动画UIImageView

Question

When I animate my imageView with image sequence memory usage increases a lot and doesn't come back to normal after animation finishes. Here's my code

override func viewDidLoad() {
    super.viewDidLoad()
    view.backgroundColor = .black
    view.addSubview(animationImage)
    animationImage.centerXAnchor.constraint(equalTo: view.centerXAnchor).isActive = true
    animationImage.centerYAnchor.constraint(equalTo: view.centerYAnchor).isActive = true
    animationImage.widthAnchor.constraint(equalTo: view.widthAnchor, multiplier: 0.9, constant: 0).isActive = true
    animationImage.heightAnchor.constraint(equalToConstant: 400).isActive = true

    var i = 0
    while i < 15 {
        let path = Bundle.main.path(forResource: "findItBaltas\(i)", ofType: "png")
        animationImages.append(UIImage(contentsOfFile: path!)!)
        i += 1
    }
    animationImage.animationImages = animationImages
    animationImage.animationDuration = 3
    animationImage.animationRepeatCount = 1
    animationImage.startAnimating()

}

var animationImages = [UIImage]()

let animationImage: UIImageView = {
   let imageView = UIImageView()
    imageView.translatesAutoresizingMaskIntoConstraints = false
    return imageView
}()

I was googling the whole day and I found out that this happens because animated images are cached into device's memory and I should use UIImage(contentsOfFile:) instead of UIImage(named:) but the problem still persists and memory doesn't come back to normal. What are some other options to play animation once and the remove it's cache from memory?

Answer 1

Your use of UIImage(contentsOfFile:) is good but you store the images in an array property instead of a locale variable. So your app keeps a longterm strong reference to all of the images.

Move:

var animationImages = [UIImage]()

to inside the viewDidLoad method so it is a local variable instead of a class property.

But even then, the image view is keeping all of the images in memory. You will need to add code to set the image view's animationImages to nil when it is done animating. Perhaps you could set its image property to just the last image if you want to keep that in view.