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>

29 files changed, 161 insertions, 192 deletions

diff --git a/examples/widgets/itemviews/addressbook/tablemodel.cpp b/examples/widgets/itemviews/addressbook/tablemodel.cpp
index 674e312753..b3704f857e 100644
--- a/examples/widgets/itemviews/addressbook/tablemodel.cpp
+++ b/examples/widgets/itemviews/addressbook/tablemodel.cpp
@@ -164,7 +164,7 @@ bool TableModel::setData(const QModelIndex &index, const QVariant &value, int ro
             return false;
 
         contacts.replace(row, contact);
-        emit(dataChanged(index, index));
+        emit dataChanged(index, index, {role});
 
         return true;
     }
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/editabletreemodel/treemodel.cpp b/examples/widgets/itemviews/editabletreemodel/treemodel.cpp
index dbd53df1e6..72818372d7 100644
--- a/examples/widgets/itemviews/editabletreemodel/treemodel.cpp
+++ b/examples/widgets/itemviews/editabletreemodel/treemodel.cpp
@@ -225,7 +225,7 @@ 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, {role});
 
     return result;
 }
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);
 };