Understanding UIResponder 

What is UIResponder? ✤ Basis of many regularly used components: UIView, UIViewController, AppDelegate, UIWindow ✤ Important for interacting with the application 

UIResponder Core Methods ✤ touchesBegan:withEvent: ✤ touchesMoved:withEvent: ✤ touchesEnded:withEvent: ✤ touchesCancelled:withEvent: ✤ becomeFirstResponder ✤ canBecomeFirstResponder ✤ canResignFirstResponder ✤ isFirstResponder 

UIResponder - First Responder ✤ An object can only become a first responder if the existing first responder returns TRUE for canResignFirstResponder and the current object returns TRUE for canBecomeFirstResponder ✤ The default for canResignFirstResponder is TRUE and FALSE for canBecomeFirstResponder ✤ InputView is shown when UIResponder becomes FirstResponder (like a keyboard) 

UIResponder Chain 

UIResponder Chain ✤ nextResponder defaults to nil; subclasses are responsible for determining the next object in the chain ✤ UIView returns its ViewController if its managed by one, or its superview if not ✤ UIViewController returns the UIWindow ✤ UIWindow returns the AppDelegate ✤ Event will be thrown out if not handled 

Questions? Magnets, how do they work? 

Thanks! My name is Dirk @dirkthedaring [email protected]