eAMEMu_RN/App.js

/**
 * Sample React Native App
 * https://github.com/facebook/react-native
 *
 * @format
 * @flow
 */

import React from 'react';
import { createAppContainer } from 'react-navigation';
import { createStackNavigator } from 'react-navigation-stack';

import MainScreen from './src/screen/MainScreen';
import CardEditScreen from './src/screen/CardEditScreen';

import * as RNLocalize from 'react-native-localize';
import i18n from 'i18n-js';
import en from './src/locales/en';
import ko from './src/locales/ko';

const MainNavigator = createStackNavigator({
  Home: {
    screen: MainScreen,
    navigationOptions: {headerShown: false}
  },
  CardEditScreen: {
    screen: CardEditScreen,
    navigationOptions: {headerShown: false}
  },
  },
    {
      initialRouteName: 'Home',
    }
);

const AppContainer = createAppContainer(MainNavigator);

const setI18nConfig = () => {
  const fallback = { languageTag: 'en' };
  const { languageTag } = RNLocalize.findBestAvailableLanguage(['en', 'ko']) || fallback;

  i18n.translations = {
      en,
      ko,
  };
  i18n.locale = languageTag;
};

export default class App extends React.Component{
    constructor(props) {
        super(props);
        setI18nConfig();
    }

    componentDidMount() {
        RNLocalize.addEventListener('change', this.handleLocalizationChange)
    }

    componentWillUnmount() {
        RNLocalize.removeEventListener('change', this.handleLocalizationChange)
    }

    handleLocalizationChange = () => {
        setI18nConfig();
        this.forceUpdate();
    };

    render(){
        return (
            <>
                <AppContainer/>
            </>
        );
    }
};