On Jul 25, 2009, at 5:32 PM, Adam R. Maxwell wrote:
On Jul 25, 2009, at 5:02 PM, Luke the Hiesterman wrote:
On Jul 25, 2009, at 3:41 PM, Adam R. Maxwell wrote:
On Jul 25, 2009, at 3:23 PM, Kyle Sluder wrote:
Internally, UITextField is going to use self.delegate to get its
delegate, following the correct accessor behavior. You've gone and
replaced -delegate to return self. But the delegate pattern says
that
messages which this object does not understand should be
forwarded to
the delegate. This means that a class with a delegate needs to
implement -respondsToSelector: this way:
- (BOOL)respondsToSelector:(SEL)aSelector {
return [super respondsToSelector:aSelector]
|| [self.delegate respondsToSelector:aSelector];
}
Where is this guaranteed by the delegate pattern? I've created a
fair number of classes with delegates and never done this; it
would be interesting to know that I've been doing it wrong for
years ;).
It's not guaranteed - it's just the right way to implement an
optional delegate method.
Who says it's the right way, though? I've never seen a delegate
implemented that way, in documentation or sample code, and wouldn't
you also have to implement forwarding code to keep this from
breaking? Maybe I'm dense, but I don't see the point of doing this.
I read the code too quickly. I just thought it was the standard if
([delegate respondsToSelector:....]) [delegate doSomething]; paradigm.
I retract my statement. That is definitely not a standard of the
delegation pattern.
Luke
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