QT-QML application: QQuickWindow to Full Screen: repaint failure ("bad window" in top-left screen corner)

Diego Donate

I have a Qt/QML application and I have a problem when setting the main window to Full Screen.

It goes Full Screen, but first it seems to be moved to the top-left corner of my screen. Then it changes to Full Screen, BUT this top-left window is there until I repaint my application. For instance, moving it to background and to foreground again.

I hope I am explaining properly...

In my code, I have a QWidget class where I create a QQmlApplicationEngine:

.h file:

QQmlApplicationEngine* m_pAppMainWindow;
QQuickWindow* m_pQuickWindow;

.cpp file:

m_pAppMainWindow = new QQmlApplicationEngine();

I use it to get app qml context

QQmlContext* pQmlContext = m_pAppMainWindow->rootContext();

to load the main QML file from resources:

m_pAppMainWindow->load(QUrl("qrc:/qml/ViewMain.qml"));

to set Image providers:

m_pAppMainWindow->addImageProvider(...);

and to get QQuickWindow object:

m_pQuickWindow = m_pQuickWindow = qobject_cast<QQuickWindow *>(m_pAppMainWindow->rootObjects()[0]);

I use the QQuickWindow object to set app window minimum size:

m_pQuickWindow->setMinimumWidth(...)

to get the QML objects to work with:

QObject* pObjViewMain = m_pQuickWindow->findChild<QObject*>("viewMain");

and to set app in full screen mode (on/off):

m_pQuickWindow->showFullScreen();
or 
m_pQuickWindow->showNormal();

My problem is with this last point, when I enter Full Screen...

Hope anyone can help me

Thanks

p3c0

@Diego-Donate
Not sure but as I understand from the description you are first creating the widget and then from there trying to load the QML using QQmlApplicationEngine. So there are 2 windows here. May be that could be the problem ?
Instead of QQmlApplicationEngine you can use QQuickWidget so that the QML type gets embedded into the widget. QQuickWidget requires root element to be of type Item.

Diego Donate

@p3c0 Thanks for your help, I will try your option, I hope I could use QQuickWidget instead of QQmlApplicationEngine with no problem or unexpected effect.