Flutter国际化完整例子

请支持原文 http://tryenough.com/flutter-translationflutter国际化实现方案这里提供一份解决方案，和一份可以直接使用的demo。1.添加依赖库需要用到flutter_localizations包，在pubspec.yaml文件中添加如下依赖内容：dependencies: flutter: sdk: flutter flutter_localizations: sdk: flutter添加完记得执行获取这个库：在terminal中运行 flutter packages get, 或者在IntelliJ\Android Studio中点击’Packages get’2.添加多种语言的文件请支持原文 http://tryenough.com/flutter-translation在项目的lib同级目录下创建locale文件夹，并创建几个json文件，用来存储不同语言的翻译文案。如下文件结构：上图中创建了三种语言的json文件，你可以根据你的需要创建其他的语言json文件。添加翻译内容，如下：i18n_en.json:{ “about_page_slogan”:“Health starts here”}i18n_zh.json:{ “about_page_slogan”:“健康从这里开始”}记得在pubspec.yaml文件中添加这几个资源文件：3.创建一个工具类，保存当前支持的语言等信息请支持原文 http://tryenough.com/flutter-translationlocale_util.dartimport ‘package:flutter/material.dart’;typedef void LocaleChangeCallback(Locale locale);class LocaleUtil { // Support languages list final List<String> supportedLanguages = [’en’,‘zh’, ‘ja’]; // Support Locales list Iterable<Locale> supportedLocales() => supportedLanguages.map<Locale>((lang) => new Locale(lang, ‘’)); // Callback for manual locale changed LocaleChangeCallback onLocaleChanged; Locale locale; String languageCode; static final LocaleUtil _localeUtil = new LocaleUtil._internal(); factory LocaleUtil() { return _localeUtil; } LocaleUtil._internal(); /// 获取当前系统语言 String getLanguageCode() { if(languageCode == null) { return “en”; } return languageCode; }}LocaleUtil localeUtil = new LocaleUtil();3.添加翻译处理类文件translations.dart系统提供了LocalizationsDelegate类帮助我们监听系统语言的切换，所以我们可以继承LocalizationsDelegate类监听语言切换，并在切换时加载不同的json文件，来获取不同的语言文案。这里我们的translations工具类就是利用这样的原理来加载不同的语言文案：import ‘package:translation/locale_util.dart’;import ‘dart:async’;import ‘dart:convert’;import ‘package:flutter/material.dart’;import ‘package:flutter/services.dart’ show rootBundle;/// Class for Translate////// For example:////// import ‘package:workout/translations.dart’;////// dart/// For TextField content/// Translations.of(context).text("home_page_title");/// ////// dart/// For speak string/// Note: Tts will speak english if currentLanguage[# Tts's parameter] can't support////// Translations.of(context).speakText("home_page_title");/// ////// “home_page_title” is the key for text value///class Translations { Translations(Locale locale) { this.locale = locale; _localizedValues = null; } Locale locale; static Map<dynamic, dynamic> _localizedValues; static Map<dynamic, dynamic> _localizedValuesEn; // English map static Translations of(BuildContext context) { return Localizations.of<Translations>(context, Translations); } String text(String key) { try { String value = _localizedValues[key]; if(value == null || value.isEmpty) { return englishText(key); } else { return value; } } catch (e) { return englishText(key); } } String englishText(String key) { return localizedValuesEn[key] ?? ‘** $key not found’; } static Future<Translations> load(Locale locale) async { Translations translations = new Translations(locale); String jsonContent = await rootBundle.loadString(“locale/i18n${locale.languageCode}.json”); _localizedValues = json.decode(jsonContent); String enJsonContent = await rootBundle.loadString(“locale/i18n_en.json”); _localizedValuesEn = json.decode(enJsonContent); return translations; } get currentLanguage => locale.languageCode;}class TranslationsDelegate extends LocalizationsDelegate<Translations> { const TranslationsDelegate(); // Support languages @override bool isSupported(Locale locale) { localeUtil.languageCode = locale.languageCode; return localeUtil.supportedLanguages.contains(locale.languageCode); } @override Future<Translations> load(Locale locale) => Translations.load(locale); @override bool shouldReload(TranslationsDelegate old) => true;}// Delegate strong init a Translations instance when language was changedclass SpecificLocalizationDelegate extends LocalizationsDelegate<Translations> { final Locale overriddenLocale; const SpecificLocalizationDelegate(this.overriddenLocale); @override bool isSupported(Locale locale) => overriddenLocale != null; @override Future<Translations> load(Locale locale) => Translations.load(overriddenLocale); @override bool shouldReload(LocalizationsDelegate<Translations> old) => true;}上面的代码我们看到有两个继承自LocalizationsDelegate类的代理类，SpecificLocalizationDelegate类是提供一种让我们强制指定一种位置的方式，通过改变传进来的local来达到从新load新json的方式。如果你没有这种需求，可以只关心TranslationsDelegate这种默认方式。5.在main方法中将代理设置好请支持原文 http://tryenough.com/flutter-translation要想监听系统的代理，就需要设置系统位置代理。方法如下：在main.dart方法中设置：import ‘package:translation/tanslations.dart’;import ‘package:translation/locale_util.dart’;import ‘package:flutter/material.dart’;import ‘package:flutter_localizations/flutter_localizations.dart’;void main() => runApp(MyApp());class MyApp extends StatelessWidget { @override Widget build(BuildContext context) { return new MaterialApp( title: ‘My Application’, theme: new ThemeData( primarySwatch: Colors.blue, ), localizationsDelegates: [ const TranslationsDelegate(), GlobalMaterialLocalizations.delegate, GlobalWidgetsLocalizations.delegate, ], supportedLocales: localeUtil.supportedLocales(), home: MyHomePage(), ); }}class MyHomePage extends StatefulWidget { _MyHomePageState createState() => new _MyHomePageState();}class _MyHomePageState extends State<MyHomePage>{ @override Widget build(BuildContext context){ return new Scaffold( appBar: new AppBar( title: new Text(Translations.of(context).text(“about_page_slogan”)), ), body: Center( child: Text(Translations.of(context).text(“about_page_slogan”)), ), ); }}请支持原文 http://tryenough.com/flutter-translationdemo下载地址：http://tryenough.com/flutter-translation