Checking to see if an optional protocol method has been implemented

Question

Does anyone know the best way to check to see if an optional protocol method has been implemented.

I tried this:

if ([self.delegate respondsToSelector:@selector(optionalProtocolMethod:)] )

where delegate is:

id<MyProtocol> delegate;

However, I get an error saying that the function respondsToSelector: is not found in the protocol!

Answer 1

respondsToSelector: is part of the NSObject protocol. Including NSObject in MyProtocol should solve your problem:

@protocol MyProtocol <NSObject>

@optional
-(void)optionalProtocolMethod:(id)anObject;

@end

Answer 2

What I do is applying the following recipe:

if(self.delegate && [self.delegate respondsToSelector:@selector(closed)]){
    [self.delegate closed];
}

Where 'closed' is the method that I wanted to call.