A new flutter plugin project.

This is library inspired by NSLocalizedString from iOS. Uses json files as language files eg. en.json , de.json

You have to add these to your pubspec.yaml:

flutter_localizations: 
    sdk: flutter

then you have to add within flutter: section:

assets:
    - assets/

When you're all set with pubspec file, you must put this in to your main.dart:

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      localizationsDelegates: [
        // ... app-specific localization delegate[s] here
        GlobalMaterialLocalizations.delegate,
        GlobalWidgetsLocalizations.delegate,
      ],
      supportedLocales: [
        const Locale('en', 'US'), // English
        // ... other locales the app supports
      ],

      title: "title",
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),      home: LocalizedWidget(widget: MyHomePage()),
    );
  }

LocalizedWidget is very important in here and it is responsible for wrapping up the class with FutureBuilder and enables plugin to load json file while loading first widget tree. You need to put it into the widget tree only once at the app startup , it can be also done in some kind of Splashscreen widget or something. We just need time to load content. :)

import 'package:flutter_localized_string/localized_widget.dart';
import 'package:flutter_localized_string/flutter_localized_string.dart';

Once you did all of these steps. You should be able to use library as follows:

LocalizedString.by(key: "title")

while en.json looks like this:

{
    "title" : "Main title"
}