Swift:不能改变数组中的CALayer背景色

Question

我只是试图更改CALayer数组最后一个元素的背景色。下面是我的整个View，但是它只有2-3行，我实际上尝试访问CALayer的最后一个元素。

这是我的progressViewClass，我给出了我的问题所在：

class ProgressBarView: UIView {

//Variables for progress bar
var holdGesture = UILongPressGestureRecognizer()
let animation = CABasicAnimation(keyPath: "bounds.size.width")
var layerHolder = [CALayer]()
var widthIndex = CGPoint(x: 0, y: 0)
var nextXOffset = CGFloat(0.0)
var checkIfFull = CGFloat()
var newLayer : CALayer?
var progressBarAnimationDuration : CFTimeInterval = (MainController.sharedInstance.totalMiliSeconsToRecord  / 10)

// Only override draw() if you perform custom drawing.
// An empty implementation adversely affects performance during animation.
override func draw(_ rect: CGRect) {

}

func startProgressBar(){

    if(RecordingViewController().currentCameraMode == .recordingMode || RecordingViewController().currentCameraMode == .record1stClipMode) {

        newLayer = CALayer()
        newLayer?.frame = CGRect(x: nextXOffset, y: 0, width: 0, height: self.bounds.height)
        newLayer?.backgroundColor = UIColor(red:0.82, green:0.01, blue:0.11, alpha:1.0).cgColor

        //print("before \(nextXOffset)")
        newLayer?.anchorPoint = widthIndex
        animation.fromValue = 0
        animation.toValue = self.bounds.width  - nextXOffset
        animation.duration = progressBarAnimationDuration - ((MainController.sharedInstance.miliSecondsPassed) / 10)
        self.layer.addSublayer(newLayer!)

        //print("Long Press Began")
        newLayer?.add(animation, forKey: "bounds.size.width")

    }
    else{
        stopProgressBar()
    }
}

func stopProgressBar(){
    if(RecordingViewController().currentCameraMode != .recordingMode){

            pauseLayer(layer: newLayer!)

            newLayer?.frame = (newLayer?.presentation()!.frame)!
            nextXOffset = (newLayer?.frame.maxX)!
            layerHolder.append(newLayer!)
            print("Layerholder has elements : \(layerHolder.count)")
    }
}

// HERE IS MY PROBLEM
func highlightLastLayer(){
    print("in highlight last layer Layerholder has elements : \(layerHolder.count)")

    // I CAN HIDE THE CALAYER SO I BELIEVE IM ACCESSING THE CORRECT LAYER
    // layerHolder.last?.isHidden = true

    // This is suppose to change the last element background color to blue but doesnt
    layerHolder.last?.backgroundColor = UIColor.blue.cgColor
}

// ALSO MY PROBLEM
func unhighlightLastLayer(){
    print("inside unhighlight last layer")

    // I CAN HIDE THE CALAYER SO I BELIEVE IM ACCESSING THE CORRECT LAYER
    //layerHolder.last?.isHidden = false

    // Changes CALayer back to red
    layerHolder.last?.backgroundColor = UIColor(red:0.82, green:0.01, blue:0.11, alpha:1.0).cgColor
}

//Function to pause the Progress Bar
func pauseLayer(layer : CALayer){
    let pausedTime : CFTimeInterval = layer.convertTime(CACurrentMediaTime(), from: nil)
    layer.speed = 0.0
    layer.timeOffset = pausedTime

}



}

简单地说，我在我的progressView中创建了一个viewController对象，然后根据特定的按钮输入调用这些函数。这个视图本质上是一个进度条，您可以在许多视频记录应用程序中看到它，以显示您记录了多少。在highlightLastLayer中，我试图获取"layerHolder“数组的最后一个元素，并将其颜色更改为蓝色。很简单对吧？不起作用。有什么想法吗？

Answer 1

你在哪里叫高亮和非高亮。我非常肯定，当您被“停止”或“暂停”时，您会这样做，因为这是您唯一一次向layerHolder数组添加任何内容。只有当你没有动画的时候，你才能做到这一点，因为当你在动画的时候，表示层是显示的，而不是“真实的”层。不要将速度设置为零，而是设置您的图层看起来像当前的动画状态和调用层。removeAllAnimations来关闭表示层，而不是显示视图的实际层。现在你可以做所有你想要的改变，它们实际上会出现。