Question

I’m attempting to attach a listener to a window object that is destroyed when the window is closed.

However, the window object does not have an OnClose type method that is called from clicking the X to close (It’s Autodesk Maya’s pymel.core.uitypes.Window if you’re curious why).

add_listener creates a listener that exists in the active session. attach_listener I am creating to cause the listener to remove itself when the window closes, and requires a window to be attached to.

My solution is as follows:

def attach_listener(window, event_name, function):
    def wrapper(*args, **kwargs):
        if window.exists():
            return function(*args, **kwargs)
        else:
            remove_listener(id_number)
    id_number = add_listener(event_name, wrapper)

This obviously won’t work because id_number is not defined until after the function is declared, however, I cannot pass the function to add_listener without defining it first. id_number cannot be passed to add_listener. What do I do to get around this?

Answer 1

You can try this kind of approach:

def attach_listener(window, event_name, function):
    def wrapper(*args, **kwargs):
        if window.exists():
            return function(*args, **kwargs)
        else:
            remove_listener(wrapper.id_number)
    wrapper.id_number = add_listener(event_name, wrapper)