QML file is not to use getContext () function, a use will prompt the following error, is really don't know where I went wrong,
Always find a EGLConfig, returning null config
QWindowsEGLContext: Failed to create the context, eglError: 300 e, this: 0 x144c5210
Qt. Qpa. Backingstore: composeAndFlush: makeCurrent () failed