Widget's “destroyed” signal is not fired (PyQT)

Question

I have a widget which would have to do some manual cleanup after it\'s destroyed (stop some threads). However for some reason the \"destroyed\" signal of the widget is not f

Answer 1

The python class instance (or at least the pyqt<->qt link) doesn't exist by the time destroyed is emitted. You can work around this by making the destroyed handler a staticmethod on the class. This way, the python method will still exist when the destroyed signal is emitted.

class MyWidget(QWidget):

    def __init__(self, parent):
        super(MyWidget, self).__init__(parent)
        self.destroyed.connect(MyWidget._on_destroyed)

    @staticmethod
    def _on_destroyed():
        # Do stuff here
        pass

If you need information specific to the class instance you can use functools.partial and the instance __dict__ to pass that info to the destruction method.

from functools import partial

class MyWidget(QWidget):

    def __init__(self, parent, arg1, arg2):
        super(MyWidget, self).__init__(parent)
        self.arg1 = arg1
        self.arg2 = arg2
        self.destroyed.connect(partial(MyWidget._on_destroyed, self.__dict__))

    @staticmethod
    def _on_destroyed(d):
        print d['arg1']