Question

The responder chain sends an event to a view and then to its controller. But how does the system know the controller object for the view ? I didn’t find any property in UIView that stores the reference to its controller. On the other hand, a controller clearly has the view property to identify its view.

Answer 1

UIView (UIResponder subclass) knows about it’s viewcontroller or superview through the instance method

- (UIResponder *)nextResponder

From UIResponder class reference:

The UIResponder class does not store
or set the next responder
automatically, instead returning nil
by default. Subclasses must override
this method to set the next responder.
UIView implements this method by
returning the UIViewController object
that manages it (if it has one) or its
superview (if it doesn’t);
UIViewController implements the method
by returning its view’s superview;
UIWindow returns the application
object, and UIApplication returns nil.