Check if Timer is running

Question

I have been trying to refill in game lives with a timer, but whenever I leave a view and return, the timer duplicates and becomes faster. I have tried to address this with the Timer?.isValid function to only run the timer when it is invalid so it never duplicates, but it cannot seem to check is the timer is invalid in an if statement.

This is the if statement that I have been using so far:

if (myTimer?.isValid){
} else{
//start timer
}

Any help would be appreciated, thanks.

Solution 1

I recommend to use self-checking startTimer() and stopTimer() functions, the timer will be started only if it's not currently running, the stop function sets the timer variable reliably to nil.

var timer : Timer?

func startTimer()
{
    if timer == nil {
        timer = Timer.scheduledTimer...
    }
}

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

Solution 2

You need to check if your Timer instance isValid (not the Timer class), let's say: if myTimer.isValid? {}.

Comments

[Jack Sullivan]

im not sure if you understand, i want to check if a timer is running, not start/stop a timer

[vadian]

Your code in the question implies: If the timer is not valid (is not running), start it. That's exactly what startTimer() does. In my suggested logic the timer is not running if it's nil.

[Jack Sullivan]

Sorry, I understand now and your function is working!