unable to loop through a Counter in Swift - ios

Question

I guys I have a working countdown timer which I can set manually and countdown from this value.
What I'm trying to achieve now though is set my INTERVALS counter to say 3 and loop through the countdown timer the amount of times that I set in this counter then when the last interval is complete the timer finishes
sounds straight forward in my head I know I need a loop somewhere but everything I have tried just hast worked this is my current code before adding a loop. Have tried adding a while statement instead of the if statement but that didn't do the job
I've now added this loop but still no joy. Anyone know how to do this?
func runIntervalTimer() {
timerForIntervals = NSTimer.scheduledTimerWithTimeInterval(1, target: self,
selector: Selector("updateTimeInterval"), userInfo: nil, repeats: true)
}
func updateTimeInterval() {
do {
if intervalCountdown > 0 {
intervalHasBeenSet = true
intervalCountdown--
IntervalTimer.text = String(format: "%02d:%02d", intervalCountdown/60,
intervalCountdown%60) }
} while intervalHasBeenSet == true
intervalHasBeenSet = false
intervalCountdown = 0
IntervalTimer.text = String(format: "%02d:%02d", intervalCountdown/60,
intervalCountdown%60)
}
#IBAction func InterValTimerIncrease(sender: AnyObject) {
intervalCountdown++
IntervalTimer.text = String(format: "%02d:%02d", intervalCountdown/60,
intervalCountdown%60)
}
#IBAction func IntervalTimerDecrease(sender: AnyObject) {
intervalCountdown--
IntervalTimer.text = String(format: "%02d:%02d", intervalCountdown/60,
intervalCountdown%60)
}
#IBAction func IntervalStart(sender: AnyObject) {
runIntervalTimer()
}

Answer 1

You're probably in an infinite loop here:
do {
if intervalCountdown > 0 {
intervalHasBeenSet = true
intervalCountdown--
IntervalTimer.text = String(format: "%02d:%02d", intervalCountdown/60,
intervalCountdown%60) }
} while intervalHasBeenSet == true
Your condition is intervalHasBeenSet == true but it's never being set to false inside the loop, so it can never exit.
If you want the timer to count down each interval, I think all you need to do is:
func updateTimeInterval() {
println(intervalCountdown)
if intervalCountdown > 0 {
intervalCountdown--
IntervalTimer.text = String(format: "%02d:%02d", intervalCountdown/60,
intervalCountdown%60)
}
}
Because the updateTimeInterval should be called each interval by NSTimer, you shouldn't need a loop inside this function.
To have the timer count down multiple times, you need an extra variable (intervalNum):
func updateTimeInterval() {
println(intervalCountdown)
if intervalCountdown > 0 && intervalNum > 0 {
// countdown in the current interval
intervalCountdown--
IntervalTimer.text = String(format: "%02d:%02d", intervalCountdown/60,
intervalCountdown%60)
}
else
{
// move on to the next interval
intervalNum--
intervalCountdown = 20 // or grab the original value from somewhere
}
if (intervalNum == 0)
{
// stop the timer
timerForIntervals.invalidate()
}
}