Add some error handling to the QQuickWidget example.

Use a QMainWindow and display errors occurring during loading
QML as well as scene graph errors (for example, failure
to create an Open GL context) in the status bar.

Change-Id: Icd9ad2bd2b809baf80d83a54e295c25b7fb1f94b
Reviewed-by: Laszlo Agocs <laszlo.agocs@digia.com>

diff --git a/examples/quickwidgets/quickwidget/main.cpp b/examples/quickwidgets/quickwidget/main.cpp
index 7251760..c130434 100644 (file)
--- a/examples/quickwidgets/quickwidget/main.cpp
+++ b/examples/quickwidgets/quickwidget/main.cpp
@@ -39,33 +39,74 @@
 ****************************************************************************/
 
 #include <QQuickWidget>
+#include <QQmlError>
 #include <QtWidgets>
 
-int main(int argc, char **argv)
-{
-    QApplication app(argc, argv);
+class MainWindow : public QMainWindow {
+    Q_OBJECT
+public:
+    MainWindow();
 
-    QMdiArea *toplevel = new QMdiArea;
+private slots:
+    void quickWidgetStatusChanged(QQuickWidget::Status);
+    void sceneGraphError(QQuickWindow::SceneGraphError error, const QString &message);
+
+private:
+    QQuickWidget *m_quickWidget;
+};
+
+MainWindow::MainWindow()
+   : m_quickWidget(new QQuickWidget)
+{
+    QMdiArea *centralWidget = new QMdiArea;
 
     QLCDNumber *lcd = new QLCDNumber;
     lcd->display(1337);
     lcd->setMinimumSize(250,100);
-    toplevel->addSubWindow(lcd);
+    centralWidget ->addSubWindow(lcd);
 
     QUrl source("qrc:quickwidget/rotatingsquare.qml");
 
-    QQuickWidget *w = new QQuickWidget;
-    w->resize(300,300);
-    w->setResizeMode(QQuickWidget::SizeRootObjectToView );
-    w->setSource(source);
+    connect(m_quickWidget, SIGNAL(statusChanged(QQuickWidget::Status)),
+            this, SLOT(quickWidgetStatusChanged(QQuickWidget::Status)));
+    connect(m_quickWidget, SIGNAL(sceneGraphError(QQuickWindow::SceneGraphError,QString)),
+            this, SLOT(sceneGraphError(QQuickWindow::SceneGraphError,QString)));
+    m_quickWidget->resize(300,300);
+    m_quickWidget->setResizeMode(QQuickWidget::SizeRootObjectToView );
+    m_quickWidget->setSource(source);
 
-    toplevel->addSubWindow(w);
+    centralWidget ->addSubWindow(m_quickWidget);
 
-    toplevel->show();
+    setCentralWidget(centralWidget);
 
-    return app.exec();
+    QMenu *fileMenu = menuBar()->addMenu(tr("File"));
+    QAction *quitAction = fileMenu->addAction(tr("Quit"));
+    connect(quitAction, SIGNAL(triggered()), qApp, SLOT(quit()));
+}
+
+void MainWindow::quickWidgetStatusChanged(QQuickWidget::Status status)
+{
+    if (status == QQuickWidget::Error) {
+        QStringList errors;
+        foreach (const QQmlError &error, m_quickWidget->errors())
+            errors.append(error.toString());
+        statusBar()->showMessage(errors.join(QStringLiteral(", ")));
+    }
 }
 
+void MainWindow::sceneGraphError(QQuickWindow::SceneGraphError, const QString &message)
+{
+     statusBar()->showMessage(message);
+}
 
+int main(int argc, char **argv)
+{
+    QApplication app(argc, argv);
+
+    MainWindow mainWindow;
+    mainWindow.show();
 
+    return app.exec();
+}
 
+#include "main.moc"