Revamp SQL examples to C++11

Changed signals and slots to new syntax, used nullptr and replaced
foreach with new C++11 range based for loops.
Also fixed a few minor flaws.

Task-number: QTBUG-60633
Change-Id: Ice4030133971912f96752d9d84c638c70fd73e35
Reviewed-by: Jesus Fernandez <Jesus.Fernandez@qt.io>
Reviewed-by: André Hartmann <aha_1980@gmx.de>
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@qt.io>

7 files changed, 48 insertions, 51 deletions

diff --git a/examples/sql/drilldown/imageitem.cpp b/examples/sql/drilldown/imageitem.cpp
index 4e440fc786..04ec614755 100644
--- a/examples/sql/drilldown/imageitem.cpp
+++ b/examples/sql/drilldown/imageitem.cpp
@@ -60,8 +60,8 @@ ImageItem::ImageItem(int id, const QPixmap &pixmap, QGraphicsItem *parent)
     timeLine.setDuration(150);
     timeLine.setFrameRange(0, 150);
 
-    connect(&timeLine, SIGNAL(frameChanged(int)), this, SLOT(setFrame(int)));
-    connect(&timeLine, SIGNAL(finished()), this, SLOT(updateItemPosition()));
+    connect(&timeLine, &QTimeLine::frameChanged, this, &ImageItem::setFrame);
+    connect(&timeLine, &QTimeLine::finished, this, &ImageItem::updateItemPosition);
 
     adjust();
 }
@@ -116,7 +116,7 @@ void ImageItem::adjust()
 //! [4]
 
 //! [5]
-int ImageItem::id()
+int ImageItem::id() const
 {
     return recordId;
 }
diff --git a/examples/sql/drilldown/imageitem.h b/examples/sql/drilldown/imageitem.h
index 4f773a6dfc..abb9103c7e 100644
--- a/examples/sql/drilldown/imageitem.h
+++ b/examples/sql/drilldown/imageitem.h
@@ -60,10 +60,10 @@ class ImageItem : public QObject, public QGraphicsPixmapItem
     Q_OBJECT
 
 public:
-    ImageItem(int id, const QPixmap &pixmap, QGraphicsItem *parent = 0);
+    ImageItem(int id, const QPixmap &pixmap, QGraphicsItem *parent = nullptr);
 
     void adjust();
-    int id();
+    int id() const;
 
 protected:
     void hoverEnterEvent(QGraphicsSceneHoverEvent *event) override;
diff --git a/examples/sql/drilldown/informationwindow.cpp b/examples/sql/drilldown/informationwindow.cpp
index 2536b0ca91..0007432672 100644
--- a/examples/sql/drilldown/informationwindow.cpp
+++ b/examples/sql/drilldown/informationwindow.cpp
@@ -84,10 +84,12 @@ InformationWindow::InformationWindow(int id, QSqlRelationalTableModel *items,
 //! [3]
 
 //! [4]
-    connect(descriptionEditor, SIGNAL(textChanged()),
-            this, SLOT(enableButtons()));
-    connect(imageFileEditor, SIGNAL(currentIndexChanged(int)),
-            this, SLOT(enableButtons()));
+    connect(descriptionEditor, &QTextEdit::textChanged, [=]() {
+        enableButtons();
+    });
+    connect(imageFileEditor, QOverload<int>::of(&QComboBox::currentIndexChanged), [=]() {
+        enableButtons();
+    });
 
     QFormLayout *formLayout = new QFormLayout;
     formLayout->addRow(itemLabel, itemText);
@@ -109,7 +111,7 @@ InformationWindow::InformationWindow(int id, QSqlRelationalTableModel *items,
 //! [4]
 
 //! [5]
-int InformationWindow::id()
+int InformationWindow::id() const
 {
     return itemId;
 }
@@ -149,9 +151,9 @@ void InformationWindow::createButtons()
 
     closeButton->setDefault(true);
 
-    connect(closeButton, SIGNAL(clicked()), this, SLOT(close()));
-    connect(revertButton, SIGNAL(clicked()), this, SLOT(revert()));
-    connect(submitButton, SIGNAL(clicked()), this, SLOT(submit()));
+    connect(closeButton, &QPushButton::clicked, this, &InformationWindow::close);
+    connect(revertButton, &QPushButton::clicked, this, &InformationWindow::revert);
+    connect(submitButton, &QPushButton::clicked, this, &InformationWindow::submit);
 //! [8]
 
 //! [9]
diff --git a/examples/sql/drilldown/informationwindow.h b/examples/sql/drilldown/informationwindow.h
index 6e87cea65a..653837d722 100644
--- a/examples/sql/drilldown/informationwindow.h
+++ b/examples/sql/drilldown/informationwindow.h
@@ -61,9 +61,9 @@ class InformationWindow : public QDialog
 
 public:
     InformationWindow(int id, QSqlRelationalTableModel *items,
-                      QWidget *parent = 0);
+                      QWidget *parent = nullptr);
 
-    int id();
+    int id() const;
 
 signals:
     void imageChanged(int id, const QString &fileName);
@@ -83,16 +83,16 @@ private:
     int itemId;
     QString displayedImage;
 
-    QComboBox *imageFileEditor;
-    QLabel *itemText;
-    QTextEdit *descriptionEditor;
+    QComboBox *imageFileEditor = nullptr;
+    QLabel *itemText = nullptr;
+    QTextEdit *descriptionEditor = nullptr;
 
-    QPushButton *closeButton;
-    QPushButton *submitButton;
-    QPushButton *revertButton;
-    QDialogButtonBox *buttonBox;
+    QPushButton *closeButton = nullptr;
+    QPushButton *submitButton = nullptr;
+    QPushButton *revertButton = nullptr;
+    QDialogButtonBox *buttonBox = nullptr;
 
-    QDataWidgetMapper *mapper;
+    QDataWidgetMapper *mapper = nullptr;
 };
 //! [2]
 
diff --git a/examples/sql/drilldown/main.cpp b/examples/sql/drilldown/main.cpp
index 3465d11b4d..db3320de48 100644
--- a/examples/sql/drilldown/main.cpp
+++ b/examples/sql/drilldown/main.cpp
@@ -48,10 +48,13 @@
 **
 ****************************************************************************/
 
-#include <QtWidgets>
-
-#include "../connection.h"
 #include "view.h"
+#include "../connection.h"
+
+#include <QApplication>
+
+#include <stdlib.h>
+
 
 int main(int argc, char *argv[])
 {
@@ -60,7 +63,7 @@ int main(int argc, char *argv[])
     QApplication app(argc, argv);
 
     if (!createConnection())
-        return 1;
+        return EXIT_FAILURE;
 
     View view("items", "images");
     view.show();
diff --git a/examples/sql/drilldown/view.cpp b/examples/sql/drilldown/view.cpp
index fc05d2fcaf..13e9310061 100644
--- a/examples/sql/drilldown/view.cpp
+++ b/examples/sql/drilldown/view.cpp
@@ -89,8 +89,6 @@ void View::addItems()
     int topMargin = 40;
 
     for (int i = 0; i < itemCount; i++) {
-        ImageItem *image;
-        QGraphicsTextItem *label;
         QSqlRecord record = itemTable->record(i);
 
         int id = record.value("id").toInt();
@@ -101,12 +99,12 @@ void View::addItems()
         int x = ((i % 2) * imageOffset) + leftMargin + columnOffset;
         int y = ((i / 2) * imageOffset) + topMargin;
 
-        image = new ImageItem(id, QPixmap(":/" + file));
+        ImageItem *image = new ImageItem(id, QPixmap(":/" + file));
         image->setData(0, i);
         image->setPos(x, y);
         scene->addItem(image);
 
-        label = scene->addText(item);
+        QGraphicsTextItem *label = scene->addText(item);
         label->setDefaultTextColor(QColor("#d7d6d5"));
         QPointF labelOffset((120 - label->boundingRect().width()) / 2, 120.0);
         label->setPos(QPointF(x, y) + labelOffset);
@@ -133,22 +131,22 @@ void View::showInformation(ImageItem *image)
         return;
 
     InformationWindow *window = findWindow(id);
-    if (window && window->isVisible()) {
-        window->raise();
-        window->activateWindow();
-    } else if (window && !window->isVisible()) {
-        window->show();
-    } else {
-        InformationWindow *window;
+    if (!window) {
         window = new InformationWindow(id, itemTable, this);
 
-        connect(window, SIGNAL(imageChanged(int,QString)),
-                this, SLOT(updateImage(int,QString)));
+        connect(window, QOverload<int,const QString &>::of(&InformationWindow::imageChanged),
+                this, QOverload<int,const QString &>::of(&View::updateImage));
 
         window->move(pos() + QPoint(20, 40));
         window->show();
         informationWindows.append(window);
     }
+
+    if (window->isVisible()) {
+        window->raise();
+        window->activateWindow();
+    } else
+        window->show();
 }
 //! [6]
 
@@ -172,19 +170,13 @@ void View::updateImage(int id, const QString &fileName)
 //! [7]
 
 //! [8]
-InformationWindow* View::findWindow(int id)
+InformationWindow *View::findWindow(int id) const
 {
-    QList<InformationWindow*>::iterator i, beginning, end;
-
-    beginning = informationWindows.begin();
-    end = informationWindows.end();
-
-    for (i = beginning; i != end; ++i) {
-        InformationWindow *window = (*i);
+    for (auto window : informationWindows) {
         if (window && (window->id() == id))
             return window;
     }
-    return 0;
+    return nullptr;
 }
 //! [8]
 
diff --git a/examples/sql/drilldown/view.h b/examples/sql/drilldown/view.h
index 9d6ef0e853..5afa1a25e9 100644
--- a/examples/sql/drilldown/view.h
+++ b/examples/sql/drilldown/view.h
@@ -63,7 +63,7 @@ class View : public QGraphicsView
     Q_OBJECT
 
 public:
-    View(const QString &items, const QString &images, QWidget *parent = 0);
+    View(const QString &items, const QString &images, QWidget *parent = nullptr);
 
 protected:
     void mouseReleaseEvent(QMouseEvent *event) override;
@@ -77,7 +77,7 @@ private slots:
 //! [2]
 private:
     void addItems();
-    InformationWindow* findWindow(int id);
+    InformationWindow *findWindow(int id) const;
     void showInformation(ImageItem *image);
 
     QGraphicsScene *scene;