Saving User Files

When a user needs to download a file from the network to a local directory or save a user file into another directory, use FilePicker to save the file.

The operations for saving images, audio or video clips, and documents are similar. Call save() of the corresponding picker instance and pass in saveOptions.

Saving Images or Video Files

Import the picker module and fs module.

import picker from '@ohos.file.picker';
import fs from '@ohos.file.fs';

Create a photoSaveOptions instance.

const photoSaveOptions = new picker.PhotoSaveOptions(); // Create a photoSaveOptions instance.
photoSaveOptions.newFileNames = ["PhotoViewPicker01.jpg"]; // (Optional) Set the names of the files to save.

Create a photoViewPicker instance and call save() to open the FilePicker page to save the files. After the user selects the target folder, the file saving operation is complete. After the files are saved successfully, the URIs of the files saved are returned.

The permission on the URIs returned by save() is read/write. Further file operations can be performed based on the URIs in the result set. Note that the URI cannot be directly used in the picker callback to open a file. You need to define a global variable to save the URI and use a button to trigger file opening.
```
let URI = null;
const photoViewPicker = new picker.PhotoViewPicker();
photoViewPicker.save(photoSaveOptions).then((photoSaveResult) => {
  URI = photoSaveResult[0];
  console.info('photoViewPicker.save to file succeed and URI is:' + URI);
}).catch((err) => {
  console.error(`Invoke photoViewPicker.save failed, code is ${err.code}, message is ${err.message}`);
})
```
Use a button to trigger invocation of other functions. Use fs.openSync() to open the file based on the URI and obtain the FD. Note that the mode parameter of fs.openSync() must be fs.OpenMode.READ_WRITE.
```
let file = fs.openSync(URI, fs.OpenMode.READ_WRITE);
console.info('file fd: ' + file.fd);
```

Use fs.writeSync() to edit the file based on the FD, and then close the FD.

let writeLen = fs.writeSync(file.fd, 'hello, world');
console.info('write data to file succeed and size is:' + writeLen);
fs.closeSync(file);

Saving Documents

Import the picker module and fs module.

import picker from '@ohos.file.picker';
import fs from '@ohos.file.fs';

Create a documentSaveOptions instance.

const documentSaveOptions = new picker.DocumentSaveOptions(); // Create a documentSaveOptions instance.
documentSaveOptions.newFileNames = ["DocumentViewPicker01.txt"]; // (Optional) Set the names of the documents to save.

Create a documentViewPicker instance, and call save() to open the FilePicker page to save the documents. After the user selects the target folder, the file saving operation is complete. After the files are saved successfully, the URIs of the files saved are returned.

The permission on the URIs returned by save() is read/write. Further file operations can be performed based on the URIs in the result set. Note that the URI cannot be directly used in the picker callback to open a file. You need to define a global variable to save the URI and use a button to trigger file opening.
```
let URI = null;
const documentViewPicker = new picker.DocumentViewPicker(); // Create a documentViewPicker instance.
documentViewPicker.save(documentSaveOptions).then((documentSaveResult) => {
  URI = documentSaveResult[0];
  console.info('documentViewPicker.save to file succeed and URI is:' + URI);
}).catch((err) => {
  console.error(`Invoke documentViewPicker.save failed, code is ${err.code}, message is ${err.message}`);
})
```
Use a button to trigger invocation of other functions. Use fs.openSync() to open the file based on the URI and obtain the FD. Note that the mode parameter of fs.openSync() must be fs.OpenMode.READ_WRITE.
```
let file = fs.openSync(URI, fs.OpenMode.READ_WRITE);
console.info('file fd: ' + file.fd);
```

Use fs.writeSync() to edit the file based on the FD, and then close the FD.

let writeLen = fs.writeSync(file.fd, 'hello, world');
console.info('write data to file succeed and size is:' + writeLen);
fs.closeSync(file);

Saving Audio Files

Import the picker module and fs module.

import picker from '@ohos.file.picker';
import fs from '@ohos.file.fs';

Create an audioSaveOptions instance.

const audioSaveOptions = new picker.AudioSaveOptions(); // Create an audioSaveOptions instance.
audioSaveOptions.newFileNames = ['AudioViewPicker01.mp3']; // (Optional) Set the names of the files to save.

Create an audioViewPicker instance, and call save() to open the FilePicker page to save the files. After the user selects the target folder, the file saving operation is complete. After the files are saved successfully, the URIs of the files saved are returned.

The permission on the URIs returned by save() is read/write. Further file operations can be performed based on the URIs in the result set. Note that the URI cannot be directly used in the picker callback to open a file. You need to define a global variable to save the URI and use a button to trigger file opening.
```
let URI = null;
const audioViewPicker = new picker.AudioViewPicker();
audioViewPicker.save(audioSaveOptions).then((audioSelectResult) => {
  URI = audioSelectResult[0];
  console.info('audioViewPicker.save to file succeed and URI is:' + URI);
}).catch((err) => {
  console.error(`Invoke audioViewPicker.save failed, code is ${err.code}, message is ${err.message}`);
})
```
Use a button to trigger invocation of other functions. Use fs.openSync() to open the file based on the URI and obtain the FD. Note that the mode parameter of fs.openSync() must be fs.OpenMode.READ_WRITE.
```
let file = fs.openSync(URI, fs.OpenMode.READ_WRITE);
console.info('file fd: ' + file.fd);
```

Use fs.writeSync to edit the file based on the FD, and then close the FD.

let writeLen = fs.writeSync(file.fd, 'hello, world');
console.info('write data to file succeed and size is:' + writeLen);
fs.closeSync(file);