大航母网站建设费用网络推广怎么做方案

一.背景

需求是需要操作用户手机中的文件，不是应用沙箱

二.解决方案

这里要注意的一点拿到fsOpen.path的路径再去进行open文件，因为这里还不知道本地文件路径在哪里，需要选择一下路径再拿到路径去请求

1.这里就是进行两个fs.open，拿到你需要操作的文件的路径以后第一个就没用了,如果是需要新建文件也可以省去这步

const DocumentSelectOptions = new picker.DocumentSelectOptions();let context = getContext(this) as common.Context;// 创建文件选择器实例。const documentViewPicker = new picker.DocumentViewPicker(context);documentViewPicker.select(DocumentSelectOptions).then(async (documentSelectResult) => {// 获取选择路径let uri = documentSelectResult[0];console.log('e2qdw',uri)// 若文件不存在则创建文件//const fsOpen = await fs.open(uri,fs.OpenMode.READ_WRITE | fs.OpenMode.READ_ONLY |fs.OpenMode.CREATE)//console.log(fsOpen.path)const fsOpen = await fs.open(这里的路径就是fsOpen.path,fs.OpenMode.READ_WRITE | fs.OpenMode.READ_ONLY |fs.OpenMode.CREATE)// 读取文件this.readFile(fsOpen)// 写入this.writeFile(fsOpen)}).catch((err:BusinessError) => {console.error(`Invoke documentPicker.select failed, code is ${err.code}, message is ${err.message}`);})

2.第一步拿到以后就可以替换成这个代码 ，找到需要操作文件的路径，DocumentSelectOptions文件选择器就没用了

 async getFiles() {try {// 若文件不存在则创建文件// OpenMode.CREATE若文件不存在，则创建文件。//OpenMode.TRUNC如果文件存在且文件具有写权限，则将其长度裁剪为零。覆盖  不是追加const fsOpen = await fs.open('/storage/Users/currentUser/Download/jrdl.json',fs.OpenMode.READ_WRITE | fs.OpenMode.READ_ONLY |fs.OpenMode.CREATE|fs.OpenMode.TRUNC)// // 读取文件this.readFile(fsOpen)// this.deleteFile(fsOpen)// 写入this.writeFile(fsOpen)} catch (e) {console.error(`Invoke documentViewPicker.save failed, code is ${e.code}, message is ${e.message}`);}}

3.读写文件代码

readFile(fsOpen:fs.File){// 读取文件let arrayBuffer = new ArrayBuffer(4096);fs.read(fsOpen.fd, arrayBuffer, (err: BusinessError, readLen: number) => {if (err) {console.error("read failed with error message: " + err.message + ", error code: " + err.code);} else {console.info("read file data succeed");let buf = buffer.from(arrayBuffer, 0, readLen);console.info(`成功读取文件内容: ${buf.toString()}`);}// fs.closeSync(fsOpen);});}writeFile(fsOpen:fs.File){let str: string = "hello,word";fs.write(fsOpen.fd, str, (err: BusinessError, writeLen: number) => {if (err) {console.error("write data to file failed with error message:" + err.message + ", error code: " + err.code);} else {promptAction.showToast({ message: '成功写入',duration:2000,alignment:Alignment.Center })console.info("成功写入大小为:" + writeLen);}fs.closeSync(fsOpen);});}

4.完整代码

封装成工具类了这里已经，直接拿着就能用

import { BusinessError } from '@kit.BasicServicesKit';
import fs, { ReadOptions, WriteOptions } from '@ohos.file.fs'; // 导入文件管理模块
import { buffer } from '@kit.ArkTS';
import { promptAction } from '@kit.ArkUI';
import { picker } from '@kit.CoreFileKit';
import { common } from '@kit.AbilityKit';//执行UDP通讯的对象
export class fileUtils {async getFiles() {try {// 若文件不存在则创建文件const fsOpen = await fs.open('/storage/Users/currentUser/Download/jrdl.json',fs.OpenMode.READ_WRITE | fs.OpenMode.READ_ONLY |fs.OpenMode.CREATE|fs.OpenMode.TRUNC)// // 读取文件this.readFile(fsOpen)// this.deleteFile(fsOpen)// 写入this.writeFile(fsOpen)} catch (e) {console.error(`Invoke documentViewPicker.save failed, code is ${e.code}, message is ${e.message}`);}}readFile(fsOpen:fs.File){// 读取文件let arrayBuffer = new ArrayBuffer(4096);fs.read(fsOpen.fd, arrayBuffer, (err: BusinessError, readLen: number) => {if (err) {console.error("read failed with error message: " + err.message + ", error code: " + err.code);} else {console.info("read file data succeed");let buf = buffer.from(arrayBuffer, 0, readLen);console.info(`成功读取文件内容: ${buf.toString()}`);}// fs.closeSync(fsOpen);});}writeFile(fsOpen:fs.File){let str: string = "hello,word";fs.write(fsOpen.fd, str, (err: BusinessError, writeLen: number) => {if (err) {console.error("write data to file failed with error message:" + err.message + ", error code: " + err.code);} else {promptAction.showToast({ message: '成功写入',duration:2000,alignment:Alignment.Center })console.info("成功写入大小为:" + writeLen);}fs.closeSync(fsOpen);});}deleteFile(){fs.unlink('/storage/Users/currentUser/Download/jrdl.json').then(() => {console.info("remove file succeed");}).catch((err: BusinessError) => {console.error("remove file failed with error message: " + err.message + ", error code: " + err.code);});}
}

5.调用

  new fileUtils().getFiles()