Question

我使用此代码添加带自动反转的脉冲圈：

let scaleAnimation = CABasicAnimation(keyPath: "transform.scale")        
scaleAnimation.duration = 6
scaleAnimation.repeatCount = 200
scaleAnimation.autoreverses = true
scaleAnimation.fromValue = 0.1
scaleAnimation.toValue = 0.8
scaleAnimation.timingFunction = CAMediaTimingFunction(controlPoints: 0.42, 0.0, 0.58, 1.0)
animationView.layer.add(scaleAnimation, forKey: "scale")

我想在这里做的是：

在fromValue = 0.1处运行动画toValue = 0.8 2x speed，并在fromValue = 0.8处向后移动toValue = 0.1 1x speed。

有没有简单的方法来实现这一目标？

Answer 1

您有两种方法：

CAKeyframeAnimation（最适合您）：

专门设计用于为具有多个关键帧的单个keyPath设置动画，并在每个间隔上使用自定义timeFunction。正是您需要的

let scaleAnimation = CAKeyframeAnimation(keyPath: "transform.scale")
scaleAnimation.duration = 18 // 6 seconds for the first part, 12 for the second
scaleAnimation.repeatCount = 200
scaleAnimation.values = [0.1, 0.8, 0.1] // make sure first and last values are equal in order to get seamless animation
scaleAnimation.keyTimes = [0, 0.333, 1] // keyframes scaled to [0; 1] interval
scaleAnimation.timingFunctions = [
    CAMediaTimingFunction(controlPoints: 0.42, 0.0, 0.58, 1.0), //first interval
    CAMediaTimingFunction(controlPoints: 0.58, 0.0, 0.42, 1.0)  //second interval (reversed)
]
layer.add(scaleAnimation, forKey: nil)

CAAnimationGroup（某种解决方法）

旨在为单个图层分组动画（可能具有不同的keyPath s）

let scaleUpAnimation = CAKeyframeAnimation(keyPath: "transform.scale")
//setup first animation as you did

let scaleDownAnimation = CAKeyframeAnimation(keyPath: "transform.scale")
//setup second animation

let groupAnimation = CAAnimationGroup()
groupAnimation.animations = [scaleUpAnimation, scaleDownAnimation]
//setup group if needed
layer.add(groupAnimation, forKey: nil)

CABasicAnimation自动反转速度是原来的两倍

1 个答案: