安裝react-native-fs

npm

npm install react-native-fs --save

yarn

yarn add react-native-fs

安卓配置

• android/settings.gradle

...
include ':react-native-fs'
project(':react-native-fs').projectDir = new File(settingsDir, '../node_modules/react-native-fs/android')

• android/app/build.gradle

...
dependencies {
    ...
    implementation project(':react-native-fs')
}

• android\app\src\main\java\com\reactnative_demo\MainApplication.kt

把原代碼

import com.rnfs.RNFSPackage; // 導入模塊

// 下麵這段代碼要改
override fun getPackages(): List<ReactPackage> {
	  // Packages that cannot be autolinked yet can be added manually here, for example:
	  // packages.add(new MyReactNativePackage());
	  return PackageList(this).packages
}

改為

import com.rnfs.RNFSPackage; // 導入模塊

// 改成這樣
override fun getPackages(): List<ReactPackage> =
    PackageList(this).packages.apply {
        // Packages that cannot be autolinked yet can be added manually here， for example:
        // packages.add(new MyReactNativePackage());
        add(RNFSPackage()) // 如果報錯提示覆蓋註冊（已經自動註冊了），那麼把這行註釋掉即可
    }

使用

import {StyleSheet, Text, View, Button} from 'react-native';
import React from 'react';
import RNFS from 'react-native-fs';

export default function CsvFile() {
  const handleClick = () => {
    const path = RNFS.ExternalStorageDirectoryPath + '/test.txt';
    RNFS.writeFile(path, 'Lorem ipsum dolor sit amet', 'utf8')
      .then(success => {
        console.log('FILE WRITTEN! --> ', path);
      })
      .catch(err => {
        console.log(err.message);
      });
  };
  return (
    <View>
      <Button title="寫入文件" onPress={() => handleClick()} />
    </View>
  );
}

const styles = StyleSheet.create({});

關於存儲路徑

RNFS.MainBundlePath (String) 主包目錄的絕對路徑（在 Android 上不可用）
RNFS.CachesDirectoryPath (String) 緩存目錄的絕對路徑
RNFS.ExternalCachesDirectoryPath (String) 外部緩存目錄的絕對路徑（僅限安卓）
RNFS.DocumentDirectoryPath (String) 文檔目錄的絕對路徑
RNFS.DownloadDirectoryPath (String) 下載目錄的絕對路徑（僅在 android 上）
RNFS.TemporaryDirectoryPath (String) 臨時目錄的絕對路徑（在 Android 上回退到 Caching-Directory）
RNFS.LibraryDirectoryPath (String) NSLibraryDirectory 的絕對路徑（僅限 iOS）
RNFS.ExternalDirectoryPath (String) 外部文件的絕對路徑，共用目錄（僅限安卓）
RNFS.ExternalStorageDirectoryPath (String) 外部存儲的絕對路徑，共用目錄（僅限安卓）