update docs

Signed-off-by: NAnnie_wang <annie.wangli@huawei.com>

en/application-dev/file-management/select-user-file.md

@@ -37,15 +37,28 @@ The **FilePicker** provides the following interfaces by file type:
    Use [PhotoSelectResult](../reference/apis/js-apis-file-picker.md#photoselectresult) to return a result set. Further operations on the selected files can be performed based on the file URIs in the result set.
 
    ```ts
+   let uri = null;
    const photoPicker = new picker.PhotoViewPicker();
-   photoPicker.select(photoSelectOptions)
-     .then(async (photoSelectResult) => {
-       let uri = photoSelectResult.photoUris[0];
-       // Perform operations on the files based on the file URIs obtained.
-     })
-     .catch((err) => {
-       console.error(`Invoke documentPicker.select failed, code is ${err.code}, message is ${err.message}`);
-     })
+   photoPicker.select(photoSelectOptions).then((photoSelectResult) => {
+     uri = photoSelectResult.photoUris[0];
+   }).catch((err) => {
+     console.error(`Invoke photoPicker.select failed, code is ${err.code}, message is ${err.message}`);
+   })
+   ```
+
+5. After the GUI is returned from FilePicker, use [**fs.openSync**](../reference/apis/js-apis-file-fs.md#fsopensync) to open the file based on the URI and obtain the FD.
+
+   ```ts
+   let file = fs.openSync(uri, fs.OpenMode.READ_WRITE);
+   console.info('file fd: ' + file.fd);
+   ```
+
+6. Use [fs.writeSync](../reference/apis/js-apis-file-fs.md#writesync) to write data to the file based on the FD, and then close the FD.
+
+   ```ts
+   let writeLen = fs.writeSync(file.fd, 'hello, world');
+   console.info('write data to file succeed and size is:' + writeLen);
+   fs.closeSync(file);
    ```
 
 ## Selecting Documents
@@ -63,23 +76,69 @@ The **FilePicker** provides the following interfaces by file type:
    ```
 
 3. Create a **documentViewPicker** instance, and call [**select()**](../reference/apis/js-apis-file-picker.md#select-3) to open the **FilePicker** page for the user to select documents.
+
      After the documents are selected successfully, a result set containing the file URIs is returned. Further operations can be performed on the documents based on the file URIs.
+
+   For example, you can use [file management APIs](../reference/apis/js-apis-file-fs.md) to obtain file attribute information, such as the file size, access time, and last modification time, based on the URI. If you need to obtain the file name, use [startAbilityForResult](../../application-dev/application-models/uiability-intra-device-interaction.md).
+
    > **NOTE**
    >
    > Currently, **DocumentSelectOptions** is not configurable. By default, all types of user files are selected.
 
    ```ts
+   let uri = null;
    const documentViewPicker = new picker.DocumentViewPicker(); // Create a documentViewPicker instance.
-   documentViewPicker.select(documentSelectOptions)
-     .then((documentSelectResult) => {
-       let uri = documentSelectResult[0];
-       // Perform operations on the documents based on the file URIs.
-     })
-     .catch((err) => {
-       console.error(`Invoke documentPicker.select failed, code is ${err.code}, message is ${err.message}`);
-     })
+   documentViewPicker.select(documentSelectOptions).then((documentSelectResult) => {
+     uri = documentSelectResult[0];
+   }).catch((err) => {
+     console.error(`Invoke documentPicker.select failed, code is ${err.code}, message is ${err.message}`);
+   })
+   ```
+
+   > **NOTE**
+   >
+   > Currently, **DocumentSelectOptions** does not provide the method for obtaining the file name. To obtain the file name, use **startAbilityForResult()**.
+
+   ```ts
+   let config = {
+     action: 'ohos.want.action.OPEN_FILE',
+     parameters: {
+       startMode: 'choose',
+     }
+   }
+   try {
+     let result = await context.startAbilityForResult(config, {windowMode: 1});
+     if (result.resultCode !== 0) {
+       console.error(`DocumentPicker.select failed, code is ${result.resultCode}, message is ${result.want.parameters.message}`);
+       return;
+     }
+     // Obtain the URI of the document.
+     let select_item_list = result.want.parameters.select_item_list;
+     // Obtain the name of the document.
+     let file_name_list = result.want.parameters.file_name_list;
+   } catch (err) {
+     console.error(`Invoke documentPicker.select failed, code is ${err.code}, message is ${err.message}`);
+   }
    ```
 
+4. After the GUI is returned from FilePicker, use [**fs.openSync**](../reference/apis/js-apis-file-fs.md#fsopensync) to open the file based on the URI and obtain the FD.
+
+   ```ts
+   let file = fs.openSync(uri, fs.OpenMode.READ_WRITE);
+   console.info('file fd: ' + file.fd);
+   ```
+
+5. Use [fs.readSync](../reference/apis/js-apis-file-fs.md#readsync) to read data from the file based on the FD, and then close the FD.
+
+   ```ts
+   let file = fs.openSync(uri, fs.OpenMode.READ_WRITE);
+   let buf = new ArrayBuffer(4096);
+   let num = fs.readSync(file.fd, buf);
+   console.info('read data to file succeed and size is:' + num);
+   fs.closeSync(file);
+   ```
+
+
 ## Selecting an Audio File
 
 1. Import the **FilePicker** module.
@@ -105,13 +164,26 @@ The **FilePicker** provides the following interfaces by file type:
    > Currently, **AudioSelectOptions** is not configurable. By default, all types of user files are selected.
 
    ```ts
+   let uri = null;
    const audioViewPicker = new picker.AudioViewPicker();
-   audioViewPicker.select(audioSelectOptions)
-     .then(audioSelectResult => {
-       let uri = audioSelectOptions[0];
-       // Perform operations on the audio files based on the file URIs.
-     })
-     .catch((err) => {
-       console.error(`Invoke audioPicker.select failed, code is ${err.code}, message is ${err.message}`);
-     })
+   audioViewPicker.select(audioSelectOptions).then(audioSelectResult => {
+     uri = audioSelectOptions[0];
+   }).catch((err) => {
+     console.error(`Invoke audioPicker.select failed, code is ${err.code}, message is ${err.message}`);
+   })
+   ```
+
+4. After the GUI is returned from FilePicker, use [**fs.openSync**](../reference/apis/js-apis-file-fs.md#fsopensync) to open the file based on the URI and obtain the FD.
+
+   ```ts
+   let file = fs.openSync(uri, fs.OpenMode.READ_WRITE);
+   console.info('file fd: ' + file.fd);
+   ```
+
+5. Use [fs.writeSync](../reference/apis/js-apis-file-fs.md#writesync) to write data to the file based on the FD, and then close the FD.
+
+   ```ts
+   let writeLen = fs.writeSync(file.fd, 'hello, world');
+   console.info('write data to file succeed and size is:' + writeLen);
+   fs.closeSync(file);
    ```