getDetailedDifference static method
Calculates the difference between two DateTime objects and returns it in a "days:hours:minutes" format.
Omits parts that are zero. For example, if the difference is only in minutes, it will return just "minutes". If it's hours and minutes, "hours:minutes".
Implementation
static String getDetailedDifference(DateTime start, DateTime end) {
Duration difference = end.difference(start);
int days = difference.inDays;
int hours = difference.inHours % 24;
int minutes = difference.inMinutes % 60;
return "${days == 0 ? "" : "$days:"}${hours == 0 ? "" : "$hours:"}$minutes";
}