Flutter语言转换插件slang的使用

简介

Slang 是一个类型安全的国际化解决方案，支持JSON、YAML、CSV或ARB文件。它具有最小化配置、无错别字或缺少参数、快速访问翻译、组织良好、Flutter独立等特性。

快速开始

添加依赖

在pubspec.yaml中添加以下依赖：

dependencies:
  slang: ^latest_version
  slang_flutter: ^latest_version # 如果你使用Flutter

dev_dependencies:
  build_runner: ^latest_version # 只有当你使用build_runner时需要
  slang_build_runner: ^latest_version # 只有当你使用build_runner时需要

创建JSON文件

创建包含翻译内容的JSON文件，通常放在assets/i18n或lib/i18n目录下。例如：

// File: en.i18n.json
{
  "hello": "Hello $name",
  "save": "Save",
  "login": {
    "success": "Logged in successfully",
    "fail": "Logged in failed"
  }
}

// File: de.i18n.json
{
  "hello": "Hallo $name",
  "save": "Speichern",
  "login": {
    "success": "Login erfolgreich",
    "fail": "Login fehlgeschlagen"
  }
}

生成Dart代码

使用命令行生成Dart代码：

dart run slang

或者如果你使用build_runner：

dart run build_runner build -d

初始化应用

确保在main.dart中初始化设备语言并包装应用：

void main() {
  WidgetsFlutterBinding.ensureInitialized();
  LocaleSettings.useDeviceLocale(); // 使用设备语言
  runApp(TranslationProvider(
    child: MyApp(),
  ));
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      locale: TranslationProvider.of(context).flutterLocale,
      supportedLocales: AppLocaleUtils.supportedLocales,
      localizationsDelegates: GlobalMaterialLocalizations.delegates,
      home: MyHomePage(),
    );
  }
}

使用翻译

在你的Widget中使用翻译：

final t = Translations.of(context);
String a = t.login.success; // 获取翻译

示例代码

以下是完整的示例代码，展示了如何在一个简单的Flutter应用程序中使用Slang进行多语言支持：

import 'package:example/i18n/strings.g.dart';
import 'package:flutter/material.dart';
import 'package:flutter_localizations/flutter_localizations.dart';

void main() {
  WidgetsFlutterBinding.ensureInitialized();
  LocaleSettings.useDeviceLocale(); // initialize with the right locale
  runApp(TranslationProvider(
    // wrap with TranslationProvider
    child: MyApp(),
  ));
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      locale: TranslationProvider.of(context).flutterLocale,
      supportedLocales: AppLocaleUtils.supportedLocales,
      localizationsDelegates: [
        ...GlobalMaterialLocalizations.delegates,
      ],
      home: MyHomePage(),
    );
  }
}

class MyHomePage extends StatefulWidget {
  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  int _counter = 0;

  @override
  void initState() {
    super.initState();

    LocaleSettings.getLocaleStream().listen((event) {
      print('locale changed: $event');
    });
  }

  @override
  Widget build(BuildContext context) {
    final t = Translations.of(context);

    return Scaffold(
      appBar: AppBar(
        title: Text(t.mainScreen.title),
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            Text(t.mainScreen.counter(n: _counter)),
            Row(
              mainAxisAlignment: MainAxisAlignment.center,
              children: AppLocale.values.map((locale) {
                bool active = LocaleSettings.currentLocale == locale;

                return Padding(
                  padding: const EdgeInsets.all(8.0),
                  child: OutlinedButton(
                    style: OutlinedButton.styleFrom(
                      backgroundColor: active ? Colors.blue.shade100 : null,
                    ),
                    onPressed: () {
                      LocaleSettings.setLocale(locale);
                    },
                    child: Text(t.locales[locale.languageTag]!),
                  ),
                );
              }).toList(),
            ),
          ],
        ),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: () {
          setState(() => _counter++);
        },
        tooltip: context.t.mainScreen.tapMe, // using extension method
        child: Icon(Icons.add),
      ),
    );
  }
}

通过以上步骤和示例代码，你可以轻松地在Flutter项目中集成Slang插件，实现多语言支持。