将Sprite的直线拖到SpriteKit中的手指位置

Question

我想知道问题是否与节点的排列有关，而不是与代码有关，但是我似乎无法使这一行正常工作。我想从触摸的节点到触摸的位置绘制一条可拖动的直线。然后，该节点将移动到结束触摸的位置。我的代码基于我在这里看到的一些内容，但仍然无法显示出来。此相关节点是SKSpriteNode的子类，并且此代码位于该类中，而不是在主GameScene类中。

override func touchesMoved(_ touches: Set<UITouch>, with event: UIEvent?) {
    self.childNode(withName: "line")?.removeFromParent()  // Remove any previous line
    guard let touch = touches.first else { return } 
    let positionInScene = touch.location(in: self.parent!)  // Use 'parent' here? 
    let path = CGMutablePath()
    let line = SKShapeNode(path: path)  // Create shape node with path as path
    line.name = "line"
    line.zPosition = 5000  // Just trying to make sure it's on top
    line.strokeColor = UIColor.red
    line.lineWidth = 20
    line.fillColor = UIColor.red
    path.move(to: CGPoint(x: self.position.x, y: self.position.y))
    path.addLine(to: CGPoint(x: positionInScene.x, y: positionInScene.y))
    self.addChild(line)
}

当我在touchesBegan中创建并添加路径时，它会显示出来，但是会画出一堆线，我只需要一个。

Answer 1

简单错误。绘制后只需将path分配给该行。

let path = CGMutablePath()    
path.move(to: CGPoint(x: self.position.x, y: self.position.y))
path.addLine(to: CGPoint(x: positionInScene.x, y: positionInScene.y))

let line = SKShapeNode(path: path)  // Create shape node with path as path
self.addChild(line)