Question

Sorry if this is a repost but I couldn’t quite search for it because I can’t explain it in a few words. I have a super class with lots of methods but they will always (not all of them) be subclassed. From the super I need to run those methods. I could either leave the methods in super empty or I could just not type them in super but call them anyway like so [self myMethod] and it will call my subclassed method even if it doesn’t exist in super. This works but Xcode gives me an error though. 'superclass' may not respond to '-subclassmethod'

What should I do so I won’t get the warnings?

Answer 1

I prefer to define the unimplemented methods in the superclass like this:

@interface GLObject : NSObject {}
- (id)someSubclassProvidedMethod;
@end

@implementation GLObject
- (id)someSubclassProvidedMethod {
  [self doesNotRecognizeSelector: _cmd];
}
@end

It’s almost entirely redundant, because the Objective-C runtime would eventually call -doesNotRecognizeSelector: if I didn’t define the method at all. But because I do define it, it’s in the class’s interface which both keeps the compiler happy and provides me with some documentation.