Change local timezone in dart

Question

On my local machine this date DateTime(2021, 10, 27, 00, 00, 00) is at GMT+4

When I push this code to our remote server, the same date is interpreted with GMT+2, because the remote server is located in the GMT+2 timezone, so the code behaves differently.

I know I could make use of the DateTime.utc constructor but I want this date to be input manually and always follow GMT+4.

So the solution is to change the local of the remote server to GMT+4 too. But how to do that in the dart context only ? (not system wide)

Answer 1

Unfortunately DateTime does not support timezones natively, as suggested by jamesdlin you will have to use a 3rd party package such as timezone.

How to use

Step 1: Install the package

dependencies:
  timezone: any

Step 2: Initialize the library

main.dart

import 'package:timezone/data/latest.dart' as tz;

void main() {
  WidgetsFlutterBinding.ensureInitialized();
  tz.initializeTimeZones();
  runApp(MyApp());
}

Note: It is recommended when you import this package to add as tz.

Step 3: Define your wanted timezone

import 'package:timezone/standalone.dart' as tz;

final detroit = tz.getLocation('America/Detroit');

Step 4: Use the TZDateTime class

import 'package:timezone/standalone.dart' as tz;

final localizedDt = tz.TZDateTime.from(DateTime.now(), detroit);

You can use the following constructor for TZDateTime depending of your needs:

• TZDateTime(...)
• TZDateTime.utc(...)
• TZDateTime.local(...)
• TZDateTime.now(...)
• TZDateTime.fromMillisecondsSinceEpoch(...)
• TZDateTime.fromMicrosecondsSinceEpoch(...)
• TZDateTime.from(...)

You can also directly parse your date from a formatted string by using TZDateTime.parse(Location location, String formattedString).

Answer 2

I want to share this answer if you dont use any package. Just Use this extension so that you will get this below output.

extension TimeZoneExtension on Object {
  DateTime _convertTimeDateTime() {
    DateTime dateTimeObject = DateTime.parse(this.toString());
    return dateTimeObject;
  }

  // Get your LocalTimeZone
  getLocalTimeZone() {
    return _convertTimeDateTime().toLocal();
  }

// Get UTC TimeZone
  getUtcTimeZone() {
    return _convertTimeDateTime().toUtc();
  }

  // Get Local TimerZoneOffset (eg:6)
  getTimeZoneOffSet() {
    int timeZoneOffset =
        _convertTimeDateTime().toLocal().timeZoneOffset.inHours;
    return timeZoneOffset;
  }

  //Now If you add UTC timeZone with Local TimeZoneOffset
  DateTime get dateTimeAfterOffset => _convertTimeDateTime().add(
        Duration(
          hours: int.parse(getTimeZoneOffSet().toString()),
        ),
      );
}

 final date = DateTime(2024, 2, 12, 10, 30);
    print("Date is:: ${date}");
    print("Date in UTC :: ${date.getUtcTimeZone()}"); // true
    print("Date in Local :: ${date.getLocalTimeZone()}");
    print(
        "Now Convert this your view Dateform :${date.dateTimeAfterOffset.formattedDateString(format: AppConstant.E_MM_D_HH_MM.key)}");