Re: nibs don't respect protocols
Re: nibs don't respect protocols
- Subject: Re: nibs don't respect protocols
- From: Jonathan Hess <email@hidden>
- Date: Thu, 3 Jun 2010 14:41:09 -0700
On Jun 2, 2010, at 2:18 PM, Christiaan Hofman wrote: On Jun 2, 2010, at 20:27, Matt Neuburg wrote: I'm moving this over from Cocoa-Dev, so if you have the feeling you've seen
this before, that's why.
I'm struck by the following sort of situation. A UIApplication's delegate
property is defined as an id <UIApplicationDelegate>. But if I hook up the
UIApplication proxy object in a nib to another instance as its delegate, and
if that other instance does _not_ formally adopt UIApplicationDelegate,
there seems to be no penalty: the nib doesn't complain, and the app runs
fine.
So... Are nibs just ignorant of protocols? This feels like a bug. If you try
to hook up an outlet to the wrong type (e.g. a UILabel instead of a declared
UITextField), you can't; Interface Builder won't let you. Well, a class that
doesn't declare conformance to UIApplicationDelegate *is* the wrong type for
UIApplication's delegate; yet Interface Builder *does* let you. In that
case, what's the point of having the protocol at all?
IB is indeed not checking protocols, only classes. Note that IB is ignorant in more ways, for instance it also does not know about informal categories in separate files.
If you have an alternate header file with:
@interface MyClass(ExtraActions)
- (IBAction)myExtraAction:(id)sender;
@end
IB will allow connections to "myExtraAction:" on instances of MyClass. Is that what you meant?
Jon Hess |
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