secondsToTime method

Implementation

String secondsToTime() {
  int h = this ~/ 3600;
  int m = (this % 3600) ~/ 60;
  int s = this % 60;
  return '${h < 10 ? '0$h' : h}:${m < 10 ? '0$m' : m}:${s < 10 ? '0$s' : s}';
}