swift - Pause and Resume SKScene -

hey guys testing game on iphone , realize got problem pause button. why? because when pause game , app when game playing without touching resume button. here's 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 touch begins */      show = self.scene skscene!       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)         } 

any help? thanks

spritekit auto resume when comeback app. need :

step 1 : create variable :

var waspaused : bool = false 

step 2 : change in pause/resume function :

waspaused = true // pause func waspaused = false // resume fun 

step 3 : in update fun of scene:

override func update(currenttime: cftimeinterval) {     if ispausing{         self.paused = true         return     } }