iOS addSubview & removeFromSuperview causing memory leaks

Question

I have the following issue:

I have one instance from class that extends UIViewController class, in this class i am adding UIImage to UIImageView, and then adding the UIImageView to the self.view using this method "addSubview:" [self.view addSubview:imageView] and finally adding the self.view to the window using [[[UIApplication sharedApplication] keyWindow] addSubview:[self view]] , and when i click on a close button i am clearing the self.view (removing the subview "UIImageView") and removing the self.view from the window.

now the issue is when i am using the same instance to add other UIImageView with other image, the first data is not freed from the memory even i have released them and removed them from the superview. the following code illustrates the problem.

- (void) setImageWithURL: (NSString *)url {

    NSData * imageData =NSData * imageData =[NSData dataWithContentsOfURL:[NSURL URLWithString:url]];

    if (imageData) {
            UIImage *image = [[UIImage alloc]initWithData:imageData];
            [[[UIApplication sharedApplication] keyWindow] addSubview:[self view]];
            [self createViewWithImage:image];
            [image release];
}

-(void) createViewWithImage: (UIImage *) image{
    [self.view setHidden:false];
     UIImageView *imageView = [[UIImageView alloc] initWithImage:image];
     [self.view addSubview:imageView];
     [imageView release];
}

// for removing the imageView when i click on close button
-(void) closeView{
            for (UIView *subView in self.view.subviews) {
                  [subView removeFromSuperview];
             }
            [self.view removeFromSuperview];

}

Note: I have used the xcode instruments to test the memory allocation.

UPDATE: after more research .. it is not addSubview & removeFromSuperview that make memory leaks.. its NSData. I dont why its not released from the memory. I have made some changes to test if its truly the NSData, i saved the image locally and set the image using two cases:

//Case 1:
NSString *path = [[NSBundle mainBundle] pathForResource:@"image" ofType:@"png"];
NSData * imageData =[[NSData dataWithContentsOfFile:path];
image = [[UIImage alloc]initWithData:imageData];


//Case 2:

NSString *path = [[NSBundle mainBundle] pathForResource:@"image" ofType:@"png"];
image = [[UIImage alloc] initWithContentsOfFile:path];

I have found that case one makes memory leaks, while case 2 is clean.

now UIImage cant take the image without using the NSData, and for some reason NSData is not released .. so how can i fix this problem !!!!

Why aren't you using ARC? It will save you a lot of time when it comes to memory management. — Eli Ganem, Jul 07 '13 at 11:55
Apple suggested at WWDC that ARC will soon be the ONLY way to go. I strongly recommend you start using it. — Adam Waite, Jul 07 '13 at 13:23
I have used ARC. but the problem was exist.. so i have compiled it without arc to see where is the problem .. — Moha Mhe, Jul 07 '13 at 13:34

score 0 · Answer 1 · answered Jul 07 '13 at 13:17

0

Do you have a:

[super dealloc];

in your deriving class's dealloc?

answered Jul 07 '13 at 13:17

shaioz

340
3
12

Yes i have [super dealloc]; – Moha Mhe Jul 07 '13 at 13:31
Do you specifically see a memory leak using Leaks in Instruments? Also look at http://stackoverflow.com/questions/8647044/viewcontroller-never-gets-deallocated – shaioz Jul 07 '13 at 13:44
Yes, when i have test the code without [self.view addSubview:imageView]; no memory problem . but adding the UIImageView to the self.view cause the problem. – Moha Mhe Jul 07 '13 at 14:15

iOS addSubview & removeFromSuperview causing memory leaks

1 Answers1