Added medialibrary api

Signed-off-by: Nwusongqing <wusongqing@huawei.com>

en/application-dev/reference/apis/js-apis-medialibrary.md

+# Media Library Management
+
+> ![icon-note.gif](public_sys-resources/icon-note.gif) **NOTE**
+> This component is supported since API version 6. Updates will be marked with a superscript to indicate their earliest API version.
+
+## Modules to Import
+```
+import mediaLibrary from '@ohos.multimedia.medialibrary';
+```
+
+## mediaLibrary.getMediaLibrary
+
+getMediaLibrary(context: Context): MediaLibrary
+
+Obtains a **MediaLibrary** instance, which is used to access and modify personal data of users.
+
+**System capability**: SystemCapability.Multimedia.MediaLibrary.Core
+
+**Parameters**
+
+| Name | Type   | Mandatory| Description                                                        |
+| ------- | ------- | ---- | ------------------------------------------------------------ |
+| context | Context | Yes  | Context of the ability. This parameter is optional for API version 7 and earlier versions, but mandatory for API version 8 and later versions.|
+
+**Return value**
+
+| Type                         | Description      |
+| ----------------------------- | :--------- |
+| [MediaLibrary](#medialibrary) | **MediaLibrary** instance.|
+
+**Example**
+
+```
+import featureAbility from '@ohos.ability.featureAbility';
+
+var context = featureAbility.getContext()
+var media = mediaLibrary.getMediaLibrary(context);
+```
+## MediaLibrary
+
+### getFileAssets<sup>8+</sup>
+
+
+getFileAssets(options: MediaFetchOptions, callback: AsyncCallback&lt;FetchFileResult&gt;): void 
+
+Obtains file assets (also called files). This API uses an asynchronous callback to return the result.
+
+**Required permissions**: ohos.permission.READ_MEDIA
+
+**System capability**: SystemCapability.Multimedia.MediaLibrary.Core
+
+**Parameters**
+
+| Name  | Type                                               | Mandatory| Description                             |
+| -------- | --------------------------------------------------- | ---- | --------------------------------- |
+| options  | [MediaFetchOptions](#mediafetchoptions8)            | Yes  | Options for fetching the files.                     |
+| callback | AsyncCallback<[FetchFileResult](#fetchfileresult8)> | Yes  | Asynchronous callback of **FetchFileResult**.|
+
+**Example**
+
+```
+let fileKeyObj = mediaLibrary.FileKey
+let imageType = mediaLibrary.MediaType.IMAGE
+let imagesfetchOp = {
+    selections: fileKeyObj.MEDIA_TYPE + '= ?',
+    selectionArgs: [imageType.toString()],
+};
+mediaLibrary.getFileAssets(imagesfetchOp, (error, fetchFileResult) => {
+    if (fetchFileResult != undefined) {
+        console.info('mediaLibraryTest : ASSET_CALLBACK fetchFileResult success');
+        fetchFileResult.getAllObject((err, fileAssetList) => {
+            if (fileAssetList != undefined) {
+                fileAssetList.forEach(getAllObjectInfo);
+            }
+    	});
+    }
+});
+```
+### getFileAssets<sup>8+</sup>
+
+getFileAssets(options: MediaFetchOptions): Promise&lt;FetchFileResult&gt;
+
+Obtains file assets. This API uses a promise to return the result.
+
+**Required permissions**: ohos.permission.READ_MEDIA
+
+**System capability**: SystemCapability.Multimedia.MediaLibrary.Core
+
+**Parameters**
+
+| Name | Type                                    | Mandatory| Description        |
+| ------- | ---------------------------------------- | ---- | ------------ |
+| options | [MediaFetchOptions](#mediafetchoptions8) | Yes  | Options for fetching the files.|
+
+**Return value**
+
+| Type                                | Description          |
+| ------------------------------------ | -------------- |
+| [FetchFileResult](#fetchfileresult8) | Result set of the file retrieval operation.|
+
+**Example**
+
+```
+let fileKeyObj = mediaLibrary.FileKey
+let imageType = mediaLibrary.MediaType.IMAGE
+let imagesfetchOp = {
+    selections: fileKeyObj.MEDIA_TYPE + '= ?',
+    selectionArgs: [imageType.toString()],
+};
+mediaLibrary.getFileAssets(imagesfetchOp).then(function(fetchFileResult){
+    console.info("getFileAssets successfully:"+ JSON.stringify(dir));
+}).catch(function(err){
+    console.info("getFileAssets failed with error:"+ err);
+});
+```
+
+### on<sup>8+</sup>
+
+on(type: 'deviceChange'|'albumChange'|'imageChange'|'audioChange'|'videoChange'|'fileChange'|'remoteFileChange', callback: Callback&lt;void&gt;): void
+
+Subscribes to the media library changes. This API uses an asynchronous callback to return the result.
+
+**System capability**: SystemCapability.Multimedia.MediaLibrary.Core
+
+**Parameters**
+
+| Name  | Type                | Mandatory| Description                                                        |
+| -------- | -------------------- | ---- | ------------------------------------------------------------ |
+| type     | string               | Yes  | Media type.<br>'deviceChange': registered device change<br>'albumChange': album change<br>'imageChange': image file change<br>'audioChange': audio file change<br>'videoChange': video file change<br>'fileChange': file change<br>'remoteFileChange': file change on the registered device|
+| callback | callback&lt;void&gt; | Yes  | Void callback.                                                  |
+
+**Example**
+
+```
+mediaLibrary.on('imageChange', () => {
+    // image file had changed, do something
+})
+```
+### off<sup>8+</sup>
+
+off(type: 'deviceChange'|'albumChange'|'imageChange'|'audioChange'|'videoChange'|'fileChange'|'remoteFileChange', callback?: Callback&lt;void&gt;): void
+
+Unsubscribes from the media library changes. This API uses an asynchronous callback to return the result.
+
+**System capability**: SystemCapability.Multimedia.MediaLibrary.Core
+
+**Parameters**
+
+| Name  | Type                | Mandatory| Description                                                        |
+| -------- | -------------------- | ---- | ------------------------------------------------------------ |
+| type     | string               | Yes  | Media type.<br>'deviceChange': registered device change<br>'albumChange': album change<br>'imageChange': image file change<br>'audioChange': audio file change<br>'videoChange': video file change<br>'fileChange': file change<br>'remoteFileChange': file change on the registered device|
+| callback | callback&lt;void&gt; | No  | Void callback.                                                  |
+
+**Example**
+
+```
+mediaLibrary.off('imageChange', () => {
+    // stop listening success
+})
+```
+
+### createAsset <sup>8+</sup>
+
+createAsset(mediaType: MediaType, displayName: string, relativePath: string, callback: AsyncCallback&lt;FileAsset&gt;): void
+
+Creates a media asset. This API uses an asynchronous callback to return the result.
+
+**Required permissions**: ohos.permission.READ_MEDIA and ohos.permission.WRITE_MEDIA
+
+**System capability**: SystemCapability.Multimedia.MediaLibrary.Core
+
+**Parameters**
+
+| Name      | Type                                   | Mandatory| Description                                                        |
+| ------------ | --------------------------------------- | ---- | ------------------------------------------------------------ |
+| mediaType    | [MediaType](#mediatype)                 | Yes  | Media type.                                                    |
+| displayName  | string                                  | Yes  | Display file name.                                                  |
+| relativePath | string                                  | Yes  | Path for storing the file. You can use [getPublicDirectory](#getpublicdirectory8) to obtain the paths for storing different types of files.|
+| callback     | AsyncCallback<[FileAsset](#fileasset8)> | Yes  | Asynchronous callback for **FileAsset**.                         |
+
+**Example**
+
+```
+async function example() {
+    // Create an image file in callback mode.
+    let mediaType = mediaLibrary.MediaType.IMAGE;
+    let DIR_IMAGE = mediaLibrary.DirectoryType.DIR_IMAGE;
+    const path = await media.getPublicDirectory(DIR_IMAGE);
+    mediaLibrary.createAsset(mediaType, 'imageCallBack.jpg', path + 'myPicture/', (err, fileAsset) => {
+        if (fileAsset != undefined) {
+            console.info('createAsset successfully, message = ' + err);
+        } else {
+            console.info('createAsset failed, message = ' + err);
+        }
+    });
+}
+```
+
+### createAsset<sup>8+</sup>
+
+createAsset(mediaType: MediaType, displayName: string, relativePath: string): Promise&lt;FileAsset&gt;
+
+Creates a media asset. This API uses a promise to return the result.
+
+**Required permissions**: ohos.permission.READ_MEDIA and ohos.permission.WRITE_MEDIA
+
+**System capability**: SystemCapability.Multimedia.MediaLibrary.Core
+
+**Parameters**
+
+| Name      | Type                   | Mandatory| Description                                                        |
+| ------------ | ----------------------- | ---- | ------------------------------------------------------------ |
+| mediaType    | [MediaType](#mediatype) | Yes  | Media type.                                                    |
+| displayName  | string                  | Yes  | Display file name.                                                  |
+| relativePath | string                  | Yes  | Relative path. You can use [getPublicDirectory](#getpublicdirectory8) to obtain the relative path of the level-1 directory of different types of media files.|
+
+**Return value**
+
+| Type                    | Description             |
+| ------------------------ | ----------------- |
+| [FileAsset](#fileasset8) | Media data (FileAsset).|
+
+**Example**
+
+```
+async function example() {
+    // Create an image file in promise mode
+    let mediaType = mediaLibrary.MediaType.IMAGE;
+    let DIR_IMAGE = mediaLibrary.DirectoryType.DIR_IMAGE;
+    const path = await media.getPublicDirectory(DIR_IMAGE);
+    mediaLibrary.createAsset(mediaType, "image01.jpg", path + 'myPicture/').then (function (asset) {
+        console.info("createAsset successfully:"+ JSON.stringify(asset));
+    }).catch(function(err){
+        console.info("createAsset failed with error:"+ err);
+    });
+}
+```
+
+### getPublicDirectory<sup>8+</sup>
+
+getPublicDirectory(type: DirectoryType, callback: AsyncCallback&lt;string&gt;): void
+
+Obtains a public directory. This API uses an asynchronous callback to return the result.
+
+**System capability**: SystemCapability.Multimedia.MediaLibrary.Core
+
+**Parameters**
+
+| Name  | Type                           | Mandatory| Description                     |
+| -------- | ------------------------------- | ---- | ------------------------- |
+| type     | [DirectoryType](#directorytype) | Yes  | Type of the public directory.             |
+| callback | AsyncCallback&lt;string&gt;     | Yes  | Callback used to return the public directory.|
+
+**Example**
+
+```
+let DIR_CAMERA = mediaLibrary.DirectoryType.DIR_CAMERA;
+media.getPublicDirectory(DIR_CAMERA, (err, dicResult) => {
+    if (dicResult == 'Camera/') {
+        console.info('mediaLibraryTest : getPublicDirectory passed');
+    } else {
+        console.info('mediaLibraryTest : getPublicDirectory failed');
+    }
+});
+```
+
+### getPublicDirectory<sup>8+</sup>
+
+getPublicDirectory(type: DirectoryType): Promise&lt;string&gt;
+
+Obtains a public directory. This API uses a promise to return the result.
+
+**System capability**: SystemCapability.Multimedia.MediaLibrary.Core
+
+**Parameters**
+
+| Name| Type                           | Mandatory| Description        |
+| ------ | ------------------------------- | ---- | ------------ |
+| type   | [DirectoryType](#directorytype) | Yes  | Type of the public directory.|
+
+**Return value**
+
+| Type           | Description            |
+| --------------- | ---------------- |
+| Promise<string> | Promise used to return the public directory.|
+
+**Example**
+
+```
+async function example() {
+    let DIR_CAMERA = mediaLibrary.DirectoryType.DIR_CAMERA;
+    const dicResult = await media.getPublicDirectory(DIR_CAMERA);
+    if (dicResult == 'Camera/') {
+        console.info('MediaLibraryTest : getPublicDirectory');
+    } else {
+        console.info('MediaLibraryTest : getPublicDirectory failed');
+    }
+}
+```
+
+### getAlbums<sup>8+</sup>
+
+getAlbums(options: MediaFetchOptions, callback: AsyncCallback<Array&lt;Album&gt;>): void
+
+Obtains the albums. This API uses an asynchronous callback to return the result.
+
+**Required permissions**: ohos.permission.READ_MEDIA
+
+**System capability**: SystemCapability.Multimedia.MediaLibrary.Core
+
+**Parameters**
+
+| Name  | Type                                        | Mandatory| Description                       |
+| -------- | -------------------------------------------- | ---- | --------------------------- |
+| options  | [MediaFetchOptions](#mediafetchoptions8)     | Yes  | Options for fetching the albums.               |
+| callback | AsyncCallback&lt;Array<[Album](#album8)>&gt; | Yes  | Callback used to return the albums.|
+
+**Example**
+
+```
+let AlbumNoArgsfetchOp = {
+    selections: '',
+    selectionArgs: [],
+};
+mediaLibrary.getAlbums(AlbumNoArgsfetchOp, (err, albumList) => {
+    if (albumList != undefined) {
+        const album = albumList[0];
+        console.info('album.albumName = ' + album.albumName);
+        console.info('album.count = ' + album.count);
+     } else {
+        console.info('getAlbum fail, message = ' + err);
+     }
+})
+```
+
+### getAlbums<sup>8+</sup>
+
+getAlbums(options: MediaFetchOptions): Promise<Array&lt;Album&gt;>
+
+Obtains the albums. This API uses a promise to return the result.
+
+**Required permissions**: ohos.permission.READ_MEDIA
+
+**System capability**: SystemCapability.Multimedia.MediaLibrary.Core
+
+**Parameters**
+
+| Name | Type                                    | Mandatory| Description        |
+| ------- | ---------------------------------------- | ---- | ------------ |
+| options | [MediaFetchOptions](#mediafetchoptions8) | Yes  | Options for fetching the albums.|
+
+**Return value**
+
+| Type                            | Description         |
+| -------------------------------- | ------------- |
+| Promise<Array<[Album](#album8)>> | Promise used to return the albums.|
+
+**Example**
+
+```
+let AlbumNoArgsfetchOp = {
+    selections: '',
+    selectionArgs: [],
+};
+mediaLibrary.getAlbums(AlbumNoArgsfetchOp).then(function(albumList){
+    console.info("getAlbums successfully:"+ JSON.stringify(albumList));
+}).catch(function(err){
+    console.info("getAlbums failed with error:"+ err);
+});
+```
+
+### release<sup>8+</sup>
+
+release(callback: AsyncCallback&lt;void&gt;): void
+
+Releases this **MediaLibrary** instance.
+Call this API when you no longer need to use the APIs in the **MediaLibrary** instance.
+
+**System capability**: SystemCapability.Multimedia.MediaLibrary.Core
+
+**Parameters**
+
+| Name  | Type                     | Mandatory| Description                |
+| -------- | ------------------------- | ---- | -------------------- |
+| callback | AsyncCallback&lt;void&gt; | Yes  | Callback used to return the execution result.|
+
+**Example**
+
+```
+var media = mediaLibrary.getMediaLibrary(context);
+media.release((err) => {
+    // do something
+});
+```
+
+### release<sup>8+</sup>
+
+release(): Promise&lt;void&gt;
+
+Releases this **MediaLibrary** instance.
+Call this API when you no longer need to use the APIs in the **MediaLibrary** instance.
+
+**System capability**: SystemCapability.Multimedia.MediaLibrary.Core
+
+**Return value**
+
+| Type               | Description                             |
+| ------------------- | --------------------------------- |
+| Promise&lt;void&gt; | Promise used to return the execution result.|
+
+**Example**
+
+```
+var media = mediaLibrary.getMediaLibrary(context);
+media.release()
+```
+
+### storeMediaAsset
+
+storeMediaAsset(option: MediaAssetOption, callback: AsyncCallback&lt;string&gt;): void
+
+Stores a media asset. This API uses an asynchronous callback to return the URI that stores the media asset.
+
+This API is defined but not implemented in OpenHarmony 3.1 Release. It will be available for use in OpenHarmony 3.1 MR.
+
+**System capability**: SystemCapability.Multimedia.MediaLibrary.Core
+
+**Parameters**
+
+| Name  | Type                                 | Mandatory| Description                                       |
+| -------- | ------------------------------------- | ---- | ------------------------------------------- |
+| option   | [MediaAssetOption](#mediaassetoption) | Yes  | Media asset option.                             |
+| callback | AsyncCallback&lt;string&gt;           | Yes  | Callback used to return the URI that stores the media asset.|
+
+**Example**
+
+  ```
+let option = {
+    src : "file:///data/data/ohos.xxx.yyy/files/image.png",
+    mimeType : "image/jpeg",
+    relativePath : "imageDir/image2/"
+};
+mediaLibrary.getMediaLibrary().storeMediaAsset(option, (err, value) => {
+    if (err) {
+        console.log("An error occurred when storing the media asset.");
+        return;
+    }
+    console.log("Media asset stored. ");
+    // Obtain the URI that stores the media asset.
+});
+  ```
+
+
+### storeMediaAsset
+
+storeMediaAsset(option: MediaAssetOption): Promise&lt;string&gt;
+
+Stores a media asset. This API uses a promise to return the URI that stores the media asset.
+
+This API is defined but not implemented in OpenHarmony 3.1 Release. It will be available for use in OpenHarmony 3.1 MR.
+
+**System capability**: SystemCapability.Multimedia.MediaLibrary.Core
+
+**Parameters**
+
+| Name| Type                                 | Mandatory| Description          |
+| ------ | ------------------------------------- | ---- | -------------- |
+| option | [MediaAssetOption](#mediaassetoption) | Yes  | Media asset option.|
+
+**Return value**
+
+| Type                 | Description                                          |
+| --------------------- | ---------------------------------------------- |
+| Promise&lt;string&gt; | Promise used to return the URI that stores the media asset.|
+
+**Example**
+
+  ```
+let option = {
+    src : "file:///data/data/ohos.xxx.yyy/files/image.jpg",
+    mimeType : "image/jpeg",
+    relativePath : "imageDir/image2/"
+};
+mediaLibrary.getMediaLibrary().storeMediaAsset(option).then((value) => {
+    console.log("Media asset stored.");
+    // Obtain the URI that stores the media asset.
+}).catch((err) => {
+    console.log("An error occurred when storing the media assets.");
+});
+  ```
+
+
+### startImagePreview
+
+startImagePreview(images: Array&lt;string&gt;, index: number, callback: AsyncCallback&lt;void&gt;): void
+
+Starts image preview, with the first image to preview specified. This API can be used to preview local images whose URIs start with **dataability://** or online images whose URIs start with **https://**. It uses an asynchronous callback to return the execution result.
+
+This API is defined but not implemented in OpenHarmony 3.1 Release. It will be available for use in OpenHarmony 3.1 MR.
+
+**System capability**: SystemCapability.Multimedia.MediaLibrary.Core
+
+**Parameters**
+
+| Name  | Type                     | Mandatory| Description                                               |
+| -------- | ------------------------- | ---- | --------------------------------------------------- |
+| images   | Array&lt;string&gt;       | Yes  | URIs of the images to preview. The value can start with either **https://** or **dataability://**.|
+| index    | number                    | Yes  | Index of the first image to preview.                               |
+| callback | AsyncCallback&lt;void&gt; | Yes  | Callback used to return the image preview result. If the preview fails, an error message is returned.                 |
+
+**Example**
+
+  ```
+let images = [
+    "dataability:///media/external/images/media/50",
+    "dataability:///media/external/images/media/55"
+];
+let images = [
+    "https://media.xxxx.com/image1.jpg",
+    "https://media.xxxx.com/image2.jpg"
+];
+let index = 1;
+mediaLibrary.getMediaLibrary().startImagePreview(images, index, (err) => {
+    if (err) {
+        console.log("An error occurred when previewing the images.");
+        return;
+    }
+    console.log("Succeeded in previewing the images.");
+});
+  ```
+
+
+### startImagePreview
+
+startImagePreview(images: Array&lt;string&gt;, callback: AsyncCallback&lt;void&gt;): void
+
+Starts image preview. This API can be used to preview local images whose URIs start with **dataability://** or online images whose URIs start with **https://**. It uses an asynchronous callback to return the execution result.
+
+This API is defined but not implemented in OpenHarmony 3.1 Release. It will be available for use in OpenHarmony 3.1 MR.
+
+**System capability**: SystemCapability.Multimedia.MediaLibrary.Core
+
+**Parameters**
+
+| Name  | Type                     | Mandatory| Description                                               |
+| -------- | ------------------------- | ---- | --------------------------------------------------- |
+| images   | Array&lt;string&gt;       | Yes  | URIs of the images to preview. The value can start with either **https://** or **dataability://**.|
+| callback | AsyncCallback&lt;void&gt; | Yes  | Callback used to return the image preview result. If the preview fails, an error message is returned.                 |
+
+**Example**
+
+  ```
+let images = [
+    "dataability:///media/external/images/media/50",
+    "dataability:///media/external/images/media/55"
+];
+let images = [
+    "https://media.xxxx.com/image1.jpg",
+    "https://media.xxxx.com/image2.jpg"
+];
+mediaLibrary.getMediaLibrary().startImagePreview(images, (err) => {
+    if (err) {
+        console.log("An error occurred when previewing the images.");
+        return;
+    }
+    console.log("Succeeded in previewing the images.");
+});
+  ```
+
+
+### startImagePreview
+
+startImagePreview(images: Array&lt;string&gt;, index?: number): Promise&lt;void&gt;
+
+Starts image preview, with the first image to preview specified. This API can be used to preview local images whose URIs start with dataability:// or online images whose URIs start with https://. It uses a promise to return the execution result.
+
+This API is defined but not implemented in OpenHarmony 3.1 Release. It will be available for use in OpenHarmony 3.1 MR.
+
+**System capability**: SystemCapability.Multimedia.MediaLibrary.Core
+
+**Parameters**
+
+| Name| Type               | Mandatory| Description                                               |
+| ------ | ------------------- | ---- | --------------------------------------------------- |
+| images | Array&lt;string&gt; | Yes  | URIs of the images to preview. The value can start with either **https://** or **dataability://**.|
+| index  | number              | No  | Index of the first image to preview. If this parameter is not specified, the default value **0** is used.              |
+
+**Return value**
+
+| Type               | Description                                                   |
+| ------------------- | ------------------------------------------------------- |
+| Promise&lt;void&gt; | Promise used to return the image preview result. If the preview fails, an error message is returned.|
+
+**Example**
+
+  ```
+let images = [
+    "dataability:///media/external/images/media/50",
+    "dataability:///media/external/images/media/55"
+];
+let images = [
+    "https://media.xxxx.com/image1.jpg",
+    "https://media.xxxx.com/image2.jpg"
+];
+let index = 1;
+mediaLibrary.getMediaLibrary().startImagePreview(images, index).then(() => {
+    console.log("Succeeded in previewing the images.");
+}).catch((err) => {
+    console.log("An error occurred when previewing the images.");
+});
+  ```
+
+
+### startMediaSelect
+
+startMediaSelect(option: MediaSelectOption, callback: AsyncCallback&lt;Array&lt;string&gt;&gt;): void
+
+Starts media selection. This API uses an asynchronous callback to return the list of URIs that store the selected media assets.
+
+This API is defined but not implemented in OpenHarmony 3.1 Release. It will be available for use in OpenHarmony 3.1 MR.
+
+**System capability**: SystemCapability.Multimedia.MediaLibrary.Core
+
+**Parameters**
+
+| Name  | Type                                    | Mandatory| Description                                                   |
+| -------- | ---------------------------------------- | ---- | ------------------------------------------------------- |
+| option   | [MediaSelectOption](#mediaselectoption)  | Yes  | Media selection option.                                         |
+| callback | AsyncCallback&lt;Array&lt;string&gt;&gt; | Yes  | Callback used to return the list of URIs (starting with **dataability://**) that store the selected media assets.|
+
+**Example**
+
+  ```
+let option = {
+    type : "image",
+    count : 2
+};
+mediaLibrary.getMediaLibrary().startMediaSelect(option, (err, value) => {
+    if (err) {
+        console.log("An error occurred when selecting the media asset.");
+        return;
+    }
+    console.log("Media asset selected.");
+    // Obtain the media selection value.
+});
+  ```
+
+
+### startMediaSelect
+
+startMediaSelect(option: MediaSelectOption): Promise&lt;Array&lt;string&gt;&gt;
+
+Starts media selection. This API uses a promise to return the list of URIs that store the selected media assets.
+
+This API is defined but not implemented in OpenHarmony 3.1 Release. It will be available for use in OpenHarmony 3.1 MR.
+
+**System capability**: SystemCapability.Multimedia.MediaLibrary.Core
+
+**Parameters**
+
+| Name| Type                                   | Mandatory| Description          |
+| ------ | --------------------------------------- | ---- | -------------- |
+| option | [MediaSelectOption](#mediaselectoption) | Yes  | Media selection option.|
+
+**Return value**
+
+| Type                              | Description                                                        |
+| ---------------------------------- | ------------------------------------------------------------ |
+| Promise&lt;Array&lt;string&gt;&gt; | Promise used to return the list of URIs (starting with **dataability://**) that store the selected media assets.|
+
+**Example**
+
+  ```
+let option = {
+    type : "image",
+    count : 2
+};
+mediaLibrary.getMediaLibrary().startMediaSelect(option).then((value) => {
+    console.log("Media asset selected.");
+    // Obtain the media selection value.
+}).catch((err) => {
+    console.log("An error occurred when selecting the media assets.");
+});
+
+  ```
+
+## FileAsset<sup>8+</sup>
+
+Provides APIs for encapsulating file asset attributes.
+
+### Attributes
+
+**System capability**: SystemCapability.Multimedia.MediaLibrary.Core
+
+| Name        | Type                   | Readable| Writable| Description                                                  |
+| ------------ | ----------------------- | ---- | ---- | ------------------------------------------------------ |
+| id           | number                  | Yes  | No  | File asset ID.                                          |
+| uri          | string                  | Yes  | No  | File asset URI, for example, dataability:///media/image/2.        |
+| mimeType     | string                  | Yes  | No  | Extended file attributes.                                          |
+| mediaType    | [MediaType](#mediatype) | Yes  | No  | Media type.                                              |
+| displayName  | string                  | Yes  | Yes  | Display file name, including the file name extension.                                |
+| title        | string                  | Yes  | Yes  | Title in the file.                                              |
+| relativePath | string                  | Yes  | Yes  | Relative public directory of the file.                                      |
+| parent       | number                  | Yes  | No  | Parent directory ID.                                              |
+| size         | number                  | Yes  | No  | File size, in bytes.                                |
+| dateAdded    | number                  | Yes  | No  | Date when the file was added. (The value is the number of seconds elapsed since the Epoch time.)        |
+| dateModified | number                  | Yes  | No  | Date when the file was modified. (The value is the number of seconds elapsed since the Epoch time.)        |
+| dateTaken    | number                  | Yes  | No  | Date when the file (photo) was taken. (The value is the number of seconds elapsed since the Epoch time.)        |
+| artist       | string                  | Yes  | No  | Artist of the file.                                                  |
+| audioAlbum   | string                  | Yes  | No  | Audio album.                                                  |
+| width        | number                  | Yes  | No  | Image width, in pixels.                                |
+| height       | number                  | Yes  | No  | Image height, in pixels.                                |
+| orientation  | number                  | Yes  | Yes  | Image display direction (clockwise rotation angle, for example, 0, 90, or 180, in degrees).|
+| duration     | number                  | Yes  | No  | Duration, in seconds.                                  |
+| albumId      | number                  | Yes  | No  | ID of the album to which the file belongs.                                  |
+| albumUri     | string                  | Yes  | No  | URI of the album to which the file belongs.                                     |
+| albumName    | string                  | Yes  | No  | Name of the album to which the file belongs.                                    |
+
+
+### isDirectory<sup>8+</sup>
+
+isDirectory(callback: AsyncCallback&lt;boolean&gt;): void
+
+Checks whether this file asset is a directory. This API uses an asynchronous callback to return the result.
+
+**Required permissions**: ohos.permission.READ_MEDIA
+
+**System capability**: SystemCapability.Multimedia.MediaLibrary.Core
+
+**Parameters**
+
+| Name  | Type                        | Mandatory| Description                         |
+| -------- | ---------------------------- | ---- | ----------------------------- |
+| callback | AsyncCallback&lt;boolean&gt; | Yes  | Callback used to return whether the file asset is a directory.|
+
+**Example**
+
+```
+async function example() {
+    let imageType = mediaLibrary.MediaType.IMAGE;
+    let getImageOp = {
+      selections: fileKeyObj.MEDIA_TYPE + '= ?',
+      selectionArgs: [imageType.toString()],
+      order: fileKeyObj.DATE_ADDED + " DESC",
+      extendArgs: "",
+    };
+    const fetchFileResult = await media.getFileAssets(getImageOp);
+    const asset = await fetchFileResult.getFirstObject();
+    asset.isDirectory((err, isDirectory) => {
+        // do something
+    });
+}
+```
+
+### isDirectory<sup>8+</sup>
+
+isDirectory():Promise&lt;boolean&gt;
+
+Checks whether this file asset is a directory. This API uses a promise to return the result.
+
+**Required permissions**: ohos.permission.READ_MEDIA
+
+**System capability**: SystemCapability.Multimedia.MediaLibrary.Core
+
+**Return value**
+
+| Type                  | Description                                    |
+| ---------------------- | ---------------------------------------- |
+| Promise&lt;boolean&gt; | Promise used to return whether the file asset is a directory.|
+
+**Example**
+
+```
+async function example() {
+    let imageType = mediaLibrary.MediaType.IMAGE;
+    let getImageOp = {
+      selections: fileKeyObj.MEDIA_TYPE + '= ?',
+      selectionArgs: [imageType.toString()],
+      order: fileKeyObj.DATE_ADDED + " DESC",
+      extendArgs: "",
+    };
+    const fetchFileResult = await media.getFileAssets(getImageOp);
+    const asset = await fetchFileResult.getFirstObject();
+    asset.isDirectory().then(function(isDirectory){
+        console.info("isDirectory result:"+ isDirectory);
+    }).catch(function(err){
+        console.info("isDirectory failed with error:"+ err);
+    });
+}
+```
+
+### commitModify<sup>8+</sup>
+
+commitModify(callback: AsyncCallback&lt;void&gt;): void
+
+Commits the modification of this file asset to the database. This API uses an asynchronous callback to return the result.
+
+**Required permissions**: ohos.permission.READ_MEDIA and ohos.permission.WRITE_MEDIA
+
+**System capability**: SystemCapability.Multimedia.MediaLibrary.Core
+
+**Parameters**
+
+| Name  | Type                     | Mandatory| Description      |
+| -------- | ------------------------- | ---- | ---------- |
+| callback | AsyncCallback&lt;void&gt; | Yes  | Void callback.|
+
+**Example**
+
+```
+async function example() {
+    let imageType = mediaLibrary.MediaType.IMAGE;
+    let getImageOp = {
+      selections: fileKeyObj.MEDIA_TYPE + '= ?',
+      selectionArgs: [imageType.toString()],
+      order: fileKeyObj.DATE_ADDED + " DESC",
+      extendArgs: "",
+    };
+    const fetchFileResult = await media.getFileAssets(getImageOp);
+    const asset = await fetchFileResult.getFirstObject();
+    asset.title = 'newtitle';
+    asset.commitModify(() => {
+        console.info('commitModify success');   
+    });
+}
+```
+
+### commitModify<sup>8+</sup>
+
+commitModify(): Promise&lt;void&gt;
+
+Commits the modification of this file asset to the database. This API uses a promise to return the result.
+
+**Required permissions**: ohos.permission.READ_MEDIA and ohos.permission.WRITE_MEDIA
+
+**System capability**: SystemCapability.Multimedia.MediaLibrary.Core
+
+**Return value**
+
+| Type               | Description         |
+| ------------------- | ------------- |
+| Promise&lt;void&gt; | Void promise.|
+
+**Example**
+
+```
+async function example() {
+    let imageType = mediaLibrary.MediaType.IMAGE;
+    let getImageOp = {
+      selections: fileKeyObj.MEDIA_TYPE + '= ?',
+      selectionArgs: [imageType.toString()],
+      order: fileKeyObj.DATE_ADDED + " DESC",
+      extendArgs: "",
+    };
+    const fetchFileResult = await media.getFileAssets(getImageOp);
+    const asset = await fetchFileResult.getFirstObject();
+    asset.title = 'newtitle';
+    asset.commitModify();
+}
+```
+
+### open<sup>8+</sup>
+
+open(mode: string, callback: AsyncCallback&lt;number&gt;): void
+
+Opens this file asset. This API uses an asynchronous callback to return the result.
+
+**Required permissions**: ohos.permission.READ_MEDIA (when **mode** is set to **r**) and ohos.permission.WRITE_MEDIA (when **mode** is set to **w**)
+
+**System capability**: SystemCapability.Multimedia.MediaLibrary.Core
+
+**Parameters**
+
+| Name  | Type                       | Mandatory| Description                                                    |
+| -------- | --------------------------- | ---- | -------------------------------------------------------- |
+| mode     | string                      | Yes  | Mode of opening the file, for example, **r** (read-only), **w** (write-only), and **rw** (read-write).|
+| callback | AsyncCallback&lt;number&gt; | Yes  | Callback used to return the file handle.                                        |
+
+**Example**
+
+```
+async function example() {
+    let mediaType = mediaLibrary.MediaType.IMAGE;
+    let DIR_IMAGE = mediaLibrary.DirectoryType.DIR_IMAGE;
+    const path = await media.getPublicDirectory(DIR_IMAGE);
+    asset = await media.createAsset(mediaType, "image00003.jpg", path);
+    asset.open('rw', (openError, fd) => {
+            if(fd > 0){
+                asset.close(fd);
+            }else{
+                console.info('File Open Failed!' + openError);
+            }
+    });
+}
+```
+
+### open<sup>8+</sup>
+
+open(mode: string): Promise&lt;number&gt;
+
+Opens this file asset. This API uses a promise to return the result.
+
+**Required permissions**: ohos.permission.READ_MEDIA (when **mode** is set to **r**) and ohos.permission.WRITE_MEDIA (when **mode** is set to **w**)
+
+**System capability**: SystemCapability.Multimedia.MediaLibrary.Core
+
+**Parameters**
+
+| Name| Type  | Mandatory| Description                                                    |
+| ------ | ------ | ---- | -------------------------------------------------------- |
+| mode   | string | Yes  | Mode of opening the file, for example, **r** (read-only), **w** (write-only), and **rw** (read-write).|
+
+**Return value**
+
+| Type                 | Description               |
+| --------------------- | ------------------- |
+| Promise&lt;number&gt; | Promise used to return the file handle.|
+
+**Example**
+
+```
+async function example() {
+    let mediaType = mediaLibrary.MediaType.IMAGE;
+    let DIR_IMAGE = mediaLibrary.DirectoryType.DIR_IMAGE;
+    const path = await media.getPublicDirectory(DIR_IMAGE);
+    asset = await media.createAsset(mediaType, "image00003.jpg", path);
+    asset.open('rw')
+        .then((fd) => {
+            console.info('File fd!' + fd);
+        })
+        .catch((err) => {
+            console.info('File err!' + err);
+        });
+}
+```
+
+### close<sup>8+</sup>
+
+close(fd: number, callback: AsyncCallback&lt;void&gt;): void
+
+Closes this file asset. This API uses an asynchronous callback to return the result.
+
+**Required permissions**: ohos.permission.READ_MEDIA ('r' enabled) and ohos.permission.WRITE_MEDIA ('w' enabled)
+
+**System capability**: SystemCapability.Multimedia.MediaLibrary.Core
+
+**Parameters**
+
+| Name  | Type                     | Mandatory| Description      |
+| -------- | ------------------------- | ---- | ---------- |
+| fd       | number                    | Yes  | File descriptor.|
+| callback | AsyncCallback&lt;void&gt; | Yes  | Void callback.|
+
+**Example**
+
+```
+async function example() {
+    let imageType = mediaLibrary.MediaType.IMAGE;
+    let getImageOp = {
+      selections: fileKeyObj.MEDIA_TYPE + '= ?',
+      selectionArgs: [imageType.toString()],
+      order: fileKeyObj.DATE_ADDED + " DESC",
+      extendArgs: "",
+    };
+    const fetchFileResult = await media.getFileAssets(getImageOp);
+    const asset = await fetchFileResult.getFirstObject();
+    asset.close(fd, (closeErr) => {
+        if (closeErr != undefined) {
+            console.info('mediaLibraryTest : close : FAIL ' + closeErr.message);
+            console.info('mediaLibraryTest : ASSET_CALLBACK : FAIL');
+        } else {
+            console.info("=======asset.close success====>");
+        }
+    });
+}
+```
+
+### close<sup>8+</sup>
+
+close(fd: number): Promise&lt;void&gt;
+
+Closes this file asset. This API uses a promise to return the result.
+
+**Required permissions**: ohos.permission.READ_MEDIA ('r' enabled) and ohos.permission.WRITE_MEDIA ('w' enabled)
+
+**System capability**: SystemCapability.Multimedia.MediaLibrary.Core
+
+**Parameters**
+
+| Name| Type  | Mandatory| Description      |
+| ------ | ------ | ---- | ---------- |
+| fd     | number | Yes  | File descriptor.|
+
+**Return value**
+
+| Type               | Description         |
+| ------------------- | ------------- |
+| Promise&lt;void&gt; | Void promise.|
+
+**Example**
+
+```
+async function example() {
+    let imageType = mediaLibrary.MediaType.IMAGE;
+    let getImageOp = {
+      selections: fileKeyObj.MEDIA_TYPE + '= ?',
+      selectionArgs: [imageType.toString()],
+      order: fileKeyObj.DATE_ADDED + " DESC",
+      extendArgs: "",
+    };
+    const fetchFileResult = await media.getFileAssets(getImageOp);
+    const asset = await fetchFileResult.getFirstObject();
+    asset.close(fd).then((closeErr) => {
+        if (closeErr != undefined) {
+            console.info('mediaLibraryTest : close : FAIL ' + closeErr.message);
+            console.info('mediaLibraryTest : ASSET_CALLBACK : FAIL');
+
+        } else {
+            console.info("=======asset.close success====>");
+        }
+    });
+}
+```
+
+### getThumbnail<sup>8+</sup>
+
+getThumbnail(callback: AsyncCallback&lt;image.PixelMap&gt;): void
+
+Obtains the thumbnail of this file asset. This API uses an asynchronous callback to return the result.
+
+**Required permissions**: ohos.permission.READ_MEDIA
+
+**System capability**: SystemCapability.Multimedia.MediaLibrary.Core
+
+**Parameters**
+
+| Name  | Type                               | Mandatory| Description                    |
+| -------- | ----------------------------------- | ---- | ------------------------ |
+| callback | AsyncCallback&lt;image.PixelMap&gt; | Yes  | Callback used to return the pixel map of the thumbnail.|
+
+**Example**
+
+```
+async function example() {
+    let imageType = mediaLibrary.MediaType.IMAGE;
+    let getImageOp = {
+      selections: fileKeyObj.MEDIA_TYPE + '= ?',
+      selectionArgs: [imageType.toString()],
+      order: fileKeyObj.DATE_ADDED + " DESC",
+      extendArgs: "",
+    };
+    const fetchFileResult = await media.getFileAssets(getImageOp);
+    const asset = await fetchFileResult.getFirstObject();
+    asset.getThumbnail((err, pixelmap) => {
+        console.info('mediaLibraryTest : getThumbnail Successfull '+ pixelmap);
+    });
+}
+```
+
+### getThumbnail<sup>8+</sup>
+
+getThumbnail(size: Size, callback: AsyncCallback&lt;image.PixelMap&gt;): void
+
+Obtains the thumbnail of this file asset, with the thumbnail size passed. This API uses an asynchronous callback to return the result.
+
+**Required permissions**: ohos.permission.READ_MEDIA
+
+**System capability**: SystemCapability.Multimedia.MediaLibrary.Core
+
+**Parameters**
+
+| Name  | Type                               | Mandatory| Description                    |
+| -------- | ----------------------------------- | ---- | ------------------------ |
+| size     | [Size](#size8)                      | Yes  | Size of the thumbnail.              |
+| callback | AsyncCallback&lt;image.PixelMap&gt; | Yes  | Callback used to return the pixel map of the thumbnail.|
+
+**Example**
+
+```
+async function example() {
+    let imageType = mediaLibrary.MediaType.IMAGE;
+    let getImageOp = {
+      selections: fileKeyObj.MEDIA_TYPE + '= ?',
+      selectionArgs: [imageType.toString()],
+      order: fileKeyObj.DATE_ADDED + " DESC",
+      extendArgs: "",
+    };
+    const fetchFileResult = await media.getFileAssets(getImageOp);
+    const asset = await fetchFileResult.getFirstObject();
+    asset.getThumbnail(size, (err, pixelmap) => {
+        console.info('mediaLibraryTest : getThumbnail Successfull '+ pixelmap);
+    });
+}
+```
+
+### getThumbnail<sup>8+</sup>
+
+getThumbnail(size?: Size): Promise&lt;image.PixelMap&gt;
+
+Obtains the thumbnail of this file asset, with the thumbnail size passed. This API uses a promise to return the result.
+
+**Required permissions**: ohos.permission.READ_MEDIA
+
+**System capability**: SystemCapability.Multimedia.MediaLibrary.Core
+
+**Parameters**
+
+| Name| Type          | Mandatory| Description      |
+| ------ | -------------- | ---- | ---------- |
+| size   | [Size](#size8) | No  | Size of the thumbnail.|
+
+**Return value**
+
+| Type                         | Description                       |
+| ----------------------------- | --------------------------- |
+| Promise&lt;image.PixelMap&gt; | Promise to return the pixel map of the thumbnail.|
+
+**Example**
+
+```
+async function example() {
+    let imageType = mediaLibrary.MediaType.IMAGE;
+    let getImageOp = {
+      selections: fileKeyObj.MEDIA_TYPE + '= ?',
+      selectionArgs: [imageType.toString()],
+      order: fileKeyObj.DATE_ADDED + " DESC",
+      extendArgs: "",
+    };
+    const fetchFileResult = await media.getFileAssets(getImageOp);
+    const asset = await fetchFileResult.getFirstObject();
+    asset.getThumbnail(size, (err, pixelmap) => {
+        console.info('mediaLibraryTest : getThumbnail Successfull '+ pixelmap);
+    });
+}
+```
+
+### favorite<sup>8+</sup>
+
+favorite(isFavorite: boolean, callback: AsyncCallback&lt;void&gt;): void
+
+Favorites or unfavorites this file asset. This API uses an asynchronous callback to return the result.
+
+**Required permissions**: ohos.permission.READ_MEDIA and ohos.permission.WRITE_MEDIA
+
+**System capability**: SystemCapability.Multimedia.MediaLibrary.Core
+
+**Parameters**
+
+| Name    | Type                     | Mandatory| Description                                                      |
+| ---------- | ------------------------- | ---- | ---------------------------------------------------------- |
+| isFavorite | boolean                   | Yes  | Whether to favorite or unfavorite the file. The value **true** means to favorite the file, and **false** means to unfavorite the file.|
+| callback   | AsyncCallback&lt;void&gt; | Yes  | Void callback.                                                |
+
+**Example**
+
+```
+async function example() {
+    let imageType = mediaLibrary.MediaType.IMAGE;
+    let getImageOp = {
+      selections: fileKeyObj.MEDIA_TYPE + '= ?',
+      selectionArgs: [imageType.toString()],
+      order: fileKeyObj.DATE_ADDED + " DESC",
+      extendArgs: "",
+    };
+    const fetchFileResult = await media.getFileAssets(getImageOp);
+    const asset = await fetchFileResult.getFirstObject();
+    asset.favorite(true,function(err){
+        // do something
+    });
+}
+```
+
+### favorite<sup>8+</sup>
+
+favorite(isFavorite: boolean): Promise&lt;void&gt;
+
+Favorites or unfavorites this file asset. This API uses a promise to return the result.
+
+**Required permissions**: ohos.permission.READ_MEDIA and ohos.permission.WRITE_MEDIA
+
+**System capability**: SystemCapability.Multimedia.MediaLibrary.Core
+
+**Parameters**
+
+| Name    | Type   | Mandatory| Description                                                      |
+| ---------- | ------- | ---- | ---------------------------------------------------------- |
+| isFavorite | boolean | Yes  | Whether to favorite or unfavorite the file. The value **true** means to favorite the file, and **false** means to unfavorite the file.|
+
+**Return value**
+
+| Type               | Description         |
+| ------------------- | ------------- |
+| Promise&lt;void&gt; | Void promise.|
+
+**Example**
+
+```
+async function example() {
+    let imageType = mediaLibrary.MediaType.IMAGE;
+    let getImageOp = {
+      selections: fileKeyObj.MEDIA_TYPE + '= ?',
+      selectionArgs: [imageType.toString()],
+      order: fileKeyObj.DATE_ADDED + " DESC",
+      extendArgs: "",
+    };
+    const fetchFileResult = await media.getFileAssets(getImageOp);
+    const asset = await fetchFileResult.getFirstObject();
+    asset.favorite(true).then(function() {
+        console.info("favorite successfully");
+    }).catch(function(err){
+        console.info("favorite failed with error:"+ err);
+    });
+}
+```
+
+### isFavorite<sup>8+</sup>
+
+isFavorite(callback: AsyncCallback&lt;boolean&gt;): void
+
+Checks whether this file asset is favorited. This API uses an asynchronous callback to return the result.
+
+**Required permissions**: ohos.permission.READ_MEDIA
+
+**System capability**: SystemCapability.Multimedia.MediaLibrary.Core
+
+**Parameters**
+
+| Name  | Type                        | Mandatory| Description                  |
+| -------- | ---------------------------- | ---- | ---------------------- |
+| callback | AsyncCallback&lt;boolean&gt; | Yes  | Callback used to return whether the file asset is favorited.|
+
+**Example**
+
+```
+async function example() {
+    let imageType = mediaLibrary.MediaType.IMAGE;
+    let getImageOp = {
+      selections: fileKeyObj.MEDIA_TYPE + '= ?',
+      selectionArgs: [imageType.toString()],
+      order: fileKeyObj.DATE_ADDED + " DESC",
+      extendArgs: "",
+    };
+    const fetchFileResult = await media.getFileAssets(getImageOp);
+    const asset = await fetchFileResult.getFirstObject();
+    asset.isFavorite((err, isFavorite) => {
+        if (isFavorite) {
+            console.info('FileAsset is favorite');
+        }else{
+            console.info('FileAsset is not favorite');
+        }
+    });
+}
+```
+
+### isFavorite<sup>8+</sup>
+
+isFavorite():Promise&lt;boolean&gt;
+
+Checks whether this file asset is favorited. This API uses a promise to return the result.
+
+**Required permissions**: ohos.permission.READ_MEDIA
+
+**System capability**: SystemCapability.Multimedia.MediaLibrary.Core
+
+**Return value**
+
+| Type                  | Description                         |
+| ---------------------- | ----------------------------- |
+| Promise&lt;boolean&gt; | Promise used to return whether the file asset is favorited.|
+
+**Example**
+
+```
+async function example() {
+    let imageType = mediaLibrary.MediaType.IMAGE;
+    let getImageOp = {
+      selections: fileKeyObj.MEDIA_TYPE + '= ?',
+      selectionArgs: [imageType.toString()],
+      order: fileKeyObj.DATE_ADDED + " DESC",
+      extendArgs: "",
+    };
+    const fetchFileResult = await media.getFileAssets(getImageOp);
+    const asset = await fetchFileResult.getFirstObject();
+    asset.isFavorite().then(function(isFavorite){
+        console.info("isFavorite result:"+ isFavorite);
+    }).catch(function(err){
+        console.info("isFavorite failed with error:"+ err);
+    });
+}
+```
+
+### trash<sup>8+</sup>
+
+trash(isTrash: boolean, callback: AsyncCallback&lt;void&gt;): void
+
+Moves this file asset to the trash. This API uses an asynchronous callback to return the result.
+
+Files in the trash are not actually deleted. You can set **isTrash** to **false** to restore the files from the trash.
+
+**Required permissions**: ohos.permission.READ_MEDIA and ohos.permission.WRITE_MEDIA
+
+**System capability**: SystemCapability.Multimedia.MediaLibrary.Core
+
+**Parameters**
+
+| Name  | Type                     | Mandatory| Description              |
+| -------- | ------------------------- | ---- | ------------------ |
+| isTrash  | boolean                   | Yes  | Whether to move the file asset to the trash. The value **true** means to move the file asset to the trash, and **false** means the opposite.|
+| callback | AsyncCallback&lt;void&gt; | Yes  | Void callback.        |
+
+**Example**
+
+```
+async function example() {
+    let imageType = mediaLibrary.MediaType.IMAGE;
+    let getImageOp = {
+      selections: fileKeyObj.MEDIA_TYPE + '= ?',
+      selectionArgs: [imageType.toString()],
+      order: fileKeyObj.DATE_ADDED + " DESC",
+      extendArgs: "",
+    };
+    const fetchFileResult = await media.getFileAssets(getImageOp);
+    const asset = await fetchFileResult.getFirstObject();
+    asset.trash(true, trashCallBack);
+    function trashCallBack(err, trash) {
+        console.info('mediaLibraryTest : ASSET_CALLBACK ASSET_CALLBACK trash');
+    }
+}
+```
+
+### trash<sup>8+</sup>
+
+trash(isTrash: boolean): Promise&lt;void&gt;
+
+Moves this file asset to the trash. This API uses a promise to return the result.
+
+Files in the trash are not actually deleted. You can set **isTrash** to **false** to restore the files from the trash.
+
+**Required permissions**: ohos.permission.READ_MEDIA and ohos.permission.WRITE_MEDIA
+
+**System capability**: SystemCapability.Multimedia.MediaLibrary.Core
+
+**Parameters**
+
+| Name | Type   | Mandatory| Description              |
+| ------- | ------- | ---- | ------------------ |
+| isTrash | boolean | Yes  | Whether to move the file asset to the trash. The value **true** means to move the file asset to the trash, and **false** means the opposite.|
+
+**Return value**
+
+| Type               | Description         |
+| ------------------- | ------------- |
+| Promise&lt;void&gt; | Void promise.|
+
+**Example**
+
+```
+async function example() {
+    let imageType = mediaLibrary.MediaType.IMAGE;
+    let getImageOp = {
+      selections: fileKeyObj.MEDIA_TYPE + '= ?',
+      selectionArgs: [imageType.toString()],
+      order: fileKeyObj.DATE_ADDED + " DESC",
+      extendArgs: "",
+    };
+    const fetchFileResult = await media.getFileAssets(getImageOp);
+    const asset = await fetchFileResult.getFirstObject();
+    asset.trash(true).then(function() {
+        console.info("trash successfully");
+    }).catch(function(err){
+        console.info("trash failed with error:"+ err);
+    });
+}
+```
+
+### isTrash<sup>8+</sup>
+
+isTrash(callback: AsyncCallback&lt;boolean&gt;): void
+
+Checks whether this file asset is in the trash. This API uses an asynchronous callback to return the result.
+
+**Required permissions**: ohos.permission.READ_MEDIA
+
+**System capability**: SystemCapability.Multimedia.MediaLibrary.Core
+
+**Parameters**
+
+| Name  | Type                        | Mandatory| Description                          |
+| -------- | ---------------------------- | ---- | ------------------------------ |
+| callback | AsyncCallback&lt;boolean&gt; | Yes  | Callback used to return whether the file asset is in the trash. If the file asset is in the trash, **true** will be returned; otherwise, **false** will be returned.|
+
+**Example**
+
+```
+async function example() {
+    let imageType = mediaLibrary.MediaType.IMAGE;
+    let getImageOp = {
+      selections: fileKeyObj.MEDIA_TYPE + '= ?',
+      selectionArgs: [imageType.toString()],
+      order: fileKeyObj.DATE_ADDED + " DESC",
+      extendArgs: "",
+    };
+    const fetchFileResult = await media.getFileAssets(getImageOp);
+    const asset = await fetchFileResult.getFirstObject();
+    asset.isTrash(isTrashCallBack);
+    function isTrashCallBack(err, isTrash) {
+            if (isTrash == true) {
+                console.info('mediaLibraryTest : ASSET_CALLBACK ASSET_CALLBACK isTrash = ' + isTrash);
+                asset.trash(true, trashCallBack);
+
+            } else {
+                console.info('mediaLibraryTest : ASSET_CALLBACK isTrash Unsuccessfull = ' + err);
+                console.info('mediaLibraryTest : ASSET_CALLBACK isTrash : FAIL');
+
+            }
+    }
+}
+```
+
+### isTrash<sup>8+</sup>
+
+isTrash():Promise&lt;boolean&gt;
+
+Checks whether this file asset is in the trash. This API uses a promise to return the result.
+
+**Required permissions**: ohos.permission.READ_MEDIA
+
+**System capability**: SystemCapability.Multimedia.MediaLibrary.Core
+
+**Return value**
+
+| Type               | Description                             |
+| ------------------- | --------------------------------- |
+| Promise&lt;void&gt; | Promise used to return whether the file asset is in the trash. If the file asset is in the trash, **true** will be returned; otherwise, **false** will be returned.|
+
+**Example**
+
+```
+async function example() {
+    let imageType = mediaLibrary.MediaType.IMAGE;
+    let getImageOp = {
+      selections: fileKeyObj.MEDIA_TYPE + '= ?',
+      selectionArgs: [imageType.toString()],
+      order: fileKeyObj.DATE_ADDED + " DESC",
+      extendArgs: "",
+    };
+    const fetchFileResult = await media.getFileAssets(getImageOp);
+    const asset = await fetchFileResult.getFirstObject();
+    asset.isTrash().then(function(isTrash){
+        console.info("isTrash result:"+ isTrash);
+    }).catch(function(err){
+        console.info("isTrash failed with error:"+ err);
+    });
+}
+```
+
+## FetchFileResult<sup>8+</sup>
+
+Implements the result set of the file retrieval operation.
+
+### getCount<sup>8+</sup>
+
+getCount(): number
+
+Obtains the total number of files in the result set.
+
+**System capability**: SystemCapability.Multimedia.MediaLibrary.Core
+
+**Return value**
+
+| Type  | Description            |
+| ------ | ---------------- |
+| number | Total number of files.|
+
+**Example**
+
+```
+async function example() {
+    let getFileCountOneOp = {
+        selections: fileKeyObj.MEDIA_TYPE + '= ?',
+        selectionArgs: [fileType.toString()],
+        order: fileKeyObj.DATE_ADDED + " DESC",
+        extendArgs: "",
+    };
+    let fetchFileResult = await media.getFileAssets(getFileCountOneOp);
+    const fetchCount = fetchFileResult.getCount();
+}
+```
+
+### isAfterLast<sup>8+</sup>
+
+isAfterLast(): boolean
+
+Checks whether the cursor is in the last row of the result set.
+
+**System capability**: SystemCapability.Multimedia.MediaLibrary.Core
+
+**Return value**
+
+| Type   | Description                                                       |
+| ------- | ----------------------------------------------------------- |
+| boolean | Returns **true** if the cursor is in the last row of the result set; returns *false** otherwise.|
+
+**Example**
+
+```
+async function example() {
+    let imageType = mediaLibrary.MediaType.IMAGE;
+    let getImageOp = {
+      selections: fileKeyObj.MEDIA_TYPE + '= ?',
+      selectionArgs: [imageType.toString()],
+      order: fileKeyObj.DATE_ADDED + " DESC",
+      extendArgs: "",
+    };
+    let fetchFileResult = await media.getFileAssets(getImageOp);
+    const fetchCount = fetchFileResult.getCount();
+    console.info('mediaLibraryTest : count:' + fetchCount);
+    let fileAsset = await fetchFileResult.getFirstObject();
+    for (var i = 1; i < fetchCount; i++) {
+            fileAsset = await fetchFileResult.getNextObject();
+            if(i == fetchCount - 1) {
+              console.info('mediaLibraryTest : isLast');
+              var result = fetchFileResult.isAfterLast();
+              console.info('mediaLibraryTest : isAfterLast:' + result);
+              console.info('mediaLibraryTest : isAfterLast end');
+              fetchFileResult.close();
+
+            }
+    }
+}
+```
+
+### close<sup>8+</sup>
+
+close(): void
+
+Releases and invalidates this **FetchFileResult** instance. Other APIs cannot be invoked after the instance is released.
+
+**System capability**: SystemCapability.Multimedia.MediaLibrary.Core
+
+**Example**
+
+```
+async function example() {
+    let imageType = mediaLibrary.MediaType.IMAGE;
+    let getImageOp = {
+      selections: fileKeyObj.MEDIA_TYPE + '= ?',
+      selectionArgs: [imageType.toString()],
+      order: fileKeyObj.DATE_ADDED + " DESC",
+      extendArgs: "",
+    };
+    let fetchFileResult = await media.getFileAssets(getImageOp);
+    fetchFileResult.close();
+}
+```
+
+### getFirstObject<sup>8+</sup>
+
+getFirstObject(callback: AsyncCallback&lt;FileAsset&gt;): void
+
+Obtains the first file asset in the result set. This API uses an asynchronous callback to return the result.
+
+**System capability**: SystemCapability.Multimedia.MediaLibrary.Core
+
+**Parameters**
+
+| Name  | Type                                         | Mandatory| Description                                       |
+| -------- | --------------------------------------------- | ---- | ------------------------------------------- |
+| callback | AsyncCallback&lt;[FileAsset](#fileasset8)&gt; | Yes  | Callback used to return the first file asset.|
+
+**Example**
+
+```
+async function example() {
+    let imageType = mediaLibrary.MediaType.IMAGE;
+    let getImageOp = {
+      selections: fileKeyObj.MEDIA_TYPE + '= ?',
+      selectionArgs: [imageType.toString()],
+      order: fileKeyObj.DATE_ADDED + " DESC",
+      extendArgs: "",
+    };
+    let fetchFileResult = await media.getFileAssets(getImageOp);
+    fetchFileResult.getFirstObject((err, value) => {
+       if (err) {
+           console.error('Failed ');
+           return;
+       }
+       console.log(value);
+    })
+}
+```
+
+### getFirstObject<sup>8+</sup>
+
+getFirstObject(): Promise&lt;FileAsset&gt;
+
+Obtains the first file asset in the result set. This API uses a promise to return the result.
+
+**System capability**: SystemCapability.Multimedia.MediaLibrary.Core
+
+**Return value**
+
+| Type                                   | Description                    |
+| --------------------------------------- | ------------------------ |
+| Promise&lt;[FileAsset](#fileasset8)&gt; | Promise used to return the file asset.|
+
+**Example**
+
+```
+async function example() {
+    let imageType = mediaLibrary.MediaType.IMAGE;
+    let getImageOp = {
+      selections: fileKeyObj.MEDIA_TYPE + '= ?',
+      selectionArgs: [imageType.toString()],
+      order: fileKeyObj.DATE_ADDED + " DESC",
+      extendArgs: "",
+    };
+    let fetchFileResult = await media.getFileAssets(getImageOp);
+    fetchFileResult.getFirstObject().then(function(fileAsset){
+        console.info("getFirstObject successfully:"+ JSON.stringify(fileAsset));
+    }).catch(function(err){
+        console.info("getFirstObject failed with error:"+ err);
+    });
+}
+```
+
+### getNextObject<sup>8+</sup>
+
+ getNextObject(callback: AsyncCallback&lt;FileAsset&gt;): void
+
+Obtains the next file asset in the result set. This API uses an asynchronous callback to return the result.
+
+**Required permissions**: ohos.permission.READ_MEDIA
+
+**System capability**: SystemCapability.Multimedia.MediaLibrary.Core
+
+**Parameters**
+
+| Name   | Type                                         | Mandatory| Description                                     |
+| --------- | --------------------------------------------- | ---- | ----------------------------------------- |
+| callbacke | AsyncCallback&lt;[FileAsset](#fileasset8)&gt; | Yes  | Callback used to return the next file asset.|
+
+**Example**
+
+```
+async function example() {
+    let imageType = mediaLibrary.MediaType.IMAGE;
+    let getImageOp = {
+      selections: fileKeyObj.MEDIA_TYPE + '= ?',
+      selectionArgs: [imageType.toString()],
+      order: fileKeyObj.DATE_ADDED + " DESC",
+      extendArgs: "",
+    };
+    let fetchFileResult = await media.getFileAssets(getImageOp);
+    fetchFileResult.getNextObject((err, value) => {
+       if (err) {
+           console.error('Failed ');
+           return;
+       }
+       console.log(value);
+    })
+}
+```
+
+### getNextObject<sup>8+</sup>
+
+ getNextObject(): Promise&lt;FileAsset&gt;
+
+Obtains the next file asset in the result set. This API uses a promise to return the result.
+
+**Required permissions**: ohos.permission.READ_MEDIA
+
+**System capability**: SystemCapability.Multimedia.MediaLibrary.Core
+
+**Return value**
+
+| Type                                   | Description             |
+| --------------------------------------- | ----------------- |
+| Promise&lt;[FileAsset](#fileasset8)&gt; | Promise used to return the next file asset.|
+
+**Example**
+
+```
+async function example() {
+    let imageType = mediaLibrary.MediaType.IMAGE;
+    let getImageOp = {
+      selections: fileKeyObj.MEDIA_TYPE + '= ?',
+      selectionArgs: [imageType.toString()],
+      order: fileKeyObj.DATE_ADDED + " DESC",
+      extendArgs: "",
+    };
+    let fetchFileResult = await media.getFileAssets(getImageOp);
+    const fetchCount = fetchFileResult.getCount();
+    console.info('mediaLibraryTest : count:' + fetchCount);
+    fileAsset = await fetchFileResult.getNextObject();
+}
+```
+
+### getLastObject<sup>8+</sup>
+
+getLastObject(callback: AsyncCallback&lt;FileAsset&gt;): void
+
+Obtains the last file asset in the result set. This API uses an asynchronous callback to return the result.
+
+**System capability**: SystemCapability.Multimedia.MediaLibrary.Core
+
+**Parameters**
+
+| Name    | Type                                         | Mandatory| Description                       |
+| -------- | --------------------------------------------- | ---- | --------------------------- |
+| callback | AsyncCallback&lt;[FileAsset](#fileasset8)&gt; | Yes  | Callback used to return the last file asset.|
+
+**Example**
+
+```
+async function example() {
+    let imageType = mediaLibrary.MediaType.IMAGE;
+    let getImageOp = {
+      selections: fileKeyObj.MEDIA_TYPE + '= ?',
+      selectionArgs: [imageType.toString()],
+      order: fileKeyObj.DATE_ADDED + " DESC",
+      extendArgs: "",
+    };
+    let fetchFileResult = await media.getFileAssets(getImageOp);
+    fetchFileResult.getLastObject((err, value) => {
+       if (err) {
+           console.error('Failed ');
+           return;
+       }
+       console.log(value);
+    })
+}
+```
+
+### getLastObject<sup>8+</sup>
+
+getLastObject(): Promise&lt;FileAsset&gt;
+
+Obtains the last file asset in the result set. This API uses a promise to return the result.
+
+**System capability**: SystemCapability.Multimedia.MediaLibrary.Core
+
+**Return value**
+
+| Type                                   | Description             |
+| --------------------------------------- | ----------------- |
+| Promise&lt;[FileAsset](#fileasset8)&gt; | Promise used to return the next file asset.|
+
+**Example**
+
+```
+async function example() {
+    let imageType = mediaLibrary.MediaType.IMAGE;
+    let getImageOp = {
+      selections: fileKeyObj.MEDIA_TYPE + '= ?',
+      selectionArgs: [imageType.toString()],
+      order: fileKeyObj.DATE_ADDED + " DESC",
+      extendArgs: "",
+    };
+    let fetchFileResult = await media.getFileAssets(getImageOp);
+    let lastObject = await fetchFileResult.getLastObject();
+}
+```
+
+### getPositionObject<sup>8+</sup>
+
+getPositionObject(index: number, callback: AsyncCallback&lt;FileAsset&gt;): void
+
+Obtains a file asset with the specified index in the result set. This API uses an asynchronous callback to return the result.
+
+**System capability**: SystemCapability.Multimedia.MediaLibrary.Core
+
+**Parameters**
+
+| Name    | Type                                         | Mandatory| Description                       |
+| -------- | --------------------------------------------- | ---- | --------------------------- |
+| index    | number                                        | Yes  | Index of the file asset to obtain. The value starts from **0**.|
+| callback | AsyncCallback&lt;[FileAsset](#fileasset8)&gt; | Yes  | Callback used to return the last file asset.|
+
+**Example**
+
+```
+async function example() {
+    let imageType = mediaLibrary.MediaType.IMAGE;
+    let getImageOp = {
+      selections: fileKeyObj.MEDIA_TYPE + '= ?',
+      selectionArgs: [imageType.toString()],
+      order: fileKeyObj.DATE_ADDED + " DESC",
+      extendArgs: "",
+    };
+    let fetchFileResult = await media.getFileAssets(getImageOp);
+    fetchFileResult.getPositionObject(0, (err, value) => {
+       if (err) {
+           console.error('Failed ');
+           return;
+       }
+       console.log(value);
+    })
+}
+```
+
+### getPositionObject<sup>8+</sup>
+
+getPositionObject(index: number): Promise&lt;FileAsset&gt;
+
+Obtains a file asset with the specified index in the result set. This API uses a promise to return the result.
+
+**Required permissions**: ohos.permission.READ_MEDIA
+
+**System capability**: SystemCapability.Multimedia.MediaLibrary.Core
+
+**Parameters**
+
+| Name | Type  | Mandatory| Description                       |
+| ----- | ------ | ---- | --------------------------- |
+| index | number | Yes  | Index of the file asset to obtain. The value starts from **0**.|
+
+**Return value**
+
+| Type                                   | Description             |
+| --------------------------------------- | ----------------- |
+| Promise&lt;[FileAsset](#fileasset8)&gt; | Promise used to return the next file asset.|
+
+**Example**
+
+```
+async function example() {
+    let imageType = mediaLibrary.MediaType.IMAGE;
+    let getImageOp = {
+      selections: fileKeyObj.MEDIA_TYPE + '= ?',
+      selectionArgs: [imageType.toString()],
+      order: fileKeyObj.DATE_ADDED + " DESC",
+      extendArgs: "",
+    };
+    let fetchFileResult = await media.getFileAssets(getImageOp);
+    fetchFileResult.getPositionObject(1, (err, value) => {
+       if (err) {
+           console.error('Failed ');
+           return;
+       }
+       console.log(value);
+    })
+}
+```
+
+### getAllObject<sup>8+</sup>
+
+getAllObject(callback: AsyncCallback&lt;Array&lt;FileAsset&gt;&gt;): void
+
+Obtains all the file assets in the result set. This API uses an asynchronous callback to return the result.
+
+**Required permissions**: ohos.permission.READ_MEDIA
+
+**System capability**: SystemCapability.Multimedia.MediaLibrary.Core
+
+**Parameters**
+
+| Name    | Type                                          | Mandatory| Description                           |
+| -------- | ---------------------------------------------- | ---- | ------------------------------- |
+| callback | AsyncCallback<Array<[FileAsset](#fileasset8)>> | Yes  | Callback used to return the file assets.|
+
+**Example**
+
+```
+async function example() {
+    let imageType = mediaLibrary.MediaType.IMAGE;
+    let getImageOp = {
+      selections: fileKeyObj.MEDIA_TYPE + '= ?',
+      selectionArgs: [imageType.toString()],
+      order: fileKeyObj.DATE_ADDED + " DESC",
+      extendArgs: "",
+    };
+    let fetchFileResult = await media.getFileAssets(getImageOp);
+    fetchFileResult.getAllObject((err, value) => {
+       if (err) {
+           console.error('Failed ');
+           return;
+       }
+       console.log(value);
+    })
+}
+```
+
+### getAllObject<sup>8+</sup>
+
+getAllObject(): Promise&lt;Array&lt;FileAsset&gt;&gt;
+
+Obtains all the file assets in the result set. This API uses a promise to return the result.
+
+**System capability**: SystemCapability.Multimedia.MediaLibrary.Core
+
+**Return value**
+
+| Type                                    | Description                 |
+| ---------------------------------------- | --------------------- |
+| Promise<Array<[FileAsset](#fileasset8)>> | Promise used to return the file assets.|
+
+**Example**
+
+```
+async function example() {
+    let imageType = mediaLibrary.MediaType.IMAGE;
+    let getImageOp = {
+      selections: fileKeyObj.MEDIA_TYPE + '= ?',
+      selectionArgs: [imageType.toString()],
+      order: fileKeyObj.DATE_ADDED + " DESC",
+      extendArgs: "",
+    };
+    let fetchFileResult = await media.getFileAssets(getImageOp);
+    var data = fetchFileResult.getAllObject();
+}
+```
+
+## Album<sup>8+</sup>
+
+Provides APIs to implement a physical album.
+
+### **Attributes**
+
+**System capability**: SystemCapability.Multimedia.MediaLibrary.Core
+
+| Name        | Type| Readable| Writable| Description          |
+| ------------ | ------ | ---- | ---- | -------------- |
+| albumId      | number | Yes  | No  | Album ID.      |
+| albumName    | string | Yes  | Yes  | Album name.      |
+| albumUri     | string | Yes  | No  | Album URI.       |
+| dateModified | number | Yes  | No  | Date when the album was modified.      |
+| count        | number | Yes  | No  | Number of files in the album.|
+| relativePath | string | Yes  | No  | Relative path of the album.      |
+| coverUri     | string | Yes  | No  | URI of the cover file of the album.   |
+
+### commitModify<sup>8+</sup>
+
+commitModify(callback: AsyncCallback&lt;void&gt;): void
+
+Commits the modification of the album attributes to the database. This API uses an asynchronous callback to return the result.
+
+**Required permissions**: ohos.permission.READ_MEDIA and ohos.permission.WRITE_MEDIA
+
+**System capability**: SystemCapability.Multimedia.MediaLibrary.Core
+
+**Parameters**
+
+| Name    | Type                     | Mandatory| Description      |
+| -------- | ------------------------- | ---- | ---------- |
+| callback | AsyncCallback&lt;void&gt; | Yes  | Void callback.|
+
+**Example**
+
+```
+async function example() {
+    let AlbumNoArgsfetchOp = {
+        selections: '',
+        selectionArgs: [],
+    };
+    const albumList = await media.getAlbums(AlbumNoArgsfetchOp);
+    const album = albumList[0];
+    album.albumName = 'hello';
+    album.commitModify((err) => {
+       if (err) {
+           console.error('Failed ');
+           return;
+       }
+       console.log('Modify successful.');
+    })
+}
+```
+
+### commitModify<sup>8+</sup>
+
+commitModify(): Promise&lt;void&gt;
+
+Commits the modification of the album attributes to the database. This API uses a promise to return the result.
+
+**Required permissions**: ohos.permission.READ_MEDIA and ohos.permission.WRITE_MEDIA
+
+**System capability**: SystemCapability.Multimedia.MediaLibrary.Core
+
+**Return value**
+
+| Type               | Description             |
+| ------------------- | ----------------- |
+| Promise&lt;void&gt; | Void promise.|
+
+**Example**
+
+```
+async function example() {
+    let AlbumNoArgsfetchOp = {
+        selections: '',
+        selectionArgs: [],
+    };
+    const albumList = await media.getAlbums(AlbumNoArgsfetchOp);
+    const album = albumList[0];
+    album.albumName = 'hello';
+    album.commitModify().then(function() {
+        console.info("commitModify successfully");
+    }).catch(function(err){
+        console.info("commitModify failed with error:"+ err);
+    });
+}
+```
+
+### getFileAssets<sup>8+</sup>
+
+getFileAssets(options: MediaFetchOptions, callback: AsyncCallback&lt;FetchFileResult&gt;): void
+
+Obtains the file assets in this album. This API uses an asynchronous callback to return the result.
+
+**Required permissions**: ohos.permission.READ_MEDIA
+
+**System capability**: SystemCapability.Multimedia.MediaLibrary.Core
+
+**Parameters**
+
+| Name    | Type                                               | Mandatory| Description                             |
+| -------- | --------------------------------------------------- | ---- | --------------------------------- |
+| options  | [MediaFetchOptions](#mediafetchoptions8)            | Yes  | Options for fetching the files.                     |
+| callback | AsyncCallback<[FetchFileResult](#fetchfileresult8)> | Yes  | Callback used to return the file assets.|
+
+**Example**
+
+```
+async function example() {
+    let AlbumNoArgsfetchOp = {
+        selections: '',
+        selectionArgs: [],
+    };
+    const albumList = await media.getAlbums(AlbumNoArgsfetchOp);
+    const album = albumList[0];
+    album.getFileAssets(fileNoArgsfetchOp, getFileAssetsCallBack);
+    function getFileAssetsCallBack(err, fetchFileResult) {
+        // do something
+    }
+}
+```
+
+### getFileAssets<sup>8+</sup>
+
+ getFileAssets(options?: MediaFetchOptions): Promise&lt;FetchFileResult&gt;
+
+Obtains the file assets in this album. This API uses a promise to return the result.
+
+**Required permissions**: ohos.permission.READ_MEDIA
+
+**System capability**: SystemCapability.Multimedia.MediaLibrary.Core
+
+**Parameters**
+
+| Name   | Type                                    | Mandatory| Description        |
+| ------- | ---------------------------------------- | ---- | ------------ |
+| options | [MediaFetchOptions](#mediafetchoptions8) | No  | Options for fetching the files.|
+
+**Return value**
+
+| Type                                         | Description                   |
+| --------------------------------------------- | ----------------------- |
+| Promise<[FetchFileResult](#fetchfileresult8)> | Promise used to return the file assets.|
+
+**Example**
+
+```
+async function example() {
+    let AlbumNoArgsfetchOp = {
+        selections: '',
+        selectionArgs: [],
+    };
+    const albumList = await media.getAlbums(AlbumNoArgsfetchOp);
+    const album = albumList[0];
+    album.getFileAssets(fileNoArgsfetchOp).then(function(albumFetchFileResult){
+        console.info("getFileAssets successfully:"+ JSON.stringify(albumFetchFileResult));
+    }).catch(function(err){
+        console.info("getFileAssets failed with error:"+ err);
+    });
+}
+```
+
+## PeerInfo<sup>8+</sup>
+
+Describes information about a registered device.
+
+**System capability**: SystemCapability.Multimedia.MediaLibrary.Core
+
+| Name      | Type      | Readable| Writable| Description            |
+| ---------- | ---------- | ---- | ---- | ---------------- |
+| deviceName | string     | Yes  | No  | Name of the registered device.  |
+| networkId  | string     | Yes  | No  | Network ID of the registered device.|
+| deviceType | DeviceType | Yes  | No  | Type of the registered device.        |
+| isOnline   | boolean    | Yes  | No  | Whether the registered device is online.        |
+
+
+
+MediaType
+---------
+
+Enumerates media types.
+
+**System capability**: SystemCapability.Multimedia.MediaLibrary.Core
+
+| Name | Default Value | Description|
+| ----- | ------ | ---- |
+| FILE  | 0      | File.|
+| IMAGE | 1      | Image.|
+| VIDEO | 2      | Video.|
+| AUDIO | 3      | Audio.|
+
+FileKey
+-------
+
+Enumerates key file information.
+
+**System capability**: SystemCapability.Multimedia.MediaLibrary.Core
+
+| Name         | Default Value              | Description                                                      |
+| ------------- | ------------------- | ---------------------------------------------------------- |
+| ID            | file_id             | File ID.                                                  |
+| RELATIVE_PATH | relative_path       | Relative public directory of the file.                                          |
+| DISPLAY_NAME  | display_name        | Display file name.                                                  |
+| PARENT        | parent              | Parent directory ID.                                                  |
+| MIME_TYPE     | mime_type           | Extended file attributes.                                              |
+| MEDIA_TYPE    | media_type          | Media type.                                                  |
+| SIZE          | size                | File size, in bytes.                                    |
+| DATE_ADDED    | date_added          | Date when the file was added. (The value is the number of seconds elapsed since the Epoch time.)            |
+| DATE_MODIFIED | date_modified       | Date when the file was modified. (The value is the number of seconds elapsed since the Epoch time.)            |
+| DATE_TAKEN    | date_taken          | Date when the file (photo) was taken. (The value is the number of seconds elapsed since the Epoch time.)            |
+| TITLE         | title               | Title in the file.                                                  |
+| ARTIST        | artist              | Artist of the file.                                                      |
+| AUDIOALBUM    | audio_album         | Audio album.                                                      |
+| DURATION      | duration            | Duration, in seconds.                                      |
+| WIDTH         | width               | Image width, in pixels.                                    |
+| HEIGHT        | height              | Image height, in pixels.                                    |
+| ORIENTATION   | orientation         | Image display direction (clockwise rotation angle, for example, 0, 90, and 180, in degrees).|
+| ALBUM_ID      | bucket_id           | ID of the album to which the file belongs.                                      |
+| ALBUM_NAME    | bucket_display_name | Name of the album to which the file belongs.                                        |
+
+DirectoryType
+-------------
+
+Enumerates directory types.
+
+**System capability**: SystemCapability.Multimedia.MediaLibrary.Core
+
+| Name         | Default Value | Description              |
+| ------------- | ------ | ------------------ |
+| DIR_CAMERA    | 0      | Directory of camera files.|
+| DIR_VIDEO     | 1      | Directory of video files.      |
+| DIR_IMAGE     | 2      | Directory of image files.      |
+| DIR_AUDIO     | 3      | Directory of audio files.      |
+| DIR_DOCUMENTS | 4      | Directory of documents.      |
+| DIR_DOWNLOAD  | 5      | Download directory.      |
+
+DeviceType
+-----------
+
+Enumerates device types.
+
+**System capability**: SystemCapability.Multimedia.MediaLibrary.Core
+
+| Name        | Default Value | Description      |
+| ------------ | ------ | ---------- |
+| TYPE_UNKNOWN | 0      | Unknown.|
+| TYPE_LAPTOP  | 1      | Laptop.|
+| TYPE_PHONE   | 2      | Phone.      |
+| TYPE_TABLET  | 3      | Tablet.  |
+| TYPE_WATCH   | 4      | Smart watch.  |
+| TYPE_CAR     | 5      | Vehicle-mounted device.  |
+| TYPE_TV      | 6      | TV.  |
+
+## MediaFetchOptions<sup>8+</sup>
+
+Describes options for fetching media files.
+
+**System capability**: SystemCapability.Multimedia.MediaLibrary.Core
+
+| Name         | Type               | Readable| Writable| Mandatory| Description                                                        |
+| ------------- | ------------------- | ---- | ---- | ---- | ------------------------------------------------------------ |
+| selections    | string              | Yes  | Yes  | Yes  | Conditions for fetching files. The enumerated values in [FileKey](#filekey) are used as the column names of the conditions. Example:<br>selections: mediaLibrary.FileKey.MEDIA_TYPE + '= ? OR' +mediaLibrary.FileKey.MEDIA_TYPE + '= ?',|
+| selectionArgs | Array&lt;string&gt; | Yes  | Yes  | Yes  | Value of the condition, which corresponds to the value of the condition column in **selections**.<br>Example:<br>selectionArgs: [mediaLibrary.MediaType.IMAGE.toString(), mediaLibrary.MediaType.VIDEO.toString()], |
+| order         | string              | Yes  | Yes  | No  | Sorting mode of the search results, which can be ascending or descending. The enumerated values in [FileKey](#filekey) are used as the columns for sorting the search results. Example:<br>Ascending: order: mediaLibrary.FileKey.DATE_ADDED + " AESC"<br>Descending: order: mediaLibrary.FileKey.DATE_ADDED + " DESC"|
+| uri           | string              | Yes  | Yes  | No  | File URI.                                                     |
+| networkId     | string              | Yes  | Yes  | No  | Network ID of the registered device.                                              |
+| extendArgs    | string              | Yes  | Yes  | No  | Extended parameters for fetching the files. Currently, no extended parameters are available.                        |
+
+## Size<sup>8+</sup>
+
+Describes the image size.
+
+| Name  | Type  | Readable| Writable| Description            |
+| ------ | ------ | ---- | ---- | ---------------- |
+| width  | number | Yes  | Yes  | Image width, in pixels.|
+| height | number | Yes  | Yes  | Image height, in pixels.|
+
+## MediaAssetOption
+
+Implements the media asset option.
+
+This API is defined but not implemented in OpenHarmony 3.1 Release. It will be available for use in OpenHarmony 3.1 MR.
+
+**System capability**: SystemCapability.Multimedia.MediaLibrary.Core
+
+
+| Name        | Type  | Mandatory| Description                                                        |
+| ------------ | ------ | ---- | ------------------------------------------------------------ |
+| src          | string | Yes  | URI of the media library.                                           |
+| mimeType     | string | Yes  | Multipurpose Internet Mail Extensions (MIME) type of the media.<br>Example: 'image/\*' and 'video/\*'.|
+| relativePath | string | No  | Custom path for storing media assets. If this parameter is unspecified, media assets are stored in the default path. For example, if you set this parameter to **imageDir/image2/**, the media assets will be stored in **default/imageDir/image2/**, where **default** represents the default path.|
+
+## MediaSelectOption
+
+Describes media selection option.
+
+This API is defined but not implemented in OpenHarmony 3.1 Release. It will be available for use in OpenHarmony 3.1 MR.
+
+**System capability**: SystemCapability.Multimedia.MediaLibrary.Core
+
+| Name | Type  | Mandatory| Description                          |
+| ----- | ------ | ---- | ------------------------------ |
+| type  | string | Yes  | Media type, which can be **image** and **video**.|
+| count | number | Yes  | Maximum number of media assets that can be selected.            |