr("&Print..."), this);
-    connect(printAct, SIGNAL(triggered()), scribbleArea, SLOT(print()));
+    connect(printAct, &QAction::triggered, scribbleArea, &ScribbleArea::print);
 
     exitAct = new QAction(tr("E&xit"), this);
     exitAct->setShortcuts(QKeySequence::Quit);
-    connect(exitAct, SIGNAL(triggered()), this, SLOT(close()));
+    connect(exitAct, &QAction::triggered, this, &MainWindow::close);
 
     penColorAct = new QAction(tr("&Pen Color..."), this);
-    connect(penColorAct, SIGNAL(triggered()), this, SLOT(penColor()));
+    connect(penColorAct, &QAction::triggered, this, &MainWindow::penColor);
 
     penWidthAct = new QAction(tr("Pen &Width..."), this);
-    connect(penWidthAct, SIGNAL(triggered()), this, SLOT(penWidth()));
+    connect(penWidthAct, &QAction::triggered, this, &MainWindow::penWidth);
 
     clearScreenAct = new QAction(tr("&Clear Screen"), this);
     clearScreenAct->setShortcut(tr("Ctrl+L"));
-    connect(clearScreenAct, SIGNAL(triggered()),
-            scribbleArea, SLOT(clearImage()));
+    connect(clearScreenAct, &QAction::triggered,
+            scribbleArea, &ScribbleArea::clearImage);
 
     aboutAct = new QAction(tr("&About"), this);
-    connect(aboutAct, SIGNAL(triggered()), this, SLOT(about()));
+    connect(aboutAct, &QAction::triggered, this, &MainWindow::about);
 
     aboutQtAct = new QAction(tr("About &Qt"), this);
-    connect(aboutQtAct, SIGNAL(triggered()), qApp, SLOT(aboutQt()));
+    connect(aboutQtAct, &QAction::triggered, qApp, &QApplication::aboutQt);
 }
 //! [14]
 
@@ -193,7 +194,7 @@ void MainWindow::createMenus()
 //! [15] //! [16]
 {
     saveAsMenu = new QMenu(tr("&Save As"), this);
-    foreach (QAction *action, saveAsActs)
+    for (QAction *action : qAsConst(saveAsActs))
         saveAsMenu->addAction(action);
 
     fileMenu = new QMenu(tr("&File"), this);
diff --git a/examples/widgets/widgets/scribble/mainwindow.h b/examples/widgets/widgets/scribble/mainwindow.h
index 9e0ddaff71..e57ff065ac 100644
--- a/examples/widgets/widgets/scribble/mainwindow.h
+++ b/examples/widgets/widgets/scribble/mainwindow.h
@@ -62,7 +62,7 @@ class MainWindow : public QMainWindow
     Q_OBJECT
 
 public:
-    MainWindow();
+    MainWindow(QWidget *parent = nullptr);
 
 protected:
     void closeEvent(QCloseEvent *event) override;
diff --git a/examples/widgets/widgets/scribble/scribblearea.cpp b/examples/widgets/widgets/scribble/scribblearea.cpp
index d32a29697b..13e46f6e1d 100644
--- a/examples/widgets/widgets/scribble/scribblearea.cpp
+++ b/examples/widgets/widgets/scribble/scribblearea.cpp
@@ -48,6 +48,8 @@
 **
 ****************************************************************************/
 
+#include "scribblearea.h"
+
 #include <QtWidgets>
 #if defined(QT_PRINTSUPPORT_LIB)
 #include <QtPrintSupport/qtprintsupportglobal.h>
@@ -57,8 +59,6 @@
 #endif
 #endif
 
-#include "scribblearea.h"
-
 //! [0]
 ScribbleArea::ScribbleArea(QWidget *parent)
     : QWidget(parent)
diff --git a/examples/widgets/widgets/scribble/scribblearea.h b/examples/widgets/widgets/scribble/scribblearea.h
index 7729fb5b89..100c45e133 100644
--- a/examples/widgets/widgets/scribble/scribblearea.h
+++ b/examples/widgets/widgets/scribble/scribblearea.h
@@ -62,7 +62,7 @@ class ScribbleArea : public QWidget
     Q_OBJECT
 
 public:
-    ScribbleArea(QWidget *parent = 0);
+    ScribbleArea(QWidget *parent = nullptr);
 
     bool openImage(const QString &fileName);
     bool saveImage(const QString &fileName, const char *fileFormat);
diff --git a/examples/widgets/widgets/shapedclock/shapedclock.cpp b/examples/widgets/widgets/shapedclock/shapedclock.cpp
index af0cd01be5..8e7d831938 100644
--- a/examples/widgets/widgets/shapedclock/shapedclock.cpp
+++ b/examples/widgets/widgets/shapedclock/shapedclock.cpp
@@ -57,12 +57,12 @@ ShapedClock::ShapedClock(QWidget *parent)
     : QWidget(parent, Qt::FramelessWindowHint | Qt::WindowSystemMenuHint)
 {
     QTimer *timer = new QTimer(this);
-    connect(timer, SIGNAL(timeout()), this, SLOT(update()));
+    connect(timer, &QTimer::timeout, this, QOverload<>::of(&ShapedClock::update));
     timer->start(1000);
 
     QAction *quitAction = new QAction(tr("E&xit"), this);
     quitAction->setShortcut(tr("Ctrl+Q"));
-    connect(quitAction, SIGNAL(triggered()), qApp, SLOT(quit()));
+    connect(quitAction, &QAction::triggered, qApp, &QCoreApplication::quit);
     addAction(quitAction);
 
     setContextMenuPolicy(Qt::ActionsContextMenu);
diff --git a/examples/widgets/widgets/shapedclock/shapedclock.h b/examples/widgets/widgets/shapedclock/shapedclock.h
index 6468d21618..a854d956b3 100644
--- a/examples/widgets/widgets/shapedclock/shapedclock.h
+++ b/examples/widgets/widgets/shapedclock/shapedclock.h
@@ -59,7 +59,7 @@ class ShapedClock : public QWidget
     Q_OBJECT
 
 public:
-    ShapedClock(QWidget *parent = 0);
+    ShapedClock(QWidget *parent = nullptr);
     QSize sizeHint() const override;
 
 protected:
diff --git a/examples/widgets/widgets/sliders/slidersgroup.cpp b/examples/widgets/widgets/sliders/slidersgroup.cpp
index 365a003047..b4eaf9bb3d 100644
--- a/examples/widgets/widgets/sliders/slidersgroup.cpp
+++ b/examples/widgets/widgets/sliders/slidersgroup.cpp
@@ -48,10 +48,10 @@
 **
 ****************************************************************************/
 
-#include <QtWidgets>
-
 #include "slidersgroup.h"
 
+#include <QtWidgets>
+
 //! [0]
 SlidersGroup::SlidersGroup(Qt::Orientation orientation, const QString &title,
                            QWidget *parent)
@@ -69,11 +69,11 @@ SlidersGroup::SlidersGroup(Qt::Orientation orientation, const QString &title,
     dial = new QDial;
     dial->setFocusPolicy(Qt::StrongFocus);
 
-    connect(slider, SIGNAL(valueChanged(int)), scrollBar, SLOT(setValue(int)));
-    connect(scrollBar, SIGNAL(valueChanged(int)), dial, SLOT(setValue(int)));
-    connect(dial, SIGNAL(valueChanged(int)), slider, SLOT(setValue(int)));
+    connect(slider, &QSlider::valueChanged, scrollBar, &QScrollBar::setValue);
+    connect(scrollBar, &QScrollBar::valueChanged, dial, &QDial::setValue);
+    connect(dial, &QDial::valueChanged, slider, &QSlider::setValue);
 //! [0] //! [1]
-    connect(dial, SIGNAL(valueChanged(int)), this, SIGNAL(valueChanged(int)));
+    connect(dial, &QDial::valueChanged, this, &SlidersGroup::valueChanged);
 //! [1] //! [2]
 
 //! [2] //! [3]
diff --git a/examples/widgets/widgets/sliders/slidersgroup.h b/examples/widgets/widgets/sliders/slidersgroup.h
index 76dcbee0d8..7be8a3b4f8 100644
--- a/examples/widgets/widgets/sliders/slidersgroup.h
+++ b/examples/widgets/widgets/sliders/slidersgroup.h
@@ -66,7 +66,7 @@ class SlidersGroup : public QGroupBox
 
 public:
     SlidersGroup(Qt::Orientation orientation, const QString &title,
-                 QWidget *parent = 0);
+                 QWidget *parent = nullptr);
 
 signals:
     void valueChanged(int value);
diff --git a/examples/widgets/widgets/sliders/window.cpp b/examples/widgets/widgets/sliders/window.cpp
index 16b60dde49..d73fafec10 100644
--- a/examples/widgets/widgets/sliders/window.cpp
+++ b/examples/widgets/widgets/sliders/window.cpp
@@ -54,7 +54,8 @@
 #include "window.h"
 
 //! [0]
-Window::Window()
+Window::Window(QWidget *parent)
+    : QWidget(parent)
 {
     horizontalSliders = new SlidersGroup(Qt::Horizontal, tr("Horizontal"));
     verticalSliders = new SlidersGroup(Qt::Vertical, tr("Vertical"));
@@ -67,13 +68,13 @@ Window::Window()
 //! [0]
 
 //! [1]
-    connect(horizontalSliders, SIGNAL(valueChanged(int)),
+    connect(horizontalSliders, &SlidersGroup::valueChanged,
 //! [1] //! [2]
-            verticalSliders, SLOT(setValue(int)));
-    connect(verticalSliders, SIGNAL(valueChanged(int)),
-            valueSpinBox, SLOT(setValue(int)));
-    connect(valueSpinBox, SIGNAL(valueChanged(int)),
-            horizontalSliders, SLOT(setValue(int)));
+            verticalSliders, &SlidersGroup::setValue);
+    connect(verticalSliders, &SlidersGroup::valueChanged,
+            valueSpinBox, &QSpinBox::setValue);
+    connect(valueSpinBox, QOverload<int>::of(&QSpinBox::valueChanged),
+            horizontalSliders, &SlidersGroup::setValue);
 
     QHBoxLayout *layout = new QHBoxLayout;
     layout->addWidget(controlsGroup);
@@ -120,25 +121,25 @@ void Window::createControls(const QString &title)
     orientationCombo->addItem(tr("Vertical slider-like widgets"));
 
 //! [6] //! [7]
-    connect(orientationCombo, SIGNAL(activated(int)),
+    connect(orientationCombo, QOverload<int>::of(&QComboBox::activated),
 //! [7] //! [8]
-            stackedWidget, SLOT(setCurrentIndex(int)));
-    connect(minimumSpinBox, SIGNAL(valueChanged(int)),
-            horizontalSliders, SLOT(setMinimum(int)));
-    connect(minimumSpinBox, SIGNAL(valueChanged(int)),
-            verticalSliders, SLOT(setMinimum(int)));
-    connect(maximumSpinBox, SIGNAL(valueChanged(int)),
-            horizontalSliders, SLOT(setMaximum(int)));
-    connect(maximumSpinBox, SIGNAL(valueChanged(int)),
-            verticalSliders, SLOT(setMaximum(int)));
-    connect(invertedAppearance, SIGNAL(toggled(bool)),
-            horizontalSliders, SLOT(invertAppearance(bool)));
-    connect(invertedAppearance, SIGNAL(toggled(bool)),
-            verticalSliders, SLOT(invertAppearance(bool)));
-    connect(invertedKeyBindings, SIGNAL(toggled(bool)),
-            horizontalSliders, SLOT(invertKeyBindings(bool)));
-    connect(invertedKeyBindings, SIGNAL(toggled(bool)),
-            verticalSliders, SLOT(invertKeyBindings(bool)));
+            stackedWidget, &QStackedWidget::setCurrentIndex);
+    connect(minimumSpinBox, QOverload<int>::of(&QSpinBox::valueChanged),
+            horizontalSliders, &SlidersGroup::setMinimum);
+    connect(minimumSpinBox, QOverload<int>::of(&QSpinBox::valueChanged),
+            verticalSliders, &SlidersGroup::setMinimum);
+    connect(maximumSpinBox, QOverload<int>::of(&QSpinBox::valueChanged),
+            horizontalSliders, &SlidersGroup::setMaximum);
+    connect(maximumSpinBox, QOverload<int>::of(&QSpinBox::valueChanged),
+            verticalSliders, &SlidersGroup::setMaximum);
+    connect(invertedAppearance, &QCheckBox::toggled,
+            horizontalSliders, &SlidersGroup::invertAppearance);
+    connect(invertedAppearance, &QCheckBox::toggled,
+            verticalSliders, &SlidersGroup::invertAppearance);
+    connect(invertedKeyBindings, &QCheckBox::toggled,
+            horizontalSliders, &SlidersGroup::invertKeyBindings);
+    connect(invertedKeyBindings, &QCheckBox::toggled,
+            verticalSliders, &SlidersGroup::invertKeyBindings);
 
     QGridLayout *controlsLayout = new QGridLayout;
     controlsLayout->addWidget(minimumLabel, 0, 0);
diff --git a/examples/widgets/widgets/sliders/window.h b/examples/widgets/widgets/sliders/window.h
index 9c4c14fa37..4894781ac2 100644
--- a/examples/widgets/widgets/sliders/window.h
+++ b/examples/widgets/widgets/sliders/window.h
@@ -69,7 +69,7 @@ class Window : public QWidget
     Q_OBJECT
 
 public:
-    Window();
+    Window(QWidget *parent = nullptr);
 
 private:
     void createControls(const QString &title);
diff --git a/examples/widgets/widgets/spinboxes/window.cpp b/examples/widgets/widgets/spinboxes/window.cpp
index 54604e35aa..82e19527a7 100644
--- a/examples/widgets/widgets/spinboxes/window.cpp
+++ b/examples/widgets/widgets/spinboxes/window.cpp
@@ -53,7 +53,8 @@
 #include "window.h"
 
 //! [0]
-Window::Window()
+Window::Window(QWidget *parent)
+    : QWidget(parent)
 {
     createSpinBoxes();
     createDateTimeEdits();
@@ -175,8 +176,8 @@ void Window::createDateTimeEdits()
     formatComboBox->addItem("hh:mm ap");
 //! [9] //! [10]
 
-    connect(formatComboBox, SIGNAL(activated(QString)),
-            this, SLOT(setFormatString(QString)));
+    connect(formatComboBox, &QComboBox::textActivated,
+            this, &Window::setFormatString);
 //! [10]
 
     setFormatString(formatComboBox->currentText());
@@ -255,9 +256,9 @@ void Window::createDoubleSpinBoxes()
     priceSpinBox->setPrefix("$");
     priceSpinBox->setValue(99.99);
 
-    connect(precisionSpinBox, SIGNAL(valueChanged(int)),
+    connect(precisionSpinBox, QOverload<int>::of(&QSpinBox::valueChanged),
 //! [17]
-            this, SLOT(changePrecision(int)));
+            this, &Window::changePrecision);
 
     groupSeparatorSpinBox_d = new QDoubleSpinBox;
     groupSeparatorSpinBox_d->setRange(-99999999, 99999999);
diff --git a/examples/widgets/widgets/spinboxes/window.h b/examples/widgets/widgets/spinboxes/window.h
index 97e9ac1083..138773a5aa 100644
--- a/examples/widgets/widgets/spinboxes/window.h
+++ b/examples/widgets/widgets/spinboxes/window.h
@@ -67,7 +67,7 @@ class Window : public QWidget
     Q_OBJECT
 
 public:
-    Window();
+    Window(QWidget *parent = nullptr);
 
 public slots:
     void changePrecision(int decimals);
diff --git a/examples/widgets/widgets/styles/norwegianwoodstyle.cpp b/examples/widgets/widgets/styles/norwegianwoodstyle.cpp
index 8aca91a686..1d7ef2637b 100644
--- a/examples/widgets/widgets/styles/norwegianwoodstyle.cpp
+++ b/examples/widgets/widgets/styles/norwegianwoodstyle.cpp
@@ -48,10 +48,10 @@
 **
 ****************************************************************************/
 
-#include <QtWidgets>
-
 #include "norwegianwoodstyle.h"
 
+#include <QtWidgets>
+
 NorwegianWoodStyle::NorwegianWoodStyle() :
     QProxyStyle(QStyleFactory::create("windows"))
 {
@@ -85,8 +85,8 @@ void NorwegianWoodStyle::polish(QPalette &palette)
     setTexture(palette, QPalette::Mid, midImage);
     setTexture(palette, QPalette::Window, backgroundImage);
 
-    QBrush brush = palette.background();
-    brush.setColor(brush.color().dark());
+    QBrush brush = palette.window();
+    brush.setColor(brush.color().darker());
 
     palette.setBrush(QPalette::Disabled, QPalette::WindowText, brush);
     palette.setBrush(QPalette::Disabled, QPalette::Text, brush);
@@ -185,7 +185,7 @@ void NorwegianWoodStyle::drawPrimitive(PrimitiveElement element,
                     qstyleoption_cast<const QStyleOptionButton *>(option);
             if (buttonOption
                     && (buttonOption->features & QStyleOptionButton::Flat)) {
-                brush = option->palette.background();
+                brush = option->palette.window();
                 darker = (option->state & (State_Sunken | State_On));
             } else {
                 if (option->state & (State_Sunken | State_On)) {
@@ -261,7 +261,7 @@ void NorwegianWoodStyle::drawPrimitive(PrimitiveElement element,
             painter->setPen(bottomPen);
             painter->drawPath(roundRect);
 
-            painter->setPen(option->palette.foreground().color());
+            painter->setPen(option->palette.windowText().color());
             painter->setClipping(false);
             painter->drawPath(roundRect);
 
diff --git a/examples/widgets/widgets/styles/widgetgallery.cpp b/examples/widgets/widgets/styles/widgetgallery.cpp
index d44547d905..34c010df74 100644
--- a/examples/widgets/widgets/styles/widgetgallery.cpp
+++ b/examples/widgets/widgets/styles/widgetgallery.cpp
@@ -48,10 +48,10 @@
 **
 ****************************************************************************/
 
-#include <QtWidgets>
-
-#include "norwegianwoodstyle.h"
 #include "widgetgallery.h"
+#include "norwegianwoodstyle.h"
+
+#include <QtWidgets>
 
 //! [0]
 WidgetGallery::WidgetGallery(QWidget *parent)
@@ -79,19 +79,19 @@ WidgetGallery::WidgetGallery(QWidget *parent)
 //! [0]
 
 //! [1]
-    connect(styleComboBox, SIGNAL(activated(QString)),
+    connect(styleComboBox, &QComboBox::textActivated,
 //! [1] //! [2]
-            this, SLOT(changeStyle(QString)));
-    connect(useStylePaletteCheckBox, SIGNAL(toggled(bool)),
-            this, SLOT(changePalette()));
-    connect(disableWidgetsCheckBox, SIGNAL(toggled(bool)),
-            topLeftGroupBox, SLOT(setDisabled(bool)));
-    connect(disableWidgetsCheckBox, SIGNAL(toggled(bool)),
-            topRightGroupBox, SLOT(setDisabled(bool)));
-    connect(disableWidgetsCheckBox, SIGNAL(toggled(bool)),
-            bottomLeftTabWidget, SLOT(setDisabled(bool)));
-    connect(disableWidgetsCheckBox, SIGNAL(toggled(bool)),
-            bottomRightGroupBox, SLOT(setDisabled(bool)));
+            this, &WidgetGallery::changeStyle);
+    connect(useStylePaletteCheckBox, &QCheckBox::toggled,
+            this, &WidgetGallery::changePalette);
+    connect(disableWidgetsCheckBox, &QCheckBox::toggled,
+            topLeftGroupBox, &QGroupBox::setDisabled);
+    connect(disableWidgetsCheckBox, &QCheckBox::toggled,
+            topRightGroupBox, &QGroupBox::setDisabled);
+    connect(disableWidgetsCheckBox, &QCheckBox::toggled,
+            bottomLeftTabWidget, &QGroupBox::setDisabled);
+    connect(disableWidgetsCheckBox, &QCheckBox::toggled,
+            bottomRightGroupBox, &QGroupBox::setDisabled);
 //! [2]
 
 //! [3]
@@ -212,7 +212,7 @@ void WidgetGallery::createBottomLeftTabWidget()
     tableWidget = new QTableWidget(10, 10);
 
     QHBoxLayout *tab1hbox = new QHBoxLayout;
-    tab1hbox->setMargin(5);
+    tab1hbox->setContentsMargins(5,5, 5, 5);
     tab1hbox->addWidget(tableWidget);
     tab1->setLayout(tab1hbox);
 
@@ -227,7 +227,7 @@ void WidgetGallery::createBottomLeftTabWidget()
                               "How I wonder what you are!\n"));
 
     QHBoxLayout *tab2hbox = new QHBoxLayout;
-    tab2hbox->setMargin(5);
+    tab2hbox->setContentsMargins(5, 5, 5, 5);
     tab2hbox->addWidget(textEdit);
     tab2->setLayout(tab2hbox);
 
@@ -279,7 +279,7 @@ void WidgetGallery::createProgressBar()
     progressBar->setValue(0);
 
     QTimer *timer = new QTimer(this);
-    connect(timer, SIGNAL(timeout()), this, SLOT(advanceProgressBar()));
+    connect(timer, &QTimer::timeout, this, &WidgetGallery::advanceProgressBar);
     timer->start(1000);
 }
 //! [13]
diff --git a/examples/widgets/widgets/styles/widgetgallery.h b/examples/widgets/widgets/styles/widgetgallery.h
index ec6edff536..9ee65c21c4 100644
--- a/examples/widgets/widgets/styles/widgetgallery.h
+++ b/examples/widgets/widgets/styles/widgetgallery.h
@@ -78,7 +78,7 @@ class WidgetGallery : public QDialog
     Q_OBJECT
 
 public:
-    WidgetGallery(QWidget *parent = 0);
+    WidgetGallery(QWidget *parent = nullptr);
 
 private slots:
     void changeStyle(const QString &styleName);
diff --git a/examples/widgets/widgets/stylesheet/mainwindow.cpp b/examples/widgets/widgets/stylesheet/mainwindow.cpp
index 9acd90658a..f187c007dd 100644
--- a/examples/widgets/widgets/stylesheet/mainwindow.cpp
+++ b/examples/widgets/widgets/stylesheet/mainwindow.cpp
@@ -53,7 +53,8 @@
 #include "mainwindow.h"
 #include "stylesheeteditor.h"
 
-MainWindow::MainWindow()
+MainWindow::MainWindow(QWidget *parent)
+    : QMainWindow(parent)
 {
     ui.setupUi(this);
 
@@ -63,8 +64,8 @@ MainWindow::MainWindow()
 
     statusBar()->addWidget(new QLabel(tr("Ready")));
 
-    connect(ui.exitAction, SIGNAL(triggered()), qApp, SLOT(quit()));
-    connect(ui.aboutQtAction, SIGNAL(triggered()), qApp, SLOT(aboutQt()));
+    connect(ui.exitAction, &QAction::triggered, qApp, &QApplication::quit);
+    connect(ui.aboutQtAction, &QAction::triggered, qApp, &QApplication::aboutQt);
 }
 
 void MainWindow::on_editStyleAction_triggered()
diff --git a/examples/widgets/widgets/stylesheet/mainwindow.h b/examples/widgets/widgets/stylesheet/mainwindow.h
index 46d3ecbb93..8af4c01da0 100644
--- a/examples/widgets/widgets/stylesheet/mainwindow.h
+++ b/examples/widgets/widgets/stylesheet/mainwindow.h
@@ -62,7 +62,7 @@ class MainWindow : public QMainWindow
     Q_OBJECT
 
 public:
-    MainWindow();
+    MainWindow(QWidget *parent = nullptr);
 
 private slots:
     void on_editStyleAction_triggered();
diff --git a/examples/widgets/widgets/stylesheet/stylesheeteditor.cpp b/examples/widgets/widgets/stylesheet/stylesheeteditor.cpp
index 3247fa774d..0874cc3554 100644
--- a/examples/widgets/widgets/stylesheet/stylesheeteditor.cpp
+++ b/examples/widgets/widgets/stylesheet/stylesheeteditor.cpp
@@ -48,10 +48,10 @@
 **
 ****************************************************************************/
 
-#include <QtWidgets>
-
 #include "stylesheeteditor.h"
 
+#include <QtWidgets>
+
 StyleSheetEditor::StyleSheetEditor(QWidget *parent)
     : QDialog(parent)
 {
diff --git a/examples/widgets/widgets/stylesheet/stylesheeteditor.h b/examples/widgets/widgets/stylesheet/stylesheeteditor.h
index 65a3018adb..f51af7877c 100644
--- a/examples/widgets/widgets/stylesheet/stylesheeteditor.h
+++ b/examples/widgets/widgets/stylesheet/stylesheeteditor.h
@@ -60,7 +60,7 @@ class StyleSheetEditor : public QDialog
     Q_OBJECT
 
 public:
-    StyleSheetEditor(QWidget *parent = 0);
+    StyleSheetEditor(QWidget *parent = nullptr);
 
 private slots:
     void on_styleCombo_activated(const QString &styleName);
diff --git a/examples/widgets/widgets/tablet/tabletapplication.cpp b/examples/widgets/widgets/tablet/tabletapplication.cpp
index 2e5ac07c95..37be018276 100644
--- a/examples/widgets/widgets/tablet/tabletapplication.cpp
+++ b/examples/widgets/widgets/tablet/tabletapplication.cpp
@@ -48,10 +48,10 @@
 **
 ****************************************************************************/
 
-#include <QtWidgets>
-
 #include "tabletapplication.h"
 
+#include <QtWidgets>
+
 //! [0]
 bool TabletApplication::event(QEvent *event)
 {
diff --git a/examples/widgets/widgets/tablet/tabletapplication.h b/examples/widgets/widgets/tablet/tabletapplication.h
index 6b3b2a1730..9b4a4f1886 100644
--- a/examples/widgets/widgets/tablet/tabletapplication.h
+++ b/examples/widgets/widgets/tablet/tabletapplication.h
@@ -61,15 +61,14 @@ class TabletApplication : public QApplication
     Q_OBJECT
 
 public:
-    TabletApplication(int &argv, char **args)
-    : QApplication(argv, args) {}
+    using QApplication::QApplication;
 
     bool event(QEvent *event) override;
     void setCanvas(TabletCanvas *canvas)
         { m_canvas = canvas; }
 
 private:
-    TabletCanvas *m_canvas;
+    TabletCanvas *m_canvas = nullptr;
 };
 //! [0]
 
diff --git a/examples/widgets/widgets/tablet/tabletcanvas.cpp b/examples/widgets/widgets/tablet/tabletcanvas.cpp
index bfcc84e182..dc56702142 100644
--- a/examples/widgets/widgets/tablet/tabletcanvas.cpp
+++ b/examples/widgets/widgets/tablet/tabletcanvas.cpp
@@ -224,7 +224,7 @@ void TabletCanvas::paintPixmap(QPainter &painter, QTabletEvent *event)
                 qWarning() << error;
 #endif
             }
-            // FALL-THROUGH
+            Q_FALLTHROUGH();
         case QTabletEvent::Stylus:
             painter.setPen(m_pen);
             painter.drawLine(lastPoint.pos, event->posF());
diff --git a/examples/widgets/widgets/tetrix/main.cpp b/examples/widgets/widgets/tetrix/main.cpp
index 2698190e76..92f245ca14 100644
--- a/examples/widgets/widgets/tetrix/main.cpp
+++ b/examples/widgets/widgets/tetrix/main.cpp
@@ -48,12 +48,10 @@
 **
 ****************************************************************************/
 
-#include <QtWidgets>
-
-#include <stdlib.h>
-
 #include "tetrixwindow.h"
 
+#include <QApplication>
+
 int main(int argc, char *argv[])
 {
     QApplication app(argc, argv);
diff --git a/examples/widgets/widgets/tetrix/tetrixboard.cpp b/examples/widgets/widgets/tetrix/tetrixboard.cpp
index 222ab1fb4d..ef3ac4fc38 100644
--- a/examples/widgets/widgets/tetrix/tetrixboard.cpp
+++ b/examples/widgets/widgets/tetrix/tetrixboard.cpp
@@ -48,10 +48,10 @@
 **
 ****************************************************************************/
 
-#include <QtWidgets>
-
 #include "tetrixboard.h"
 
+#include <QtWidgets>
+
 //! [0]
 TetrixBoard::TetrixBoard(QWidget *parent)
     : QFrame(parent)
@@ -358,7 +358,7 @@ void TetrixBoard::showNextPiece()
 
     QPixmap pixmap(dx * squareWidth(), dy * squareHeight());
     QPainter painter(&pixmap);
-    painter.fillRect(pixmap.rect(), nextPieceLabel->palette().background());
+    painter.fillRect(pixmap.rect(), nextPieceLabel->palette().window());
 
     for (int i = 0; i < 4; ++i) {
         int x = nextPiece.x(i) - nextPiece.minX();
@@ -405,11 +405,11 @@ void TetrixBoard::drawSquare(QPainter &painter, int x, int y, TetrixShape shape)
     painter.fillRect(x + 1, y + 1, squareWidth() - 2, squareHeight() - 2,
                      color);
 
-    painter.setPen(color.light());
+    painter.setPen(color.lighter());
     painter.drawLine(x, y + squareHeight() - 1, x, y);
     painter.drawLine(x, y, x + squareWidth() - 1, y);
 
-    painter.setPen(color.dark());
+    painter.setPen(color.darker());
     painter.drawLine(x + 1, y + squareHeight() - 1,
                      x + squareWidth() - 1, y + squareHeight() - 1);
     painter.drawLine(x + squareWidth() - 1, y + squareHeight() - 1,
diff --git a/examples/widgets/widgets/tetrix/tetrixboard.h b/examples/widgets/widgets/tetrix/tetrixboard.h
index 7c6871dfbd..86bcfa4d6e 100644
--- a/examples/widgets/widgets/tetrix/tetrixboard.h
+++ b/examples/widgets/widgets/tetrix/tetrixboard.h
@@ -67,7 +67,7 @@ class TetrixBoard : public QFrame
     Q_OBJECT
 
 public:
-    TetrixBoard(QWidget *parent = 0);
+    TetrixBoard(QWidget *parent = nullptr);
 
     void setNextPieceLabel(QLabel *label);
     QSize sizeHint() const override;
diff --git a/examples/widgets/widgets/tetrix/tetrixpiece.cpp b/examples/widgets/widgets/tetrix/tetrixpiece.cpp
index 3d8fa86860..b1b3ca9a99 100644
--- a/examples/widgets/widgets/tetrix/tetrixpiece.cpp
+++ b/examples/widgets/widgets/tetrix/tetrixpiece.cpp
@@ -48,12 +48,10 @@
 **
 ****************************************************************************/
 
-#include <QtCore>
-
-#include <stdlib.h>
-
 #include "tetrixpiece.h"
 
+#include <QtCore>
+
 //! [0]
 void TetrixPiece::setRandomShape()
 {
diff --git a/examples/widgets/widgets/tetrix/tetrixwindow.cpp b/examples/widgets/widgets/tetrix/tetrixwindow.cpp
index 7e951aceb8..970a38c1dc 100644
--- a/examples/widgets/widgets/tetrix/tetrixwindow.cpp
+++ b/examples/widgets/widgets/tetrix/tetrixwindow.cpp
@@ -54,7 +54,8 @@
 #include "tetrixwindow.h"
 
 //! [0]
-TetrixWindow::TetrixWindow()
+TetrixWindow::TetrixWindow(QWidget *parent)
+    : QWidget(parent)
 {
     board = new TetrixBoard;
 //! [0]
diff --git a/examples/widgets/widgets/tetrix/tetrixwindow.h b/examples/widgets/widgets/tetrix/tetrixwindow.h
index a21cef2ecf..3743d6cd2a 100644
--- a/examples/widgets/widgets/tetrix/tetrixwindow.h
+++ b/examples/widgets/widgets/tetrix/tetrixwindow.h
@@ -51,7 +51,6 @@
 #ifndef TETRIXWINDOW_H
 #define TETRIXWINDOW_H
 
-#include <QFrame>
 #include <QWidget>
 
 QT_BEGIN_NAMESPACE
@@ -67,7 +66,7 @@ class TetrixWindow : public QWidget
     Q_OBJECT
 
 public:
-    TetrixWindow();
+    TetrixWindow(QWidget *parent = nullptr);
 
 private:
     QLabel *createLabel(const QString &text);
diff --git a/examples/widgets/widgets/tooltips/shapeitem.cpp b/examples/widgets/widgets/tooltips/shapeitem.cpp
index 70c1cc03dc..68cc744b84 100644
--- a/examples/widgets/widgets/tooltips/shapeitem.cpp
+++ b/examples/widgets/widgets/tooltips/shapeitem.cpp
@@ -48,8 +48,6 @@
 **
 ****************************************************************************/
 
-#include <QtWidgets>
-
 #include "shapeitem.h"
 
 //! [0]
diff --git a/examples/widgets/widgets/tooltips/sortingbox.cpp b/examples/widgets/widgets/tooltips/sortingbox.cpp
index 4769a30c64..685eaa7d1d 100644
--- a/examples/widgets/widgets/tooltips/sortingbox.cpp
+++ b/examples/widgets/widgets/tooltips/sortingbox.cpp
@@ -48,14 +48,13 @@
 **
 ****************************************************************************/
 
-#include <QtWidgets>
-
-#include <stdlib.h>
-
 #include "sortingbox.h"
 
+#include <QtWidgets>
+
 //! [0]
-SortingBox::SortingBox()
+SortingBox::SortingBox(QWidget *parent)
+    : QWidget(parent)
 {
 //! [0] //! [1]
     setMouseTracking(true);
@@ -63,7 +62,7 @@ SortingBox::SortingBox()
     setBackgroundRole(QPalette::Base);
 //! [2]
 
-    itemInMotion = 0;
+    itemInMotion = nullptr;
 
 //! [3]
     newCircleButton = createToolButton(tr("New Circle"),
@@ -139,7 +138,7 @@ void SortingBox::paintEvent(QPaintEvent * /* event */)
 {
     QPainter painter(this);
     painter.setRenderHint(QPainter::Antialiasing);
-    foreach (ShapeItem shapeItem, shapeItems) {
+    for (const ShapeItem &shapeItem : qAsConst(shapeItems)) {
 //! [8] //! [9]
         painter.translate(shapeItem.position());
 //! [9] //! [10]
@@ -178,7 +177,7 @@ void SortingBox::mouseReleaseEvent(QMouseEvent *event)
 {
     if (event->button() == Qt::LeftButton && itemInMotion) {
         moveItemTo(event->pos());
-        itemInMotion = 0;
+        itemInMotion = nullptr;
     }
 }
 //! [13]
diff --git a/examples/widgets/widgets/tooltips/sortingbox.h b/examples/widgets/widgets/tooltips/sortingbox.h
index 2ac27614a5..3d0cecea2b 100644
--- a/examples/widgets/widgets/tooltips/sortingbox.h
+++ b/examples/widgets/widgets/tooltips/sortingbox.h
@@ -51,10 +51,10 @@
 #ifndef SORTINGBOX_H
 #define SORTINGBOX_H
 
-#include <QWidget>
-
 #include "shapeitem.h"
 
+#include <QWidget>
+
 QT_BEGIN_NAMESPACE
 class QAction;
 class QPoint;
@@ -67,7 +67,7 @@ class SortingBox : public QWidget
     Q_OBJECT
 
 public:
-    SortingBox();
+    SortingBox(QWidget *parent = nullptr);
 
 protected:
     bool event(QEvent *event) override;
diff --git a/examples/widgets/widgets/validators/CMakeLists.txt b/examples/widgets/widgets/validators/CMakeLists.txt
index a1770d5337..9da1da775e 100644
--- a/examples/widgets/widgets/validators/CMakeLists.txt
+++ b/examples/widgets/widgets/validators/CMakeLists.txt
@@ -13,7 +13,8 @@ add_qt_executable(validators
         localeselector.cpp localeselector.h
         main.cpp
         validators.ui
-    LIBRARIES
+        validatorwidget.cpp validatorwidget.h
+    PUBLIC_LIBRARIES
         Qt::Widgets
 )
 
diff --git a/examples/widgets/widgets/validators/ledwidget.cpp b/examples/widgets/widgets/validators/ledwidget.cpp
index 65248741b5..462f416c86 100644
--- a/examples/widgets/widgets/validators/ledwidget.cpp
+++ b/examples/widgets/widgets/validators/ledwidget.cpp
@@ -56,7 +56,7 @@ LEDWidget::LEDWidget(QWidget *parent)
     setPixmap(offPixmap);
     flashTimer.setInterval(200);
     flashTimer.setSingleShot(true);
-    connect(&flashTimer, SIGNAL(timeout()), this, SLOT(extinguish()));
+    connect(&flashTimer, &QTimer::timeout, this, &LEDWidget::extinguish);
 };
 
 void LEDWidget::extinguish()
diff --git a/examples/widgets/widgets/validators/ledwidget.h b/examples/widgets/widgets/validators/ledwidget.h
index dcbfb176c2..c4b406db23 100644
--- a/examples/widgets/widgets/validators/ledwidget.h
+++ b/examples/widgets/widgets/validators/ledwidget.h
@@ -59,7 +59,7 @@ class LEDWidget : public QLabel
 {
     Q_OBJECT
 public:
-    LEDWidget(QWidget *parent = 0);
+    LEDWidget(QWidget *parent = nullptr);
 public slots:
     void flash();
 
diff --git a/examples/widgets/widgets/validators/localeselector.cpp b/examples/widgets/widgets/validators/localeselector.cpp
index 2f702c9753..1382da0cc9 100644
--- a/examples/widgets/widgets/validators/localeselector.cpp
+++ b/examples/widgets/widgets/validators/localeselector.cpp
@@ -59,7 +59,9 @@ LocaleSelector::LocaleSelector(QWidget *parent)
     int index = 0;
     for (int _lang = QLocale::C; _lang <= QLocale::LastLanguage; ++_lang) {
         QLocale::Language lang = static_cast<QLocale::Language>(_lang);
-        foreach (const QLocale &l, QLocale::matchingLocales(lang, QLocale::AnyScript, QLocale::AnyCountry)) {
+        const QList<QLocale> locales =
+                QLocale::matchingLocales(lang, QLocale::AnyScript, QLocale::AnyCountry);
+        for (const QLocale &l : locales) {
             QString label = QLocale::languageToString(l.language());
             label += QLatin1Char('/');
             label += QLocale::countryToString(l.country());
@@ -79,7 +81,8 @@ LocaleSelector::LocaleSelector(QWidget *parent)
     if (curIndex != -1)
         setCurrentIndex(curIndex);
 
-    connect(this, SIGNAL(activated(int)), this, SLOT(emitLocaleSelected(int)));
+    connect(this, QOverload<int>::of(&LocaleSelector::activated),
+            this, &LocaleSelector::emitLocaleSelected);
 }
 
 void LocaleSelector::emitLocaleSelected(int index)
diff --git a/examples/widgets/widgets/validators/localeselector.h b/examples/widgets/widgets/validators/localeselector.h
index 05290eae81..611e2da66e 100644
--- a/examples/widgets/widgets/validators/localeselector.h
+++ b/examples/widgets/widgets/validators/localeselector.h
@@ -58,7 +58,7 @@ class LocaleSelector : public QComboBox
     Q_OBJECT
 
 public:
-    LocaleSelector(QWidget *parent = 0);
+    LocaleSelector(QWidget *parent = nullptr);
 
 signals:
     void localeSelected(const QLocale &locale);
diff --git a/examples/widgets/widgets/validators/main.cpp b/examples/widgets/widgets/validators/main.cpp
index d8ba2943d0..1fbf12410d 100644
--- a/examples/widgets/widgets/validators/main.cpp
+++ b/examples/widgets/widgets/validators/main.cpp
@@ -48,88 +48,9 @@
 **
 ****************************************************************************/
 
-#include <qdebug.h>
-#include <QApplication>
-#include <QLineEdit>
-#include <QValidator>
-
-#include "ui_validators.h"
-
-class ValidatorWidget : public QWidget, public Ui::ValidatorsForm
-{
-    Q_OBJECT
-public:
-    ValidatorWidget(QWidget *parent = 0);
-
-private slots:
-    void updateValidator();
-    void updateDoubleValidator();
-    void _setLocale(const QLocale &l) { setLocale(l); updateValidator(); updateDoubleValidator(); }
-
-private:
-    QIntValidator *validator;
-    QDoubleValidator *doubleValidator;
-};
-
-ValidatorWidget::ValidatorWidget(QWidget *parent)
-    : QWidget(parent)
-{
-    setupUi(this);
-
-    connect(localeSelector, SIGNAL(localeSelected(QLocale)), this, SLOT(_setLocale(QLocale)));
-
-    connect(minVal, SIGNAL(editingFinished()), this, SLOT(updateValidator()));
-    connect(maxVal, SIGNAL(editingFinished()), this, SLOT(updateValidator()));
-    connect(editor, SIGNAL(editingFinished()), ledWidget, SLOT(flash()));
-
-    connect(doubleMaxVal, SIGNAL(editingFinished()), this, SLOT(updateDoubleValidator()));
-    connect(doubleMinVal, SIGNAL(editingFinished()), this, SLOT(updateDoubleValidator()));
-    connect(doubleDecimals, SIGNAL(valueChanged(int)), this, SLOT(updateDoubleValidator()));
-    connect(doubleFormat, SIGNAL(activated(int)), this, SLOT(updateDoubleValidator()));
-    connect(doubleEditor, SIGNAL(editingFinished()), doubleLedWidget, SLOT(flash()));
+#include "validatorwidget.h"
 
-    validator = 0;
-    doubleValidator = 0;
-    updateValidator();
-    updateDoubleValidator();
-};
-
-void ValidatorWidget::updateValidator()
-{
-    QIntValidator *v = new QIntValidator(minVal->value(), maxVal->value(), this);
-    v->setLocale(locale());
-    editor->setValidator(v);
-    delete validator;
-    validator = v;
-
-    QString s = editor->text();
-    int i = 0;
-    if (validator->validate(s, i) == QValidator::Invalid) {
-        editor->clear();
-    } else {
-        editor->setText(s);
-    }
-}
-
-void ValidatorWidget::updateDoubleValidator()
-{
-    QDoubleValidator *v
-        = new QDoubleValidator(doubleMinVal->value(), doubleMaxVal->value(),
-                                doubleDecimals->value(), this);
-    v->setNotation(static_cast<QDoubleValidator::Notation>(doubleFormat->currentIndex()));
-    v->setLocale(locale());
-    doubleEditor->setValidator(v);
-    delete doubleValidator;
-    doubleValidator = v;
-
-    QString s = doubleEditor->text();
-    int i = 0;
-    if (doubleValidator->validate(s, i) == QValidator::Invalid) {
-        doubleEditor->clear();
-    } else {
-        doubleEditor->setText(s);
-    }
-}
+#include <QApplication>
 
 int main(int argc, char **argv)
 {
@@ -142,5 +63,3 @@ int main(int argc, char **argv)
 
     return app.exec();
 }
-
-#include "main.moc"
diff --git a/examples/widgets/widgets/validators/validators.pro b/examples/widgets/widgets/validators/validators.pro
index ab1eb7809b..029cf95aca 100644
--- a/examples/widgets/widgets/validators/validators.pro
+++ b/examples/widgets/widgets/validators/validators.pro
@@ -4,8 +4,8 @@ requires(qtConfig(combobox))
 FORMS += validators.ui
 RESOURCES += validators.qrc
 
-SOURCES += main.cpp ledwidget.cpp localeselector.cpp
-HEADERS += ledwidget.h localeselector.h
+SOURCES += main.cpp ledwidget.cpp localeselector.cpp validatorwidget.cpp
+HEADERS += ledwidget.h localeselector.h validatorwidget.h
 
 # install
 target.path = $$[QT_INSTALL_EXAMPLES]/widgets/widgets/validators
diff --git a/examples/widgets/widgets/validators/validatorwidget.cpp b/examples/widgets/widgets/validators/validatorwidget.cpp
new file mode 100644
index 0000000000..fa0a55aa52
--- /dev/null
+++ b/examples/widgets/widgets/validators/validatorwidget.cpp
@@ -0,0 +1,122 @@
+/****************************************************************************
+**
+** Copyright (C) 2018 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the examples of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:BSD$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** BSD License Usage
+** Alternatively, you may use this file under the terms of the BSD license
+** as follows:
+**
+** "Redistribution and use in source and binary forms, with or without
+** modification, are permitted provided that the following conditions are
+** met:
+**   * Redistributions of source code must retain the above copyright
+**     notice, this list of conditions and the following disclaimer.
+**   * Redistributions in binary form must reproduce the above copyright
+**     notice, this list of conditions and the following disclaimer in
+**     the documentation and/or other materials provided with the
+**     distribution.
+**   * Neither the name of The Qt Company Ltd nor the names of its
+**     contributors may be used to endorse or promote products derived
+**     from this software without specific prior written permission.
+**
+**
+** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "validatorwidget.h"
+
+#include <QtWidgets>
+
+ValidatorWidget::ValidatorWidget(QWidget *parent)
+    : QWidget(parent)
+{
+    setupUi(this);
+
+    connect(localeSelector, &LocaleSelector::localeSelected,
+            this, &ValidatorWidget::setLocale);
+    connect(localeSelector, &LocaleSelector::localeSelected,
+            this, &ValidatorWidget::updateValidator);
+    connect(localeSelector, &LocaleSelector::localeSelected,
+            this, &ValidatorWidget::updateDoubleValidator);
+
+    connect(minVal, &QSpinBox::editingFinished,
+            this, &ValidatorWidget::updateValidator);
+    connect(maxVal, &QSpinBox::editingFinished,
+            this, &ValidatorWidget::updateValidator);
+    connect(editor, &QLineEdit::editingFinished,
+            ledWidget, &LEDWidget::flash);
+
+    connect(doubleMaxVal, &QDoubleSpinBox::editingFinished,
+            this, &ValidatorWidget::updateDoubleValidator);
+    connect(doubleMinVal, &QDoubleSpinBox::editingFinished,
+            this, &ValidatorWidget::updateDoubleValidator);
+    connect(doubleDecimals, QOverload<int>::of(&QSpinBox::valueChanged),
+            this, &ValidatorWidget::updateDoubleValidator);
+    connect(doubleFormat, QOverload<int>::of(&QComboBox::activated),
+            this, &ValidatorWidget::updateDoubleValidator);
+    connect(doubleEditor, &QLineEdit::editingFinished,
+            doubleLedWidget, &LEDWidget::flash);
+
+    updateValidator();
+    updateDoubleValidator();
+}
+
+void ValidatorWidget::updateValidator()
+{
+    QIntValidator *v = new QIntValidator(minVal->value(), maxVal->value(), this);
+    v->setLocale(locale());
+    delete editor->validator();
+    editor->setValidator(v);
+
+    QString s = editor->text();
+    int i = 0;
+    if (v->validate(s, i) == QValidator::Invalid) {
+        editor->clear();
+    } else {
+        editor->setText(s);
+    }
+}
+
+void ValidatorWidget::updateDoubleValidator()
+{
+    QDoubleValidator *v
+        = new QDoubleValidator(doubleMinVal->value(), doubleMaxVal->value(),
+                                doubleDecimals->value(), this);
+    v->setNotation(static_cast<QDoubleValidator::Notation>(doubleFormat->currentIndex()));
+    v->setLocale(locale());
+    delete doubleEditor->validator();
+    doubleEditor->setValidator(v);
+
+    QString s = doubleEditor->text();
+    int i = 0;
+    if (v->validate(s, i) == QValidator::Invalid) {
+        doubleEditor->clear();
+    } else {
+        doubleEditor->setText(s);
+    }
+}
diff --git a/examples/widgets/widgets/validators/validatorwidget.h b/examples/widgets/widgets/validators/validatorwidget.h
new file mode 100644
index 0000000000..bcc4a9b91e
--- /dev/null
+++ b/examples/widgets/widgets/validators/validatorwidget.h
@@ -0,0 +1,64 @@
+/****************************************************************************
+**
+** Copyright (C) 2018 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the examples of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:BSD$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** BSD License Usage
+** Alternatively, you may use this file under the terms of the BSD license
+** as follows:
+**
+** "Redistribution and use in source and binary forms, with or without
+** modification, are permitted provided that the following conditions are
+** met:
+**   * Redistributions of source code must retain the above copyright
+**     notice, this list of conditions and the following disclaimer.
+**   * Redistributions in binary form must reproduce the above copyright
+**     notice, this list of conditions and the following disclaimer in
+**     the documentation and/or other materials provided with the
+**     distribution.
+**   * Neither the name of The Qt Company Ltd nor the names of its
+**     contributors may be used to endorse or promote products derived
+**     from this software without specific prior written permission.
+**
+**
+** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include <QWidget>
+
+#include "ui_validators.h"
+
+class ValidatorWidget : public QWidget, public Ui::ValidatorsForm
+{
+    Q_OBJECT
+public:
+    ValidatorWidget(QWidget *parent = nullptr);
+
+private slots:
+    void updateValidator();
+    void updateDoubleValidator();
+};
diff --git a/examples/widgets/widgets/wiggly/dialog.cpp b/examples/widgets/widgets/wiggly/dialog.cpp
index 010648eda6..a7a72b3570 100644
--- a/examples/widgets/widgets/wiggly/dialog.cpp
+++ b/examples/widgets/widgets/wiggly/dialog.cpp
@@ -48,12 +48,12 @@
 **
 ****************************************************************************/
 
-#include <QLineEdit>
-#include <QVBoxLayout>
-
 #include "dialog.h"
 #include "wigglywidget.h"
 
+#include <QLineEdit>
+#include <QVBoxLayout>
+
 //! [0]
 Dialog::Dialog(QWidget *parent)
     : QDialog(parent)
diff --git a/examples/widgets/widgets/wiggly/dialog.h b/examples/widgets/widgets/wiggly/dialog.h
index a0981dc6b6..357b6354b5 100644
--- a/examples/widgets/widgets/wiggly/dialog.h
+++ b/examples/widgets/widgets/wiggly/dialog.h
@@ -59,7 +59,7 @@ class Dialog : public QDialog
     Q_OBJECT
 
 public:
-    explicit Dialog(QWidget *parent = 0);
+    explicit Dialog(QWidget *parent = nullptr);
 };
 //! [0]
 
diff --git a/examples/widgets/widgets/wiggly/main.cpp b/examples/widgets/widgets/wiggly/main.cpp
index bd2a50a8eb..cd888c4084 100644
--- a/examples/widgets/widgets/wiggly/main.cpp
+++ b/examples/widgets/widgets/wiggly/main.cpp
@@ -48,10 +48,10 @@
 **
 ****************************************************************************/
 
-#include <QApplication>
-
 #include "dialog.h"
 
+#include <QApplication>
+
 int main(int argc, char *argv[])
 {
     QApplication app(argc, argv);
diff --git a/examples/widgets/widgets/wiggly/wigglywidget.cpp b/examples/widgets/widgets/wiggly/wigglywidget.cpp
index 1b8f3cffad..0399fe9056 100644
--- a/examples/widgets/widgets/wiggly/wigglywidget.cpp
+++ b/examples/widgets/widgets/wiggly/wigglywidget.cpp
@@ -48,10 +48,10 @@
 **
 ****************************************************************************/
 
-#include <QtWidgets>
-
 #include "wigglywidget.h"
 
+#include <QtWidgets>
+
 //! [0]
 WigglyWidget::WigglyWidget(QWidget *parent)
     : QWidget(parent)
diff --git a/examples/widgets/widgets/wiggly/wigglywidget.h b/examples/widgets/widgets/wiggly/wigglywidget.h
index 58a7d045e1..1d909c34da 100644
--- a/examples/widgets/widgets/wiggly/wigglywidget.h
+++ b/examples/widgets/widgets/wiggly/wigglywidget.h
@@ -60,7 +60,7 @@ class WigglyWidget : public QWidget
     Q_OBJECT
 
 public:
-    WigglyWidget(QWidget *parent = 0);
+    WigglyWidget(QWidget *parent = nullptr);
 
 public slots:
     void setText(const QString &newText) { text = newText; }
diff --git a/examples/widgets/widgets/windowflags/controllerwindow.cpp b/examples/widgets/widgets/windowflags/controllerwindow.cpp
index 78323810ed..e2abad89f4 100644
--- a/examples/widgets/widgets/windowflags/controllerwindow.cpp
+++ b/examples/widgets/widgets/windowflags/controllerwindow.cpp
@@ -53,7 +53,8 @@
 #include "controllerwindow.h"
 
 //! [0]
-ControllerWindow::ControllerWindow()
+ControllerWindow::ControllerWindow(QWidget *parent)
+    : QWidget(parent)
 {
     previewWindow = new PreviewWindow(this);
 
@@ -61,7 +62,8 @@ ControllerWindow::ControllerWindow()
     createHintsGroupBox();
 
     quitButton = new QPushButton(tr("&Quit"));
-    connect(quitButton, SIGNAL(clicked()), qApp, SLOT(quit()));
+    connect(quitButton, &QPushButton::clicked,
+            qApp, &QApplication::quit);
 
     QHBoxLayout *bottomLayout = new QHBoxLayout;
     bottomLayout->addStretch();
@@ -219,7 +221,8 @@ void ControllerWindow::createHintsGroupBox()
 QCheckBox *ControllerWindow::createCheckBox(const QString &text)
 {
     QCheckBox *checkBox = new QCheckBox(text);
-    connect(checkBox, SIGNAL(clicked()), this, SLOT(updatePreview()));
+    connect(checkBox, &QCheckBox::clicked,
+            this, &ControllerWindow::updatePreview);
     return checkBox;
 }
 //! [7]
@@ -228,7 +231,8 @@ QCheckBox *ControllerWindow::createCheckBox(const QString &text)
 QRadioButton *ControllerWindow::createRadioButton(const QString &text)
 {
     QRadioButton *button = new QRadioButton(text);
-    connect(button, SIGNAL(clicked()), this, SLOT(updatePreview()));
+    connect(button, &QRadioButton::clicked,
+            this, &ControllerWindow::updatePreview);
     return button;
 }
 //! [8]
diff --git a/examples/widgets/widgets/windowflags/controllerwindow.h b/examples/widgets/widgets/windowflags/controllerwindow.h
index cfb88ed20f..43ec67e27f 100644
--- a/examples/widgets/widgets/windowflags/controllerwindow.h
+++ b/examples/widgets/widgets/windowflags/controllerwindow.h
@@ -69,7 +69,7 @@ class ControllerWindow : public QWidget
     Q_OBJECT
 
 public:
-    ControllerWindow();
+    ControllerWindow(QWidget *parent = nullptr);
 
 private slots:
     void updatePreview();
diff --git a/examples/widgets/widgets/windowflags/previewwindow.cpp b/examples/widgets/widgets/windowflags/previewwindow.cpp
index 725a134daf..8773dccb05 100644
--- a/examples/widgets/widgets/windowflags/previewwindow.cpp
+++ b/examples/widgets/widgets/windowflags/previewwindow.cpp
@@ -48,10 +48,10 @@
 **
 ****************************************************************************/
 
-#include <QtWidgets>
-
 #include "previewwindow.h"
 
+#include <QtWidgets>
+
 //! [0]
 PreviewWindow::PreviewWindow(QWidget *parent)
     : QWidget(parent)
@@ -61,7 +61,8 @@ PreviewWindow::PreviewWindow(QWidget *parent)
     textEdit->setLineWrapMode(QTextEdit::NoWrap);
 
     closeButton = new QPushButton(tr("&Close"));
-    connect(closeButton, SIGNAL(clicked()), this, SLOT(close()));
+    connect(closeButton, &QPushButton::clicked,
+            this, &PreviewWindow::close);
 
     QVBoxLayout *layout = new QVBoxLayout;
     layout->addWidget(textEdit);
diff --git a/examples/widgets/widgets/windowflags/previewwindow.h b/examples/widgets/widgets/windowflags/previewwindow.h
index e9efd09507..9bb487e8ab 100644
--- a/examples/widgets/widgets/windowflags/previewwindow.h
+++ b/examples/widgets/widgets/windowflags/previewwindow.h
@@ -64,7 +64,7 @@ class PreviewWindow : public QWidget
     Q_OBJECT
 
 public:
-    PreviewWindow(QWidget *parent = 0);
+    PreviewWindow(QWidget *parent = nullptr);
 
     void setWindowFlags(Qt::WindowFlags flags);
author	Tobias Hunger <tobias.hunger@qt.io>	2019-04-16 16:32:08 +0200
committer	Tobias Hunger <tobias.hunger@qt.io>	2019-04-16 16:32:08 +0200
commit	6630937e63ae5797487b86743a7733c8ae5cc42c (patch)
tree	3d53dacf6430f9099e1fb20835881205de674961 /examples/widgets
parent	37ed6dae00640f9cc980ffda05347c12a7eb5d7e (diff)
parent	c7af193d2e49e9f10b86262e63d8d13abf72b5cf (diff)