在 Swift 中“尝试添加一个已经有父节点的 SKNode”

Question

我有这个函数用来每秒在随机位置生成 Flower 对象：

func spawnFlower() {
    //Create flower with random position
    let tempFlower = Flower()
    let height = UInt32(self.size.height / 2)
    let width = UInt32(self.size.width / 2)
    let randomPosition = CGPoint(x: Int(arc4random_uniform(width)), y: Int(arc4random_uniform(height)))
    tempFlower.position = randomPosition

    var tooClose = false
    flowerArray.append(tempFlower)

    // enumerate flowerArray
    for flower in flowerArray {

        // get the difference in position between the current node
        // and each node in the array
        let xPos = abs(flower.position.x - tempFlower.position.x)
        let yPos = abs(flower.position.y - tempFlower.position.y)

        // check if the spawn position is less than 10 for the x or y in relation
        // to the current node in the array
        if (xPos < 10) || (yPos < 10) {
            tooClose = true
        }

        if tooClose == false {
            //Spawn node
            addChild(tempFlower)
        }
    }
}

每次调用该函数时，我都会为花创建一个新实例，但由于某种原因，当我调用如下函数时，它给了我错误：

Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: 'Attemped to add a SKNode which already has a parent:

spawnFlower() 函数每秒调用一次。它在第一次调用时工作，第二次崩溃。我做错了什么？

Answer 1

addChild() 调用需要移出 for 循环，以便 tempFlower 只添加到其父级一次。

func spawnFlower() {
    //Create flower with random position
    let tempFlower = Flower()
    let height = UInt32(self.size.height / 2)
    let width = UInt32(self.size.width / 2)
    let randomPosition = CGPoint(x: Int(arc4random_uniform(width)), y: Int(arc4random_uniform(height)))
    tempFlower.position = randomPosition

    var tooClose = false
    flowerArray.append(tempFlower)

    // enumerate flowerArray
    for flower in flowerArray {

        // get the difference in position between the current node
        // and each node in the array
        let xPos = abs(flower.position.x - tempFlower.position.x)
        let yPos = abs(flower.position.y - tempFlower.position.y)

        // check if the spawn position is less than 10 for the x or y in relation
        // to the current node in the array
        if (xPos < 10) || (yPos < 10) {
            tooClose = true
        }
    }

    if tooClose == false {
        // Spawn node
        addChild(tempFlower)
    }
}