“Must construct a QApplication before a QPaintDevice” from QWidget

Question

I\'m busy porting an IRC client from Python 2.6 to 3.3 and I\'ve stumbled across a problem with PyQt. The application originally used PyQt4, I\'m also recoding it to get it

Answer 1

I'm afraid single file will not be enough in this situation - the execution flow is not clear just from this one module. The message in question usually appears when you try to use some resources/create some objects that require initialized QApplication - like QIcon, for example.

Instantiation of Qt-based GUI application usually looks like this:

if __name__ == "__main__":
    app = QtGui.QApplication(sys.argv)
    main_window = MainWindowClass()
    main_window.show()
    sys.exit(app.exec_())