我试图创建一个每隔x
秒执行一次动画的CALayer子类。在下面的示例中,我尝试将背景从一种随机颜色更改为另一种颜色,但在操场上运行时似乎没有发生任何事情
import UIKit
import XCPlayground
import QuartzCore
let view = UIView(frame: CGRect(x: 0.0, y: 0.0, width: 200, height: 200))
XCPShowView("view", view)
class CustomLayer: CALayer {
var colors = [
UIColor.blueColor().CGColor,
UIColor.greenColor().CGColor,
UIColor.yellowColor().CGColor
]
override init!() {
super.init()
self.backgroundColor = randomColor()
let animation = CABasicAnimation(keyPath: "backgroundColor")
animation.fromValue = backgroundColor
animation.toValue = randomColor()
animation.duration = 3.0
animation.repeatCount = Float.infinity
addAnimation(animation, forKey: "backgroundColor")
}
required init(coder aDecoder: NSCoder) {
super.init(coder: aDecoder)
}
private func randomColor() -> CGColor {
let index = Int(arc4random_uniform(UInt32(colors.count)))
return colors[index]
}
}
let layer = CustomLayer()
layer.frame = view.frame
view.layer.addSublayer(layer)
答案 0 :(得分:1)
重复动画的参数只设置一次,因此您无法在每次重复时更改颜色。您应该实现委托方法,而不是重复动画,
animationDidStop:finished:
,然后使用新的随机颜色再次调用动画。我还没有在操场上试过这个,但它在应用程序中运行正常。请注意,除了你拥有的其他init方法之外,你还必须实现init!(layer layer:AnyObject!)。
import UIKit
class CustomLayer: CALayer {
var newColor: CGColorRef!
var colors = [
UIColor.blueColor().CGColor,
UIColor.greenColor().CGColor,
UIColor.yellowColor().CGColor
]
required init(coder aDecoder: NSCoder) {
super.init(coder: aDecoder)
}
override init!(layer: AnyObject!) {
super.init(layer: layer)
}
override init!() {
super.init()
backgroundColor = randomColor()
newColor = randomColor()
self.animateLayerColors()
}
func animateLayerColors() {
let animation = CABasicAnimation(keyPath: "backgroundColor")
animation.fromValue = backgroundColor
animation.toValue = newColor
animation.duration = 3.0
animation.delegate = self
addAnimation(animation, forKey: "backgroundColor")
}
override func animationDidStop(anim: CAAnimation!, finished flag: Bool) {
backgroundColor = newColor
newColor = randomColor()
self.animateLayerColors()
}
private func randomColor() -> CGColor {
let index = Int(arc4random_uniform(UInt32(colors.count)))
return colors[index]
}
}