iOS NSURLConnection memory leak

Question

i got code like this

#import "UIWebImageView.h"

@interface UIWebImageView (hiddenMethods)

- (void) initDefaults;

@end

@implementation UIWebImageView (hiddenMethods)

- (void) initDefaults
{
    self.showActivityIndicator = NO;
    self.activityIndicatorStyle = UIActivityIndicatorViewStyleWhite;
    self.activityIndicatorSize = CGSizeMake(20.0, 20.0);
    //data = [[NSMutableData alloc] init];
}

@end

@implementation UIWebImageView

@synthesize showActivityIndicator;
@synthesize activityIndicatorStyle;
@synthesize activityIndicatorSize;

- (id) init
{
    if (self = [super init])
    {
        [self initDefaults];
    }
    return self;
}

- (void) loadFromURL:(NSString *) url
{
    [self.image release];
    self.image = nil;
    request = [NSURLRequest requestWithURL:[NSURL URLWithString:url] 
                                             cachePolicy:NSURLRequestReturnCacheDataElseLoad
                                         timeoutInterval:30.0];

    if (connection == nil)
        connection = [[NSURLConnection alloc] initWithRequest:request delegate:self];

    // activity indicator start
    indicator = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:activityIndicatorStyle];
    indicator.frame = CGRectMake((self.frame.size.width - activityIndicatorSize.width)/2, (self.frame.size.height - activityIndicatorSize.height)/2,
                                 activityIndicatorSize.width, activityIndicatorSize.height);

    [self addSubview:indicator];
    [indicator startAnimating];
}

- (void) dealloc
{
    [data release];
    [indicator release];
    [connection release];
    [super dealloc];
}

#pragma mark -
#pragma mark connection delegate

- (void) connection:(NSURLConnection *)theConnection didReceiveData:(NSData *)incrementalData 
{

    if (data == nil)
        data = [[NSMutableData alloc] initWithCapacity:2048];

    [data appendData:incrementalData];
}

- (void) connectionDidFinishLoading:(NSURLConnection *)theConnection 
{
    self.image = [UIImage imageWithData:data];

    [indicator removeFromSuperview];
    //data = nil;
    [data release], data = nil;
    [connection release], connection = nil;
    [indicator release], indicator = nil;
}

- (void) connection:(NSURLConnection *)theConnection didFailWithError:(NSError *)error
{
    self.image = [UIImage imageNamed:@"icon.jpg"];
    [indicator removeFromSuperview];
    //data = nil;
    [data release], data = nil;
    [connection release], connection = nil;
    [indicator release], indicator = nil;
}

I'm using this for downloading images from web. one image for every cell in in table. and it works fine when image is not going out of the screen. BUT when u scrolling tableView fast and some images did not finished loading while they are on screen there huge memory leaks.

i know where is the leak and why its leaking. but i can't find solution. any thoughts ? thank you

PS sorry for my english

UPDATE

here is a code for adding images into tableView

UIWebImageView *tmpImageView = [[UIWebImageView alloc] initWithFrame:CGRectMake(0, 0, 57, 76)];
    tmpImageView.showActivityIndicator = YES;
    tmpImageView.contentMode = UIViewContentModeScaleAspectFit;
    tmpImageView.activityIndicatorStyle = UIActivityIndicatorViewStyleGray;
    [tmpImageView loadFromURL:[[tableArray objectAtIndex:indexPath.row] objectForKey:@"picurl"]];
    [cell addSubview:tmpImageView];
    [tmpImageView release];

and I'm repeating = ) its leaking only when it not finished loading and went off the screen while scrolling

Answer 1

The leaks are happening due to the allocation of UIWebImageView objects recursively (considering you are using reusable cells).

you should change your code to:

    UIWebImageView *tmpImageView = [cell viewWithTag:2011];

    if(!tmpImageView)
    {
    tmpImageView = [[UIWebImageView alloc] initWithFrame:CGRectMake(0, 0, 57, 76)];
        tmpImageView.showActivityIndicator = YES;
        tmpImageView.tag = 2011;
        tmpImageView.contentMode = UIViewContentModeScaleAspectFit;
        tmpImageView.activityIndicatorStyle = UIActivityIndicatorViewStyleGray;
        [cell addSubview:tmpImageView];
        [tmpImageView release];
    }


        [tmpImageView loadFromURL:[[tableArray objectAtIndex:indexPath.row] objectForKey:@"picurl"]];

you have to handle for the showActivityIndicator thing some how...based upon your code but the above mentioned change will remove your memory leaks.

Answer 2

Autorelase your NSURLConnection with this syntax

connection = [NSURLConnection connectionWithRequest:request delegate:self];

and delete your [connection release], connection = nil;