Memory Warning & Crash ImageIO-jpeg-data

Question

I have created an app and it is (well it was) ready to submit.

The app is basically a flash cards apps for kids where there are 12 cards per page.

It is currently iPad only and when the cards are touched a image view animates out of the card to full screen with a full resolution 2048 x 1536 and it plays a sound of the animal, you tap the full size image and it goes back in the card. Each card has 5 images assigned to it. The app has been working perfectly all though the design period and now that I have loaded all of the animals and I have been testing it and noticed it crashed.

Long story short the memory continually grows by 12MB per image (although each image is around 200-400KB) until it reaches 700MB of Memory and it crashes. This memory never reduces.

I have run the app through the xcode instruments and can see no leaks but have identified in the 'Allocations' that it is the 'ImageIO-jpeg-data' category that is the culprit.

I have spent all evening reading up about this as I have found some promising results however these results have not worked for me so I am assuming that I have misunderstood what has been advised or I have not understood so was hoping that someone could maybe help me out or explain in laymen terms how I can resolve this.

OK so to explain how I have the view contoller set up.

Originally I set up the 5 images for each card in an array but there was a delay so someone on here recommended that I pre load the images in viewDidLoad and then call them when the card/button was touched.

So for example I was using this format in viewDidLoad

domestic100 = [UIImage imageNamed:@"ferret-00"];
domestic101 = [UIImage imageNamed:@"ferret-01"];
domestic102 = [UIImage imageNamed:@"ferret-02"];
domestic103 = [UIImage imageNamed:@"ferret-03"];
domestic104 = [UIImage imageNamed:@"ferret-04"];

and then in the the button pressed I assigned the image to the image view by calling:

domestic01ImageContainer.image = domestic100; 

inside a if else look checking if the image number was 1 to 4.

Anyway it worked perfectly (apart form this memeory issue)

I have read online that I would be better off declaring the uiimages using

[UIImage imageWithContentsOfFile:path]

as seen in this post: UIImage memory not deallocating VM: ImageIO_JPEG_DATA?

So the alterations I have made in my code are:

in my viewDidLoad I now create uiimages as so:

domestic200 = [UIImage imageWithContentsOfFile: [[NSBundle mainBundle] pathForResource: @"dog-00" ofType: @"jpg"]];
domestic201 = [UIImage imageWithContentsOfFile: [[NSBundle mainBundle] pathForResource: @"dog-01" ofType: @"jpg"]];
domestic202 = [UIImage imageWithContentsOfFile: [[NSBundle mainBundle] pathForResource: @"dog-02" ofType: @"jpg"]];
domestic203 = [UIImage imageWithContentsOfFile: [[NSBundle mainBundle] pathForResource: @"dog-03" ofType: @"jpg"]];
domestic204 = [UIImage imageWithContentsOfFile: [[NSBundle mainBundle] pathForResource: @"dog-04" ofType: @"jpg"]];

and then in the button pressed call the image in to the imageview using

[domestic01ImageContainer setImage:domestic100];

I am getting the same results - the image are just building up in the same memory and not releasing or deallocating.

I'm no wiz when it comes of objective-c and this is my first real app.

If someone could be kind enough to spare a moment of their time to help me I would be really appreciative.

Thanks in advance.

****** Edit ******

So I have told you how I load my images above, I also in the viewDidLoad give the 12 imageviews a starting point and a hidden alpha.

domestic01ImageContainer = [[UIImageView alloc] initWithFrame:CGRectMake(30, 123, 152, 224)];
domestic01ImageContainer.Alpha = 0;

I then add the subview with:

[self.view addSubview:domestic01ImageContainer];

each imageview is allocated a tap gesture to hide the image at a later point:

UITapGestureRecognizer *domestic01Tap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(imageTaped:)];
[domestic01ImageContainer addGestureRecognizer:domestic01Tap];
[domestic01ImageContainer setUserInteractionEnabled:YES];

When the thumb / card is pressed a streamlined version of the button would be:

- (IBAction)domestic01ButtonClicked:(id)sender {
static int imageNumber = 0;

if (imageNumber == 0) {
    [domestic01ImageContainer setImage:domestic100];
    imageNumber++;
}

else if (imageNumber == 1) {
    [domestic01ImageContainer setImage:domestic101];
    imageNumber++;
}

else if (imageNumber == 2) {
    [domestic01ImageContainer setImage:domestic102];
    imageNumber++;
}

else if (imageNumber == 3) {
    [domestic01ImageContainer setImage:domestic103];
    imageNumber++;

}

else if (imageNumber == 4) {
    [domestic01ImageContainer setImage:domestic104];
    imageNumber = 0;
}

domestic01ImageContainer.Alpha = 1;

[UIView animateWithDuration:0.2 delay:0.0 options:UIViewAnimationOptionCurveEaseIn animations:^{
        domestic01ImageContainer.frame = CGRectMake(0, 0, 768, 1024);
    } completion:^(BOOL finished) {

}];

}

The in my imageTapped recognizer to shrink the full size image back to the card I use:

[UIView animateWithDuration:0.2 delay:0.0 options:UIViewAnimationOptionCurveEaseIn animations:^{
        domestic01ImageContainer.frame = CGRectMake(30, 123, 152, 224);
    } completion:^(BOOL finished) {
        domestic01ImageContainer.Alpha = 0;
    }];

Which basically put the flash card back from full screen to the size of the card / thumbnail and the sets alpha again to 0.

Like I said it all works but as you have suggested the image is being retained somewhere.

Hope this sheds a bit more light on what could be causing the issue.

I had tried setting the image to nil in after the alpha was set to 0 in the imageTapped but this didn't clear the memory.

[domestic05ImageContainer setImage:nil];

Answer 1

Ok so if anyone else is suffering from this issue then here is the solution that I found that work perfectly.

http://xcodenoobies.blogspot.co.uk/2011/02/best-way-to-use-uiimageview-memory.html

Thanks Anna for your input, it pointed me in the right direct but his was the answer that did it for me.