iphone - NSTimeInterval to HH:mm:ss?

Question

If I have an NSTimeInterval that is set to say 200.0, is there a way to convert that into 00:03:20, I was thinking I could initialise an NSDate with it and then use NSDateFormatter using HH:mm:ss. My question is, is there a quick way to do this or do I have to break up the number myself and use [NSString stringWithFormat: %02d:%02d:%02d, myHour, myMin, mySec]?

Answer 1

No need to use NSDateFormatter or anything else than division and modulo. NSTimeInterval is just a double containing seconds.

Swift

func stringFromTimeInterval(interval: NSTimeInterval) -> String {
    let interval = Int(interval)
    let seconds = interval % 60
    let minutes = (interval / 60) % 60
    let hours = (interval / 3600)
    return String(format: "%02d:%02d:%02d", hours, minutes, seconds)
}

Objective-C

- (NSString *)stringFromTimeInterval:(NSTimeInterval)interval {
    NSInteger ti = (NSInteger)interval;
    NSInteger seconds = ti % 60;
    NSInteger minutes = (ti / 60) % 60;
    NSInteger hours = (ti / 3600);
    return [NSString stringWithFormat:@"%02ld:%02ld:%02ld", (long)hours, (long)minutes, (long)seconds];
}