Re: KVO and object release timing (for a NSCollectionView)
Re: KVO and object release timing (for a NSCollectionView)
- Subject: Re: KVO and object release timing (for a NSCollectionView)
- From: vincent habchi <email@hidden>
- Date: Sat, 23 Jan 2010 10:48:31 +0100
Hi Corbin,
>> I have a NSButton in C to remove from the array controller the A object it represents. However, each time I click on that button, I first get a warning telling me that I remove an observed object before releasing the observer, and then the program crash,
>
> If you have a crash, it is always best to post the crash report.
Well, I wrote a workaround, so I can't give you a crash report anymore.
The crash happens in the KVO unregistering routine.
The problem is that when the represented object is removed from the array controller, the corresponding NSView is not immediately released. Instead, there is an implied CAAnimation (or something similar) that makes the NSView slowly fade away. Net result is that the NSView survives some tenths of a second after the represented object is released, and the KVO unregistering crashes.
The (very dirty) workaround is this: instead of immediately release the represented object, retain it, target it for delayed deletion, and then remove it from the array; the real deletion is triggered in the dealloc routine of the corresponding NSView (or subclass thereof) :
// Highly heterodox
- (void)dealloc {
[super dealloc];
[[[[NSApp delegate] appController] layerManager] removeTargetedCALayer];
}
I had to write it this way, instead of the more orthodox :
- (void)dealloc {
[[[[NSApp delegate] appController] layerManager] removeTargetedCALayer];
[super dealloc];
}
because the KVO removal takes place in the [super dealloc] routine…
Great WE,
Vincent_______________________________________________
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