如果我将手指从节点上移到 GameView 中，为什么我的节点会停止旋转？

Question

我有这个节点，如果我的手指放在它上面我可以旋转。我遇到的问题是，当我旋转节点时，我的手指从节点滑落到视图上，它停止旋转。如果我的手指不再在节点上，我怎么还能触摸到？

例如，我的应用程序中有一个 UISlider，如果我的手指放在滑块上并向下移动，然后尝试将滑块向左和向右移动，它仍然可以工作。我如何能够对触摸事件仍然存在的节点执行相同的操作？如果你不明白我在说什么，请告诉我。这是我用来旋转节点的代码：

override func touchesMoved(touches: Set<UITouch>, withEvent event: UIEvent?) {
for touch in touches {
let location = touch.locationInNode(self)
let node = self.nodeAtPoint(location)

    if node.name == "circle"                 
       //lets user rotate when there is one finger on node.
       let dy = circle.position.y - location.y
       let dx = circle.position.x - location.x
       let angle2 = atan2(dy, dx)
       circle.zRotation =  angle2
    }

Answer 1

您应该将最后一个节点存储在实例变量中，然后使用它尝试保持旋转，即使它没有碰到它。

class MyClass  {
var lastNodeSelected:SKNode?

override func touchesStart(touches: Set<UITouch>, withEvent event: UIEvent?) {
for touch in touches {
let location = touch.locationInNode(self)
let node = self.nodeAtPoint(location)

    if node.name == "circle"                 
       lastNodeSelected = node
    }
}


override func touchesMoved(touches: Set<UITouch>, withEvent event: UIEvent?) {
for touch in touches {
let location = touch.locationInNode(self)

    if lastNodeSelected != nil {
       let touchedNode = lastNodeSelected!                 
       let dy = touchedNode.position.y - location.y
       let dx = touchedNode.position.x - location.x
       let angle2 = atan2(dy, dx)
       touchedNode.zRotation =  angle2
    }

override func touchesEnd(touches: Set<UITouch>, withEvent event: UIEvent?) {
   lastNodeSelected = nil