Swift-animate CAshapeLayer stroke color

Question

I'm trying to find a way to animate the color of the stroke that I am creating

circleLayer = CAShapeLayer()
circleLayer.path = circlePath.CGPath
circleLayer.lineCap =  kCALineCapRound
circleLayer.fillColor = UIColor.clearColor().CGColor
CABasicAnimation fill = CABasicAnimation.
circleLayer.strokeColor = UIColor(red: 0.4, green: 1.0, blue: 0.2, alpha: 0.5).CGColor
circleLayer.lineWidth = 20.0;
circleLayer.lineJoin = kCALineJoinRound
// Don't draw the circle initially
circleLayer.strokeEnd = 0.0

// Add the circleLayer to the view's layer's sublayers
layer.addSublayer(circleLayer)

What I want to achieve is: while it's being created (I'm creating it over a duration of 1 seconds), the color will animate itself

Answer 1

Updated to Swift 5.

Found out the solution. Enjoy. After you create the CAShapeLayer of course :

    let animcolor = CABasicAnimation(keyPath: "strokeColor")
    animcolor.fromValue         = UIColor.green.cgColor
    animcolor.toValue           = UIColor.orange.cgColor
    animcolor.duration          = 1.0
    animcolor.repeatCount       = 0
    animcolor.autoreverses      = true
    myLayer.add(animcolor, forKey: "strokeColor")