View Controller being sent a message even though it has been deallocated

Question

I am not sure if something has changed in the iPhone SDK 3.0 but I am getting the strangest error. I have a view controller hierarchy where I switch between view controllers

Answer 1

I've run into this problem as well. The order of events is:

(1) create the application's single UIWindow object

(2) add a subview that's managed by a view controller to the window

(3) remove the first view and add a new one

If I rotate the device afterwards, the application crashes because of a message sent to the deallocated view controller. (Well, it's actually sending it to a sub-controller of the first view controller.) It's trying to send -[respondsToSelector:@selector(shouldAutorotateToInterfaceOrientation:)].

If your application only runs in portrait mode, you can make the problem go away by adding a category to UIWindow that overrides _shouldAutorotateToInterfaceOrientation: to return NO for everything other than portrait mode.

Obviously, this isn't a real solution. I've double-triple-checked my code and I can find no reason why the window should be sending this message to the controller for a view that's been removed from the screen and deallocated. This problem also seems to have appeared in 3.0 and not before. Perhaps I'm doing something stupid, but there really seems to be something strange at work here.