从swift 3中的触摸位置获取矢量

Question

正如标题所说，我怎样才能做到这一点？我可以进行第一次触摸，但如果是滑动手势，我不知道如何进行最后一次触摸。使用以下代码，我得到错误：“Set”类型的值没有成员“last”。不确定如何在释放触摸时获得位置。

override func touchesMoved(_ touches: Set<UITouch>, with: UIEvent?){
    let firstTouch:UITouch = touches.first! as UITouch
    let lastTouch:UITouch = touches.last! as UITouch

    let firstTouchLocation = firstTouch.location(in: self)
    let lastTouchLocation = lastTouch.location(in: self)

}

我想获取第一个点的位置和第二个点的位置。然后我想使用滑动的持续时间、线条的大小和线条的角度来创建一个脉冲向量以在 SKNode 上使用。有没有办法使用 UITouch 提取这些信息？任何帮助是极大的赞赏。感谢您的宝贵时间！

我在屏幕上也有基本的触摸来运行功能

 override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
    let touch:UITouch = touches.first! as UITouch
    let touchLocation = touch.location(in: self)
    if playButton.contains(touchLocation) && proceed == true{
        playSound1()
        Ball.physicsBody?.affectedByGravity = true
        proceed = false}
    else if infoButton.contains(touchLocation) && proceed == true{
        playSound1()
        loadScene2()}
    else {}
}

Answer 1

您必须存储 touches begin 中的值并与 touches end 中的值进行比较，然后在那里进行计算。请注意，触摸可以通过电话等方式取消，因此您也需要对此进行预测。

    class v: UIViewController {
        var startPoint: CGPoint?
        var touchTime = NSDate()
        override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
            guard touches.count == 1 else {
                return
            }
            if let touch = touches.first {
                startPoint = touch.location(in: view)
                touchTime = NSDate()
            }
        }

        override func touchesEnded(_ touches: Set<UITouch>, with event: UIEvent?) {
            defer {
                startPoint = nil
            }
            guard touches.count == 1, let startPoint = startPoint else {
                return
            }
            if let touch = touches.first {
                let endPoint = touch.location(in: view)
                //Calculate your vector from the delta and what not here
                let direction = CGVector(dx: endPoint.x - startPoint.x, dy: endPoint.y - startPoint.y)
                let elapsedTime = touchTime.timeIntervalSinceNow
                let angle = atan2f(Float(direction.dy), Float(direction.dx))
            }
        }

        override func touchesCancelled(_ touches: Set<UITouch>, with event: UIEvent?) {
            startPoint = nil
        }
    }