自定义CALayer动画视图 - 无法动画

Question

我正在处理由CALayers组成的自定义视图，但我无法为其设置动画。

我的申请是结帐流程。每个屏幕都是结帐购物车中的一个项目。当用户通过购物车到达发票时，新控制器被推入堆栈。我使用我的进度视图来更新用户在购物车中的位置。

我可以更新进度视图，但是我无法将其设置为动画。将在每个新视图控制器上重新创建进度视图，并将其填充到指定的量。

//creates the shape layer, grayed with spaces in between
func createShapeLayer(_ count: Int) {

    //calculate width of the view
    let width = self.frame.width

    //divide by the number of items(count) = single progress length
    let singleProgressLength = width/CGFloat(count)


    // take 10% off that as the gap length
    let gapLength = singleProgressLength * 0.10

    //new single progress length = progress length - gap
    var newSingleProgressLength : CGFloat = 0.0
    let staticWidth = singleProgressLength - gapLength

    //loop through the count
    for i in 1...count {
        let layer = CAShapeLayer()

        //start at 0 for the first layer
        layer.path = UIBezierPath(roundedRect: CGRect(x: 0 + (newSingleProgressLength + gapLength), y: 0, width: staticWidth, height: self.frame.height), cornerRadius: 1).cgPath
        newSingleProgressLength += (staticWidth + gapLength)
        if i <= coloredUpToIndex {
            layer.fillColor = UIColor(netHex:0xF7B445).cgColor

        }else {
            layer.fillColor = UIColor(netHex:0xD8D8D8).cgColor
        }
        self.layer.addSublayer(layer)
        layerArray.append(layer)
    }


}


// Adds increment to the progress view, filling a rectangle with animation
func animateViewUpdate() {
    var delay : TimeInterval = 0.5
    for layer in layerArray {

        DispatchQueue.main.asyncAfter(deadline: .now() + delay) { () -> Void in
            let animation = CABasicAnimation(keyPath: "opacity")
            animation.duration = 1.0
            animation.fromValue = NSNumber(value: 0.0 as Float)
            animation.toValue = NSNumber(value: 1.0 as Float)
            layer.add(animation, forKey: "animateOpacity")
            self.perform(#selector(ECProgressView.animateViewUpdate), with: nil, afterDelay: delay)
        }
        delay += 0.5
    }
}