formatDateTime method
Implementation
String formatDateTime() {
DateTime dateTime = DateTime.fromMillisecondsSinceEpoch(this);
DateTime now = DateTime.now();
String format = 'HH:mm';
if (dateTime.year != now.year) {
format = 'yyyy-MM-dd HH:mm';
} else if (dateTime.day != now.day) {
format = 'MM-dd HH:mm';
}
return DateFormat(format).format(dateTime);
}