CAShapeLayer在动画Swift中检测触摸 [英] CAShapeLayer detect touch during animation Swift

问题描述

我可以这样检测一下CAShapeLayer的触摸（touchesEnded）：

I can detect a touch of a CAShapeLayer like this (touchesEnded):

let touchLocation : CGPoint = (touch as! UITouch).locationInView(self.view)

for shape in shapes{
    if CGPathContainsPoint(shape.path, nil, touchLocation, false){
        print("Layer touch")
    }
}

我可以为CAShapeLayer设置动画路径

And I can animate the path of a CAShapeLayer like this:

let newShapePath = UIBezierPath(arcCenter: toPoint, radius: 20, startAngle: CGFloat(0), endAngle: CGFloat(M_PI * 2), clockwise: true).CGPath

// animate the `path`
let animation = CABasicAnimation(keyPath: "path")
animation.toValue = newShapePath
animation.duration = CFTimeInterval(duration)

animation.timingFunction = CAMediaTimingFunction(name: kCAMediaTimingFunctionEaseIn)
animation.fillMode = kCAFillModeBoth
animation.removedOnCompletion = false

shape.addAnimation(animation, forKey: animation.keyPath)

但是，在动画制作过程中，CAShapeLayer上没有检测到触摸。

But while the animation is happening, touches aren't detected on the CAShapeLayer. Is it possible to detect a touch on the a CAShapeLayer while animating the path?

推荐答案

您可以访问图层的 presentationLayer 为此。这将使您在制作动画时大致估计给定层的飞行中值。例如：

You can access the layer's presentationLayer in order to do this. This will provide you with a rough approximation to the 'in flight' values of a given layer while animating. For example:

for shape in shapes {

    // gets the layer's presentation layer if it exists – else fallback on the model layer
    let presentationLayer = shape.presentationLayer() as? CAShapeLayer ?? shape

    if CGPathContainsPoint(presentationLayer.path, nil, touchLocation, false){
        print("Layer touch")
    }
}

此外，作为旁注，使用 removedOnCompletion = false （如果您不使用动画委托）。您应该只更新图层的模型值以表示其新状态，而不要让动画挥之不去。您可以通过 CATransaction 执行此操作，以确保不生成任何隐式动画。例如：

Also, as a side note, it's generally considered bad practice to use removedOnCompletion = false if you're not using the animation delegate. Instead of leaving the animation lingering, you should just update the layer's model values to represent its new state. You can do this through a CATransaction to ensure that no implicit animations are generated. For example:

let animation = CABasicAnimation(keyPath: "path")
animation.fromValue = shape.path
animation.toValue = newShapePath
animation.duration = CFTimeInterval(duration)

animation.timingFunction = CAMediaTimingFunction(name: kCAMediaTimingFunctionEaseIn)

shape.addAnimation(animation, forKey: animation.keyPath)

// update the layer's model values
CATransaction.begin()
CATransaction.setDisableActions(true)
shape.path = newShapePath
CATransaction.commit()

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