以Ben Flynn的出色回答为基础。
在斯威夫特 3 中:
// This needs to happen around init.
// NSView (and who inherit from it) does not come with a layer.
// self.layer will be nil at init.
self.layer = CALayer()
self.wantsLayer = true
let layer = CALayer()
let keyPath = "contents" // (I did not find a constant for that key.)
let frameAnimation = CAKeyframeAnimation(keyPath: keyPath)
frameAnimation.calculationMode = kCAAnimationDiscrete
// Duration
// This is the duration of one cycle
let durationOfAnimation: CFTimeInterval = 2.5
frameAnimation.duration = durationOfAnimation
frameAnimation.repeatCount = HUGE// can also use Float.infinity
let imageSeq: [NSImage] = imageSequance // Your images to animate
frameAnimation.values = imageSeq
// Sadly, there are no layout constraints on CALayer.
// If your view will be resized while animating, you'll need to override
// 'func layout()' and calculate aspect ratio if needs be
let layerRect = CGRect(origin: CGPoint.zero, size: self.frame.size)
layer.frame = layerRect
layer.bounds = layerRect
layer.add(frameAnimation, forKey: keyPath)
self.layer?.addSublayer(layer)
如果预计视图会调整大小:
删除这些行:
let layerRect = CGRect(origin: CGPoint.zero, size: self.frame.size)
layer.frame = layerRect
layer.bounds = layerRect
并self.needsLayout = true
在添加子层后调用。这将导致layout()
被调用。
//let layerRect = CGRect(origin: CGPoint.zero, size: self.frame.size)
//layer.frame = layerRect
//layer.bounds = layerRect
layer.add(frameAnimation, forKey: keyPath)
self.layer?.addSublayer(layer)
self.needsLayout = true
最后,覆盖layout()
:
override func layout() {
super.layout()
var layerFrame = CGRect(origin: CGPoint.zero, size: self.frame.size)
self.myLayer.frame = layerFrame
self.myLayer.bounds = // Adjust ratio as needed.
}