ios - 确定响应者链是否会处理一个动作

Answer 1

There's a delightful solution here to finding the first responder by exploiting the responder chain.

Once you know the first responder, it's easy to ask if the current responder chain handles a particular action. You can even find out who'll be handling it, should you wish.

const SEL action = @selector(theActionYouWantToSend);
UIResponder *const currentTarget = [[UIResponder firstResponder] targetForAction: action  withSender: self];
const bool actionIsHandled = currentTarget != nil;

Answer 2

You can check if the responder can respond to the action like this:

[aResponder respondsToSelector:@selector(methodToSend)];

If it can respond, it'll return YES. Then you know it's safe to call that method