Applying impulse on a SpriteKit node - ios

Question

I'm developing a Sprite Kit Game, which I have a node named hero who dodges approaching villains. I have an issue with applyImpulse for a jump action and, in this case, the hero can jump repeatedly and fly instead of dodging the villains. I'm used a boolean variable to change the status with a timer value to jump only once in 3 seconds but that is not working. Here is my code
override func touchesBegan(touches: NSSet, withEvent event: UIEvent) {
if isGameOver == true {
self.restart()
}
if isstarted {
self.runAction(SKAction.playSoundFileNamed("jump.wav", waitForCompletion: false))
for touch: AnyObject in touches{
if jumpon == false { //hero has not jumped
let location = touch.locationInNode(self)
heroAction()
jumpon = true //hero jumped
}
}
} else {
isstarted = true
hero.stop()
hero.armMove()
hero.rightLegMove()
hero.leftLegMove()
treeMove()
villanMove()
let clickToStartLable = childNodeWithName("clickTostartLable")
clickToStartLable?.removeFromParent()
addGrass()
// star.generateStarWithSpawnTime()
}
}
func changeJump(){
jumpon = false // hero has landed
}
and function update is called in every second and then changeJump must be called
override func update(currentTime: CFTimeInterval) {
if isstarted == true {
let pointsLabel = childNodeWithName("pointsLabel") as MLpoints
pointsLabel.increment()
}
if jumpon == true { // checked everyframe that hero jumped
jumpingTimer = NSTimer.scheduledTimerWithTimeInterval(3, target: self, selector: "changeJump", userInfo: nil, repeats: true) // changing jump status
}
}
How should I update my code to make the hero jump only once in three seconds. Thanks in advance.

Answer 1

Some thoughts...
I suggest you use an SKAction or two instead of an NSTimer in Sprite Kit games. SKActions pause/resume appropriately when you pause/resume the scene and/or view
The update method is called ~60 times a second not every second
Checking the status of a jump in update is not need
Alternatively, you can check if the hero is on the ground before starting another jump sequence instead of using a timer. The game may frustrate the user if the hero is on the ground (and ready to jump) but the timer is still counting down
and some code...
if (!jumping) {
jumping = true
let wait = SKAction.waitForDuration(3)
let leap = SKAction.runBlock({
// Play sound and apply impulse to hero
self.jump()
})
let action = SKAction.group([leap, wait])
runAction(action) {
// This runs only after the action has completed
self.jumping = false
}
}