FileSystemManager.open

Introduction

Opens a file and returns the file descriptor.

Usage Restrictions

Supported by basic library version 3.0.0 or higher.

Parameters

Object object

Property	Type	Default	Required	Description
filePath	string		Yes	File path (relative path)
flag	string	r	No	File system flag, default value: 'r'
success	function		No	Callback function executed upon successful call
fail	function		No	Callback function executed upon failed call
complete	function		No	Callback function executed upon completion of call

Valid Values for File System Flag (flag)

Value	Description
a	Open the file for appending. If the file does not exist, create the file.
a+	Open the file for reading and appending. If the file does not exist, create the file.
ax	Similar to 'a', but fails if the path exists.
ax+	Similar to 'a+', but fails if the path exists.
w	Open the file for writing. If the file does not exist, create the file.
w+	Open the file for reading and writing. If the file does not exist, create the file.
wx	Similar to 'w', but fails if the path exists.
wx+	Similar to 'w+', but fails if the path exists.
r	Open the file for reading. If the file does not exist, an exception occurs.
r+	Open the file for reading and writing. If the file does not exist, an exception occurs.

object.success Callback Function

Parameters

Object res

Property	Type	Description
fd	string	File descriptor
success	string	true-Operation successful

object.fail Callback Function

Parameters

Object res

Property	Type	Description
errMsg	string	Error message
success	string	false-Operation failed

errMsg Description

Error message	Description
parameter error: F10001	Invalid parameter
fail sdcard not mounted: F10002	Failed to mount Android sdcard
fail no such file or directory: F10007 ${dirPath}	Parent directory does not exist

Sample Code

// pages/index/index.js
Page({
  open() {
    const fs = dlt.getFileSystemManager();
    fs.open({
      filePath: `${dlt.env.USER_DATA_PATH}/hello.txt`,
      flag: 'a+',
      success: (res) => {
        console.log('success', res);
      },
      fail: (res) => {
        console.log('fail', res);
      },
      complete: (res) => {
        console.log('complete', res);
      },
    });
  },
});