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POProblem dealloc'ing memory used by UIImageViews with fairly large image in an UIScrollView
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  1. POProblem dealloc'ing memory used by UIImageViews with fairly large image in an UIScrollView
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    copied!<p>I have a large UIScrollView into which I'm placing 3-4 rather large (320x1500 pixels or so) UIImageView image tiles. I'm adding these UIImageViews to the scroll view inside of my NIB files. I have one outlet on my controller, and that is to the UIScrollView. I'm using a property (nonatomic, retain) for this, and sythesizing it.</p> <p>My question is this: When I observe this in Memory Monitor, I can see that the memory used goes up quite a bit when the view with all these images is loaded (as expected). But when I leave the view, it and its controller are dealloc'd, but do not seem to give up anywhere near the memory they had taken up. When I cut one of these views (there are several in my app) down to just 1-3 images that were 320x460 and left everything else the same, it recaptures the memory just fine.</p> <p>Is there some issue with using images this large? Am I doing something wrong in this code (pasted below)?</p> <p>This is a snippet from the viewController that is causing problems.</p> <pre><code>- (CGFloat)findHeight { UIImageView *imageView = nil; NSArray *subviews = [self.scrollView subviews]; CGFloat maxYLoc = 0; for (imageView in subviews) { if ([imageView isKindOfClass:[UIImageView class]]) { CGRect frame = imageView.frame; if ((frame.origin.y + frame.size.height) &gt; maxYLoc) { maxYLoc = frame.origin.y; maxYLoc += frame.size.height; } } } return maxYLoc; } - (void)viewDidLoad { [super viewDidLoad]; [self.scrollView setContentSize:CGSizeMake(320, [self findHeight])]; [self.scrollView setCanCancelContentTouches:NO]; self.scrollView.indicatorStyle = UIScrollViewIndicatorStyleWhite; self.scrollView.clipsToBounds = YES; self.scrollView.scrollEnabled = YES; self.scrollView.pagingEnabled = NO; } - (void)dealloc { NSLog(@"DAY Controller Dealloc'd"); self.scrollView = nil; [super dealloc]; } </code></pre> <p>UPDATE: I've noticed another weird phenomenon. If I don't use the scroll on the view, it seems to be hanging on to the memory. But if I scroll around a bunch and ensure that all of the UIImageViews became visible at one point, it will free up and regain most of the memory it lost.</p> <p>UPDATE2: The reason I'm asking this is my app is actually crashing due to low memory. I wouldn't mind if it were just caching and using up extra memory, but it doesn't seem to ever release it - even in didReceiveMmoryWarning conditions</p>
 

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