Question

I wrote an objective-C class that needs to notify another class, so i defined a protocol for a delegate:

@protocol glob_protocol <NSObject>
  @required
  - (IBAction) call:(int) val val2:(int) val2;
@end

In my class i have a member to store the delegate:

  IBOutlet id <glob_protocol> delegate;

When connecting the classes / instances in the Interface Builder there is no type checking now. I can connect any class as a delegate.

Is there a way to enable type checking? I’d like that only classes / instances that implement the protocol can be set as delegates.

Thanks for any hints,
Torsten.

EDIT:
I just checked in the Header files of UIKit to see if there are any additional infos or keywords but i did not find any. I wonder where InterfaceBuilder got tthe information from what instances can be set as delegate.

Answer 1

this usually works:

- (void)setDelegate:(id<glob_protocol>)inDelegate
{
  if (inDelegate) {
    assert([inDelegate conformsToProtocol:@protocol(glob_protocol)]);
  }
  ...
}

although that’s not at the level/phase you want, it works well because connections don’t change often.