Itemviews: Cleanup examples

Cleanup some minor issues in the chart example:
 - remove unused members
 - use initializer list for members
 - pass a proper role to dataChanged()
 - honor roles parameter in PieView::dataChanged()
 - use nullptr instead 0
 - use new-style connect
 - fix indentation and other whitespaces

Change-Id: Idb212b07c006fe3ae31bee9cd9b1ba4d03043b5e
Reviewed-by: André Hartmann <aha_1980@gmx.de>
Reviewed-by: Paul Wicking <paul.wicking@qt.io>

23 files changed, 114 insertions, 139 deletions

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);
 };