How to fix this NSTimer issue? - swift

Question

Everything is fine until I use NSTimer to run the tree, that the images of tree is gone. I use SKview to show the physic then I find out that the code is still run, just only the image is gone. How can I fix it?
Part 1
class PlayScene: SKScene {
var BG6 = SKSpriteNode()
var balloon = SKSpriteNode()
var tree1 = SKSpriteNode()
var tree2 = SKSpriteNode()
Part 2
override func didMoveToView(view: SKView) {
MakeBG()
// add balloon
var ballontexture = SKTexture(imageNamed: "Balloon.png")
balloon = SKSpriteNode(texture: ballontexture)
balloon.position = CGPoint(x: self.frame.size.width/2, y: self.frame.size.height/5)
balloon.physicsBody = SKPhysicsBody(rectangleOfSize: balloon.size)
balloon.physicsBody?.dynamic = true
balloon.physicsBody?.allowsRotation = false
balloon.zPosition = 5
self.addChild(balloon)
var timer = NSTimer.scheduledTimerWithTimeInterval(3, target: self, selector: Selector("MakeTree"), userInfo: nil, repeats: true)
var ground = SKNode()
ground.position = CGPointMake(0, 0)
ground.physicsBody = SKPhysicsBody(rectangleOfSize: CGSizeMake(self.frame.size.width,1))
ground.physicsBody?.dynamic = false
self.addChild(ground)
}
Part 3
func MakeBG(){
// chen hinh nen
//BG1
var BG1texture = SKTexture(imageNamed: "BG2")
var BG1 = SKSpriteNode(texture: BG1texture)
BG1.position = CGPoint(x: self.frame.size.width/2, y: self.frame.size.height/2)
BG1.size.height = self.size.height
var BG1move = SKAction.moveToY(-self.frame.size.height, duration: 90)
BG1.runAction(BG1move)
self.addChild(BG1)
//BG2
var BG2texture = SKTexture(imageNamed: "BG3")
var BG2 = SKSpriteNode(texture: BG2texture)
BG2.position = CGPoint(x: self.frame.size.width/2, y: self.frame.size.height/2 + self.frame.size.height)
BG2.size.height = self.size.height
var BG2move = SKAction.moveToY(-self.frame.size.height, duration: 140)
BG2.runAction(BG2move)
self.addChild(BG2)
//BG3
var BG3texture = SKTexture(imageNamed: "BG4")
var BG3 = SKSpriteNode(texture: BG3texture)
BG3.position = CGPoint(x: self.frame.size.width/2, y: self.frame.size.height/2 + self.frame.size.height*2)
BG3.size.height = self.size.height
var BG3move = SKAction.moveToY(-self.frame.size.height, duration: 195)
BG3.runAction(BG3move)
self.addChild(BG3)
//BG4
var BG4texture = SKTexture(imageNamed: "BG5")
var BG4 = SKSpriteNode(texture: BG4texture)
BG4.position = CGPoint(x: self.frame.size.width/2, y: self.frame.size.height/2 + self.frame.size.height*3)
BG4.size.height = self.size.height
var BG4move = SKAction.moveToY(-self.frame.size.height, duration: 250)
BG4.runAction(BG4move)
self.addChild(BG4)
//BG5
var BG5texture = SKTexture(imageNamed: "BG6")
var BG5 = SKSpriteNode(texture: BG5texture)
BG5.position = CGPoint(x: self.frame.size.width/2, y: self.frame.size.height/2 + self.frame.size.height*4)
BG5.size.height = self.size.height
var BG5move = SKAction.moveToY(-self.frame.size.height, duration: 305)
BG5.runAction(BG5move)
self.addChild(BG5)
// BG6
var BG6texture = SKTexture(imageNamed: "BG7")
BG6 = SKSpriteNode(texture: BG6texture)
BG6.position = CGPoint(x: self.frame.size.width/2, y: self.frame.size.height/2 + self.frame.size.height*5 + self.frame.size.height*5)
BG6.size.height = self.size.height
BG6.runAction(SKAction.moveTo(CGPoint(x: self.size.width/2 , y: self.size.height/2), duration: 276.5))
self.addChild(BG6)
}
func MakeTree(){
// between
let between = balloon.size.width
// random
var movementAmount = arc4random() % UInt32(self.frame.size.height/2)
var treeoffset = CGFloat(movementAmount) - self.frame.size.height/4
// move tree
var treemove = SKAction.moveByX(0, y: -self.frame.size.width*2, duration: NSTimeInterval(self.frame.size.height/50))
var treeremove = SKAction.removeFromParent()
var treemoveandremove = SKAction.sequence([treemove, treeremove])
// add tree1
var tree1texture = SKTexture(imageNamed: "C2.png")
tree1 = SKSpriteNode(texture: tree1texture)
tree1.position = CGPointMake(CGRectGetMidX(self.frame) - tree1texture.size().width/2 - between + treeoffset, CGRectGetMidY(self.frame) + self.frame.size.height)
tree1.runAction(treemoveandremove)
tree1.physicsBody = SKPhysicsBody(rectangleOfSize: tree1.size)
tree1.physicsBody?.dynamic = false
self.addChild(tree1)
// add tree2
var tree2texture = SKTexture(imageNamed: "C1.png")
tree2 = SKSpriteNode(texture: tree2texture)
tree2.position = CGPointMake(CGRectGetMidX(self.frame) + tree2texture.size().width/2 + between + treeoffset, CGRectGetMidY(self.frame) + self.frame.size.height)
tree2.runAction(treemoveandremove)
tree2.physicsBody = SKPhysicsBody(rectangleOfSize: tree2.size)
tree2.physicsBody?.dynamic = false
[enter image description here][1]
self.addChild(tree2)
}

Answer 1

If I understood your question correctly, then you want to know why your "tree" is gone.
It appears that your MakeTree() method moves all the tree sprite nodes off the screen:
var treemove = SKAction.moveByX(0, y: -self.frame.size.width*2, duration: NSTimeInterval(self.frame.size.height/50))
Also, you shouldn't use NSTimers in SpriteKit. Use SKAction.waitForDuration instead. Like this:
let delay = SKAction.waitForDuration(3)
someNode.runAction(delay) {
//run code here after 3 seconds
}