What exactly willMoveToParentViewController: and didMoveToParentViewController: do?

Question

I know that starting with iOS5 and the new UIViewController containment methods, you are supposed to call these methods together with addChildViewController:

Answer 1

In addition to what has been said, they do call some delegate methods:

addChildViewController calls [child willMoveToParentViewController:self]

and removeFromParentViewController: calls [child didMoveToParentViewController:nil]

Also, they modify the childViewControllers property, which holds an array of child view controllers.