memory issue for image animation with GIF - ios - ios

Question

I am using the following code to show the splash screen :
UIImageView *defaultImage = [[UIImageView alloc] init];
defaultImage.frame = defaultImageFrame;
// for iOS 9 Compatability
//NSMutableArray *buttonsArray = [[NSMutableArray alloc] initWithCapacity:1];
NSMutableArray *buttonsArray = [NSMutableArray arrayWithCapacity:1];
for (int i = 1; i<=3; i++)
{
[buttonsArray addObject:[UIImage imageWithContentsOfFile:[[NSBundle mainBundle] pathForResource:[NSString stringWithFormat:#"img00%d", i] ofType:#"png"]]];
}
mAnimatedButtons = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, WIDTH_DEVICE, HEIGHT_DEVICE)];
[mAnimatedButtons setUserInteractionEnabled:NO];
[mAnimatedButtons setAnimationImages:buttonsArray];
[mAnimatedButtons setAnimationRepeatCount:0];
[mAnimatedButtons setAnimationDuration:2.0];
[mAnimatedButtons startAnimating];
[defaultImage addSubview:mAnimatedButtons];
[self.view addSubview:defaultImage];
And i will remove the splash screen after this
[mAnimatedButtons stopAnimating]; //here animation stops
[mAnimatedButtons removeFromSuperview]; // here view removes from view hierarchy
mAnimatedButtons = nil;
self.defaultImage=nil;
[self.defaultImage removeFromSuperview];
[self.view.layer removeAllAnimations];
for (CALayer* layer in [self.view.layer sublayers])
{
[layer removeAllAnimations];
}
Adding this code increases the memory usage upto 300 Mb.
Removing this it has only 100 Mb.
I tried the following code also
self.defaultImage = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, WIDTH_DEVICE, HEIGHT_DEVICE)];
self.defaultImage.animationImages = [NSArray arrayWithObjects:
[UIImage imageNamed:#"img001.png"],
[UIImage imageNamed:#"img002.png"],
[UIImage imageNamed:#"img003.png"],
nil];
//self.defaultImage.animationDuration = 1.0f;
self.defaultImage.animationRepeatCount = 0;
[self.defaultImage setAnimationDuration:2.0];
[ self.defaultImage startAnimating];
[self.view addSubview: self.defaultImage];
Even though the result is same.

Answer 1

Images, when used in the app, may require considerably more memory than the size of the asset in persistent storage might otherwise suggest. Assets are frequently compressed (e.g. JPG or PNG), but when you use the image, they're uncompressed, often requiring 4 bytes per pixel (one byte for red, green, blue, and alpha, respectively). So, for example, a iPhone 7+ full-screen retina image can require 14mb when you use the image. So, the memory-efficient technique is to employ lazy loading, not creating the UIImage objects until you absolutely need them. And, as Jerry suggested, because the amount of memory is determined by the size of the image and not the imageview in which you use the image, if your images have dimensions greater than required by the UIImageView in which you use them (i.e. width and height of the imageview times the "scale" of the device), you may want to resize the image accordingly.