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>

3 files changed, 17 insertions, 22 deletions

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;