How to cast a QML object as QQuickWindow from c code?-CodePudding

I am using QQmlVTKPlugin, which allows me to directly access to VTKRenderWindow and VTKRenderItem with QML. To setup this I need to give to my QQMLApplicationEngine a QQuickWindow and a QQuickItem. If I just do this initialization from the main.cpp everything works correctly but for some reason I need to do that by calling a class constructor inside my QML file with a singleton. I call the following constructor from the QML but when I do window->show() my application crashes

SceneManage::SceneManage(QObject *topLevel)
{
    window = qobject_cast<QQuickWindow *>(topLevel);   // QQuickWindow window
    window->show();
    QQuickItem *item = topLevel->findChild<QQuickItem *>("3DViewer");
...

Does someone have a way to do what I want ?

CodePudding user response：

Solution : Don't decide to show the window from c but only set visible parameter in QML.