如何创建一个文件并将其存储在android下载文件夹中？

我在用rn-fetch-blob https://github.com/joltup/rn-fetch-blob https://github.com/joltup/rn-fetch-blob我正在创建新文件并将其存储在下载文件夹中。注意：我使用的是模拟器。现在，当我尝试创建新文件并且使用下载目录时，请参阅此 ->https://github.com/joltup/rn-fetch-blob/wiki/File-System-Access-API#dirs https://github.com/joltup/rn-fetch-blob/wiki/File-System-Access-API#dirs但我收到错误消息说权限被拒绝为什么会这样？如何启用权限以便文件存储在 android React Native 应用程序的下载文件夹内？

Code:

saveFile = () => {
        const fs = RNFetchBlob.fs;

        const dirs = RNFetchBlob.fs.dirs;
        console.log("directory path: ",dirs.DownloadDir );

        const NEW_FILE_PATH = dirs.DownloadDir + '/demo.txt';

        console.log("file path: ", NEW_FILE_PATH);

        fs.createFile(NEW_FILE_PATH, 'foo', 'utf8');

    }

AndroidManifest.xml：

    <uses-permission android:name="android.permission.INTERNET" />
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" /> 
    <uses-permission android:name="android.permission.SYSTEM_ALERT_WINDOW"/>
    <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
    <uses-permission tools:node="remove" android:name="android.permission.READ_PHONE_STATE" />
    <uses-permission tools:node="remove" android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
    <uses-permission tools:node="remove" android:name="android.permission.READ_EXTERNAL_STORAGE" />

截屏：

为了允许访问 rn-fetch-blob 中的其他 die，如果 android 版本高于 6，那么您需要请求运行时权限。关联：https://facebook.github.io/react-native/docs/permissionsandroid https://facebook.github.io/react-native/docs/permissionsandroid

修改后的代码：

import {PermissionsAndroid} from 'react-native';

    saveFile = async () => {

            try {
                const granted = await PermissionsAndroid.request(
                    PermissionsAndroid.PERMISSIONS.WRITE_EXTERNAL_STORAGE
                );
                if (granted === PermissionsAndroid.RESULTS.GRANTED) {
                    console.log("Permission granted");

                    const fs = RNFetchBlob.fs;
                    // const base64 = RNFetchBlob.base64;

                    const dirs = RNFetchBlob.fs.dirs;
                    console.log(dirs.DownloadDir);

                    const NEW_FILE_PATH = dirs.DownloadDir + '/test.txt';
                    fs.createFile(NEW_FILE_PATH, 'foo', 'utf8');

                } else {
                    console.log('Permission denied');
                }
                } catch (err) {
                    console.warn(err);
                }

        }

rn-fetch-blob 的附加链接：

1) https://github.com/joltup/rn-fetch-blob/wiki/File-System-Access-API#dirs https://github.com/joltup/rn-fetch-blob/wiki/File-System-Access-API#dirs

2) https://github.com/joltup/rn-fetch-blob https://github.com/joltup/rn-fetch-blob