Get UINavController from subview of UIView?

问题:

I added a custom subview to a UIViewController's content view. From that subview, how can I get a reference to the superview's controller? Thanks

回答1:

The correct answer is "You're Doing It Wrong™" ;-)

You shouldn't need to reference to a view controller from a view, and you certainly should never retain a view controller in one of your views -- or you'll end up with a retain loop and leak memory.

Cocoa provides multiple patterns to solve this problem:

• Use a delegate: Define a protocol called DemoViewDelegate and add a delegate property to DemoView. Then have your view controller implement this protocol. Important: delegates should never be retained! Any delegate property you create should be set to assign. See Apple's Delegation docs or just google "delegation pattern".

• Use the responder chain: Call UIApplication's sendAction:to:from:forEvent: and leave to: set to nil to have your action message automatically routed up the responder chain to your view controller. See Apple's Responder docs and the more detailed Action Messages docs.

• Use a notification: Less common in this particular scenario, but you could also have your view controller listen for a notification, which the view sends.