dosya adı: main.dart

kaynak: Anılcan Çakır
GitHub: GitHub
medium: Makale

import 'dart:async';
import 'dart:convert';

import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:flutter_localizations/flutter_localizations.dart';

class DemoLocalizations {
  DemoLocalizations(this.locale);

  final Locale locale;

  static DemoLocalizations of(BuildContext context) {
    return Localizations.of(context, DemoLocalizations);
  }

  Map<String, String> _sentences;

  Future load() async {
    String data = await rootBundle.loadString('resources/lang/${this.locale.languageCode}.json');
    Map<String, dynamic> _result = json.decode(data);

    this._sentences = new Map();
    _result.forEach((String key, dynamic value) {
      this._sentences[key] = value.toString();
    });

    return true;
  }

  String trans(String key) {
    return this._sentences[key];
  }
}

class DemoLocalizationsDelegate extends LocalizationsDelegate {
  const DemoLocalizationsDelegate();

  @override
  bool isSupported(Locale locale) => ['tr', 'en'].contains(locale.languageCode);

  @override
  Future load(Locale locale) async {
    DemoLocalizations localizations = new DemoLocalizations(locale);
    await localizations.load();

    print("Load ${locale.languageCode}");

    return localizations;
  }

  @override
  bool shouldReload(DemoLocalizationsDelegate old) => false;
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return new MaterialApp(
      supportedLocales: [
        const Locale('tr', 'TR'),
        const Locale('en', 'US')
      ],
      localizationsDelegates: [
        const DemoLocalizationsDelegate(),
        GlobalMaterialLocalizations.delegate,
        GlobalWidgetsLocalizations.delegate
      ],
      localeResolutionCallback: (Locale locale, Iterable supportedLocales) {
        for (Locale supportedLocale in supportedLocales) {
          if (supportedLocale.languageCode == locale.languageCode || supportedLocale.countryCode == locale.countryCode) {
            return supportedLocale;
          }
        }

        return supportedLocales.first;
      },
      title: 'Flutter Internationalization',
      home: new MyPage(),
    );
  }
}

class MyPage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return new Scaffold(
      body: new Center(
        child: new Text(
          DemoLocalizations.of(context).trans('hello_world')
        ),
      ),
    );
  }
}

void main() {
  runApp(new MyApp());
}