Properly initialize WebEngineView

S0ulM1ke

I've decided to add YouTube video playback feature in my app (in QML), so I choose WebEngineView

As I watched the documentation I do this in main.cpp :

    QCoreApplication::setAttribute(Qt::AA_ShareOpenGLContexts);
    QtWebEngineQuick::initialize();

Before initializing QCoreApplication.

And in my view i use this:

import QtWebEngine 1.10
...
                        WebEngineView {
                            width: 600
                            height: 300
                            Component.onCompleted: {
                                url = model.gameVideoUrl
                            }
                        }
...

This works but I have this message in output (happens when item initializes):

QWebEngineFileSystemAccessRequest is neither a QObject, nor default- and copy-constructible. You should not use it as a QML type.
QWebEngineCertificateError is neither a QObject, nor default- and copy-constructible. You should not use it as a QML type.
QWebEngineFullScreenRequest is neither a QObject, nor default- and copy-constructible. You should not use it as a QML type.
QWebEngineLoadingInfo is neither a QObject, nor default- and copy-constructible. You should not use it as a QML type.

What am I doing wrong?

Drazz

Does anyone know why this warnings appear?

JonB

@Drazz
Seemingly same as https://github.com/OmixVisualization/qtjambi/issues/94#issuecomment-1290511207 ?
I don't know whether QCoreApplication (rather than QApplication) is enough for your purposes, but what happens if you do it before the QtWebEngineQuick::initialize();?
Otherwise is it a harmless warning which should just be ignored, because of the order of initialization?

Drazz

Thanks for your answer.

In my case, I've tested WebEngine Quick Nano Browser example using Qt 6.4.3. It uses QGuiApplication and QtWebEngineQuick::initialize is called before creating the application instance.

If I move QtWebEngine::initialize() below QGuiApplication, I not only get the same warnings but also an additional message:

QtWebEngineQuick::initialize() called with QCoreApplication object already created and should be called before. This is deprecated and may fail in the future.

I like to take care of warnings whenever possible, as they can indicate potential issues. Is there any official explanation for these specific warnings?