Cleanup QtWidgets (widgets) examples

Cleanup QtWidgets widgets 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

Change-Id: Ib56bb507eb2ef885f1ddc664050d3c7af92adb70
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@qt.io>

3 files changed, 12 insertions, 6 deletions

diff --git a/examples/widgets/widgets/tooltips/main.cpp b/examples/widgets/widgets/tooltips/main.cpp
index 8276b3dc8d..0890020f77 100644
--- a/examples/widgets/widgets/tooltips/main.cpp
+++ b/examples/widgets/widgets/tooltips/main.cpp
@@ -48,7 +48,7 @@
 **
 ****************************************************************************/
 
-#include <QtWidgets>
+#include <QApplication>
 
 #include "sortingbox.h"
 
diff --git a/examples/widgets/widgets/tooltips/sortingbox.cpp b/examples/widgets/widgets/tooltips/sortingbox.cpp
index 685eaa7d1d..f99c38b233 100644
--- a/examples/widgets/widgets/tooltips/sortingbox.cpp
+++ b/examples/widgets/widgets/tooltips/sortingbox.cpp
@@ -50,7 +50,13 @@
 
 #include "sortingbox.h"
 
-#include <QtWidgets>
+#include <QMouseEvent>
+#include <QIcon>
+#include <QPainter>
+#include <QRandomGenerator>
+#include <QStyle>
+#include <QToolButton>
+#include <QToolTip>
 
 //! [0]
 SortingBox::SortingBox(QWidget *parent)
@@ -277,12 +283,12 @@ QToolButton *SortingBox::createToolButton(const QString &toolTip,
 QPoint SortingBox::initialItemPosition(const QPainterPath &path)
 {
     int x;
-    int y = (height() - (int)path.controlPointRect().height()) / 2;
+    int y = (height() - qRound(path.controlPointRect().height()) / 2);
     if (shapeItems.size() == 0)
-        x = ((3 * width()) / 2 - (int)path.controlPointRect().width()) / 2;
+        x = ((3 * width()) / 2 - qRound(path.controlPointRect().width())) / 2;
     else
         x = (width() / shapeItems.size()
-             - (int)path.controlPointRect().width()) / 2;
+             - qRound(path.controlPointRect().width())) / 2;
 
     return QPoint(x, y);
 }
diff --git a/examples/widgets/widgets/tooltips/sortingbox.h b/examples/widgets/widgets/tooltips/sortingbox.h
index 3d0cecea2b..785154746e 100644
--- a/examples/widgets/widgets/tooltips/sortingbox.h
+++ b/examples/widgets/widgets/tooltips/sortingbox.h
@@ -99,7 +99,7 @@ private:
                                   const char *member);
 
 //! [2]
-    QList<ShapeItem> shapeItems;
+    QVector<ShapeItem> shapeItems;
     QPainterPath circlePath;
     QPainterPath squarePath;
     QPainterPath trianglePath;