如何将多个节点添加到场景并一次移动所有节点。 迅速。 精灵套件

Question

I am new to swift and spriteKit. I am creating a side scrolling game. I want it to add multiple nodes(called Impenitrible) from the right side of the screen at any height and move left. My function for creating the "Impenitrible" node is :

func spawnImpenitrible(){
   Impenitrible.physicsBody = SKPhysicsBody(rectangleOfSize: Impenitrible.size)
           let actionDone =  SKAction.removeFromParent()
    var MinValue = sand.size.height
    var MaxValue = self.size.height - Impenitrible.size.height / 2
    var spawnPoint = UInt32(MaxValue - MinValue)
    Impenitrible.position = CGPoint(x: self.size.width - 60 , y: CGFloat(arc4random_uniform(spawnPoint)))

    Impenitrible.physicsBody?.categoryBitMask = physicsCategory.impenitrible
    Impenitrible.physicsBody?.contactTestBitMask = physicsCategory.sub
    Impenitrible.physicsBody?.affectedByGravity = false
    Impenitrible.physicsBody?.dynamic = true
    self.addChild(Impenitrible)


}

I call this function with:

var impenitribleTimer = NSTimer.scheduledTimerWithTimeInterval(2.0, target: self, selector: Selector("spawnImpenitrible"), userInfo: nil, repeats: true)

I move it by subtracting a number from the x position in the "Update" function.

It works fine adding Impenitrible once. but once it calls the function again the app crashes with error of :
Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: 'Attemped to add a SKNode which already has a parent where did i go wrong? Any help would be great! Thank you.

Answer 1

First, I want to point out that your line of code: let actionDone = SKAction.removeFromParent() is effectively useless because you never call runAction to use it.

The error message sums it up quite nicely. "Attempted to add a SKNode which already has a parent". You never actually call removeFromParent() .

Adding Impenitrible once works fine as you found out, because at the start, Impenitrible has no parent. Subsequent calls will have a conflict because Impenitrible already has the parent that was added via the first call.

A quick and dirty fix is to do a runAction(SKAction.removeFromParent()) before the next call of spawnImpenitrible , somewhere, referencing Imprenitrible .