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>

1 files changed, 3 insertions, 5 deletions

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