NSAutoreleasePool leaking

I know this must be something simple that I am overlooking, but why is this leaking:

//add a pool for this since it is on its own thread
NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];

//add the image
NSURL * imageURL = [NSURL URLWithString:[recipeData objectForKey:@"imagePath"]];
NSData * imageData = [NSData dataWithContentsOfURL:imageURL];
UIImage * image = [UIImage imageWithData:imageData];
UIImageView *开发者_运维知识库 myImageView = [[UIImageView alloc] initWithImage:image];

//resize to make it fit the screen space 
CGRect frame = myImageView.frame;
frame.size.width = 320;
frame.size.height = 357;
myImageView.frame = frame;

[self.view addSubview:myImageView];


[activity stopAnimating];

[pool drain];
[self placeItems];

I get the error:

_NSAutoreleaseNoPool(): Object 0x4e2fdf0 of class NSPathStore2 autoreleased with no pool in place - just leaking

I tried moving the placement of [pool drain] but that did nothing. I see a lot of code that looks just like this while searching Google for a cause.

Thanks for your help.

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Draining the pool has the effect of releasing and subsequently deallocating it, since autoreleasepools cannot be retained. I suspect there must be some need for an autoreleasepool within placeItems (or some other place called after [pool drain]) since at that point the pool is propably gone already.

So, you might want to try commenting out the drain message to see if that will make the leak go away.

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A lot of things to say here :

• first, you're leaking myImageView. You have to release it after the -addSubview.
• next, since you're on another thread, your [pool drain] must be at the end
• last, since you're not on the main thread, you can't perform any UI operation. Try to replace [self.view addSubview:myImageView] by [self.view performSelectorOnMainThread:@selector(addSubview:) withObject:myImageView waitUntilDone:YES]. Same with [activity stopAnimating].

And like Brian said, the -drain message must be at the end of your thread.