Question

I have a class that declares and implements this :

- (void) callbackme:(OneClass*)p1 error:(NSString*)errStr {

}

and that calls in an instance method :

[self.obj oneAction:@"a string" sendAnswerToObject:self]; // obj is a custom class

in oneAction method of the custom class, I have :

- (void) oneAction:(NSString*)p1 sendAnswerToObject:(id)listener {

     if (listener != nil && ![listener respondsToSelector:@selector(callbackme::)]) 
             NSLog(@"Listener does not respond to selector 'callbackme:error:'");
}

The NSLog is triggered and I don’t understand why ?

The listener must be an id as it can be any object instance of any class.

Answer 1

Your if should be

if (listener != nil && ![listener respondsToSelector:@selector(callbackme:error:)]

just as the log you created.