White screen observed while launching the QGraphicsView application - c++

Question

Our application uses Qt's Graphics View framework to load the html pages. QGraphicsWebView loads local html page which is black background. But always observed the white screen while launching the application. I have tried setting black background for both QGraphicsView and QGraphicsScene. Nothing worked for me.
Here's the sample code for your reference.
MainWindow which inherited from QMainWindow class
mGraphicsScene = new QGraphicsScene(this);
mGraphicsView = new QGraphicsView(mGraphicsScene);
mGraphicsView->setViewport(new QGLWidget(this));
mGraphicsWebView = new QGraphicsWebView;
mGraphicsWebView->setUrl(QUrl("https://www.google.co.in/"));
mGraphicsScene->addItem(mGraphicsWebView);
setCentralWidget(mGraphicsView);
Is there any way to avoid white screen of the application?
Best Regards,
Pratap

Answer 1

Try next. Why did you see white? Because item already added, but page not loaded, so you see white(blank) item without page. Set to your scene some black pixmap, connect loadFinished signal to special slot, where you add item to your scene. In this case scene will be black, but when page will be loaded, your slot will add this on scnen and you will see only page.
mGraphicsScene = new QGraphicsScene(this);
mGraphicsScene->addItem(new QGraphicsPixmapItem(QPixmap("G:/2/qt.jpg")));
mGraphicsView = new QGraphicsView(mGraphicsScene);
mGraphicsView->setViewport(new QGLWidget(this));
mGraphicsWebView = new QGraphicsWebView;
mGraphicsWebView->setUrl(QUrl("https://www.google.co.in/"));
connect(mGraphicsWebView,SIGNAL(loadFinished(bool)),this,SLOT(slotLoaded()));
//mGraphicsScene->addItem(mGraphicsWebView);
mGraphicsView->resize(1000,700);
mGraphicsView->show();
Slot:
void MainWindow::slotLoaded()
{
mGraphicsScene->addItem(mGraphicsWebView);
}
For example black pixmap which was created by code:
QPixmap black(1000,700);
black.fill(Qt::black);
mGraphicsScene = new QGraphicsScene(this);
mGraphicsScene->addItem(new QGraphicsPixmapItem(black));
When application start:
As you can see, all is black, when page was loaded:
As you can see, it is normal page. It is not very beautiful because I use fast settings and resize window and so on, but you set graphicsview as central widget, do it will be more beautiful.

Answer 2

Thank you very much for the response.
I have tried your solution and also observed white screen while launching the application on Windows
I found the culprit is mGraphicsWebView->setUrl(QUrl("https://www.google.co.in/")); This is blocking all other widgets on the scene. So I have added a singleShot timer and kept this statement under that.
//QTimer::singleShot(100, this, SLOT(loadUrl())); Then it works fine.
Please let me know if you have any better idea.