intl package and date formatting strange behaviour

Question

I start to use intl package in my dart project. After start to use this package i use this code:

  DateTime now = new DateTime.now();
  var formatter = new DateFormat("yyyy-MM-dd'T'HH:mm:ss'Z'");
  String nowFormatted = formatter.format(now);

And it works correctly. After i use intl i obtain this message in log:

Uncaught LocaleDataException: Locale data has not been initialized, call initializeDateFormatting(<locale>).

I cannot understand why i should pass locale in this code snippet

Answer 1

intl: ^0.15.7

I've the same issue to the current Intl version so I've solved with

these imports:

import 'package:intl/intl.dart';
import 'package:intl/date_symbol_data_local.dart';

and the code:

initializeDateFormatting();
DateTime now = DateTime.now();
var dateString = DateFormat('dd-MM-yyyy').format(now);
final String configFileName = 'lastConfig.$dateString.json';

Answer 2

Verify your imports:

import 'package:intl/date_symbol_data_local.dart';
import 'package:intl/intl.dart';

Set initializeDateFormatting according to your language, example:

initializeDateFormatting('pt_BR', null);

Answer 3

If you encounter this problem, write initializeDateFormatting('az'); top of "Material App". I searched for 1 hour and nobody wrote it clearly.

it is really solved.

Answer 4

I have solved this use in this way:

DateTime now = new DateTime.now();
var formatter = new DateFormat("yyyy-MM-dd'T'HH:mm:ss'Z'", 'en');
String nowFormatted = formatter.format(now);

But I have to make this to my dart file used to configure itnl support:

library translation_helper;

import 'dart:async';
import 'package:intl/date_symbol_data_local.dart';
import '../../resources/messages_all.dart';


void setupLanguage(){
  //var germanDatesFuture = initializeDateFormatting('de_DE', null);
  var enDatesFuture = initializeDateFormatting('en', null);
  var germanMessagesFuture = initializeMessages('de');
  var englishMessagesFuture = initializeMessages('en');
  var italianMessagesFuture = initializeMessages('it');
  var polishMessagesFuture = initializeMessages('pl');
  Future
      .wait([
    enDatesFuture,
    germanMessagesFuture,
    englishMessagesFuture,
    italianMessagesFuture,
    polishMessagesFuture
  ]);
}

Before I was missing:

 var enDatesFuture = initializeDateFormatting('en', null);

For more info I use:

• dart 1.15.0
• intl 0.12.7

Answer 5

Use this function in main

initializeDateFormatting();

and import like this

import 'package:intl/date_symbol_data_local.dart';

Answer 6

• In your pubspec.yaml, add this dependencie package: intl:

• In your highest StatefulWidget (in your dart file), add these imports:

    import 'package:intl/intl.dart';
    import 'package:intl/date_symbol_data_local.dart';

• In its State, override initState add :

      @override
      void initState() {
        super.initState();
        initializeDateFormatting(); //very important
      }

• And the code:

     DateTime now = new DateTime.now();
     var formatter = new DateFormat("yyyy-MM-dd'T'HH:mm:ss'Z'");
     String nowFormatted = formatter.format(now);

Answer 7

My issue was that I was getting error specifically for the "en_US" Locale even when I was not particularly using it. But I solved it by:

initializeDateFormatting('en', null);
initializeDateFormatting('en_US,', null);

Answer 8

There's no need to call initializeDateFormatting directly from your code. Just call load method of app's localization delegates.

So you specify delegates like this:

final localizationsDelegates = <LocalizationsDelegate>[
  AppLocalizationsDelegate(),
  GlobalMaterialLocalizations.delegate,
  GlobalWidgetsLocalizations.delegate,
  CupertinoLocalizationsDelegate()
];

...

  MaterialApp(
    localizationsDelegates: localizationsDelegates,
  )

And pre-load them with system's locale:

import 'dart:ui' as ui;

...

for (final delegate in localizationsDelegates) {
  await delegate.load(ui.Locale(ui.window.locale.languageCode));
}

Answer 9

In your class with MaterialApp add this code

import 'package:intl/date_symbol_data_local.dart';

@override
  void initState() {
    // TODO: implement initState
    super.initState();`enter code here`
    initializeDateFormatting();
  }

Answer 10

I got the same error. But, only when switching between locales ('en' and 'si') within the app. None of the other solutions worked for me. So I just came up with this dumbest solution, and it worked. Just wrapped date-formatting in a try-catch block while initializeDateFormatting() is being called inside the catch block

String  date(DateTime date, String _languageCode) {
    try {
        var formatter = new DateFormat.yMMMMd(_languageCode);
        return formatter.format(date);
    } catch(e) {
        initializeDateFormatting();
        var formatter = new DateFormat.yMMMMd(_languageCode);
        return formatter.format(date);
    }
}

Answer 11

To initialize the date format as per the system locale.

import 'package:intl/intl_standalone.dart'; // For standlone app
import 'package:intl/intl_browser.dart'; // For standlone app
import 'package:intl/date_symbol_data_local.dart';
...
await initializeDateFormatting(await findSystemLocale(), null);