Javascript 如何将一个本地Expo应用程序国际化?
制作React应用程序时,建议使用哪种技术 我正在考虑编写以下代码:Javascript 如何将一个本地Expo应用程序国际化?,javascript,reactjs,react-native,internationalization,expo,Javascript,Reactjs,React Native,Internationalization,Expo,制作React应用程序时,建议使用哪种技术 我正在考虑编写以下代码: 创建React上下文“语言” 创建不同的模块,导出包含每种语言“pt”、“en”、“fr”、“sp”、“it”所有字符串的映射 尝试使用语言上下文提供程序提供的方法从我的启动屏幕中的AsyncStorage加载默认语言 如果找不到,请根据他的位置获取用户语言 对我来说,这是有道理的,但可能还有其他更简单的方法来达到同样的目的,让我感觉更专业 // This is my Languages Context import Reac
// This is my Languages Context
import React, { createContext, useState } from "react";
import * as Localization from "expo-localization";
import { VALID_LANGUAGES } from "../../utils/languages/constants"; // "English", "Spanish", "Portuguese"...
import languages from "../../languages"; // en, sp, pt, ... modules with all texts (key, value)
import AsyncStorage from "../../lib/async-storage/AsyncStorage";
const LanguagesContext = createContext(null);
export default LanguagesContext;
export function LanguagesProvider({ children }) {
const [language, setLanguage] = useState(undefined);
const loadLanguage = async () => {
// Get the default language from async storage
const language = await AsyncStorage.getData("language");
// TODO - if undefined -> get user location and use the corresponding lang
// TODO - if not supported, use english
if (!language) {
setLanguage(VALID_LANGUAGES[0]);
}
};
const changeLanguage = async (language) => {
// Update state
setLanguage(language);
// Save language in async storage
await AsyncStorage.storeData("language", language);
};
return (
<LanguagesContext.Provider
value={{ language, loadLanguage, changeLanguage }}
>
{children}
</LanguagesContext.Provider>
);
}
export { LanguagesProvider };
//这是我的语言上下文
从“React”导入React,{createContext,useState};
从“世博会本地化”导入*作为本地化;
从“./../utils/LANGUAGES/constants”;//“英语”、“西班牙语”、“葡萄牙语”。。。
从“../../languages”;//导入语言恩,sp,pt。。。包含所有文本(键、值)的模块
从“../../lib/async storage/async storage”导入异步存储;
const LanguagesContext=createContext(null);
导出默认语言上下文;
导出函数语言Provider({children}){
const[language,setLanguage]=useState(未定义);
const loadLanguage=async()=>{
//从异步存储中获取默认语言
const language=await AsyncStorage.getData(“语言”);
//TODO-如果未定义->获取用户位置并使用相应的语言
//TODO-如果不支持,请使用英语
如果(!语言){
setLanguage(有效的_语言[0]);
}
};
const changeLanguage=异步(语言)=>{
//更新状态
语言;
//在异步存储中保存语言
等待AsyncStorage.storeData(“语言”,语言);
};
返回(
{儿童}
);
}
导出{LanguagesProvider};
我所做的是在我的闪屏组件中使用“loadLanguage”方法,这可以确保应用程序在呈现任何内容之前准备好使用。您认为这项技术怎么样?
如何使用应用程序中的文本?我想在上下文提供程序中创建另一个方法getAppText(),只是为了从我的语言模块(“en”、“it”、“pt”和……)返回正确的映射
任何库和示例?
谢谢。首先,您只需启动一个新项目
$ npx react-native init rn_example_translation
我更愿意创建一个src文件夹来放置我们所有的JS代码,因此我们在下面的项目根目录中修改index.JS,如下所示:
import {AppRegistry} from 'react-native';
import App from './src/App';
import {name as appName} from './app.json';
AppRegistry.registerComponent(appName, () => App);
import {I18nManager} from 'react-native';
import * as RNLocalize from 'react-native-localize';
import i18n from 'i18n-js';
import memoize from 'lodash.memoize';
export const DEFAULT_LANGUAGE = 'en';
export const translationGetters = {
// lazy requires (metro bundler does not support symlinks)
en: () => require('./assets/locales/en/translations.json'),
fr: () => require('./assets/locales/fr/translations.json'),
};
export const translate = memoize(
(key, config) => i18n.t(key, config),
(key, config) => (config ? key + JSON.stringify(config) : key),
);
export const t = translate;
export const setI18nConfig = (codeLang = null) => {
// fallback if no available language fits
const fallback = {languageTag: DEFAULT_LANGUAGE, isRTL: false};
const lang = codeLang ? {languageTag: codeLang, isRTL: false} : null;
# Use RNLocalize to detect the user system language
const {languageTag, isRTL} = lang
? lang
: RNLocalize.findBestAvailableLanguage(Object.keys(translationGetters)) ||
fallback;
// clear translation cache
translate.cache.clear();
// update layout direction
I18nManager.forceRTL(isRTL);
// set i18n-js config
i18n.translations = {[languageTag]: translationGetters[languageTag]()};
i18n.locale = languageTag;
return languageTag;
};
管理翻译
我们将使用“i18n js”模块翻译该应用程序,因此我们将使用以下模块安装该应用程序:
$ npm install --save i18n-js
然后创建一个文件“i18n.js”,其中包含:
import {I18nManager} from 'react-native';
import i18n from 'i18n-js';
import memoize from 'lodash.memoize';
export const DEFAULT_LANGUAGE = 'en';
export const translationGetters = {
// lazy requires (metro bundler does not support symlinks)
en: () => require('./assets/locales/en/translations.json'),
fr: () => require('./assets/locales/fr/translations.json'),
};
export const translate = memoize(
(key, config) => i18n.t(key, config),
(key, config) => (config ? key + JSON.stringify(config) : key),
);
export const t = translate;
export const setI18nConfig = (codeLang = null) => {
// fallback if no available language fits
const fallback = {languageTag: DEFAULT_LANGUAGE, isRTL: false};
const lang = codeLang ? {languageTag: codeLang, isRTL: false} : null;
const {languageTag, isRTL} = lang ? lang : fallback;
// clear translation cache
translate.cache.clear();
// update layout direction
I18nManager.forceRTL(isRTL);
// set i18n-js config
i18n.translations = {[languageTag]: translationGetters[languageTag]()};
i18n.locale = languageTag;
return languageTag;
};
然后创建空翻译文件,如下所示:
'./src/assets/locales/en/translations.json' and './src/assets/locales/fr/translations.json'
i18n.t('Hello world!')
现在我们可以用法语和英语翻译app JS字符串,如下所示:
'./src/assets/locales/en/translations.json' and './src/assets/locales/fr/translations.json'
i18n.t('Hello world!')
在应用程序中切换区域设置
现在,我们将设置一个react上下文以保持当前用户语言,并设置一个开关以向用户提供更改语言的选项。翻译字符串很酷,但翻译的字符串必须与用户语言相匹配
要使应用程序中的当前用户语言与react上下文保持一致,我们需要在上下文文件夹中创建一个文件'LocalisationContext.js',其中包含:
import React from 'react';
const LocalizationContext = React.createContext();
export default LocalizationContext;
现在在你的App.js中
import React, {useEffect, useCallback} from 'react';
import {StyleSheet} from 'react-native';
import * as i18n from './i18n';
import LocalizationContext from './context/LocalizationContext';
import HomeScreen from './HomeScreen';
const App: () => React$Node = () => {
const [locale, setLocale] = React.useState(i18n.DEFAULT_LANGUAGE);
const localizationContext = React.useMemo(
() => ({
t: (scope, options) => i18n.t(scope, {locale, ...options}),
locale,
setLocale,
}),
[locale],
);
return (
<>
<LocalizationContext.Provider value={localizationContext}>
<HomeScreen localizationChange={handleLocalizationChange} />
</LocalizationContext.Provider>
</>
);
};
然后将app.js修改为
import React, {useEffect, useCallback} from 'react';
import {StyleSheet} from 'react-native';
import * as RNLocalize from 'react-native-localize';
import * as i18n from './i18n';
import LocalizationContext from './context/LocalizationContext';
import HomeScreen from './HomeScreen';
const App: () => React$Node = () => {
const [locale, setLocale] = React.useState(i18n.DEFAULT_LANGUAGE);
const localizationContext = React.useMemo(
() => ({
t: (scope, options) => i18n.t(scope, {locale, ...options}),
locale,
setLocale,
}),
[locale],
);
const handleLocalizationChange = useCallback(
(newLocale) => {
const newSetLocale = i18n.setI18nConfig(newLocale);
setLocale(newSetLocale);
},
[locale],
);
useEffect(() => {
handleLocalizationChange();
RNLocalize.addEventListener('change', handleLocalizationChange);
return () => {
RNLocalize.removeEventListener('change', handleLocalizationChange);
};
}, []);
return (
<>
<LocalizationContext.Provider value={localizationContext}>
<HomeScreen localizationChange={handleLocalizationChange} />
</LocalizationContext.Provider>
</>
);
};
生成翻译
为了生成语言文件,您可以使用i18next scanner。
我们需要在全球范围内安装它
npm install -g i18next-scanner
使用以下命令在项目目录根目录下创建“i18next scanner.config.js”文件:
const fs = require('fs');
const chalk = require('chalk');
module.exports = {
input: [
'src/**/*.{js,jsx}',
// Use ! to filter out files or directories
'!app/**/*.spec.{js,jsx}',
'!app/i18n/**',
'!**/node_modules/**',
],
output: './',
options: {
debug: false,
removeUnusedKeys: true,
func: {
list: ['i18next.t', 'i18n.t', 't'],
extensions: ['.js', '.jsx'],
},
trans: {
component: 'Trans',
i18nKey: 'i18nKey',
defaultsKey: 'defaults',
extensions: [],
fallbackKey: function (ns, value) {
return value;
},
acorn: {
ecmaVersion: 10, // defaults to 10
sourceType: 'module', // defaults to 'module'
// Check out https://github.com/acornjs/acorn/tree/master/acorn#interface for additional options
},
},
lngs: ['en', 'fr'],
ns: ['translations'],
defaultLng: 'en',
defaultNs: 'translations',
defaultValue: '__STRING_NOT_TRANSLATED__',
resource: {
loadPath: 'src/assets/locales/{{lng}}/{{ns}}.json',
savePath: 'src/assets/locales/{{lng}}/{{ns}}.json',
jsonIndent: 2,
lineEnding: '\n',
},
nsSeparator: false, // namespace separator
keySeparator: false, // key separator
interpolation: {
prefix: '{{',
suffix: '}}',
},
},
transform: function customTransform(file, enc, done) {
'use strict';
const parser = this.parser;
const options = {
presets: ['@babel/preset-flow'],
plugins: [
'@babel/plugin-syntax-jsx',
'@babel/plugin-proposal-class-properties',
],
configFile: false,
};
const content = fs.readFileSync(file.path, enc);
let count = 0;
const code = require('@babel/core').transform(content, options);
parser.parseFuncFromString(
code.code,
{list: ['i18next._', 'i18next.__']},
(key, options) => {
parser.set(
key,
Object.assign({}, options, {
nsSeparator: false,
keySeparator: false,
}),
);
++count;
},
);
if (count > 0) {
console.log(
`i18next-scanner: count=${chalk.cyan(count)}, file=${chalk.yellow(
JSON.stringify(file.relative),
)}`,
);
}
done();
},
};
在这里,我们可以使用以下命令:
$ i18next-scanner
现在它将生成预填充翻译文件
'./src/assets/locales/en/translations.json' and './src/assets/locales/fr/translations.json'.
我们只需要通过正确的翻译来更改这些文件
现在运行应用程序
npx react-native run-android
它将成功运行。为什么不使用设备的操作系统语言而不是位置来设置默认语言?