Inheritance: Restricting rather than extending? [duplicate]

Answer 1

Actually, you CAN restrict with a subclass. You can override whichever methods you want to block in your subclass's .h file. You can make initWithFrame unavailable by placing the following in your .h file.

- (id) initWithFrame:(CGRect) frame __attribute__((unavailable("message")));

This will make the initWithFrame: method unavailable to anyone using your subclass.

To keep other code form calling this method, you can further restrict by putting this in your .m file.

- (id) initWithFrame:(CGRect) frame
{
    return nil;     
}