Examples: Fix unused variable warnings by Clang

mainwindow.cpp(59,11):  warning: unused variable 'ROWS' [-Wunused-const-variable]
const int ROWS = 2;
mainwindow.cpp(60,11):  warning: unused variable 'COLUMNS' [-Wunused-const-variable]
const int COLUMNS = 3;
mainwindow.cpp(76,19):  warning: unused variable 'message' [-Wunused-const-variable]

Task-number: QTBUG-60635
Change-Id: I97c31462ffa826da9baa32c33c0ff0140bf46dfc
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>
Reviewed-by: Richard Moe Gustavsen <richard.gustavsen@qt.io>

3 files changed, 14 insertions, 4 deletions

diff --git a/examples/widgets/mainwindows/mainwindow/mainwindow.cpp b/examples/widgets/mainwindows/mainwindow/mainwindow.cpp
index b2c5ccc473..fe31207326 100644
--- a/examples/widgets/mainwindows/mainwindow/mainwindow.cpp
+++ b/examples/widgets/mainwindows/mainwindow/mainwindow.cpp
@@ -187,6 +187,13 @@ void MainWindow::setupMenuBar()
 #endif
 
     dockWidgetMenu = menuBar()->addMenu(tr("&Dock Widgets"));
+
+    QMenu *aboutMenu = menuBar()->addMenu(tr("About"));
+    QAction *aboutAct = aboutMenu->addAction(tr("&About"), this, &MainWindow::about);
+    aboutAct->setStatusTip(tr("Show the application's About box"));
+
+    QAction *aboutQtAct = aboutMenu->addAction(tr("About &Qt"), qApp, &QApplication::aboutQt);
+    aboutQtAct->setStatusTip(tr("Show the Qt library's About box"));
 }
 
 void MainWindow::setDockOptions()
@@ -476,3 +483,8 @@ void MainWindow::destroyDockWidget(QAction *action)
     if (destroyDockWidgetMenu->isEmpty())
         destroyDockWidgetMenu->setEnabled(false);
 }
+
+void MainWindow::about()
+{
+    QMessageBox::about(this, tr("About MainWindows"), message);
+}
diff --git a/examples/widgets/mainwindows/mainwindow/mainwindow.h b/examples/widgets/mainwindows/mainwindow/mainwindow.h
index 9b1af6df80..a2c9d30ded 100644
--- a/examples/widgets/mainwindows/mainwindow/mainwindow.h
+++ b/examples/widgets/mainwindows/mainwindow/mainwindow.h
@@ -77,6 +77,8 @@ public slots:
     void createDockWidget();
     void destroyDockWidget(QAction *action);
 
+    void about();
+
 private:
     void setupToolBar();
     void setupMenuBar();
diff --git a/examples/widgets/tutorials/modelview/6_treeview/mainwindow.cpp b/examples/widgets/tutorials/modelview/6_treeview/mainwindow.cpp
index f33155375c..1016afba07 100644
--- a/examples/widgets/tutorials/modelview/6_treeview/mainwindow.cpp
+++ b/examples/widgets/tutorials/modelview/6_treeview/mainwindow.cpp
@@ -55,10 +55,6 @@
 #include <QStandardItem>
 #include "mainwindow.h"
 
-
-const int ROWS = 2;
-const int COLUMNS = 3;
-
 MainWindow::MainWindow(QWidget *parent)
     : QMainWindow(parent)
 {