react-native-fs实现文件下载、文本存储的示例代码

npm install react-native-fs --save

react-native link react-native-fs

import RNFS from 'react-native-fs';

/*下载文件*/
 downloadFile() {
 // On Android, use "RNFS.DocumentDirectoryPath" (MainBundlePath is not defined)

 // 图片
 // const downloadDest = `${RNFS.MainBundlePath}/${((Math.random() * 1000) | 0)}.jpg`;
 // const formUrl = 'http://img.kaiyanapp.com/c7b46c492261a7c19fa880802afe93b3.png?imageMogr2/quality/60/format/jpg';

 // 文件
 // const downloadDest = `${RNFS.MainBundlePath}/${((Math.random() * 1000) | 0)}.zip`;
 // const formUrl = 'http://files.cnblogs.com/zhuqil/UIWebViewDemo.zip';

 // 视频
 // const downloadDest = `${RNFS.MainBundlePath}/${((Math.random() * 1000) | 0)}.mp4`;
 // http://gslb.miaopai.com/stream/SnY~bbkqbi2uLEBMXHxGqnNKqyiG9ub8.mp4?vend=miaopai&
 // https://gslb.miaopai.com/stream/BNaEYOL-tEwSrAiYBnPDR03dDlFavoWD.mp4?vend=miaopai&
 // const formUrl = 'https://gslb.miaopai.com/stream/9Q5ADAp2v5NHtQIeQT7t461VkNPxvC2T.mp4?vend=miaopai&';

 // 音频
 const downloadDest = `${RNFS.MainBundlePath}/${((Math.random() * 1000) | 0)}.mp3`;
 // http://wvoice.spriteapp.cn/voice/2015/0902/55e6fc6e4f7b9.mp3
 const formUrl = 'http://wvoice.spriteapp.cn/voice/2015/0818/55d2248309b09.mp3';

 const options = {
 fromUrl: formUrl,
 toFile: downloadDest,
 background: true,
 begin: (res) => {
 console.log('begin', res);
 console.log('contentLength:', res.contentLength / 1024 / 1024, 'M');
 },
 progress: (res) => {

 let pro = res.bytesWritten / res.contentLength;

 this.setState({
 progressNum: pro,
 });
 }
 };
 try {
 const ret = RNFS.downloadFile(options);
 ret.promise.then(res => {
 console.log('success', res);

 console.log('file://' + downloadDest)

 }).catch(err => {
 console.log('err', err);
 });
 }
 catch (e) {
 console.log(error);
 }

 }

 /*将文本写入本地 txt*/
 writeFile() {
 // create a path you want to write to
 const path = RNFS.MainBundlePath + '/test.txt';

 // write the file
 RNFS.writeFile(path, '这是一段文本，YES', 'utf8')
 .then((success) => {
 console.log('path', path);
 })
 .catch((err) => {
 console.log(err.message);
 });
 }

/*读取txt文件内容*/
 readFile() {
 // create a path you want to delete
 const path = RNFS.MainBundlePath + '/test.txt';

 return RNFS.readFile(path)
 .then((result) => {
 console.log(result);

 this.setState({
 readTxtResult: result,
 })
 })
 .catch((err) => {
 console.log(err.message);

 });
 }

/*在已有的txt上添加新的文本*/
 appendFile() {
 const path = RNFS.MainBundlePath + '/test.txt';

 return RNFS.appendFile(path, '新添加的文本', 'utf8')
 .then((success) => {
 console.log('success');
 })
 .catch((err) => {
 console.log(err.message);

 });
 }

 /*删除文件*/
 deleteFile() {
 // create a path you want to delete
 const path = RNFS.MainBundlePath + '/test.txt';

 return RNFS.unlink(path)
 .then(() => {
 console.log('FILE DELETED');
 })
 // `unlink` will throw an error, if the item to unlink does not exist
 .catch((err) => {
 console.log(err.message);
 });
 }

 /*上传文件 only iOS*/
 uploadFile() {
 const uploadSrc = `${RNFS.MainBundlePath}/test.txt`;

 const uploadUrl = 'http://buz.co/rnfs/upload-tester.php';

 const options = {
 toUrl: uploadUrl,
 files: [{name: 'myfile', filename: 'test.txt', filepath: uploadSrc, filetype: 'text/plain'}],
 background: true,
 method: 'POST', // PUT
 begin: (res) => {
 console.log('begin', res);
 },
 progress: (res) => {
 console.log('progress', res);
 }
 };

 const ret = RNFS.uploadFiles(options);

 return ret.promise.then(res => {
 const response = JSON.parse(res.body);
 console.log(response);

 })
 .catch(err => {
 console.log('err', err);
 });
 }