Flutter 国际化相关

2019-10-12 15:58:05

一、纯SDK实现：

1、直接使用SDK提供的API，代码如下：

abstract class LangangeBase {
  Map<String, String> langStr = new HashMap();
}

class LangangeEn extends LangangeBase {
  LangangeEn() {
    langStr['title'] = 'Title';
    langStr['desc'] = 'Description';
    langStr['content'] = 'Content：Hello World!';
  }
}

class LangangeZh extends LangangeBase {
  LangangeZh() {
    langStr['title'] = '标题';
    langStr['desc'] = '描述';
    langStr['content'] = '内容：世界，你好！';
  }
}

2、Delegate及包装类代码：

class Translations {
  static LangangeBase _langangeBase;

  // 默认使用简体中文
  static Future<Translations> load(Locale locale) async {
    print('加载语言 langCode = ${locale.languageCode}');
    Translations translations = new Translations();
    if (locale.languageCode == 'en') {
      _langangeBase = new LangangeEn();
    } else {
      _langangeBase = new LangangeZh();
    }

    return translations;
  }

  String text(String key) {
    return _langangeBase.langStr[key];
  }

  static Translations of(BuildContext context) {
    Translations ret = Localizations.of(context, Translations);
    print('Translations of result = $ret');
    return ret;
  }
}

class MyLocalizations extends LocalizationsDelegate<Translations> {
  @override
  bool isSupported(Locale locale) {
    print('isSupported ${locale.languageCode}');
    // 只支持简体中文、美式英语
    return /*['zh', 'en'].contains(locale.languageCode)*/true;
  }

  @override
  bool shouldReload(LocalizationsDelegate<Translations> old) {
    return false;
  }

  @override
  Future<Translations> load(Locale locale) {
    return Translations.load(locale);
  }

  static MyLocalizations delegate = new MyLocalizations();
}

二、使用Intl库

1、创建一个独立的dart字符串类，便于生产arb文件，如下：

class LocalStr {
  /**
   * 这里的是兜底文案，在没有相对应的本地化资源时使用
   */
  static String get title =>
      Intl.message('Default:天王盖地虎', name: 'title', desc: 'APP标题');

  static String get desc =>
      Intl.message('Default:智取威虎山', name: 'desc', desc: '标题的描述');

  static String get content => Intl.message('Default:电影讲述了东北解放军如何消灭盘踞山岭的土匪的故事',
      name: 'content', desc: 'App的主要内容');
}

2、Delegate及包装类代码：

class IntlLocalizations {

  static Future<IntlLocalizations> load(Locale locale) {
    String name = locale.countryCode.isEmpty ? locale.languageCode : locale.toString();
    print('local = ${Intl.canonicalizedLocale(name)}');
    return initializeMessages(name).then((b) {
      Intl.defaultLocale = name;
      return new IntlLocalizations();
    });
  }

  String get title1 => LocalStr.title;

  String get desc1 => LocalStr.desc;

  String get content1 => LocalStr.content;

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

class IntlLocalizatoinsDelegate extends LocalizationsDelegate<IntlLocalizations> {
  @override
  bool isSupported(Locale locale) {
    print('lang code = ${locale.languageCode}');
    return /*['zh', 'en'].contains(locale.languageCode)*/true;
  }

  @override
  Future<IntlLocalizations> load(Locale locale) {
    return IntlLocalizations.load(locale);
  }

  @override
  bool shouldReload(LocalizationsDelegate old) {
    return false;
  }

  static IntlLocalizatoinsDelegate delegate = new IntlLocalizatoinsDelegate();
}

3、最终的代码结构图：