通过文件管理器使用三方应用对文件进行读写

"module": { 
  ... 
  "abilities": [ 
    { 
      ... 
      "skills": [ 
        { 
          ... 
          "actions": [ 
            "ohos.want.action.viewData" 
          ], 
          "uris": [ 
            { 
              "scheme": "file", 
              "type": "text/plain" 
            }， 
            { 
              "scheme": "file", 
              "type": "image/png" 
            }, 
            { 
              "scheme": "file", 
              "type": "text/h323" 
            }, 
          ] 
        } 
      ] 
    } 
  ] 
}

import fs from '@ohos.file.fs'; 
import Want from '@ohos.app.ability.Want'; 
import { BusinessError } from '@ohos.base'; 
import { util } from '@kit.ArkTS'; 
import * as chardet from '@changwei/chardet'; 
 
getShareFileText(Uri: string):string { 
  // let want: Want = Uri; // 此处实际使用时应该修改为获取到的分享方传递过来的want信息 
  // 从want信息中获取uri字段 
  let uri = Uri; 
  if (uri == null || uri == undefined) { 
    console.info('uri is invalid'); 
    return ""; 
  } 
  let point = uri.lastIndexOf(".") 
  let typ = uri.slice(point) 
  // 根据需要对被分享文件的URI进行相应操作。例如读写的方式打开URI获取file对象 
  let file = fs.openSync(uri, fs.OpenMode.READ_WRITE); 
  let arrayBuffer = new ArrayBuffer(1024) 
  fs.readSync(file.fd,arrayBuffer) 
  let charset = chardet.detect(new Uint8Array(arrayBuffer, 0, 512)); 
  let textDecoder = util.TextDecoder.create(charset); 
  let result = new Uint8Array(arrayBuffer); 
  return textDecoder.decodeWithStream(result); 
}

import fs from '@ohos.file.fs' 
 
let file=fs.openSync('/path/to/file',fs.OpenMode.READ_ONLY); 
let arrayBuffer=new ArrayBuffer(1024);// 读取文本文件内容 
let readLen = fs.readSync(file.fd, arrayBuffer,{ 
  offset: 0, 
  length: arrayBuffer.length 
}); 
// 提取前512个字节内容以提高性能，长文本建议这样做 
let charset = chardet.detect(new Uint8Array(arrayBuffer, 0, 512)); 
// or 
const encoding = await chardet.detectFile('/path/to/file'); 
// or 
const encoding = chardet.detectFileSync('/path/to/file');

import uniformTypeDescriptor from '@ohos.data.uniformTypeDescriptor'; 
try { 
  // 可根据.mp3文件后缀查询对应UTD数据类型。 
  let fileExtention = '.mp3'; 
  let typeId = uniformTypeDescriptor.getUniformDataTypeByFilenameExtension(fileExtention); 
  // 根据UTD数据类型查询对应的MIMEType列表。 
  let typeObj = uniformTypeDescriptor.getTypeDescriptor(typeId); 
  let mimeTypes = typeObj.mimeTypes; 
  console.info('mimeTypes:' + mimeTypes); 
} catch (err) { 
  console.error('err message:' + err.message + ', err code:' + err.code); 
}

import uniformTypeDescriptor from '@ohos.data.uniformTypeDescriptor'; 
try { 
  // 可根据audio/mp3MIMEType查询对应UTD数据类型。 
  let mineType = 'audio/mp3'; 
  let typeId = uniformTypeDescriptor.getUniformDataTypeByMIMEType(mineType); 
  // 根据UTD数据类型查询对应的MIMEType列表 
  let typeObj = uniformTypeDescriptor.getTypeDescriptor(typeId); 
  let filenameExtensions = typeObj.filenameExtensions; 
  console.info('filenameExtensions:' + filenameExtensions); 
} catch (err) { 
  console.error('err message:' + err.message + ', err code:' + err.code); 
}