NSTimeInterval是Double，使用扩展。例子:

extension Double {

    var formattedTime: String {

        var formattedTime = "0:00"

        if self > 0 {

            let hours = Int(self / 3600)
            let minutes = Int(truncatingRemainder(dividingBy: 3600) / 60)

            formattedTime = String(hours) + ":" + (minutes < 10 ? "0" + String(minutes) : String(minutes))
        }

        return formattedTime
    }
}

我已经构建了一个现有答案的mashup，以简化一切并减少Swift 3所需的代码量。

func hmsFrom(seconds: Int, completion: @escaping (_ hours: Int, _ minutes: Int, _ seconds: Int)->()) {

        completion(seconds / 3600, (seconds % 3600) / 60, (seconds % 3600) % 60)

}

func getStringFrom(seconds: Int) -> String {

    return seconds < 10 ? "0\(seconds)" : "\(seconds)"
}

用法:

var seconds: Int = 100

hmsFrom(seconds: seconds) { hours, minutes, seconds in

    let hours = getStringFrom(seconds: hours)
    let minutes = getStringFrom(seconds: minutes)
    let seconds = getStringFrom(seconds: seconds)

    print("\(hours):\(minutes):\(seconds)")                
}

打印:

00:01:40

斯威夫特4

func formatSecondsToString(_ seconds: TimeInterval) -> String {
    if seconds.isNaN {
        return "00:00"
    }
    let Min = Int(seconds / 60)
    let Sec = Int(seconds.truncatingRemainder(dividingBy: 60))
    return String(format: "%02d:%02d", Min, Sec)
}

根据GoZoner的答案，我写了一个扩展，以获得时间格式化根据小时，分钟和秒:

extension Double {

    func secondsToHoursMinutesSeconds () -> (Int?, Int?, Int?) {
        let hrs = self / 3600
        let mins = (self.truncatingRemainder(dividingBy: 3600)) / 60
        let seconds = (self.truncatingRemainder(dividingBy:3600)).truncatingRemainder(dividingBy:60)
        return (Int(hrs) > 0 ? Int(hrs) : nil , Int(mins) > 0 ? Int(mins) : nil, Int(seconds) > 0 ? Int(seconds) : nil)
    }

    func printSecondsToHoursMinutesSeconds () -> String {

        let time = self.secondsToHoursMinutesSeconds()

        switch time {
        case (nil, let x? , let y?):
            return "\(x) min \(y) sec"
        case (nil, let x?, nil):
            return "\(x) min"
        case (let x?, nil, nil):
            return "\(x) hr"
        case (nil, nil, let x?):
            return "\(x) sec"
        case (let x?, nil, let z?):
            return "\(x) hr \(z) sec"
        case (let x?, let y?, nil):
            return "\(x) hr \(y) min"
        case (let x?, let y?, let z?):
            return "\(x) hr \(y) min \(z) sec"
        default:
            return "n/a"
        }
    }
}

let tmp = 3213123.printSecondsToHoursMinutesSeconds() // "892 hr 32 min 3 sec"

将数字转换为字符串形式的时间

func convertToHMS(number: Int) -> String {
  let hour    = number / 3600;
  let minute  = (number % 3600) / 60;
  let second = (number % 3600) % 60 ;
  
  var h = String(hour);
  var m = String(minute);
  var s = String(second);
  
  if h.count == 1{
      h = "0\(hour)";
  }
  if m.count == 1{
      m = "0\(minute)";
  }
  if s.count == 1{
      s = "0\(second)";
  }
  
  return "\(h):\(m):\(s)"
}
print(convertToHMS(number:3900))

Neek的答案不正确。

这是正确的版本

func seconds2Timestamp(intSeconds:Int)->String {
   let mins:Int = (intSeconds/60)%60
   let hours:Int = intSeconds/3600
   let secs:Int = intSeconds%60

   let strTimestamp:String = ((hours<10) ? "0" : "") + String(hours) + ":" + ((mins<10) ? "0" : "") + String(mins) + ":" + ((secs<10) ? "0" : "") + String(secs)
   return strTimestamp
}