Question

I recently tried to subclass UITextField and set the delegate to myself (found this trying ti solve my problem: http://www.cocoabuilder.com/archive/cocoa/241465-iphone-why-can-a-uitextfield-be-its-own-delegate.html)

@interface MyObject :UITextField <UITextFieldDelegate>
@end

@implementation MyObject

-(id) initWithFrame:(CGRect) frame
{
  if((self=[super initWithFrame:frame]))
  {
      self.delegate=self;
  }
  return self;
}

-(BOOL) respondsToSelector:(SEL)selector
{
    NSLog(@"responds to selector");
    return [super respondsToSelector:selector];
}

// Implement all the missing methods
@end

Calling a method defined on the interface results in an infinite recursion. I don’t see anything in the Apple docs that defines how respondsToSelector is supposed to behave in the presence of a delegate.

Answer 1

The docs for respondsToSelector states the following:

You cannot test whether an object
inherits a method from its superclass
by sending respondsToSelector: to the
object using the super keyword. [..]
Therefore, sending respondsToSelector:
to super is equivalent to sending it
to self. Instead, you must invoke the
NSObject class method
instancesRespondToSelector: directly
on the object’s superclass

It seems that this could be the cause for your recursion problem. I don’t know if the delegate stuff is even related. Just a guess though.