Formatting a Duration like HH:mm:ss

问题:

Is there a good way to format a Duration in something like hh:mm:ss, without having to deal with time zones?

I tried this:

DateTime durationDate = DateTime.fromMillisecondsSinceEpoch(0);
String duration = DateFormat('hh:mm:ss').format(durationDate);

But I always get 1 hour to much, in this case it would say 01:00:00

And When I do this:

Duration(milliseconds: 0).toString();

I get this: 0:00:00.000000

回答1:

You can use Duration and implement this method:

      String _printDuration(Duration duration) {
        String twoDigits(int n) {
          if (n >= 10) return "$n";
          return "0$n";
        }

        String twoDigitMinutes = twoDigits(duration.inMinutes.remainder(60));
        String twoDigitSeconds = twoDigits(duration.inSeconds.remainder(60));
        return "${twoDigits(duration.inHours)}:$twoDigitMinutes:$twoDigitSeconds";
      }

Usage:

 final now = Duration(seconds: 30);
  print("${_printDuration(now)}");

回答2:

You can start creating a format yourself, come on this one:

String sDuration="${duration.inHours}:${duration.inMinutes.remainder(60)}:${(duration.inSeconds.remainder(60))}

回答3:

Here's another version. It's all preference at this point, but I liked that it was dry and didn't need a function declaration (the wrapping function is obviously optional) though it is definately a bit function chaining heavy.

Compact

String formatTime(double time) {
    Duration duration = Duration(milliseconds: time.round());
    return [duration.inHours, duration.inMinutes, duration.inSeconds].map((seg) => seg.remainder(60).toString().padLeft(2, '0')).join(':');
}

Formatted version

String timeFormatter (double time) {
    Duration duration = Duration(milliseconds: time.round());

    return [duration.inHours, duration.inMinutes, duration.inSeconds]
      .map((seg) => seg.remainder(60).toString().padLeft(2, '0'))
      .join(':');
}

回答4:

The shortest, most elegant and reliable way to get HH:mm:ss from a Duration is doing:

format(Duration d) => d.toString().split('.').first.padLeft(8, "0");

Example usage:

main() {
  final d1 = Duration(hours: 17, minutes: 3);
  final d2 = Duration(hours: 9, minutes: 2, seconds: 26);
  final d3 = Duration(milliseconds: 0);
  print(format(d1)); // 17:03:00
  print(format(d2)); // 09:02:26
  print(format(d3)); // 00:00:00
}

回答5:

You can use this:

print('${duration.inHours.toString().padLeft(2, '0')}:
${duration.inMinutes.remainder(60).toString().padLeft(2, '0')}:
${duration.inSeconds.remainder(60).toString().padLeft(2, '0')}');

回答6:

To do this in a way that is portable, consider the intl package DateFormat class: https://pub.dartlang.org/documentation/intl/latest/intl/DateFormat-class.html