setDelegate type constraint is too strict

[dementrock]

In general, any object may conform to a delegate protocol as long as it implements the required methods. For example, some classes in UIKit may already be conforming to some protocols, but these information are not captured by the Java class hierarchy.

A more specific example: UIViewController actually conforms to UIGestureRecognizerDelegate.

[neocxi]

I actually like the constraint placed by setDelegate. Usually the optional method/required method thingy could be handled by xxDelegateAdapter. In the case of reusing other classes, I think the best we can do is to model after Xamarin, ie providing a setWeakDelegate(Object) that puts all the trust on developers

[dementrock]

That's better.