Format timer label to hours:minutes:seconds in Swift

Question

I have an NSTimer which counts DOWN from 2 hours until 0.

Here are some of my code:

var timer = NSTimer() let timeInterval:NSTimeInterval = 0.5 let timerEnd:NSTimeInterval = 0.0 var timeCount:NSTimeInterval = 7200.0 // seconds or 2 hours  // TimeString Function  func timeString(time:NSTimeInterval) -> String {     let minutes = Int(time) / 60     let seconds = time - Double(minutes) * 60     let secondsFraction = seconds - Double(Int(seconds))     return String(format:"%02i:%02i.%01i",minutes,Int(seconds),Int(secondsFraction * 10.0)) } 

The Timer Label is:

TimerLabel.text = "Time: \(timeString(timeCount))" 

HOWEVER, my timer label shows as:

Time: 200:59.0 

How do I format my timer label to look like this:

Time: 01:59:59 // (which is hours:minutes:seconds)? 

[Please note that I have no problems with my countdown timer, I only need to know how to CHANGE THE TIME FORMAT using the TimeString function.]

EDIT: Someone mentioned that my question is a possible duplicate of this one: Swift - iOS - Dates and times in different format. HOWEVER, I am asking on how do I change the time format using the TimeString function that I gave above. I am not asking for another WAY on how to do it.

For instance:

let minutes = Int(time) / 60 

gives me "200" minutes. etc.

Answer 1

Your calculations are all wrong.

let hours = Int(time) / 3600 let minutes = Int(time) / 60 % 60 let seconds = Int(time) % 60 return String(format:"%02i:%02i:%02i", hours, minutes, seconds) 

Answer 2

@rmaddy's solution is accurate and answers the question. However, neither the question nor the solution take into account international users. I suggest using DateComponentsFormatter and let the framework handle the calculations and formatting. Doing so makes your code less error prone and more future proof.

I came across this blog post that provides a concise solution: http://crunchybagel.com/formatting-a-duration-with-nsdatecomponentsformatter/

Pulled from that post, this is the code snippet that would replace the code you're currently using to make your calculations. Updated for Swift 3:

let duration: TimeInterval = 7200.0  let formatter = DateComponentsFormatter() formatter.unitsStyle = .positional // Use the appropriate positioning for the current locale formatter.allowedUnits = [ .hour, .minute, .second ] // Units to display in the formatted string formatter.zeroFormattingBehavior = [ .pad ] // Pad with zeroes where appropriate for the locale  let formattedDuration = formatter.string(from: duration)