ios - 动画阴影属性

Question

我想要为 View 的阴影属性设置动画。最初我尝试过:

func animateIn(delay: TimeInterval = 0) {
        UIView.animate(withDuration: 0.2, delay: delay, options: .allowUserInteraction, animations: {
            self.shadowView.layer.shadowColor = UIColor.black.cgColor
            self.shadowView.layer.shadowOffset = CGSize(width: 15, height: 15)
            self.shadowView.layer.shadowRadius = 20
            self.shadowView.layer.shadowOpacity = 0.2
            self.layoutIfNeeded()
        }, completion: nil)
    }

鉴于 UIView.animate 不适用于图层，这不起作用。

我测试了以下帖子( How to animate layer shadowOpacity? )，但它仅指定如何对阴影不透明度进行动画处理。有没有办法像使用动画 block 一样为我的所有阴影属性设置动画？

Answer 1

你已经非常接近了，你只需为所有属性更改创建多个CABasicAnimation，然后就可以使用CAAnimationGroup

假设您有 2 个 CABasicAnimation 动画，例如:

let shadownOpacityAnimation = CABasicAnimation(keyPath: "shadowOpacity")
...
let shadowRadiusAnimation = CABasicAnimation(keyPath: "shadowRadius")
...

然后您可以使用CAAnimationGroup添加它们

let group = CAAnimationGroup()
group.duration = 0.2
group.repeatCount = 1
group.autoreverses = false
group.timingFunction = CAMediaTimingFunction(name: .easeInEaseOut)
group.animations = [shadownOpacityAnimation, shadowRadiusAnimation]
layer.add(group, forKey: "allAnimations")

您可以在此答案中阅读更多相关信息:

How can I create an CABasicAnimation for multiple properties?