'How to specify a TimeZone when creating a DateTime object in Dart/Flutter?
Dart?flutter does not appear to allow a timezone (eg: "Australia/Sydney" or "America/Detroit") to be specified when creating a DateTime object. Either the local timezone will be used, or UT may be specified.
Is anyone aware of a workaround?
There's the Dart package TimeZone, but it appears to be unusable within a flutter app.
See https://pub.dartlang.org/packages/timezone for the package I'm referring to.
EDIT: The timezone package does work in Flutter, with some setup. See Richard Heap's answer below.
Solution 1:[1]
You have to do a bit of magic to get package:timezone
to work in flutter.
Extract whichever data file you need (there are 3: default, all and 2010-2020) and move it to your flutter assets folder. (I use 2018c_2010-2020.tzf
, which is available in a branch.)
Add it as an asset in pubspec.yaml
:
assets:
- assets/2018c_2010-2020.tzf
Then load that file on startup (e.g. from the initState
of a top level StatefulWidget) and use it to initialise the database.
ByteData tzf = await rootBundle.load('assets/2018c_2010-2020.tzf');
initializeDatabase(tzf.buffer.asUint8List());
...
Location newYork = getLocation('US/Eastern');
I haven't tried, but you may even be able to load it from main
if you mark it async.
I also notice that I must have cloned the latest branch, as I see this in my pubspec
timezone:
path: ../../dart/source/timezone
... but looks like you just need to grab 0.5.0-dev-2 from pub
dependencies:
timezone: "^0.5.0-dev-2"
Solution 2:[2]
This solution worked for me
simple add these lines in initState
import 'package:timezone/timezone.dart' as tz;
import 'package:timezone/data/latest.dart' as tz;
@override
void initState() {
super.initState();
tz.initializeTimeZones();
final String locationName = await FlutterNativeTimezone.getLocalTimezone();
tz.setLocalLocation(tz.getLocation(locationName));
}
Solution 3:[3]
The TimeZone package does work. From the issues list on GitHub:
Sorry this took 6 months but I have a good solution. I think it will be the recommended solution.
See Flutter's docs on Adding Assets. You should be able to add to your Flutter app's pubspec.yaml:
flutter:
assets:
- packages/timezone/data/2015b.tzf
and load in your app with:
Future<List<int>> loadDefaultData() async {
var byteData = await rootBundle.load('packages/timezone/data/2015b.tzf');
return byteData.buffer.asUint8List();
}
// Call the above with something like:
loadDefaultData().then((rawData) {
initializeDatabase(rawData);
var zurich = getLocation('Europe/Zurich');
});
Sources
This article follows the attribution requirements of Stack Overflow and is licensed under CC BY-SA 3.0.
Source: Stack Overflow
Solution | Source |
---|---|
Solution 1 | |
Solution 2 | Arslan Kaleem |
Solution 3 | Yahya Uddin |