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Can't create a QWidget from dynamic library: "Must construct a QApplication before a QWidget"

  • I built a QtMmlWidget as a dynamic library and included it in my project. But when I'm trying to create this widget, I'm getting "Must construct a QApplication before a QWidget" error.
    How can I solve this issue?

  • Moderators


    Like the error message says, you need to create a QApplication object in order to use widgets. You also need to start the event loop by calling QApplication::exec().

    This needs to be done in a separate thread, to avoid blocking your main thread. Start a new std::thread, and call the initialization function there.

  • Thanks, it helped me.

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