Ios 设置CAShapeLayer/CAGradientLayer的动画

这是我昨天问的一个问题的补充。结果很好，但我想修改一下

下面的代码，基于上面的线程，生成了一个CABasicAnimation，它生长出深蓝色的“三角形”。我希望这是一个具有3个停止点的CAGradientLayer，而不是深蓝色的纯色

我尝试添加一个CAGradientLayer来配置渐变，然后使用addSubLayer将渐变添加到制作动画的CAShapeLayer。我在下面发布的结果没有动画效果。颜色和形状保持不变。渐变看起来很棒，只需设置动画即可：

我需要foregroundGradient对象（带有gradientLayer子层！）从左到右设置动画。

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如果您从上面的代码中删除渐变，并将foregroundGradient保持为纯色，您将看到动画。

我认为您必须在视图中使用

遮罩，如下所述

//Remove below line
view.layer.addSublayer(backgroundGray)

//Add your mask to view
view.layer.mask = backgroundGray

整个函数如下所示：

func getGradientView() {
    let view = UIView(frame: CGRect(x: 0, y: 50, width: 521, height: 40))
    view.backgroundColor = UIColor.grayColor()
    self.view.addSubview(view)

    let maskPath = UIBezierPath()

    maskPath.moveToPoint(CGPoint(x: 0, y: 30))
    maskPath.addLineToPoint(CGPoint(x: 0, y: 25))
    maskPath.addLineToPoint(CGPoint(x: 300, y: 10))
    maskPath.addLineToPoint(CGPoint(x: 300, y: 30))
    maskPath.closePath()

    let maskLayer = CAShapeLayer()
    maskLayer.path = maskPath.CGPath
    maskLayer.fillColor = UIColor.whiteColor().CGColor

    let rectToAnimateFrom = UIBezierPath(rect: CGRect(x: 0, y: 0, width: 0, height: 40))
    let rectToAnimateTo = UIBezierPath(rect: CGRect(x: 0, y: 0, width: 300, height: 40))

    let backgroundGray = CAShapeLayer()
    backgroundGray.path = maskPath.CGPath
    backgroundGray.fillColor = UIColor.grayColor().CGColor

    let foregroundGradient = CAShapeLayer()
    foregroundGradient.mask = maskLayer
    foregroundGradient.backgroundColor = UIColor.clearColor().CGColor


    let gradientLayer = CAGradientLayer()
    gradientLayer.startPoint = CGPointMake(0, 0)
    gradientLayer.endPoint = CGPointMake(1, 0)
    gradientLayer.frame = maskPath.bounds

    let colors = [UIColor.redColor().CGColor, UIColor.greenColor().CGColor, UIColor.blueColor().CGColor]
    gradientLayer.colors = colors

    foregroundGradient.addSublayer(gradientLayer)

    //Remove below line
    //view.layer.addSublayer(backgroundGray)

    view.layer.addSublayer(foregroundGradient)

    //Add you mask to view
    view.layer.mask = backgroundGray

    let animation = CABasicAnimation(keyPath: "path")
    animation.fromValue = rectToAnimateFrom.CGPath
    animation.toValue = rectToAnimateTo.CGPath
    animation.duration = 1
    animation.repeatCount = 1000
    animation.removedOnCompletion = false
    animation.fillMode = kCAFillModeForwards


    maskLayer.addAnimation(animation, forKey: "fill animation")
}

让我知道它是否符合您的例外情况。
您能告诉我您在这里面临什么问题吗？@Dhanesh-第3段提到了这一点。渐变看起来很完美。我需要的确切尺寸和颜色。但是，动画不起作用。看看我贴的帖子。蓝色从左向右设置动画，而灰色三角形为背景。我需要同样的结果，除了使用梯度。
func getGradientView() {
    let view = UIView(frame: CGRect(x: 0, y: 50, width: 521, height: 40))
    view.backgroundColor = UIColor.grayColor()
    self.view.addSubview(view)

    let maskPath = UIBezierPath()

    maskPath.moveToPoint(CGPoint(x: 0, y: 30))
    maskPath.addLineToPoint(CGPoint(x: 0, y: 25))
    maskPath.addLineToPoint(CGPoint(x: 300, y: 10))
    maskPath.addLineToPoint(CGPoint(x: 300, y: 30))
    maskPath.closePath()

    let maskLayer = CAShapeLayer()
    maskLayer.path = maskPath.CGPath
    maskLayer.fillColor = UIColor.whiteColor().CGColor

    let rectToAnimateFrom = UIBezierPath(rect: CGRect(x: 0, y: 0, width: 0, height: 40))
    let rectToAnimateTo = UIBezierPath(rect: CGRect(x: 0, y: 0, width: 300, height: 40))

    let backgroundGray = CAShapeLayer()
    backgroundGray.path = maskPath.CGPath
    backgroundGray.fillColor = UIColor.grayColor().CGColor

    let foregroundGradient = CAShapeLayer()
    foregroundGradient.mask = maskLayer
    foregroundGradient.backgroundColor = UIColor.clearColor().CGColor


    let gradientLayer = CAGradientLayer()
    gradientLayer.startPoint = CGPointMake(0, 0)
    gradientLayer.endPoint = CGPointMake(1, 0)
    gradientLayer.frame = maskPath.bounds

    let colors = [UIColor.redColor().CGColor, UIColor.greenColor().CGColor, UIColor.blueColor().CGColor]
    gradientLayer.colors = colors

    foregroundGradient.addSublayer(gradientLayer)

    //Remove below line
    //view.layer.addSublayer(backgroundGray)

    view.layer.addSublayer(foregroundGradient)

    //Add you mask to view
    view.layer.mask = backgroundGray

    let animation = CABasicAnimation(keyPath: "path")
    animation.fromValue = rectToAnimateFrom.CGPath
    animation.toValue = rectToAnimateTo.CGPath
    animation.duration = 1
    animation.repeatCount = 1000
    animation.removedOnCompletion = false
    animation.fillMode = kCAFillModeForwards


    maskLayer.addAnimation(animation, forKey: "fill animation")
}