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Re: superclass and awakeFromNib

When -[DummyViewA awakeFromNib] is called with [aDummyViewB awakeFromNib], the "self" pointer still points to an instance of DummyViewB. Therefore [self superclass] will be DummyViewA.

Keep repeating to yourself: Objective-C messages are resolved at run time, not compile time.

"super," however, still refers to the implementation in the superclass of the current implementation, which is why your code attempts to send -[NSView awakeFromNib], and fails.

What you do know at compile time is what classes you're implementing awakeFromNib for, what the superclass of each class is, and that NSView does not implement awakeFromNib, It isn't cheating to simply send [super awakeFromNib] in -[DummyViewB awakeFromNib] and not send it in -[DummyViewA awakeFromNib].

-- F

On Saturday, November 30, 2002, at 10:52 AM, Simon Bovet wrote:

@interface DummyViewA : NSView {
}
@end

@interface DummyViewB : NSViewA {
}
@end

@implementation DummyViewA // same for DummyViewB

-(void)awakeFromNib
{
if ([[self superclass]
instancesRespondToSelector:@selector(awakeFromNib)])
[super awakeFromNib];
}

@end

When [DummyViewB awakeFromNib] is performed during program execution,
it works fine and calls [DummyViewA awakeFromNib]. Now, [self
superclass] in DummyViewA returns DummyViewA (!) and [super
awakeFromNib] throws the exception "*** -[DummyViewB awakeFromNib]:
selector not recognized".

--
Fritz Anderson - Consulting Programmer - Chicago, IL
Mail: <email@hidden>
Risumi: <http://resume.manoverboard.org>
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References: 
 >superclass and awakeFromNib (From: Simon Bovet <email@hidden>)



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