Swift 雷达动画

雷达动画，或者说水波动画，就是用的一个动画组。效果如下：

Mar-28-2018 19-19-01.gif

全部代码，除了两个按钮是SB上的。留有详细注释，留作以后参考。其余复制可用：

import UIKit

class ViewController: UIViewController {
    
    private let radarAnimation = "radarAnimation"
    
    private var animationLayer: CALayer?
    private var animationGroup: CAAnimationGroup?
    
    private var opBtn: UIButton!

    override func viewDidLoad() {
        super.viewDidLoad()

        let first = makeRadarAnimation(showRect: CGRect(x: 120, y: 100, width: 100, height: 100), isRound: true)
        view.layer.addSublayer(first)

        opBtn = UIButton(frame: CGRect(x: 100, y: 450, width: 80, height: 80))
        opBtn.backgroundColor = UIColor.red
        opBtn.clipsToBounds = true
        opBtn.setTitle("Hsu", for: .normal)
        opBtn.layer.cornerRadius = 10
        view.addSubview(opBtn)
        
        let second = makeRadarAnimation(showRect: opBtn.frame, isRound: false)
        view.layer.insertSublayer(second, below: opBtn.layer)
    }

    @IBAction func startAction(_ sender: UIButton) {
        animationLayer?.add(animationGroup!, forKey: radarAnimation)
    }
    
    @IBAction func stopAction(_ sender: UIButton) {
        animationLayer?.removeAnimation(forKey: radarAnimation)
    }
    
    private func makeRadarAnimation(showRect: CGRect, isRound: Bool) -> CALayer {
        // 1. 一个动态波
        let shapeLayer = CAShapeLayer()
        shapeLayer.frame = showRect
        // showRect 最大内切圆
        if isRound {
            shapeLayer.path = UIBezierPath(ovalIn: CGRect(x: 0, y: 0, width: showRect.width, height: showRect.height)).cgPath
        } else {
            // 矩形
            shapeLayer.path = UIBezierPath(roundedRect: CGRect(x: 0, y: 0, width: showRect.width, height: showRect.height), cornerRadius: 10).cgPath
        }
        
        shapeLayer.fillColor = UIColor.orange.cgColor
        // 默认初始颜色透明度
        shapeLayer.opacity = 0.0
        
        animationLayer = shapeLayer
        
        // 2. 需要重复的动态波，即创建副本
        let replicator = CAReplicatorLayer()
        replicator.frame = shapeLayer.bounds
        replicator.instanceCount = 4
        replicator.instanceDelay = 1.0
        replicator.addSublayer(shapeLayer)

        // 3. 创建动画组
        let opacityAnimation = CABasicAnimation(keyPath: "opacity")
        opacityAnimation.fromValue = NSNumber(floatLiteral: 1.0)  // 开始透明度
        opacityAnimation.toValue = NSNumber(floatLiteral: 0)      // 结束时透明底
        
        let scaleAnimation = CABasicAnimation(keyPath: "transform")
        if isRound {
            scaleAnimation.fromValue = NSValue.init(caTransform3D: CATransform3DScale(CATransform3DIdentity, 0, 0, 0))      // 缩放起始大小
        } else {
            scaleAnimation.fromValue = NSValue.init(caTransform3D: CATransform3DScale(CATransform3DIdentity, 1.0, 1.0, 0))      // 缩放起始大小
        }
        scaleAnimation.toValue = NSValue.init(caTransform3D: CATransform3DScale(CATransform3DIdentity, 1.5, 1.5, 0))      // 缩放结束大小
        
        let animationGroup = CAAnimationGroup()
        animationGroup.animations = [opacityAnimation, scaleAnimation]
        animationGroup.duration = 3.0       // 动画执行时间
        animationGroup.repeatCount = HUGE   // 最大重复
        animationGroup.autoreverses = false
        
        self.animationGroup = animationGroup
        
        shapeLayer.add(animationGroup, forKey: radarAnimation)
        
        return replicator
    }
}