title: How to be alerted when uiviewcontroller is pushed / popped from navigation stack
body: <p>I need to do certain things when my view controller is both pushed or popped from the navigation stack, but don't want to use viewillappear / viewdidappear or viewwilldisappear / viewdiddisappear since those cover cases besides when the view controller is pushed / popped. Is the correct way to go about this to use the navigationcontroller delegate and the navigationController:didShowViewController:animated: and navigationController:willShowViewController:animated: ? If not, how is the best way to go about this?</p>