定义函数

func animation1(layerParam: CAShapeLayer){        let animation = CABasicAnimation(keyPath: "strokeEnd")        animation.fromValue = 0        animation.toValue = 1        animation.duration = 2.0        layerParam.addAnimation(animation, forKey: "")    }

 layerParam：CAShapeLayer为需要传入参数，调用时⬇️

self.animation1(layer)

 注意格式，layer为传入animation1的参数，在这里是一个CAShapeLayer