Dart与Flutter教程 多语言支持开发

在Flutter中实现多语言支持通常使用flutter_localizations和intl包。以下是实现多语言支持的步骤：

1. 添加依赖

在pubspec.yaml中添加以下依赖：

dependencies:
  flutter:
    sdk: flutter
  flutter_localizations:
    sdk: flutter
  intl: ^0.17.0

2. 创建多语言文件

在lib目录下创建一个l10n文件夹，并在其中创建app_localizations.dart和intl_en.arb、intl_zh.arb等语言文件。

app_localizations.dart:

import 'package:flutter/material.dart';
import 'package:intl/intl.dart';
import 'l10n/messages_all.dart';

class AppLocalizations {
  static Future<AppLocalizations> load(Locale locale) {
    final String name = locale.countryCode.isEmpty ? locale.languageCode : locale.toString();
    final String localeName = Intl.canonicalizedLocale(name);
    return initializeMessages(localeName).then((_) {
      Intl.defaultLocale = localeName;
      return AppLocalizations();
    });
  }

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

  String get title {
    return Intl.message(
      'Hello World',
      name: 'title',
      desc: 'Title for the application',
    );
  }
}

intl_en.arb:

{
  "title": "Hello World"
}

intl_zh.arb:

{
  "title": "你好世界"
}

3. 生成多语言代码

在终端运行以下命令生成多语言代码：

flutter pub pub run intl_translation:generate_from_arb --output-dir=lib/l10n --no-use-deferred-loading lib/l10n/app_localizations.dart lib/l10n/intl_*.arb

4. 配置MaterialApp

在main.dart中配置MaterialApp以支持多语言：

import 'package:flutter/material.dart';
import 'package:flutter_localizations/flutter_localizations.dart';
import 'l10n/app_localizations.dart';

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      localizationsDelegates: [
        AppLocalizations.delegate,
        GlobalMaterialLocalizations.delegate,
        GlobalWidgetsLocalizations.delegate,
      ],
      supportedLocales: [
        const Locale('en', ''),
        const Locale('zh', ''),
      ],
      home: MyHomePage(),
    );
  }
}

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

5. 使用多语言

在需要的地方使用AppLocalizations.of(context).title来获取翻译后的文本。

通过以上步骤，你可以在Flutter应用中实现多语言支持。