examples: Use QOverload to select overloaded signals and slots

We can use QOverload since Qt 5.7 (it depends on Q_COMPILER_VARIADIC_TEMPLATES
which is required since Qt 5.7).
Use it in the examples to show the best practice.
qOverload currently can't be used because it requires c++14.

Change-Id: I94a3c0db9d551fe169fa3d19c07ec0b329d5946c
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@qt.io>
Reviewed-by: Olivier Goffart (Woboq GmbH) <ogoffart@woboq.com>

3 files changed, 6 insertions, 11 deletions

diff --git a/examples/widgets/widgets/charactermap/mainwindow.cpp b/examples/widgets/widgets/charactermap/mainwindow.cpp
index 8b406ba1ca..5f17128a2f 100644
--- a/examples/widgets/widgets/charactermap/mainwindow.cpp
+++ b/examples/widgets/widgets/charactermap/mainwindow.cpp
@@ -74,8 +74,7 @@ MainWindow::MainWindow()
     filterCombo->addItem(tr("Monospaced"), QVariant::fromValue(QFontComboBox::MonospacedFonts));
     filterCombo->addItem(tr("Proportional"), QVariant::fromValue(QFontComboBox::ProportionalFonts));
     filterCombo->setCurrentIndex(0);
-    typedef void (QComboBox::*QComboBoxIntSignal)(int);
-    connect(filterCombo, static_cast<QComboBoxIntSignal>(&QComboBox::currentIndexChanged),
+    connect(filterCombo, QOverload<int>::of(&QComboBox::currentIndexChanged),
             this, &MainWindow::filterChanged);
 
     QLabel *fontLabel = new QLabel(tr("Font:"));
@@ -114,10 +113,9 @@ MainWindow::MainWindow()
             this, &MainWindow::findSizes);
     connect(fontCombo, &QFontComboBox::currentFontChanged,
             characterWidget, &CharacterWidget::updateFont);
-    typedef void (QComboBox::*QComboBoxStringSignal)(const QString &);
-    connect(sizeCombo, static_cast<QComboBoxStringSignal>(&QComboBox::currentIndexChanged),
+    connect(sizeCombo, QOverload<const QString &>::of(&QComboBox::currentIndexChanged),
             characterWidget, &CharacterWidget::updateSize);
-    connect(styleCombo, static_cast<QComboBoxStringSignal>(&QComboBox::currentIndexChanged),
+    connect(styleCombo, QOverload<const QString &>::of(&QComboBox::currentIndexChanged),
             characterWidget, &CharacterWidget::updateStyle);
 //! [4] //! [5]
     connect(characterWidget, &CharacterWidget::characterSelected,
diff --git a/examples/widgets/widgets/icons/imagedelegate.cpp b/examples/widgets/widgets/icons/imagedelegate.cpp
index 980013daee..3c873f1e24 100644
--- a/examples/widgets/widgets/icons/imagedelegate.cpp
+++ b/examples/widgets/widgets/icons/imagedelegate.cpp
@@ -71,8 +71,7 @@ QWidget *ImageDelegate::createEditor(QWidget *parent,
     else if (index.column() == 2)
         comboBox->addItems(IconPreviewArea::iconStateNames());
 
-    typedef void (QComboBox::*QComboBoxIntSignal)(int);
-    connect(comboBox, static_cast<QComboBoxIntSignal>(&QComboBox::activated),
+    connect(comboBox, QOverload<int>::of(&QComboBox::activated),
             this, &ImageDelegate::emitCommitData);
 
     return comboBox;
diff --git a/examples/widgets/widgets/icons/mainwindow.cpp b/examples/widgets/widgets/icons/mainwindow.cpp
index 5f3882de94..f704b8306f 100644
--- a/examples/widgets/widgets/icons/mainwindow.cpp
+++ b/examples/widgets/widgets/icons/mainwindow.cpp
@@ -362,8 +362,7 @@ QWidget *MainWindow::createIconSizeGroupBox()
     sizeButtonGroup = new QButtonGroup(this);
     sizeButtonGroup->setExclusive(true);
 
-    typedef void (QButtonGroup::*QButtonGroupIntBoolSignal)(int, bool);
-    connect(sizeButtonGroup, static_cast<QButtonGroupIntBoolSignal>(&QButtonGroup::buttonToggled),
+    connect(sizeButtonGroup, QOverload<int, bool>::of(&QButtonGroup::buttonToggled),
             this, &MainWindow::changeSize);
 
     QRadioButton *smallRadioButton = new QRadioButton;
@@ -391,8 +390,7 @@ QWidget *MainWindow::createIconSizeGroupBox()
 //! [26]
 
 //! [27]
-    typedef void (QSpinBox::*QSpinBoxIntSignal)(int);
-    connect(otherSpinBox, static_cast<QSpinBoxIntSignal>(&QSpinBox::valueChanged),
+    connect(otherSpinBox, QOverload<int>::of(&QSpinBox::valueChanged),
             this, &MainWindow::triggerChangeSize);
 
     QHBoxLayout *otherSizeLayout = new QHBoxLayout;