Question

I have an application in which i am calling image from URL in image view. Image view is add as subview of scroll view. In my implementation file i have use this code

    - (void)loadView {
    [super loadView];


        // add gesture recognizers to the image view
    UITapGestureRecognizer *singleTap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(handleSingleTap:)];
    UITapGestureRecognizer *doubleTap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(handleDoubleTap:)];
    UITapGestureRecognizer *twoFingerTap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(handleTwoFingerTap:)];

    [doubleTap setNumberOfTapsRequired:2];
    [twoFingerTap setNumberOfTouchesRequired:2];


    NSURL *imgUrl=[[NSURL alloc] initWithString:@"http://www.deviantart.com/download/80153093/Sexy_Kabuto_by_dark_tarou.jpg"];                 
    NSData *imgData = [NSData dataWithContentsOfURL:imgUrl];
    UIImage *img = [UIImage imageWithData:imgData];
    imageView = [[UIImageView alloc] initWithImage:img];



    // set the tag for the image view
    [imageView setTag:ZOOM_VIEW_TAG];



    [imageView addGestureRecognizer:singleTap];
    [imageView addGestureRecognizer:doubleTap];
    [imageView addGestureRecognizer:twoFingerTap];

    [singleTap release];
    [doubleTap release];
    [twoFingerTap release];

    [self.imageScrollView addSubview:imageView];
    [imgUrl release]; 

    // calculate minimum scale to perfectly fit image width, and begin at that scale
    float minimumScale = [imageScrollView frame].size.width  / [imageView frame].size.width;
    [imageScrollView setMinimumZoomScale:minimumScale];
    [imageScrollView setZoomScale:minimumScale];
    NSLog(@"%d",imageView.tag);
}

When i run on simulator then it did not detect tap recognizer. In console window it show this message

2011-08-01 10:01:46.999 ImageScroll[443:1907] * __NSAutoreleaseNoPool(): Object 0x4e412d0 of class UIView autoreleased with no pool in place – just leaking
Unable to access variable “doubleTap”
”
Unable to access variable “singleTap”
Unable to access variable “doubleTap”
Unable to access variable “doubleTap”

What is error in this code so that it show this type of message.

Answer 1

Try autoreleasing instead of immediately releasing like this:

//EDIT:1
NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
UITapGestureRecognizer *singleTap = [[[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(handleSingleTap:)] autorelease];
UITapGestureRecognizer *doubleTap = [[[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(handleDoubleTap:)] autorelease];
UITapGestureRecognizer *twoFingerTap = [[[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(handleTwoFingerTap:)] autorelease];
//EDIT:2
[pool release];

and then comment out the lines

[singleTap release];
[doubleTap release];
[twoFingerTap release];

Hope this helps.