swift版
实现代码
// View
let newView = UIView()
// 背景色
newView.backgroundColor = UIColor.blackColor()
// 创建label
let myLabel = UILabel(frame: CGRectMake(0,0,300,50))
myLabel.text = "房子房子房子房子房子房子"
myLabel.textColor = UIColor.whiteColor()
// 创建CAGradientLayer
let gradientLaber = CAGradientLayer()
// 什么颜色不重要,但必须写
gradientLaber.colors = [
UIColor.clearColor().colorWithAlphaComponent(0.3).CGColor,
UIColor.yellowColor().CGColor,
UIColor.yellowColor().colorWithAlphaComponent(0.3).CGColor
]
gradientLaber.locations = [(0.0),(0.0),(0.1)]
// 设置效果方向Y同X不同水平放方向,X同Y不同垂直方向
gradientLaber.startPoint = CGPoint(x: 0, y: 0)
gradientLaber.endPoint = CGPoint(x: 1 , y: 0)
gradientLaber.frame = myLabel.frame
// 创建核心动画动画
let animation = CABasicAnimation(keyPath: "locations")
animation.fromValue = [0.0,0.0,0.2]
animation.toValue = [0.9,1.0,1.0]
animation.duration = 2.5
animation.removedOnCompletion = false
animation.fillMode = kCAFillModeForwards
animation.repeatCount = Float.infinity
gradientLaber.addAnimation(animation, forKey: nil)
// 我也不懂?
myLabel.layer.mask = gradientLaber
newView.addSubview(myLabel)
