NSAutoreleasePool and class variables

I'm getting what looks like a crash due to overreleasing but as far as I can tell I'm not doing anything wrong, however I may have the wrong idea about AutoreleasePools and class variables.

If I have a class variable:

UIImageView *imageView;

and I allocate it in a thread like so:

 - (void)setupThreaded {
     NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];

     UIImage *image = [UIImage imageNamed:@"myimage.png"];
     imageView = [[UIImageView alloc] initWithImage:image];

     [self performSelectorOnMainThread:@selector(addViewOnMain开发者_运维问答Thread) withObject:nil waitUntilDone:YES];

     [pool release];
}

- (void)addViewOnMainThread {
    [self.view addSubView:imageView];
}

I'm currently occasionally getting an error suggesting that either imageView was prematurely released OR that imageView's image is getting prematurely released.

What could be causing that?

---

It is extremely unusual to store a view in a class variable. Why are you doing this?

It is, in general, illegal to access UIView on background threads. The docs are a little dodgy on whether construction of a UIView is legal on a background thread, but once you dive into initWithImage:, it definitely is not explicitly supported and is probably not allowed.

If there is some reason you're creating the UIImage on a background thread, that's fine, but then just pass the UIImage itself to the main thread and create the view there. You don't need a class variable to pass it between the threads. Just pass it as the object to performSelectorOnMainThread:withObject.