ios - 用 SKShapeNode 画一条线

我想简单地使用 SKShapeNode 画一条线。我正在使用 SpriteKit 和 Swift。

到目前为止，这是我的代码:

var line = SKShapeNode()
var ref = CGPathCreateMutable()

    override func touchesBegan(touches: NSSet, withEvent event: UIEvent) {

    for touch: AnyObject in touches {
        let location = touch.locationInNode(self)

    }
}

override func touchesMoved(touches: NSSet, withEvent event: UIEvent) {

    for touch: AnyObject in touches {
        let locationInScene = touch.locationInNode(self)

        CGPathMoveToPoint(ref, nil, locationInScene.x, locationInScene.y)
        CGPathAddLineToPoint(ref, nil, locationInScene.x, locationInScene.y)
        line.path = ref
        line.lineWidth = 4
        line.fillColor = UIColor.redColor()
        line.strokeColor = UIColor.redColor()
        self.addChild(line)

    }
}

每当我运行它并尝试画一条线时，应用程序就会因错误而崩溃:
原因:'试图添加一个已经有父级的 SKNode:SKShapeNode 名称:'(空)'accumulatedFrame:{{0, 0}, {0, 0}}'

为什么会这样？

最佳答案

好吧，您一遍又一遍地添加相同的子实例。每次创建线节点并将其添加到父节点，然后它将解决您的问题。

var ref = CGPathCreateMutable()

override func touchesBegan(touches: NSSet, withEvent event: UIEvent) {

    if let touch = touches.anyObject() as? UITouch {
        let location = touch.locationInNode(self)
        CGPathMoveToPoint(ref, nil, location.x, location.y)
    }
}

override func touchesMoved(touches: NSSet, withEvent event: UIEvent) {

    for touch: AnyObject in touches {
        let locationInScene = touch.locationInNode(self)
        var line = SKShapeNode()
        CGPathAddLineToPoint(ref, nil, locationInScene.x, locationInScene.y)
        line.path = ref
        line.lineWidth = 4
        line.fillColor = UIColor.redColor()
        line.strokeColor = UIColor.redColor()
        self.addChild(line)
    }
}

关于ios - 用 SKShapeNode 画一条线，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/27493261/