@ohos.file.fileAccess (User File Access and Management)

The fileAccess module provides a framework for accessing and operating user files based on the ExtensionAbility mechanism. This module interacts with a variety of file management services, such as the storage management service, and provides a set of unified file access and management interfaces for system applications. The storage management service manages both the directories of the built-in storage and resources on external devices, such as shared disks, USB flash drives, and SD cards.

NOTE

• The initial APIs of this module are supported since API version 9. Newly added APIs will be marked with a superscript to indicate their earliest API version.
• The APIs provided by this module are system APIs and cannot be called by third-party applications. Currently, the APIs can be called only by FilePicker and FileManager.

Modules to Import

import fileAccess from '@ohos.file.fileAccess';

fileAccess.getFileAccessAbilityInfo

getFileAccessAbilityInfo() : Promise<Array<Want>>

Obtains information about all Wants with extension set to fileAccess in the system. A Want contains information for starting an ability. This API uses a promise to return the result.

Model restriction: This API can be used only in the stage model.

System capability: SystemCapability.FileManagement.UserFileService

Required permissions: ohos.permission.FILE_ACCESS_MANAGER and ohos.permission.GET_BUNDLE_INFO_PRIVILEGED

Return value

Error codes

For details about the error codes, see File Management Error Codes.

Example

import { BusinessError } from '@ohos.base';
import Want from '@ohos.app.ability.Want';
async getFileAccessAbilityInfo() {
  let wantInfos: Array<Want> = [];
  try {
    wantInfos = await fileAccess.getFileAccessAbilityInfo();
    console.log("getFileAccessAbilityInfo data " + JSON.stringify(wantInfos));
  } catch (err) {
    let error: BusinessError = err as BusinessError;
    console.error("getFileAccessAbilityInfo failed, errCode:" + error.code + ", errMessage:" + error.message);
  }
}

fileAccess.getFileAccessAbilityInfo

getFileAccessAbilityInfo(callback: AsyncCallback<Array<Want>>): void

Obtains information about all Wants with extension set to fileAccess in the system. A Want contains information for starting an ability. This API uses an asynchronous callback to return the result.

Model restriction: This API can be used only in the stage model.

System capability: SystemCapability.FileManagement.UserFileService

Required permissions: ohos.permission.FILE_ACCESS_MANAGER and ohos.permission.GET_BUNDLE_INFO_PRIVILEGED

Parameters

Error codes

For details about the error codes, see File Management Error Codes.

Example

import { BusinessError } from '@ohos.base';
import Want from '@ohos.app.ability.Want';
async getFileAccessAbilityInfo() {
  try {
    fileAccess.getFileAccessAbilityInfo((err: BusinessError, wantInfos: Array<Want>) => {
      if (err) {
        console.error("Failed to getFileAccessAbilityInfo in async, errCode:" + err.code + ", errMessage:" + err.message);
        return;
      }
      console.log("getFileAccessAbilityInfo data " + JSON.stringify(wantInfos));
    });
  } catch (err) {
    let error: BusinessError = err as BusinessError;
    console.error("getFileAccessAbilityInfo failed, errCode:" + error.code + ", errMessage:" + error.message);
  }
}

fileAccess.createFileAccessHelper

createFileAccessHelper(context: Context, wants: Array<Want>) : FileAccessHelper

Creates a Helper object to bind with the specified Wants. This API returns the result synchronously. The Helper object provides file access and management capabilities.

Model restriction: This API can be used only in the stage model.

System capability: SystemCapability.FileManagement.UserFileService

Required permissions: ohos.permission.FILE_ACCESS_MANAGER and ohos.permission.GET_BUNDLE_INFO_PRIVILEGED

Parameters

Return value

Error codes

For details about the error codes, see File Management Error Codes.

Example

import { BusinessError } from '@ohos.base';
import Want from '@ohos.app.ability.Want';
import common from '@ohos.app.ability.common';
let context = getContext(this) as common.UIAbilityContext;
function createFileAccessHelper01() {
  let fileAccessHelper: fileAccess.FileAccessHelper;
  // Obtain wantInfos by using getFileAccessAbilityInfo().
  let wantInfos: Array<Want> = [
    {
      bundleName: "com.ohos.UserFile.ExternalFileManager",
      abilityName: "FileExtensionAbility",
    },
  ]
  try {
    // context is passed by EntryAbility.
    fileAccessHelper = fileAccess.createFileAccessHelper(context, wantInfos);
    if (!fileAccessHelper) {
      console.error("createFileAccessHelper interface returns an undefined object");
    }
  } catch (err) {
    let error: BusinessError = err as BusinessError;
    console.error("createFileAccessHelper failed, errCode:" + error.code + ", errMessage:" + error.message);
  }
}

fileAccess.createFileAccessHelper

createFileAccessHelper(context: Context) : FileAccessHelper

Creates a Helper object to bind with all file management services in the system. This API returns the result synchronously.

Model restriction: This API can be used only in the stage model.

System capability: SystemCapability.FileManagement.UserFileService

Required permissions: ohos.permission.FILE_ACCESS_MANAGER and ohos.permission.GET_BUNDLE_INFO_PRIVILEGED

Parameters

Return value

Error codes

For details about the error codes, see File Management Error Codes.

Example

import { BusinessError } from '@ohos.base';
import common from '@ohos.app.ability.common';
let context = getContext(this) as common.UIAbilityContext;
function createFileAccessHelper02() {
  let fileAccessHelperAllServer: fileAccess.FileAccessHelper;
  // Create a Helper object to interact with all file management services configured with fileAccess in the system.
  try {
    // context is passed by EntryAbility.
    fileAccessHelperAllServer = fileAccess.createFileAccessHelper(context);
    if (!fileAccessHelperAllServer)
      console.error("createFileAccessHelper interface returns an undefined object");
  } catch (err) {
    let error: BusinessError = err as BusinessError;
    console.error("createFileAccessHelper failed, errCode:" + error.code + ", errMessage:" + error.message);
  }
}

FileInfo

Provides APIs for managing file or folder attribute information.

Model restriction: This API can be used only in the stage model.

System capability: SystemCapability.FileManagement.UserFileService

Required permissions: ohos.permission.FILE_ACCESS_MANAGER

Attributes

listFile

listFile(filter?: Filter) : FileIterator

Obtains a FileIterator object that lists the next-level files (folders) matching the specified conditions of this directory. This API returns the result synchronously. FileInfo is returned by next(). Currently, only built-in storage devices support the file filter.

Model restriction: This API can be used only in the stage model.

System capability: SystemCapability.FileManagement.UserFileService

Required permissions: ohos.permission.FILE_ACCESS_MANAGER

Parameters

Return value

Error codes

For details about the error codes, see File Management Error Codes.

Example

import { BusinessError } from '@ohos.base';
// fileInfoDir indicates information about a directory.
// let filter = { suffix : [".txt", ".jpg", ".xlsx"] };
let fileInfoDir: fileAccess.FileInfo; // = fileInfos[0];
let subfileInfos: Array<fileAccess.FileInfo> = [];
let isDone: boolean = false;
try {
  let fileIterator = fileInfoDir.listFile();
  // listFile() with the filter implementation.
  // let fileIterator = fileInfoDir.listFile(filter);
  if (!fileIterator) {
    console.error("listFile interface returns an undefined object");
  }
  while (!isDone) {
    let result = fileIterator.next();
    console.log("next result = " + JSON.stringify(result));
    isDone = result.done;
    if (!isDone) {
      subfileInfos.push(result.value);
    }
  }
} catch (err) {
  let error: BusinessError = err as BusinessError;
  console.error("listFile failed, errCode:" + error.code + ", errMessage:" + error.message);
}

scanFile

scanFile(filter?: Filter) : FileIterator;

Obtains a FileIterator object that recursively retrieves the files matching the specified conditions of this directory. This API returns the result synchronously. FileInfo is returned by next(). Currently, this API supports only built-in storage devices.

Model restriction: This API can be used only in the stage model.

System capability: SystemCapability.FileManagement.UserFileService

Required permissions: ohos.permission.FILE_ACCESS_MANAGER

Parameters

Return value

Error codes

For details about the error codes, see File Management Error Codes.

Example

import { BusinessError } from '@ohos.base';
// fileInfoDir indicates information about a directory.
// let filter = {suffix : [".txt", ".jpg", ".xlsx"]};
let fileInfoDir: fileAccess.FileInfo; // = fileInfos[0];
let subfileInfos: Array<fileAccess.FileInfo> = [];
let isDone: boolean = false;
try {
  let fileIterator = fileInfoDir.scanFile();
  // scanFile() with the filter implementation.
  // let fileIterator = fileInfoDir.scanFile(filter);
  if (!fileIterator) {
    console.error("scanFile interface returns an undefined object");
  }
  while (!isDone) {
    let result = fileIterator.next();
    console.log("next result = " + JSON.stringify(result));
    isDone = result.done;
    if (!isDone) {
      subfileInfos.push(result.value);
    }
  }
} catch (err) {
  let error: BusinessError = err as BusinessError;
  console.error("scanFile failed, errCode:" + error.code + ", errMessage:" + error.message);
}

FileIterator

Provides the FileIterator object.

Model restriction: This API can be used only in the stage model.

System capability: SystemCapability.FileManagement.UserFileService

Required permissions: ohos.permission.FILE_ACCESS_MANAGER

next

next() : { value: FileInfo, done: boolean }

Obtains information about the next-level files or folders.

Model restriction: This API can be used only in the stage model.

System capability: SystemCapability.FileManagement.UserFileService

Required permissions: ohos.permission.FILE_ACCESS_MANAGER

Return value

Error codes

For details about the error codes, see File Management Error Codes.

RootInfo

Provides APIs for managing the device's root attribute information.

Model restriction: This API can be used only in the stage model.

System capability: SystemCapability.FileManagement.UserFileService

Required permissions: ohos.permission.FILE_ACCESS_MANAGER

Attributes

listFile

listFile(filter?: Filter) : FileIterator

Obtains a FileIterator object that lists the first-level files (directories) matching the specified conditions from the device root directory. This API returns the result synchronously. FileInfo is return by next(). Currently, only built-in storage devices support the file filter.

Model restriction: This API can be used only in the stage model.

System capability: SystemCapability.FileManagement.UserFileService

Required permissions: ohos.permission.FILE_ACCESS_MANAGER

Parameters

Return value

Error codes

For details about the error codes, see File Management Error Codes.

Example

import { BusinessError } from '@ohos.base';
// Obtain rootInfos by using getRoots().
// let filter = {suffix : [".txt", ".jpg", ".xlsx"]};
let rootInfo: fileAccess.RootInfo; // = rootinfos[0];
let fileInfos: Array<fileAccess.FileInfo> = [];
let isDone: boolean = false;
try {
  let fileIterator = rootInfo.listFile();
  // listFile() with the filter implementation.
  // let fileIterator = rootInfo.listFile(filter);
  if (!fileIterator) {
    console.error("listFile interface returns an undefined object");
  }
  while (!isDone) {
    let result = fileIterator.next();
    console.log("next result = " + JSON.stringify(result));
    isDone = result.done;
    if (!isDone) {
      fileInfos.push(result.value);
    }
  }
} catch (err) {
  let error: BusinessError = err as BusinessError;
  console.error("listFile failed, errCode:" + error.code + ", errMessage:" + error.message);
}

scanFile

scanFile(filter?: Filter) : FileIterator

Obtains a FileIterator object that recursively retrieves the files matching the specified conditions from the device root directory. This API returns the result synchronously. FileInfo is returned by next(). Currently, this API supports only built-in storage devices.

Model restriction: This API can be used only in the stage model.

System capability: SystemCapability.FileManagement.UserFileService

Required permissions: ohos.permission.FILE_ACCESS_MANAGER

Parameters

Return value

Error codes

For details about the error codes, see File Management Error Codes.

Example

import { BusinessError } from '@ohos.base';
// Obtain rootInfos by using getRoots().
// let filter = {suffix : [".txt", ".jpg", ".xlsx"]};
let rootInfo: fileAccess.RootInfo; // = rootinfos[0];
let fileInfos: Array<fileAccess.FileInfo> = [];
let isDone: boolean = false;
try {
  let fileIterator = rootInfo.scanFile();
  // scanFile with the filter implementation.
  // let fileIterator = rootInfo.scanFile(filter);
  if (!fileIterator) {
    console.error("scanFile interface returns undefined object");
  }
  while (!isDone) {
    let result = fileIterator.next();
    console.log("next result = " + JSON.stringify(result));
    isDone = result.done;
    if (!isDone) {
      fileInfos.push(result.value);
    }
  }
} catch (err) {
  let error: BusinessError = err as BusinessError;
  console.error("scanFile failed, errCode:" + error.code + ", errMessage:" + error.message);
}

RootIterator

Provides an iterator object of the device root directory.

Model restriction: This API can be used only in the stage model.

System capability: SystemCapability.FileManagement.UserFileService

Required permissions: ohos.permission.FILE_ACCESS_MANAGER

next

next() : { value: RootInfo, done: boolean }

Obtains the next-level root directory.

Model restriction: This API can be used only in the stage model.

System capability: SystemCapability.FileManagement.UserFileService

Required permissions: ohos.permission.FILE_ACCESS_MANAGER

Return value

Error codes

For details about the error codes, see File Management Error Codes.

FileAccessHelper

Provides a FileAccessHelper object.

System capability: SystemCapability.FileManagement.UserFileService

Required permissions: ohos.permission.FILE_ACCESS_MANAGER

getRoots

getRoots() : Promise<RootIterator>

Obtains information about the device root nodes of the file management services associated with the Helper object. This API uses a promise to return a RootIterator object. You can use next to return RootInfo.

System capability: SystemCapability.FileManagement.UserFileService

Required permissions: ohos.permission.FILE_ACCESS_MANAGER

Return value

Error codes

For details about the error codes, see File Management Error Codes.

Example

import { BusinessError } from '@ohos.base';
async function getRoots() {
  let rootIterator: fileAccess.RootIterator;
  let rootinfos: Array<fileAccess.RootInfo> = [];
  let isDone: boolean = false;
  try {
    // Obtain fileAccessHelper by referring to the sample code of fileAccess.createFileAccessHelper.
    rootIterator = await fileAccessHelper.getRoots();
    if (!rootIterator) {
      console.error("getRoots interface returns an undefined object");
    }
    while (!isDone) {
      let result = rootIterator.next();
      console.log("next result = " + JSON.stringify(result));
      isDone = result.done;
      if (!isDone) {
        rootinfos.push(result.value);
      }
    }
  } catch (err) {
    let error: BusinessError = err as BusinessError;
    console.error("getRoots failed, errCode:" + error.code + ", errMessage:" + error.message);
  }
}

getRoots

getRoots(callback:AsyncCallback<RootIterator>) : void

Obtains information about the device root nodes of the file management services associated with the Helper object. This API uses an asynchronous callback to return a RootIterator object. You can use next to return RootInfo.

System capability: SystemCapability.FileManagement.UserFileService

Required permissions: ohos.permission.FILE_ACCESS_MANAGER

Parameters

Error codes

For details about the error codes, see File Management Error Codes.

Example

import { BusinessError } from '@ohos.base';
async function getRoots() {
  let rootinfos: Array<fileAccess.RootInfo> = [];
  let isDone: boolean = false;
  try {
    // Obtain fileAccessHelper by referring to the sample code of fileAccess.createFileAccessHelper.
    fileAccessHelper.getRoots((err: BusinessError, rootIterator: fileAccess.RootIterator) => {
      if (err) {
        console.error("Failed to getRoots in async, errCode:" + err.code + ", errMessage:" + err.message);
      }
      while (!isDone) {
        let result = rootIterator.next();
        console.log("next result = " + JSON.stringify(result));
        isDone = result.done;
        if (!isDone) {
          rootinfos.push(result.value);
        }
      }
    });
  } catch (err) {
    let error: BusinessError = err as BusinessError;
    console.error("getRoots failed, errCode:" + error.code + ", errMessage:" + error.message);
  }
}

createFile

createFile(uri: string, displayName: string) : Promise<string>

Creates a file in a directory. This API uses a promise to return the result.

System capability: SystemCapability.FileManagement.UserFileService

Required permissions: ohos.permission.FILE_ACCESS_MANAGER

Parameters

Return value

Error codes

For details about the error codes, see File Management Error Codes.

Example

import { BusinessError } from '@ohos.base';
// A built-in storage directory is used as an example.
// In the sample code, sourceUri indicates the Download directory. The URI is the URI in fileInfo.
// You can use the URI obtained.
let sourceUri: string = "file://docs/storage/Users/currentUser/Download";
let displayName: string = "file1";
let fileUri: string;
try {
  // Obtain fileAccessHelper by referring to the sample code of fileAccess.createFileAccessHelper.
  fileUri = await fileAccessHelper.createFile(sourceUri, displayName);
  if (!fileUri) {
    console.error("createFile return undefined object");
  }
  console.log("createFile sucess, fileUri: " + JSON.stringify(fileUri));
} catch (err) {
  let error: BusinessError = err as BusinessError;
  console.error("createFile failed, errCode:" + error.code + ", errMessage:" + error.message);
}

createFile

createFile(uri: string, displayName: string, callback: AsyncCallback<string>) : void

Creates a file in a directory. This API uses an asynchronous callback to return the result.

System capability: SystemCapability.FileManagement.UserFileService

Required permissions: ohos.permission.FILE_ACCESS_MANAGER

Parameters

Error codes

For details about the error codes, see File Management Error Codes.

Example

import { BusinessError } from '@ohos.base';
// A built-in storage directory is used as an example.
// In the sample code, sourceUri indicates the Download directory. The URI is the URI in fileInfo.
// You can use the URI obtained.
let sourceUri: string = "file://docs/storage/Users/currentUser/Download";
let displayName: string = "file1";
try {
  // Obtain fileAccessHelper by referring to the sample code of fileAccess.createFileAccessHelper.
  fileAccessHelper.createFile(sourceUri, displayName, (err: BusinessError, fileUri: string) => {
    if (err) {
      console.error("Failed to createFile in async, errCode:" + err.code + ", errMessage:" + err.message);
      return;
    }
    console.log("createFile sucess, fileUri: " + JSON.stringify(fileUri));
  });
} catch (err) {
  let error: BusinessError = err as BusinessError;
  console.error("createFile failed, errCode:" + error.code + ", errMessage:" + error.message);
}

mkDir

mkDir(parentUri: string, displayName: string) : Promise<string>

Creates a folder in a directory. This API uses a promise to return the result.

System capability: SystemCapability.FileManagement.UserFileService

Required permissions: ohos.permission.FILE_ACCESS_MANAGER

Parameters

Return value

Error codes

For details about the error codes, see File Management Error Codes.

Example

import { BusinessError } from '@ohos.base';
// A built-in storage directory is used as an example.
// In the sample code, sourceUri indicates the Download directory. The URI is the URI in fileInfo.
// You can use the URI obtained.
let sourceUri: string = "file://docs/storage/Users/currentUser/Download";
let dirName: string = "dirTest";
let dirUri: string;
try {
  // Obtain fileAccessHelper by referring to the sample code of fileAccess.createFileAccessHelper.
  dirUri = await fileAccessHelper.mkDir(sourceUri, dirName);
  if (!dirUri) {
    console.error("mkDir return undefined object");
  }
  console.log("mkDir sucess, dirUri: " + JSON.stringify(dirUri));
} catch (err) {
  let error: BusinessError = err as BusinessError;
  console.error("mkDir failed, errCode:" + error.code + ", errMessage:" + error.message);
}

mkDir

mkDir(parentUri: string, displayName: string, callback: AsyncCallback<string>) : void

Creates a folder. This API uses an asynchronous callback to return the result.

System capability: SystemCapability.FileManagement.UserFileService

Required permissions: ohos.permission.FILE_ACCESS_MANAGER

Parameters

Error codes

For details about the error codes, see File Management Error Codes.

Example

import { BusinessError } from '@ohos.base';
// A built-in storage directory is used as an example.
// In the sample code, sourceUri indicates the Download directory. The URI is the URI in fileInfo.
// You can use the URI obtained.
let sourceUri: string = "file://docs/storage/Users/currentUser/Download";
let dirName: string = "dirTest";
try {
  // Obtain fileAccessHelper by referring to the sample code of fileAccess.createFileAccessHelper.
  fileAccessHelper.mkDir(sourceUri, dirName, (err: BusinessError, dirUri: string) => {
    if (err) {
      console.error("Failed to mkDir in async, errCode:" + err.code + ", errMessage:" + err.message);
      return;
    }
    console.log("mkDir sucess, dirUri: " + JSON.stringify(dirUri));
  });
} catch (err) {
  let error: BusinessError = err as BusinessError;
  console.error("mkDir failed, errCode:" + error.code + ", errMessage:" + error.message);
}

openFile

openFile(uri: string, flags: OPENFLAGS) : Promise<number>

Opens a file. This API uses a promise to return the result.

System capability: SystemCapability.FileManagement.UserFileService

Required permissions: ohos.permission.FILE_ACCESS_MANAGER

Parameters

Return value

Error codes

For details about the error codes, see File Management Error Codes.

Example

import { BusinessError } from '@ohos.base';
async function openFile01() {
  // A built-in storage directory is used as an example.
  // In the sample code, targetUri indicates a file in the Download directory. The URI is the URI in fileInfo.
  // You can use the URI obtained.
  let targetUri: string = "file://docs/storage/Users/currentUser/Download/1.txt";
  try {
    // Obtain fileAccessHelper by referring to the sample code of fileAccess.createFileAccessHelper.
    let fd = await fileAccessHelper.openFile(targetUri, fileAccess.OPENFLAGS.READ);
  } catch (err) {
    let error: BusinessError = err as BusinessError;
    console.error("openFile failed, errCode:" + error.code + ", errMessage:" + error.message);
  }
}

openFile

openFile(uri: string, flags: OPENFLAGS, callback: AsyncCallback<number>) : void

Opens a file. This API uses an asynchronous callback to return the result.

System capability: SystemCapability.FileManagement.UserFileService

Required permissions: ohos.permission.FILE_ACCESS_MANAGER

Parameters

Error codes

For details about the error codes, see File Management Error Codes.

Example

import { BusinessError } from '@ohos.base';
// A built-in storage directory is used as an example.
// In the sample code, targetUri indicates a file in the Download directory. The URI is the URI in fileInfo.
// You can use the URI obtained.
let targetUri: string = "file://docs/storage/Users/currentUser/Download/1.txt";
try {
  // Obtain fileAccessHelper by referring to the sample code of fileAccess.createFileAccessHelper.
  fileAccessHelper.openFile(targetUri, fileAccess.OPENFLAGS.READ, (err: BusinessError, fd: number) => {
    if (err) {
      console.error("Failed to openFile in async, errCode:" + err.code + ", errMessage:" + err.message);
    }
    console.log("openFile sucess, fd: " + fd);
  });
} catch (err) {
  let error: BusinessError = err as BusinessError;
  console.error("openFile failed, errCode:" + error.code + ", errMessage:" + error.message);
}

delete

delete(uri: string) : Promise<number>

Deletes a file or folder. This API uses a promise to return the result.

System capability: SystemCapability.FileManagement.UserFileService

Required permissions: ohos.permission.FILE_ACCESS_MANAGER

Parameters

Return value

Error codes

For details about the error codes, see File Management Error Codes.

Example

import { BusinessError } from '@ohos.base';
async function deleteFile01() {
  // A built-in storage directory is used as an example.
  // In the sample code, targetUri indicates a file in the Download directory. The URI is the URI in fileInfo.
  // You can use the URI obtained.
  let targetUri: string = "file://docs/storage/Users/currentUser/Download/1.txt";
  try {
    // Obtain fileAccessHelper by referring to the sample code of fileAccess.createFileAccessHelper.
    let code = await fileAccessHelper.delete(targetUri);
    if (code != 0)
      console.error("delete failed, code " + code);
  } catch (err) {
    let error: BusinessError = err as BusinessError;
    console.error("delete failed, errCode:" + error.code + ", errMessage:" + error.message);
  }
}

delete

delete(uri: string, callback: AsyncCallback<number>) : void

Deletes a file or folder. This API uses an asynchronous callback to return the result.

System capability: SystemCapability.FileManagement.UserFileService

Required permissions: ohos.permission.FILE_ACCESS_MANAGER

Parameters

Error codes

For details about the error codes, see File Management Error Codes.

Example

import { BusinessError } from '@ohos.base';
// A built-in storage directory is used as an example.
// In the sample code, targetUri indicates a file in the Download directory. The URI is the URI in fileInfo.
// You can use the URI obtained.
let targetUri: string = "file://docs/storage/Users/currentUser/Download/1.txt";
try {
  // Obtain fileAccessHelper by referring to the sample code of fileAccess.createFileAccessHelper.
  fileAccessHelper.delete(targetUri, (err: BusinessError, code: number) => {
    if (err) {
      console.error("Failed to delete in async, errCode:" + err.code + ", errMessage:" + err.message);
      return;
    }
    console.log("delete sucess, code: " + code);
  });
} catch (err) {
  let error: BusinessError = err as BusinessError;
  console.error("delete failed, errCode:" + error.code + ", errMessage:" + error.message);
}

move

move(sourceFile: string, destFile: string) : Promise<string>

Moves a file or folder. This API uses a promise to return the result. Currently, this API does not support move of files or folders across devices.

System capability: SystemCapability.FileManagement.UserFileService

Required permissions: ohos.permission.FILE_ACCESS_MANAGER

Parameters

Return value

Error codes

For details about the error codes, see File Management Error Codes.

Example

import { BusinessError } from '@ohos.base';
async function moveFile01() {
  // A built-in storage directory is used as an example.
  // In the sample code, sourceFile and destFile indicate the files and directories in the Download directory. The URI is the URI in fileInfo.
  // You can use the URI obtained.
  let sourceFile: string = "file://docs/storage/Users/currentUser/Download/1.txt";
  let destFile: string = "file://docs/storage/Users/currentUser/Download/test";
  try {
    // Obtain fileAccessHelper by referring to the sample code of fileAccess.createFileAccessHelper.
    let fileUri = await fileAccessHelper.move(sourceFile, destFile);
    console.log("move sucess, fileUri: " + JSON.stringify(fileUri));
  } catch (err) {
    let error: BusinessError = err as BusinessError;
    console.error("move failed, errCode:" + error.code + ", errMessage:" + error.message);
  }
}

move

move(sourceFile: string, destFile: string, callback: AsyncCallback<string>) : void

Moves a file or folder. This API uses an asynchronous callback to return the result. Currently, this API does not support move of files or folders across devices.

System capability: SystemCapability.FileManagement.UserFileService

Required permissions: ohos.permission.FILE_ACCESS_MANAGER

Parameters

Error codes

For details about the error codes, see File Management Error Codes.

Example

import { BusinessError } from '@ohos.base';
// A built-in storage directory is used as an example.
// In the sample code, sourceFile and destFile indicate the files and directories in the Download directory. The URI is the URI in fileInfo.
// You can use the URI obtained.
let sourceFile: string = "file://docs/storage/Users/currentUser/Download/1.txt";
let destFile: string = "file://docs/storage/Users/currentUser/Download/test";
try {
  // Obtain fileAccessHelper by referring to the sample code of fileAccess.createFileAccessHelper.
  fileAccessHelper.move(sourceFile, destFile, (err: BusinessError, fileUri: string) => {
    if (err) {
      console.error("Failed to move in async, errCode:" + err.code + ", errMessage:" + err.message);
      return;
    }
    console.log("move sucess, fileUri: " + JSON.stringify(fileUri));
  });
} catch (err) {
  let error: BusinessError = err as BusinessError;
  console.error("move failed, errCode:" + error.code + ", errMessage:" + error.message);
}

rename

rename(uri: string, displayName: string) : Promise<string>

Renames a file or folder. This API uses a promise to return the result.

System capability: SystemCapability.FileManagement.UserFileService

Required permissions: ohos.permission.FILE_ACCESS_MANAGER

Parameters

Return value

Error codes

For details about the error codes, see File Management Error Codes.

Example

import { BusinessError } from '@ohos.base';
async function renameFile01() {
  // A built-in storage directory is used as an example.
  // In the sample code, sourceDir indicates a file in the Download directory. The URI is the URI in fileInfo.
  // You can use the URI obtained.
  let sourceDir: string = "file://docs/storage/Users/currentUser/Download/1.txt";
  try {
    // Obtain fileAccessHelper by referring to the sample code of fileAccess.createFileAccessHelper.
    let DestDir = await fileAccessHelper.rename(sourceDir, "testDir");
    console.log("rename sucess, DestDir: " + JSON.stringify(DestDir));
  } catch (err) {
    let error: BusinessError = err as BusinessError;
    console.error("rename failed, errCode:" + error.code + ", errMessage:" + error.message);
  }
}

rename

rename(uri: string, displayName: string, callback: AsyncCallback<string>) : void

Renames a file or folder. This API uses an asynchronous callback to return the result.

System capability: SystemCapability.FileManagement.UserFileService

Required permissions: ohos.permission.FILE_ACCESS_MANAGER

Parameters

Error codes

For details about the error codes, see File Management Error Codes.

Example

import { BusinessError } from '@ohos.base';
// A built-in storage directory is used as an example.
// In the sample code, sourceDir indicates a file in the Download directory. The URI is the URI in fileInfo.
// You can use the URI obtained.
let sourceDir: string = "file://docs/storage/Users/currentUser/Download/1.txt";
try {
  // Obtain fileAccessHelper by referring to the sample code of fileAccess.createFileAccessHelper.
  fileAccessHelper.rename(sourceDir, "testDir", (err: BusinessError, DestDir: string) => {
    if (err) {
      console.error("Failed to rename in async, errCode:" + err.code + ", errMessage:" + err.message);
    }
    console.log("rename sucess, DestDir: " + JSON.stringify(DestDir));
  });
} catch (err) {
  let error: BusinessError = err as BusinessError;
  console.error("rename failed, errCode:" + error.code + ", errMessage:" + error.message);
}

access

access(sourceFileUri: string) : Promise<boolean>

Checks whether a file or folder exists. This API uses a promise to return the result.

System capability: SystemCapability.FileManagement.UserFileService

Required permissions: ohos.permission.FILE_ACCESS_MANAGER

Parameters

Return value

Error codes

For details about the error codes, see File Management Error Codes.

Example

import { BusinessError } from '@ohos.base';
// A built-in storage directory is used as an example.
// In the sample code, sourceDir indicates a file in the Download directory. The URI is the URI in fileInfo.
// You can use the URI obtained.
async function accessFunc() {
  let sourceDir: string = "file://docs/storage/Users/currentUser/Download/1.txt";
  try {
    // Obtain fileAccessHelper by referring to the sample code of fileAccess.createFileAccessHelper.
    let existJudgment = await fileAccessHelper.access(sourceDir);
    if (existJudgment) {
      console.log("sourceDir exists");
    } else {
      console.log("sourceDir does not exist");
    }
  } catch (err) {
    let error: BusinessError = err as BusinessError;
    console.error("access failed, errCode:" + error.code + ", errMessage:" + error.message);
  }
}

access

access(sourceFileUri: string, callback: AsyncCallback<boolean>) : void

Checks whether a file or folder exists. This API uses an asynchronous callback to return the result.

System capability: SystemCapability.FileManagement.UserFileService

Required permissions: ohos.permission.FILE_ACCESS_MANAGER

Parameters

Error codes

For details about the error codes, see File Management Error Codes.

Example

import { BusinessError } from '@ohos.base';
// A built-in storage directory is used as an example.
// In the sample code, sourceDir indicates a folder in the Download directory. The URI is the URI in fileInfo.
// You can use the URI obtained.
let sourceDir: string = "file://docs/storage/Users/currentUser/Download/test";
try {
  // Obtain fileAccessHelper by referring to the sample code of fileAccess.createFileAccessHelper.
  fileAccessHelper.access(sourceDir, (err: BusinessError, existJudgment: boolean) => {
    if (err) {
      console.error("Failed to access in async, errCode:" + err.code + ", errMessage:" + err.message);
      return;
    }
    if (existJudgment)
      console.log("sourceDir exists");
    else
      console.log("sourceDir does not exist");
  });
} catch (err) {
  let error: BusinessError = err as BusinessError;
  console.error("access failed, errCode:" + error.code + ", errMessage:" + error.message);
}

getFileInfoFromUri¹⁰⁺

getFileInfoFromUri(uri: string) : Promise<FileInfo>

Obtains a FileInfo object based on a URI. This API uses a promise to return the result.

System capability: SystemCapability.FileManagement.UserFileService

Required permissions: ohos.permission.FILE_ACCESS_MANAGER

Parameters

Return value

Example

import { BusinessError } from '@ohos.base';
// A built-in storage directory is used as an example.
// In the sample code, sourceUri indicates the Download directory. The URI is the URI in fileInfo.
// You can use the URI obtained.
async function getUri() {
  let sourceUri: string = "file://docs/storage/Users/currentUser/Download";
  try {
    // Obtain fileAccessHelper by referring to the sample code of fileAccess.createFileAccessHelper.
    let fileInfo = await fileAccessHelper.getFileInfoFromUri(sourceUri);
  } catch (err) {
    let error: BusinessError = err as BusinessError;
    console.error("getFileInfoFromUri failed, errCode:" + error.code + ", errMessage:" + error.message);
  }
}

getFileInfoFromUri¹⁰⁺

getFileInfoFromUri(uri: string, callback: AsyncCallback<FileInfo>) : void

Obtains a FileInfo object based on a URI. This API uses an asynchronous callback to return the result.

System capability: SystemCapability.FileManagement.UserFileService

Required permissions: ohos.permission.FILE_ACCESS_MANAGER

Parameters

Example

import { BusinessError } from '@ohos.base';
// A built-in storage directory is used as an example.
// In the sample code, sourceUri indicates the Download directory. The URI is the URI in fileInfo.
// You can use the URI obtained.
let sourceUri: string = "file://docs/storage/Users/currentUser/Download";
try {
  // Obtain fileAccessHelper by referring to the sample code of fileAccess.createFileAccessHelper.
  fileAccessHelper.getFileInfoFromUri(sourceUri, (err: BusinessError, fileInfo: fileAccess.FileInfo) => {
    if (err) {
      console.error("Failed to getFileInfoFromUri in async, errCode:" + err.code + ", errMessage:" + err.message);
      return;
    }
    console.log("getFileInfoFromUri success, fileInfo: " + JSON.stringify(fileInfo));
  });
} catch (err) {
  let error: BusinessError = err as BusinessError;
  console.error("getFileInfoFromUri failed, errCode:" + error.code + ", errMessage:" + error.message);
}

getFileInfoFromRelativePath¹⁰⁺

getFileInfoFromRelativePath(relativePath: string) : Promise<FileInfo>

Obtains a FileInfo object based on a relative path. This API uses a promise to return the result.

System capability: SystemCapability.FileManagement.UserFileService

Required permissions: ohos.permission.FILE_ACCESS_MANAGER

Parameters

Return value

Example

import { BusinessError } from '@ohos.base';
// In the sample code, relativePath indicates the Download directory, which is the relativePath in fileInfo.
// You can use the relativePath obtained.
async function getRelativePath() {
  let relativePath: string = "Download/";
  try {
    // Obtain fileAccessHelper by referring to the sample code of fileAccess.createFileAccessHelper.
    let fileInfo = await fileAccessHelper.getFileInfoFromRelativePath(relativePath);
  } catch (err) {
    let error: BusinessError = err as BusinessError;
    console.error("getFileInfoFromRelativePath failed, errCode:" + error.code + ", errMessage:" + error.message);
  }
}

getFileInfoFromRelativePath¹⁰⁺

getFileInfoFromRelativePath(relativePath: string, callback: AsyncCallback<FileInfo>) : void

Obtains a FileInfo object based on a relative path. This API uses an asynchronous callback to return the result.

System capability: SystemCapability.FileManagement.UserFileService

Required permissions: ohos.permission.FILE_ACCESS_MANAGER

Parameters

Example

import { BusinessError } from '@ohos.base';
// In the sample code, relativePath indicates the Download directory, which is the relativePath in fileInfo.
// You can use the relativePath obtained.
let relativePath: string = "Download/";
try {
  // Obtain fileAccessHelper by referring to the sample code of fileAccess.createFileAccessHelper.
  fileAccessHelper.getFileInfoFromRelativePath(relativePath, (err: BusinessError, fileInfo: fileAccess.FileInfo) => {
    if (err) {
      console.error("Failed to getFileInfoFromRelativePath in async, errCode:" + err.code + ", errMessage:" + err.message);
      return;
    }
    console.log("getFileInfoFromRelativePath success, fileInfo: " + JSON.stringify(fileInfo));
  });
} catch (err) {
  let error: BusinessError = err as BusinessError;
  console.error("getFileInfoFromRelativePath failed, errCode:" + error.code + ", errMessage:" + error.message);
}

query¹⁰⁺

query(uri:string, metaJson: string) : Promise<string>

Queries the attribute information about a file or folder based on a URI. This API uses a promise to return the result.

System capability: SystemCapability.FileManagement.UserFileService

Required permissions: ohos.permission.FILE_ACCESS_MANAGER

Parameters

Return value

Example

import { BusinessError } from '@ohos.base';
async function getQuery01() {
  let imageFileRelativePath: string = "/storage/Users/currentUser/Download/queryTest/image/01.jpg";
  let jsonStrSingleRelativepath: string = JSON.stringify({ [fileAccess.FileKey.RELATIVE_PATH]: "" });
  try {
    // Obtain fileAccessHelper by referring to the sample code of fileAccess.createFileAccessHelper.
    let fileInfo = await fileAccessHelper.getFileInfoFromRelativePath(imageFileRelativePath);
    let queryResult = await fileAccessHelper.query(fileInfo.uri, jsonStrSingleRelativepath);
    console.log("query_file_single faf query, queryResult.relative_path: " + JSON.parse(queryResult).relative_path);
  } catch (err) {
    let error: BusinessError = err as BusinessError;
    console.error("query_file_single faf query failed, error.code :" + error.code + ", errorMessage :" + error.message);
  }
}

query¹⁰⁺

query(uri:string, metaJson: string, callback: AsyncCallback<string>) : void

Queries the attribute information about a file or folder based on a URI. This API uses an asynchronous callback to return the result.

System capability: SystemCapability.FileManagement.UserFileService

Required permissions: ohos.permission.FILE_ACCESS_MANAGER

Parameters

Example

import { BusinessError } from '@ohos.base';
async function getQuery02() {
  let imageFileRelativePath: string = "/storage/Users/currentUser/Download/queryTest/image/01.jpg";
  let jsonStrSingleRelativepath: string = JSON.stringify({ [fileAccess.FileKey.RELATIVE_PATH]: "" });
  try {
    // Obtain fileAccessHelper by referring to the sample code of fileAccess.createFileAccessHelper.
    let fileInfo = await fileAccessHelper.getFileInfoFromRelativePath(imageFileRelativePath);
    fileAccessHelper.query(fileInfo.uri, jsonStrSingleRelativepath, (err: BusinessError, queryResult: string) => {
      if (err) {
        console.log("query_file_single faf query Failed, errCode:" + err.code + ", errMessage:" + err.message);
        return;
      }
      console.log("query_file_single faf query, queryResult.relative_path: " + JSON.parse(queryResult).relative_path);
    })
  } catch (err) {
    let error: BusinessError = err as BusinessError;
    console.error("query_file_single faf query failed, error.code :" + error.code + ", errorMessage :" + error.message);
  }
}

copy¹⁰⁺

copy(sourceUri: string, destUri: string, force?: boolean) : Promise<Array<CopyResult>>

Copies a file or folder. This API uses a promise to return the result.

System capability: SystemCapability.FileManagement.UserFileService

Required permissions: ohos.permission.FILE_ACCESS_MANAGER

Parameters

Return value

Example 1: Copy a file with force unspecified.

import { BusinessError } from '@ohos.base';
// A built-in storage directory is used as an example.
// In the sample code, sourceFile indicates the file (directory) in the Download directory to copy, destFile indicates the destination directory in the Download directory, and uri is to URI in fileInfo.
// You can use the URI obtained.
async function copyFunc01() {
  let sourceFile: string = "file://docs/storage/Users/currentUser/Download/1.txt";
  let destFile: string = "file://docs/storage/Users/currentUser/Download/test";
  try {
    // Obtain fileAccessHelper by referring to the sample code of fileAccess.createFileAccessHelper.
    let copyResult = await fileAccessHelper.copy(sourceFile, destFile);
    if (copyResult.length === 0) {
      console.log("copy success");
    } else {
      for (let i = 0; i < copyResult.length; i++) {
        console.error("errCode" + copyResult[i].errCode);
        console.error("errMsg" + copyResult[i].errMsg);
        console.error("sourceUri" + copyResult[i].sourceUri);
        console.error("destUri" + copyResult[i].destUri);
      }
    }
  } catch (err) {
    let error: BusinessError = err as BusinessError;
    console.error("copy failed, errCode:" + error.code + ", errMessage:" + error.message);
  }
}

Example 2: Copy a file or folder when force set to true.

import { BusinessError } from '@ohos.base';
// A built-in storage directory is used as an example.
// In the sample code, sourceFile indicates the file (directory) in the Download directory to copy, destFile indicates the destination directory in the Download directory, and uri is to URI in fileInfo.
// You can use the URI obtained.
async function copyFunc02() {
  let sourceFile: string = "file://docs/storage/Users/currentUser/Download/1.txt";
  let destFile: string = "file://docs/storage/Users/currentUser/Download/test";
  try {
    // Obtain fileAccessHelper by referring to the sample code of fileAccess.createFileAccessHelper.
    let copyResult = await fileAccessHelper.copy(sourceFile, destFile, true);
    if (copyResult.length === 0) {
      console.log("copy success");
    } else {
      for (let i = 0; i < copyResult.length; i++) {
        console.error("errCode" + copyResult[i].errCode);
        console.error("errMsg" + copyResult[i].errMsg);
        console.error("sourceUri" + copyResult[i].sourceUri);
        console.error("destUri" + copyResult[i].destUri);
      }
    }
  } catch (err) {
    let error: BusinessError = err as BusinessError;
    console.error("copy failed, errCode:" + error.code + ", errMessage:" + error.message);
  }
}

copy¹⁰⁺

copy(sourceUri: string, destUri: string, callback: AsyncCallback<Array<CopyResult>>) : void

Copies a file or folder. This API uses an asynchronous callback to return the result.

System capability: SystemCapability.FileManagement.UserFileService

Required permissions: ohos.permission.FILE_ACCESS_MANAGER

Parameters

Example

import { BusinessError } from '@ohos.base';
// A built-in storage directory is used as an example.
// In the sample code, sourceFile indicates the file (directory) in the Download directory to copy, destFile indicates the destination directory in the Download directory, and uri is to URI in fileInfo.
// You can use the URI obtained.
let sourceFile: string = "file://docs/storage/Users/currentUser/Download/1.txt";
let destFile: string = "file://docs/storage/Users/currentUser/Download/test";
try {
// Obtain fileAccessHelper by referring to the sample code of fileAccess.createFileAccessHelper.
  fileAccessHelper.copy(sourceFile, destFile, async (err: BusinessError, copyResult: Array<fileAccess.CopyResult>) => {
    if (err) {
      console.error("copy failed, errCode:" + err.code + ", errMessage:" + err.message);
    }
    if (copyResult.length === 0) {
      console.log("copy success");
    } else {
      for (let i = 0; i < copyResult.length; i++) {
        console.error("errCode" + copyResult[i].errCode);
        console.error("errMsg" + copyResult[i].errMsg);
        console.error("sourceUri" + copyResult[i].sourceUri);
        console.error("destUri" + copyResult[i].destUri);
      }
    }
  });
} catch (err) {
  let error: BusinessError = err as BusinessError;
  console.error("copy failed, errCode:" + error.code + ", errMessage:" + error.message);
}

copy¹⁰⁺

copy(sourceUri: string, destUri: string, force: boolean, callback: AsyncCallback<Array<CopyResult>>) : void

Copies a file or folder. This API uses an asynchronous callback to return the result.

System capability: SystemCapability.FileManagement.UserFileService

Required permissions: ohos.permission.FILE_ACCESS_MANAGER

Parameters

Example

import { BusinessError } from '@ohos.base';
// A built-in storage directory is used as an example.
// In the sample code, sourceFile indicates the file (directory) in the Download directory to copy, destFile indicates the destination directory in the Download directory, and uri is to URI in fileInfo.
// You can use the URI obtained.
let sourceFile: string = "file://docs/storage/Users/currentUser/Download/1.txt";
let destFile: string = "file://docs/storage/Users/currentUser/Download/test";
try {
    // Obtain fileAccessHelper by referring to the sample code of fileAccess.createFileAccessHelper.
  fileAccessHelper.copy(sourceFile, destFile, true, async (err: BusinessError, copyResult: Array<fileAccess.CopyResult>) => {
    if (err) {
      console.error("copy failed, errCode:" + err.code + ", errMessage:" + err.message);
    }
    if (copyResult.length === 0) {
      console.log("copy success");
    } else {
      for (let i = 0; i < copyResult.length; i++) {
        console.error("errCode" + copyResult[i].errCode);
        console.error("errMsg" + copyResult[i].errMsg);
        console.error("sourceUri" + copyResult[i].sourceUri);
        console.error("destUri" + copyResult[i].destUri);
      }
    }
  });
} catch (err) {
  let error: BusinessError = err as BusinessError;
  console.error("copy failed, errCode:" + error.code + ", errMessage:" + error.message);
}

registerObserver¹⁰⁺

registerObserver(uri: string, notifyForDescendants: boolean, callback: Callback<NotifyMessage>): void

Registers a callback to listen for a URI. URIs and callbacks can be in many-to-many relationships. You are advised to use one callback to listen for one URI.

System capability: SystemCapability.FileManagement.UserFileService

Required permissions: ohos.permission.FILE_ACCESS_MANAGER

Parameters

Example 1: Register a callback to listen for a URI.

import { BusinessError } from '@ohos.base';
async function registerObserver01() {
  let DirUri: string = 'file://docs/storage/Users/currentUser/Documents';
  try {
    // Obtain fileAccessHelper by referring to the sample code of fileAccess.createFileAccessHelper.
    let dirUri1 = await fileAccessHelper.mkDir(DirUri, 'NOTIFY_DIR1');
    let dirUri2 = await fileAccessHelper.mkDir(DirUri, 'NOTIFY_DIR2');
    // Two notifications are expected to receive because notifyForDescendants is set to true during registration.
    // The URI is 'file://docs/storage/Users/currentUser/Documents/NOTIFY_DIR1/SUB_FILE', and the event type is NOTIFY_MOVED_FROM.
    // The URI is 'file://docs/storage/Users/currentUser/Documents/NOTIFY_DIR1/SUB_FILE', and the event type is NOTIFY_MOVE_SELF.
    const callbackDir1 = (NotifyMessageDir: fileAccess.NotifyMessage) => {
      if (NotifyMessageDir != undefined) {
        console.log('NotifyType: ' + NotifyMessageDir.type + 'NotifyUri:' + NotifyMessageDir.uri[0]);
      } else {
        console.error("NotifyMessageDir is undefined");
      }
    }
    // The notification expected to receive is about the NOTIFY_MOVED_TO event of the URI 'file://docs/storage/Users/currentUser/Documents/NOTIFY_DIR2/SUB_FILE'.
    const callbackDir2 = (NotifyMessageDir: fileAccess.NotifyMessage) => {
      if (NotifyMessageDir != undefined) {
        console.log('NotifyType: ' + NotifyMessageDir.type + 'NotifyUri:' + NotifyMessageDir.uri[0]);
      } else {
        console.error("NotifyMessageDir is undefined");
      }
    }
    // The notification expected to receive is about the NOTIFY_MOVE_SELF event of the URI 'file://docs/storage/Users/currentUser/Documents/NOTIFY_DIR1/SUB_FILE'.
    // The notification expected to receive is about the NOTIFY_MOVED_FROM event of the URI 'file://docs/storage/Users/currentUser/Documents/NOTIFY_DIR1/SUB_FILE'.
    const callbackFile = (NotifyMessageDir: fileAccess.NotifyMessage) => {
      if (NotifyMessageDir != undefined) {
        console.log('NotifyType: ' + NotifyMessageDir.type + 'NotifyUri:' + NotifyMessageDir.uri[0]);
      } else {
        console.error("NotifyMessageDir is undefined");
      }
    }
    let fileUri = await fileAccessHelper.createFile(dirUri1, 'SUB_FILE');
    fileAccessHelper.registerObserver(dirUri1, true, callbackDir1);
    fileAccessHelper.registerObserver(dirUri2, true, callbackDir2);
    // If the moved file itself is not listened for, the NOTIFY_MOVE_SELF event will not be triggered.
    fileAccessHelper.registerObserver(fileUri, true, callbackFile);
    let moveFileUri = await fileAccessHelper.move(fileUri, dirUri2);
    // Do not unregister the callback immediately after the registration is complete, because the unregistration result may be returned before the notification is returned. If this occurs, the notification wll not be received.
    fileAccessHelper.unregisterObserver(dirUri1, callbackDir1);
    fileAccessHelper.unregisterObserver(dirUri2, callbackDir2);
    fileAccessHelper.unregisterObserver(fileUri, callbackFile);
  } catch (err) {
    let error: BusinessError = err as BusinessError;
    console.error("registerObserver failed, errCode:" + error.code + ", errMessage:" + error.message);
  }
}

Example 2: Use the same uri, notifyForDescendants, and callback to register repeatedly.

import { BusinessError } from '@ohos.base';
async function registerObserver02() {
  let DirUri: string = 'file://docs/storage/Users/currentUser/Documents';
  try {
    // Obtain fileAccessHelper by referring to the sample code of fileAccess.createFileAccessHelper.
    let dirUri = await fileAccessHelper.mkDir(DirUri, 'NOTIFY_DIR');
    // The notification expected to receive is about the NOTIFY_ADD event of the URI 'file://docs/storage/Users/currentUser/Documents/NOTIFY_DIR/SUB_DIR'.
    const callbackDir = (NotifyMessageDir: fileAccess.NotifyMessage) => {
      if (NotifyMessageDir != undefined) {
        console.log('NotifyType: ' + NotifyMessageDir.type + 'NotifyUri:' + NotifyMessageDir.uri[0]);
      } else {
        console.error("NotifyMessageDir is undefined");
      }
    }
    fileAccessHelper.registerObserver(dirUri, true, callbackDir);
    // A message is returned indicating that the registration is successful. Repeated registration is reported only in the log.
    fileAccessHelper.registerObserver(dirUri, true, callbackDir);
    let subDirUri = await fileAccessHelper.mkDir(dirUri, 'SUB_DIR');
    // Do not unregister the callback immediately after the registration is complete, because the unregistration result may be returned before the notification is returned. If this occurs, the notification wll not be received.
    fileAccessHelper.unregisterObserver(dirUri, callbackDir);
  } catch (err) {
    let error: BusinessError = err as BusinessError;
    console.error("registerObserver failed, errCode:" + error.code + ", errMessage:" + error.message);
  }

Example 3: Use the same uri and callback but different notifyForDescendants for registration. In this case, notifyForDescendants will be reset.

import { BusinessError } from '@ohos.base';
async function registerObserver03() {
  let DirUri: string = 'file://docs/storage/Users/currentUser/Documents';
  try {
    // Obtain fileAccessHelper by referring to the sample code of fileAccess.createFileAccessHelper.
    let dirUri = await fileAccessHelper.mkDir(DirUri, 'NOTIFY_DIR');
    // The first notification expected to receive is about the NOTIFY_ADD event of the URI 'file://docs/storage/Users/currentUser/Documents/NOTIFY_DIR/SUB_FILE_1'.
    // No second return is expected.
    const callbackDir = (NotifyMessageDir: fileAccess.NotifyMessage) => {
      if (NotifyMessageDir != undefined) {
        console.log('NotifyType: ' + NotifyMessageDir.type + 'NotifyUri:' + NotifyMessageDir.uri[0]);
      } else {
        console.error("NotifyMessageDir is undefined");
      }
    }
    fileAccessHelper.registerObserver(dirUri, true, callbackDir);
    let subFile1 = await fileAccessHelper.createFile(dirUri, 'SUB_FILE_1');
    // After the registration is successful, change notifyForDescendants to false.
    fileAccessHelper.registerObserver(dirUri, false, callbackDir);
    let subFile2 = await fileAccessHelper.createFile(dirUri, 'SUB_FILE_2');
    // Do not unregister the callback immediately after the registration is complete, because the unregistration result may be returned before the notification is returned. If this occurs, the notification wll not be received.
    fileAccessHelper.unregisterObserver(dirUri, callbackDir);
  } catch (err) {
    let error: BusinessError = err as BusinessError;
    console.error("registerObserver failed, errCode:" + error.code + ", errMessage:" + error.message);
  }
}

unregisterObserver¹⁰⁺

unregisterObserver(uri: string, callback?: Callback<NotifyMessage>): void

Unregisters a callback that is used to listen for the specified URI.

System capability: SystemCapability.FileManagement.UserFileService

Required permissions: ohos.permission.FILE_ACCESS_MANAGER

Parameters

Example 1: Unregister a callback of the specified URI.

import { BusinessError } from '@ohos.base';
async function UnregisterObserver01() {
  let DirUri: string = 'file://docs/storage/Users/currentUser/Documents';
  try {
    // Obtain fileAccessHelper by referring to the sample code of fileAccess.createFileAccessHelper.
    let dirUri = await fileAccessHelper.mkDir(DirUri, 'NOTIFY_DIR');
    // The notification expected to receive is about the NOTIFY_DELETE event of the URI 'file://docs/storage/Users/currentUser/Documents/NOTIFY_DIR'.
    const callbackDir = (NotifyMessageDir: fileAccess.NotifyMessage) => {
      if (NotifyMessageDir != undefined) {
        console.log('NotifyType: ' + NotifyMessageDir.type + 'NotifyUri:' + NotifyMessageDir.uri[0]);
      } else {
        console.error("NotifyMessageDir is undefined");
      }
    }
    fileAccessHelper.registerObserver(dirUri, true, callbackDir);
    await fileAccessHelper.delete(dirUri);
    // Do not unregister the callback immediately after the registration is complete, because the unregistration result may be returned before the notification is returned. If this occurs, the notification wll not be received.
    fileAccessHelper.unregisterObserver(dirUri, callbackDir);
  } catch (err) {
    let error: BusinessError = err as BusinessError;
    console.error("unregisterObserver failed, errCode:" + error.code + ", errMessage:" + error.message);
  }
}

Example 2: Repeatedly unregister a callback of the specified URI.

import { BusinessError } from '@ohos.base';
async function UnregisterObserver02() {
  let DirUri: string = 'file://docs/storage/Users/currentUser/Documents';
  try {
    // Obtain fileAccessHelper by referring to the sample code of fileAccess.createFileAccessHelper.
    let dirUri = await fileAccessHelper.mkDir(DirUri, 'NOTIFY_DIR');
    // The notification expected to receive is about the NOTIFY_DELETE event of the URI 'file://docs/storage/Users/currentUser/Documents/NOTIFY_DIR'.
    const callbackDir = (NotifyMessageDir: fileAccess.NotifyMessage) => {
      if (NotifyMessageDir != undefined) {
        console.log('NotifyType: ' + NotifyMessageDir.type + 'NotifyUri:' + NotifyMessageDir.uri[0]);
      } else {
        console.error("NotifyMessageDir is undefined");
      }
    }
    fileAccessHelper.registerObserver(dirUri, true, callbackDir);
    await fileAccessHelper.delete(dirUri);
    // Do not unregister the callback immediately after the registration is complete, because the unregistration result may be returned before the notification is returned. If this occurs, the notification wll not be received.
    fileAccessHelper.unregisterObserver(dirUri, callbackDir);
    // If the unregistration fails, throw the error code E_CAN_NOT_FIND_URI.
    fileAccessHelper.unregisterObserver(dirUri, callbackDir);
  } catch (err) {
    let error: BusinessError = err as BusinessError;
    console.error("unregisterObserver failed, errCode:" + error.code + ", errMessage:" + error.message);
  }
}

Example 3: Unregister all callbacks of the specified URI.

import { BusinessError } from '@ohos.base';
async function UnregisterObserver03() {
  let DirUri: string = 'file://docs/storage/Users/currentUser/Documents';
  try {
    // Obtain fileAccessHelper by referring to the sample code of fileAccess.createFileAccessHelper.
    let dirUri = await fileAccessHelper.mkDir(DirUri, 'NOTIFY_DIR');
    // The notification expected to receive is about the NOTIFY_MOVED_FROM event of the URI 'file://docs/storage/Users/currentUser/Documents/NOTIFY_DIR/SUB_FILE'.
    // The notification expected to receive is about the NOTIFY_MOVED_TO event of the URI 'file://docs/storage/Users/currentUser/Documents/NOTIFY_DIR/RENAME_FILE'.
    const callbackDir1 = (NotifyMessageDir: fileAccess.NotifyMessage) => {
      if (NotifyMessageDir != undefined) {
        console.log('NotifyType: ' + NotifyMessageDir.type + 'NotifyUri:' + NotifyMessageDir.uri[0]);
      } else {
        console.error("NotifyMessageDir is undefined");
      }
    }
    // No notification is expected to receive.
    const callbackDir2 = (NotifyMessageDir: fileAccess.NotifyMessage) => {
      if (NotifyMessageDir != undefined) {
        console.log('NotifyType: ' + NotifyMessageDir.type + 'NotifyUri:' + NotifyMessageDir.uri[0]);
      } else {
        console.error("NotifyMessageDir is undefined");
      }
    }
    let fileUri = await fileAccessHelper.createFile(dirUri, 'SUB_FILE');
    fileAccessHelper.registerObserver(dirUri, true, callbackDir1);
    // The registration does not include the events about the next-level directory.
    fileAccessHelper.registerObserver(dirUri, false, callbackDir2);
    let renameUri = await fileAccessHelper.rename(fileUri, 'RENAME_FILE');
    // Unregister all callbacks (callbackDir1 and callbackDir2) of dirUri.
    // Do not unregister the callback immediately after the registration is complete, because the unregistration result may be returned before the notification is returned. If this occurs, the notification wll not be received.
    fileAccessHelper.unregisterObserver(dirUri);
    await fileAccessHelper.delete(dirUri);
  } catch (err) {
    let error: BusinessError = err as BusinessError;
    console.error("unregisterObserver failed, errCode:" + error.code + ", errMessage:" + error.message);
  }
}

CopyResult¹⁰⁺

Defines the information returned when the file copy operation fails. If the copy operation is successful, no information is returned.

System capability: SystemCapability.FileManagement.UserFileService

Required permissions: ohos.permission.FILE_ACCESS_MANAGER

OPENFLAGS

Enumerates the file open modes.

Model restriction: This API can be used only in the stage model.

System capability: SystemCapability.FileManagement.UserFileService

FILEKEY¹⁰⁺

Enumerates the keys of the file attributes to query.

Model restriction: This API can be used only in the stage model.

System capability: SystemCapability.FileManagement.UserFileService

NotifyType¹⁰⁺

Enumerates the notification types.

Model restriction: This API can be used only in the stage model.

System capability: SystemCapability.FileManagement.UserFileService

NotifyMessage¹⁰⁺

Represents the notification message.

Model restriction: This API can be used only in the stage model.

System capability: SystemCapability.FileManagement.UserFileService

Required permissions: ohos.permission.FILE_ACCESS_MANAGER