我正在尝试找到一种方法来为我正在创建的笔触的颜色设置动画circleLayer=CAShapeLayer()circleLayer.path=circlePath.CGPathcircleLayer.lineCap=kCALineCapRoundcircleLayer.fillColor=UIColor.clearColor().CGColorCABasicAnimationfill=CABasicAnimation.circleLayer.strokeColor=UIColor(red:0.4,green:1.0,blue:0.2,alpha:0.5).CGColorcircleLa