iphone image is leaking, but where? - iphone

Question

the image that is being displayed in this code is leaking but I cant figure out how. What I have a tableview that displays images to be displayed. Each time a user selects an image, it should remove the old image, download a new one, then add it to the scroll view. But the old image is not being released and I cant figure out why...
-(void)tableView:(UITableView *)tableView
didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
[imageView removeFromSuperview];
self.imageView = nil;
NSUInteger row = [indexPath row];
NSString *tempC = [[NSString alloc]initWithFormat:#"http://www.website.com/%#_0001.jpg",[pdfNamesFinalArray objectAtIndex:row] ];
chartFileName = tempC;
pdfName = [pdfNamesFinalArray objectAtIndex:row];
[tableView deselectRowAtIndexPath:indexPath animated:YES];
NSArray* paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,
NSUserDomainMask, YES);
NSString *docsPath = [paths objectAtIndex:0];
NSString *tempString = [[[NSString alloc]initWithFormat:#"%#/%#.jpg",docsPath,pdfName]autorelease];
NSData *data = [NSData dataWithContentsOfFile:tempString];
if (data != NULL){
self.imageView = nil;
[imageView removeFromSuperview];
self.imageView = nil;
UIImageView *tempImage = [[[UIImageView alloc]initWithImage:[UIImage imageWithData:data]]autorelease];
self.imageView = tempImage;
[data release];
scrollView.contentSize = CGSizeMake(imageView.frame.size.width , imageView.frame.size.height);
scrollView.maximumZoomScale = 1;
scrollView.minimumZoomScale = .6;
scrollView.clipsToBounds = YES;
scrollView.delegate = self;
[scrollView addSubview:imageView];
scrollView.zoomScale = .37;
}
else {
[data release];
self.imageView = nil;
[imageView removeFromSuperview];
self.imageView = nil;
activityIndicator.hidden = NO;
getChartsButton.enabled = NO;
chartListButton.enabled = NO;
saveChartButton.enabled = NO;
[NSThread detachNewThreadSelector:#selector(downloadImages) toTarget:self withObject:nil];
}
chartPanel.hidden = YES;
}
-(void) downloadImages {
NSAutoreleasePool* pool = [[NSAutoreleasePool alloc] init];
self.imageView = nil;
[imageView removeFromSuperview];
NSURL *url = [[[NSURL alloc]initWithString:chartFileName]autorelease];
NSData *data = [NSData dataWithContentsOfURL:url];
UIImageView *tempImage = [[[UIImageView alloc]initWithImage:[UIImage imageWithData:data]]autorelease];
self.imageView = tempImage;
tempImage = nil;
scrollView.contentSize = CGSizeMake(imageView.frame.size.width , imageView.frame.size.height);
scrollView.maximumZoomScale = 1;
scrollView.minimumZoomScale = .37;
scrollView.clipsToBounds = YES;
scrollView.delegate = self;
[scrollView addSubview:imageView];
scrollView.zoomScale = .6;
activityIndicator.hidden = YES;
getChartsButton.enabled = YES;
chartListButton.enabled = YES;
saveChartButton.enabled = YES;
[pool drain];
[pool release];
}

Answer 1

This looks wrong:
self.imageView = nil;
[imageView removeFromSuperview];
You are setting imageView to nil before removing it from the superview, so the 2nd statement is really just [nil removeFromSuperview];, which isn't going to do anything.

Answer 2

I think the leak is what David Gelhar said, but I just wanted to add that you shouldn't access UI stuff from threads other than the main thread (so for instance, don't do [imageView removeFromSuperview] under a separate thread). This can cause very odd problems, including mysterious leaks. Try putting all that stuff in a separate method on the main thread that you call with [self performSelectorOnMainThread:] and see if it still leaks.
Also (although this wouldn't cause the leak), [pool drain] releases the autorelease pool, so you shouldn't invoke [pool release] after it--it might release the pool on the main thread, possibly causing a crash somewhere down the line (since you could over-release the pool).