更新了swift 4

Question

嘿，我的感觉非常好，感动它是由@Sam_M给我的。

我试图在移动时基本上跟踪多个手指的位置。就像手指1在这里，手指2在那里。因此，截至目前，它将打印当前在视图和位置上的手指/触摸的数量，但它不会分别跟踪两个单独的手指。我看了看stackoverflow上唯一的另外三个问题。但没有人能给我一个好的结果，我可以在swift中实现。

override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) {

for touch: UITouch in event!.allTouches()! {

for (index,touch) in touches.enumerate() {
    let ptTouch = touch.locationInNode(self.view)
    print("Finger \(index+1): x=\(pTouch.x) , y=\(pTouch.y)")
 }
}

}

override func touchesMoved(touches: Set<UITouch>, withEvent event: UIEvent?) {

for touch: UITouch in event!.allTouches()! {

for (index,touch) in touches.enumerate() {
    let ptTouch = touch.locationInNode(self.view)
    print("Finger \(index+1): x=\(pTouch.x) , y=\(pTouch.y)")
  }
 }
}

Answer 1

每个手指的触摸对象将在屏幕上显示相同的内存地址。您可以通过将触摸对象的地址存储在数组中，然后与该数组进行比较以确切知道哪个手指正在移动来跟踪多点触控场景中的各个手指。

var fingers = [String?](count:5, repeatedValue: nil)

override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) {
    super.touchesBegan(touches, withEvent: event)
    for touch in touches{
        let point = touch.locationInView(self.view)
        for (index,finger)  in fingers.enumerate() {
            if finger == nil {
                fingers[index] = String(format: "%p", touch)
                print("finger \(index+1): x=\(point.x) , y=\(point.y)")
                break
            }
        }            
    }        
}

override func touchesMoved(touches: Set<UITouch>, withEvent event: UIEvent?) {
    super.touchesMoved(touches, withEvent: event)
    for touch in touches {
        let point = touch.locationInView(self.view)
        for (index,finger) in fingers.enumerate() {
            if let finger = finger where finger == String(format: "%p", touch) {
                print("finger \(index+1): x=\(point.x) , y=\(point.y)")
                break
            }
        }
    }
}

override func touchesEnded(touches: Set<UITouch>, withEvent event: UIEvent?) {
    super.touchesEnded(touches, withEvent: event)
    for touch in touches {
        for (index,finger) in fingers.enumerate() {
            if let finger = finger where finger == String(format: "%p", touch) {
                fingers[index] = nil
                break
            }
        }
    }        
}

override func touchesCancelled(touches: Set<UITouch>?, withEvent event: UIEvent?) {
    super.touchesCancelled(touches, withEvent: event)
    guard let touches = touches else {
        return
    }
    touchesEnded(touches, withEvent: event)
}

更新了swift 4

归功于@Klowne

var fingers = [UITouch?](repeating: nil, count:5)

override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
    super.touchesBegan(touches, with: event)
    for touch in touches{
        let point = touch.location(in: self.view)
        for (index,finger)  in fingers.enumerated() {
            if finger == nil {
                fingers[index] = touch
                print("finger \(index+1): x=\(point.x) , y=\(point.y)")
                break
            }
        }
    }
}

override func touchesMoved(_ touches: Set<UITouch>, with event: UIEvent?) {
    super.touchesMoved(touches, with: event)
    for touch in touches {
        let point = touch.location(in: self.view)
        for (index,finger) in fingers.enumerated() {
            if let finger = finger, finger == touch {
                print("finger \(index+1): x=\(point.x) , y=\(point.y)")
                break
            }
        }
    }
}

override func touchesEnded(_ touches: Set<UITouch>, with event: UIEvent?) {
    super.touchesEnded(touches, with: event)
    for touch in touches {
        for (index,finger) in fingers.enumerated() {
            if let finger = finger, finger == touch {
                fingers[index] = nil
                break
            }
        }
    }
}

override func touchesCancelled(_ touches: Set<UITouch>, with event: UIEvent?) {
    super.touchesCancelled(touches, with: event)
    guard let touches = touches else {
        return
    }
    touchesEnded(touches, with: event)
}

*根据苹果公司的更新文档，现在可以在多点触控序列中保留触摸，只要它们在序列结束时释放

Answer 2

触摸是一根手指。手指是触摸。您可以通过识别触摸来识别手指;只要手指触摸屏幕，特定手指的触摸将与相同的对象完全相同。要获取特定UITouch的唯一标识符，请获取其内存地址，如下所示：

let uuid = String(format: "%p", theTouch)

您可以在属性中存储每次触摸的唯一标识符。但不存储触摸本身; Apple禁止它。

如何跟踪多个触摸

2 个答案:

更新了swift 4