swift invalidate timer doesn't work

Question

I have this problem for a few days now and I don\'t get what I am doing wrong.

My application is basically just creating some timers. I need to stop them and create

Answer 1

The usual way to start and stop a timer safely is

var timer : NSTimer?

func startTimer()
{
  if timer == nil {
    timer = NSTimer.scheduledTimerWithTimeInterval(timeInterval, target: self, selector: "timerFired", userInfo: nil, repeats: true)
  }
}

func stopTimer()
{
  if timer != nil {
    timer!.invalidate()
    timer = nil
  }
}

startTimer() starts the timer only if it's nil and stopTimer() stops it only if it's not nil.

You have only to take care of stopping the timer before creating/starting a new one.

In Swift 3 replace

• NSTimer with Timer,
• NSTimer.scheduledTimerWithTimeInterval( with Timer.scheduledTimer(timeInterval:
• selector: "timerFired" with selector: #selector(timerFired).