Flutter example of a localized title

flutter_localized_title.dart

// Copyright 2017 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

// Note: I'm not the original author, I'm sharing via Gist to make
// it easy for folks to check it out. Please email
// [email protected] if you have questions about that.

// A simple "rough and ready" example of localizing a Flutter app.
// Spanish and English (locale language codes 'en' and 'es') are
// supported.

// The pubspec.yaml file must include flutter_localizations in its
// dependencies section. For example:
//
// dependencies:
//   flutter:
//   sdk: flutter
//  flutter_localizations:
//    sdk: flutter

// If you run this app with the device's locale set to anything but
// English or Spanish, the app's locale will be English. If you
// set the device's locale to Spanish, the app's locale will be
// Spanish.

import 'dart:async';

import 'package:flutter/material.dart';
import 'package:flutter/foundation.dart' show SynchronousFuture;
import 'package:flutter_localizations/flutter_localizations.dart';

class DemoLocalizations {
  DemoLocalizations(this.locale);

  final Locale locale;

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

  static Map<String, Map<String, String>> _localizedValues = {
    'en': {
      'title': 'Hello World',
    },
    'es': {
      'title': 'Hola Mundo',
    },
  };

  String get title {
    return _localizedValues[locale.languageCode]['title'];
  }
}

class DemoLocalizationsDelegate extends LocalizationsDelegate<DemoLocalizations> {
  const DemoLocalizationsDelegate();

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

  @override
  Future<DemoLocalizations> load(Locale locale) {
    return new SynchronousFuture<DemoLocalizations>(new DemoLocalizations(locale));
  }

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

class DemoApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return new Scaffold(
      appBar: new AppBar(
        title: new Text(DemoLocalizations.of(context).title),
      ),
      body: new Center(
        child: new Text(DemoLocalizations.of(context).title),
      ),
    );
  }
}

class Demo extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return new MaterialApp(
      onGenerateTitle: (BuildContext context) => DemoLocalizations.of(context).title,
      localizationsDelegates: [
        const DemoLocalizationsDelegate(),
        GlobalMaterialLocalizations.delegate,
        GlobalWidgetsLocalizations.delegate,
      ],
      supportedLocales: [
        const Locale('en', ''),
        const Locale('es', ''),
      ],
      // Watch out: MaterialApp creates a Localizations widget
      // with the specified delegates. DemoLocalizations.of()
      // will only find the app's Localizations widget if its
      // context is a child of the app.
      home: new DemoApp(),
    );
  }
}

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