How to parse date time in flutter

Question

I getting below date time from server

   "datetime":"2020-07-17T03:18:31.177769-04:00"

and I'm using below code to parse to get time from above date

      var format = DateFormat('HH:mm a');
      debugPrint('LocalTime ${format.parse(timeZoneData.datetime)}');

I'm getting below exception

flutter: Error 123: FormatException: Trying to read : from 2020-07-17T03:22:09.959577-04:00 at position 5

and i want display the above time like this 3:18 AM

Can anybody know how can parse date time in flutter

If need more information please do let me know. Thanks in advance. Your efforts will be appreciated.

Solution

Your problem is you are trying to parse "2020-07-17T03:18:31.177769-04:00" with the pattern "HH:mm a" which is impossible since the pattern are not even close to the provided string.

Instead, what you properly want is to parse your datetime string into a DateTime object and use your DateFormat to convert the DateTime into a String. Since your provided datetime string are formatted in a format which dart can parse out of the box, we can just use DateTime.parse.

An example on this can be seen here:

import 'package:intl/intl.dart';

void main() {
  const dateTimeString = '2020-07-17T03:18:31.177769-04:00';
  final dateTime = DateTime.parse(dateTimeString);

  final format = DateFormat('HH:mm a');
  final clockString = format.format(dateTime);

  print(clockString); // 07:18 AM
}

About the clock, it will by default parse the datetime into UTC if there are provided a timezone in the string like the example.

You can output local time by doing:

final clockString = format.format(dateTime.toLocal());

But this solution will of course only work if your own computer has the timezone offset "-04:00". But it will be the most correct solution since the inner state of the DateTime is correct.

If you want to parse the datetime string directly to local time I think the easiest way is to remove the timezone part of your datetime string like:

final dateTime = DateTime.parse(dateTimeString.replaceFirst(RegExp(r'-\d\d:\d\d'), ''));

This will give a DateTime object which contains local time and will print your timestamp as you want:

import 'package:intl/intl.dart';

void main() {
  const dateTimeString = '2020-07-17T03:18:31.177769-04:00';
  final dateTime =
      DateTime.parse(dateTimeString.replaceFirst(RegExp(r'-\d\d:\d\d'), ''));

  final format = DateFormat('HH:mm a');
  final clockString = format.format(dateTime);

  print(clockString); // 03:18 AM
}

Comments

[Goku]

Yes I'm getting 07:18 AM but my actual required is to get 03:18 AM, actually I'm using worldtimeapi to get time of different location

[julemand101]

Yes, I saw that requirement after posting my answer and I am working on a solution. :)