前言

开发中经常需要加载数据，这时候就需要一个加载动画，最近写了2个加载动画，希望对大家有所帮助。文章末尾有提供OC和Swift双语的CLDemo下载，代码比较简单，就不详细解析了，Demo中已经进行封装，可以直接使用，这里贴出核心代码。

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效果图

1.第一个
核心代码

 private func initLayer() -> Void {
        let origin_x: CGFloat = frame.size.width * 0.5
        let origin_y: CGFloat = frame.size.height * 0.5
        for item in 0 ..< defaultConfigure.number {
            //创建layer
            let scale: CGFloat = CGFloat(defaultConfigure.number + 1 - item) / CGFloat(defaultConfigure.number + 1)
            let layer: CALayer = CALayer()
            layer.backgroundColor = defaultConfigure.backgroundColor.cgColor
            layer.frame = CGRect.init(x: -5000, y: -5000, width: scale * defaultConfigure.diameter, height: scale * defaultConfigure.diameter)
            layer.cornerRadius = scale * defaultConfigure.diameter * 0.5;
            //运动路径
            let pathAnimation: CAKeyframeAnimation = CAKeyframeAnimation.init(keyPath: "position")
            pathAnimation.calculationMode = .paced;
            pathAnimation.fillMode = .forwards;
            pathAnimation.isRemovedOnCompletion = false;
            pathAnimation.duration = (defaultConfigure.duration) - Double((defaultConfigure.intervalDuration) * Double(defaultConfigure.number));
            pathAnimation.beginTime = Double(item) * defaultConfigure.intervalDuration;
            pathAnimation.timingFunction = CAMediaTimingFunction.init(name: .easeInEaseOut)
            pathAnimation.path = UIBezierPath(arcCenter: CGPoint.init(x: origin_x, y: origin_y), radius: (self.frame.size.width - self.defaultConfigure.diameter) * 0.5, startAngle: defaultConfigure.startAngle, endAngle: defaultConfigure.endAngle, clockwise: true).cgPath
            //动画组，动画组时间长于单个动画时间，会有停留效果
            let group: CAAnimationGroup = CAAnimationGroup()
            group.animations = [pathAnimation]
            group.duration = defaultConfigure.duration
            group.isRemovedOnCompletion = false
            group.fillMode = .forwards
            group.repeatCount = MAXFLOAT
            
            layer.add(group, forKey: "RotateAnimation")
            layerArray.append(layer)
        }
    }

2.第二个
核心代码

override init(frame: CGRect) {
        super.init(frame: frame)
        width = frame.size.width
        height = frame.size.height
        
        layer.backgroundColor = configure.outBackgroundColor.cgColor
        layer.mask = shapeLayer(lineWidth: configure.outLineWidth, start: 0, end: 1)
        animationLayer.frame = layer.bounds
        animationLayer.backgroundColor = configure.inBackgroundColor.cgColor
        animationLayer.mask = shapeLayer(lineWidth: configure.inLineWidth, start: configure.strokeStart, end: configure.strokeEnd)
        layer.addSublayer(animationLayer)
        rotationAnimation.fromValue = 0
        rotationAnimation.toValue = Double.pi * 2
        rotationAnimation.repeatCount = MAXFLOAT
        rotationAnimation.duration = configure.duration
        rotationAnimation.isRemovedOnCompletion = false
        rotationAnimation.fillMode = .forwards
        rotationAnimation.timingFunction = CAMediaTimingFunction(name: .linear)
    }

3.总结
核心代码已经贴出，完整代码请查看Demo，为了方便大家学习，这里提供了OC和Swift两种语言分别实现的----->>>CLDemo，如果对你有所帮助，欢迎Star。

原文作者：季末微夏
原文地址：https://www.jianshu.com/p/ab938514bc34