Cleanup QtWidgets (tools) examples

Cleanup QtWidgets tools examples:
 - use member-init (clang-tidy)
 - fix includes/don't include QtWidgets globally
 - include own header first
 - use nullptr (clang-tidy)
 - avoid c-style casts
 - use QVector instead QList
 - use QItemDelegate instead QStyledItemDelegate

Change-Id: Ibe9440cdf711e5cc2138c054864edebe1fc95731
Reviewed-by: Paul Wicking <paul.wicking@qt.io>

6 files changed, 9 insertions, 19 deletions

diff --git a/examples/widgets/tools/styleplugin/plugin/simplestyle.cpp b/examples/widgets/tools/styleplugin/plugin/simplestyle.cpp
index 59da6a8672..765c9c2745 100644
--- a/examples/widgets/tools/styleplugin/plugin/simplestyle.cpp
+++ b/examples/widgets/tools/styleplugin/plugin/simplestyle.cpp
@@ -48,8 +48,6 @@
 **
 ****************************************************************************/
 
-#include <QtWidgets>
-
 #include "simplestyle.h"
 
 void SimpleStyle::polish(QPalette &palette)
diff --git a/examples/widgets/tools/styleplugin/plugin/simplestyle.h b/examples/widgets/tools/styleplugin/plugin/simplestyle.h
index 51d6d5b77e..4f49de8cbc 100644
--- a/examples/widgets/tools/styleplugin/plugin/simplestyle.h
+++ b/examples/widgets/tools/styleplugin/plugin/simplestyle.h
@@ -53,16 +53,12 @@
 
 #include <QProxyStyle>
 
-QT_BEGIN_NAMESPACE
-class QPalette;
-QT_END_NAMESPACE
-
 class SimpleStyle : public QProxyStyle
 {
     Q_OBJECT
 
 public:
-    SimpleStyle() {};
+    SimpleStyle() = default;
 
     void polish(QPalette &palette) override;
 };
diff --git a/examples/widgets/tools/styleplugin/plugin/simplestyleplugin.cpp b/examples/widgets/tools/styleplugin/plugin/simplestyleplugin.cpp
index 344e46061c..cbe7c15cc0 100644
--- a/examples/widgets/tools/styleplugin/plugin/simplestyleplugin.cpp
+++ b/examples/widgets/tools/styleplugin/plugin/simplestyleplugin.cpp
@@ -48,15 +48,13 @@
 **
 ****************************************************************************/
 
-#include <QtWidgets>
-
 #include "simplestyleplugin.h"
 #include "simplestyle.h"
 
 //! [0]
 QStringList SimpleStylePlugin::keys() const
 {
-    return QStringList() << "SimpleStyle";
+    return {"SimpleStyle"};
 }
 //! [0]
 
@@ -65,6 +63,6 @@ QStyle *SimpleStylePlugin::create(const QString &key)
 {
     if (key.toLower() == "simplestyle")
         return new SimpleStyle;
-    return 0;
+    return nullptr;
 }
 //! [1]
diff --git a/examples/widgets/tools/styleplugin/plugin/simplestyleplugin.h b/examples/widgets/tools/styleplugin/plugin/simplestyleplugin.h
index 88805d4887..3ce37410eb 100644
--- a/examples/widgets/tools/styleplugin/plugin/simplestyleplugin.h
+++ b/examples/widgets/tools/styleplugin/plugin/simplestyleplugin.h
@@ -53,11 +53,6 @@
 
 #include <QStylePlugin>
 
-QT_BEGIN_NAMESPACE
-class QStringList;
-class QStyle;
-QT_END_NAMESPACE
-
 //! [0]
 class SimpleStylePlugin : public QStylePlugin
 {
@@ -65,7 +60,7 @@ class SimpleStylePlugin : public QStylePlugin
     Q_PLUGIN_METADATA(IID "org.qt-project.Qt.QStyleFactoryInterface" FILE "simplestyle.json")
 
 public:
-    SimpleStylePlugin() {}
+    SimpleStylePlugin() = default;
 
     QStringList keys() const;
     QStyle *create(const QString &key) override;
diff --git a/examples/widgets/tools/styleplugin/stylewindow/main.cpp b/examples/widgets/tools/styleplugin/stylewindow/main.cpp
index 93816d393d..ff29eb119e 100644
--- a/examples/widgets/tools/styleplugin/stylewindow/main.cpp
+++ b/examples/widgets/tools/styleplugin/stylewindow/main.cpp
@@ -48,7 +48,8 @@
 **
 ****************************************************************************/
 
-#include <QtWidgets>
+#include <QApplication>
+#include <QStyleFactory>
 
 #include "stylewindow.h"
 
diff --git a/examples/widgets/tools/styleplugin/stylewindow/stylewindow.cpp b/examples/widgets/tools/styleplugin/stylewindow/stylewindow.cpp
index 7a05a3ae92..90413ed12e 100644
--- a/examples/widgets/tools/styleplugin/stylewindow/stylewindow.cpp
+++ b/examples/widgets/tools/styleplugin/stylewindow/stylewindow.cpp
@@ -48,7 +48,9 @@
 **
 ****************************************************************************/
 
-#include <QtWidgets>
+#include <QGridLayout>
+#include <QGroupBox>
+#include <QPushButton>
 
 #include "stylewindow.h"