Pause and Resume SKScene - swift

Question

I was testing my game on my iPhone and I realized that I have a problem with the home button. When I pause the game and load another app the game is not paused and continues when the app is not on screen.
Here's the code:
class GameScene: SKScene, SKPhysicsContactDelegate{
var PauseButton = SKSpriteNode(imageNamed: "pause")
var Resume = SKSpriteNode(imageNamed: "resume1")
}
init(size: CGSize, won: Bool) {
super.init(size: size)
//pause
PauseButton.position = CGPointMake(330, 700)
PauseButton.zPosition = 3;
PauseButton.size = CGSizeMake(40, 40);
PauseButton.name = "PauseButton"
self.addChild(PauseButton)
//resume
Resume = SKSpriteNode(imageNamed: "resume1")
Resume.position = CGPointMake(520, 450)
Resume.zPosition = 100
Resume.setScale(1.3)
}
override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) {
/* Called when a touch begins */
show = self.scene as SKScene!
for touch in touches {
let Location:CGPoint = touch.locationInNode(self)
let Node:SKNode = self.nodeAtPoint(Location)
if(Node == PauseButton){
self.show.paused = true
PauseButton.removeFromParent()
self.addChild(Resume)
}
if(Node == Resume){
Resume.removeFromParent()
self.show.paused = false
self.addChild(PauseButton)
}
How do I get the game to pause when I press the home button?

Answer 1

Pause the view not the scene.
override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) {
guard let view = view else {
return
}
view.paused = !view.paused
}

Answer 2

SpriteKit will auto Resume when you comeback to your app. so you need :
Step 1 : create a variable :
var wasPaused : Bool = false
Step 2 : change it in your pause/resume function :
wasPaused = true // pause func
wasPaused = false // resume fun
Step 3 : in update fun of your scene:
override func update(currentTime: CFTimeInterval) {
if isPausing{
self.paused = true
return
}
}