iOS how to detect programmatically when top view controller is popped?

Question

Suppose I have a nav controller stack with 2 view controllers: VC2 is on top and VC1 is underneath. Is there code I can include in VC1 that will detect that VC2 has just be

Answer 1

You can also detect in the view controller that is being popped

- (void)viewWillDisappear:(BOOL)animated {
    [super viewWillDisappear:animated];

    if ([self isMovingFromParentViewController]) {
        ....
    }
}