第一次实现加购动画，小小记录一下🙃

需求效果图

50830a6902032731058eb7a036d19616.png

代码实现

class AnimationTools: NSObject {
    static let shared = AnimationTools()
    
    private var layer: CALayer?
    private var toView: UIView?
    
    var animationDidCompete: (() -> Void)?
    
    func startAnimation(fromView: UIView, toView: UIView, sourceViewController: UIViewController) {
        self.toView = toView
        
        layer = CALayer()
        layer?.contents = fromView.layer.contents
        layer?.backgroundColor = UIColor.blue.cgColor
        // 图层对齐方式
        layer?.contentsGravity = .resizeAspectFill
        layer?.frame = fromView.frame
        layer?.cornerRadius = fromView.frame.size.height / 2.0
        layer?.masksToBounds = true
        
        sourceViewController.view.layer.addSublayer(layer!)
        
        let halfWidth: CGFloat = fromView.frame.width / 2.0
        createAnimation(to: CGPoint(x: toView.frame.minX + toView.frame.width / 2.0, y: toView.frame.maxY), controlPoint1: CGPoint(x: fromView.frame.minX + halfWidth, y: fromView.frame.minY + halfWidth), controlPoint2: CGPoint(x: 30, y: fromView.frame.maxY))
    }
    
    /// 路径
    func createAnimation(to endPoint: CGPoint, controlPoint1: CGPoint, controlPoint2: CGPoint) {
        // 透明动画
        let alphaAnimation = CABasicAnimation(keyPath: "opacity")
        // 开始值
        alphaAnimation.fromValue = 0
        // 结束值（绝对值）
        alphaAnimation.toValue = 1
        // 单位s，1s = 60帧
        alphaAnimation.duration = 10 / 60.0
        layer?.add(alphaAnimation, forKey: "alphaAnimation")
        
        // 路径动画
        let bezierPath = UIBezierPath()
        bezierPath.move(to: layer?.position ?? .zero)
        bezierPath.addCurve(to: endPoint, controlPoint1: controlPoint1, controlPoint2: controlPoint2)
        let pathAnimation = CAKeyframeAnimation(keyPath: "position")
        pathAnimation.path = bezierPath.cgPath
        
        // 缩放动画
        let scaleAnimation = CABasicAnimation(keyPath: "transform.scale")
        scaleAnimation.fromValue = 1
        scaleAnimation.toValue = 0.2
        
        // 动画组
        let groups = CAAnimationGroup()
        groups.animations = [pathAnimation, scaleAnimation]
        groups.duration = 40 / 60.0
        groups.delegate = self
        groups.fillMode = .forwards
        groups.isRemovedOnCompletion = false
        scaleAnimation.timingFunction = CAMediaTimingFunction(name: .easeInEaseOut)
        layer?.add(groups, forKey: "addCartGroup")
    }
    
    // 呼吸动画, 执行1次
    func breathAnimation() {
        let breathAnimation = CABasicAnimation(keyPath: "transform.scale")
        breathAnimation.fromValue = 1
        breathAnimation.toValue = 1.2
        // 重复次数
        breathAnimation.repeatCount = 1
        // 动画结束时执行逆动画
        breathAnimation.autoreverses = true
        breathAnimation.duration = 5 / 60.0
        breathAnimation.isRemovedOnCompletion = false
        breathAnimation.delegate = self
        toView?.layer.add(breathAnimation, forKey: "countBreath")
    }
    
    // 缩放动画，从0-1
    func scaleAnimation() {
        let scaleAnimation = CABasicAnimation(keyPath: "transform.scale")
        scaleAnimation.fromValue = 0
        scaleAnimation.toValue = 1
        scaleAnimation.isRemovedOnCompletion = false
        scaleAnimation.delegate = self
        scaleAnimation.duration = 10 / 60.0
        toView?.layer.add(scaleAnimation, forKey: "countSalce")
    }
}

extension AnimationTools: CAAnimationDelegate {
    func animationDidStop(_ anim: CAAnimation, finished flag: Bool) {
        if anim == layer?.animation(forKey: "addCartGroup") {
            // 要设置groups.isRemovedOnCompletion = false，这里才会执行
            layer?.removeFromSuperlayer()
            layer = nil
            if toView?.isHidden ?? false {
                toView?.isHidden = false
                self.scaleAnimation()
            } else {
                breathAnimation()
            }
        } else if anim == toView?.layer.animation(forKey: "countSalce") {
            breathAnimation()
        } else if anim == toView?.layer.animation(forKey: "countBreath") {
            self.toView = nil
            animationDidCompete?()
        }
    }
}

啊～这里不能上传.mov，不会生成.gif，在Github中上传了动图效果
Demo地址：AddCartAnimatedDemo

参考文章：
https://developer.apple.com/documentation/quartzcore/cabasicanimation
https://blog.csdn.net/iosevanhuang/article/details/14488239