TimeOfDay documentation has no comparison operator and primitive comparison does not work. My only solution that I can thinking of right now is to convert TimeOfDay to DateTime and use DateTime's difference method.
Does anyone have a better solution?
Convert it to a double then compare.
double toDouble(TimeOfDay myTime) => myTime.hour + myTime.minute/60.0
extension TimeOfDayExtension on TimeOfDay {
int compareTo(TimeOfDay other) {
if (hour < other.hour) return -1;
if (hour > other.hour) return 1;
if (minute < other.minute) return -1;
if (minute > other.minute) return 1;
return 0;
}
}
Thanks from @Lucas idea, you can calculate hour and minute by
TimeOfDay yourTime ;
TimOfDay nowTime = TimeOfDay.now()
double _doubleYourTime = yourTime.hour.toDouble() +
(yourTime.minute.toDouble() / 60);
double _doubleNowTime = nowTime.hour.toDouble() +
(nowTime.minute.toDouble() / 60);
double _timeDiff = _doubleYourTime - _doubleNowTime;
double _hr = _timeDiff.truncate();
double _minute = (_timeDiff - _timeDiff.truncate()) * 60;
print('Here your Happy $_hr Hour and also $_minute min');
I calculated the difference by turning both values into minute-counts, and comparing those :)
TimeOfDay now = TimeOfDay.now();
int nowInMinutes = now.hour * 60 + now.minute;
TimeOfDay testDate = TimeOfDay(hour: 2, minute: 20);
int testDateInMinutes = testDate.hour * 60 + testDate.minute;
You can use this method. Where you have to provide starttime and endTime in TimesofDay format.
getTime(startTime, endTime) {
bool result = false;
int startTimeInt = (startTime.hour * 60 + startTime.minute) * 60;
int EndTimeInt = (endTime.hour * 60 + endTime.minute) * 60;
int dif = EndTimeInt - startTimeInt;
if (EndTimeInt > startTimeInt) {
result = true;
} else {
result = false;
}
return result;
}
LikeThis
getTime(v1, v2);
TimeOfDay n = TimeOfDay.now();
int nowSec = (n.hour * 60 + n.minute) * 60;
int veiSec = (t.hour * 60 + t.minute) * 60;
int dif = veiSec - nowSec;
Solution for negative duration calculations
All these answers are pretty good but they didn't help me when I had a user select a range of times in my app. In order to calculate the total duration of the specified time period, I tried all the solutions which work pretty well but fail in certain scenarios. The scenarios are:
And the code to overcome it is:
String durationFromTimeOfDay(TimeOfDay? start, TimeOfDay? end) {
if (start == null || end == null) return '';
// DateTime(year, month, day, hour, minute)
final startDT = DateTime(9, 9, 9, start.hour, start.minute);
final endDT = DateTime(9, 9, 10, end.hour, end.minute);
final range = DateTimeRange(start: startDT, end: endDT);
final hours = range.duration.inHours % 24;
final minutes = range.duration.inMinutes % 60;
final _onlyHours = minutes == 0;
final _onlyMinutes = hours == 0;
final hourText = _onlyMinutes
? ''
: '$hours${_onlyHours ? hours > 1 ? ' hours' : ' hour' : 'h'}';
final minutesText = _onlyHours
? ''
: '$minutes${_onlyMinutes ? minutes > 1 ? ' mins' : ' min' : 'm'}';
return hourText + minutesText;
}
It is important to note that you need to prefill the DateTime for end TimeOfDay with a day value which is greater than the same in start DateTime. The other parameters (for year and month) can be anything you want.
This outputs a really nicely formatted string that is short, concise, and extremely legible
This, however, doesn't satisfy the requirement that the solution is devoid of conversion to DateTime. But at least it uses a different approach over the difference method. And this makes the correct duration calculation more reliable in a few lines of code comparatively.
Card(
child: ListTile(
onTap: () {
showTimePicker(
context: context,
initialTime: TimeOfDay.now(),
).then((TimeOfDay time) {
double _doubleyourTime =
time.hour.toDouble() + (time.minute.toDouble() /60);
double _doubleNowTime = TimeOfDay.now().hour.toDouble() +
(TimeOfDay.now().minute.toDouble() / 60);`enter code here`
if (_doubleyourTime > _doubleNowTime) {
print('correct format')
});
} else {
print('Sorry You can not set the time')
}
});
},
//dense: true,
leading: Icon(Icons.timer),
title: Text(
'Today On Time',`enter code here`
),
),
),
We can actually use the subtract operator.
Code to make magic happen :
Here I wanted to get the difference in time after the user selects the time (in TimeOfDay format) using showTimePicker()
// current time will be used to find the difference between the time selected by the user.
TimeOfDay _cur_time = TimeOfDay(hour: DateTime.now().hour, minute: DateTime.now().minute);
// scheduled time will be updated as soon as the user inputs a new time using the showTimePicker() function available in Flutter Material librabry.
TimeOfDay _scheduled_time = TimeOfDay(hour: DateTime.now().hour, minute: DateTime.now().minute);
// toDouble Function to convert time to double so that we can compare time and check that the time selected is greater than current time.
double toDouble(TimeOfDay myTime) => myTime.hour + myTime.minute / 60.0;
void _selectTime() async {
Flutter Material widget to select time.
final TimeOfDay? newTime = await showTimePicker(
context: context,
initialTime: _scheduled_time,
);
//Check if the selected time is greater than the cur time
if (toDouble(newTime!) > toDouble(_cur_time)) {
setState(() {
_scheduled_time = newTime;
});
}
}
Function to get the difference between cur time and selected time.
Duration _getDelayedDuration(){
var hourDelay = _scheduled_time.hour - _cur_time.hour;
print(hourDelay);
var minuteDelay = _scheduled_time.minute - _cur_time.minute;
print(minuteDelay);
return Duration(hours: hourDelay, minutes: minuteDelay);
}
I don't think this is possible. You can use .subtract in DateTime as also .difference
