Interface (MediaAssetDataHandler)

MediaAssetDataHandler is a media asset handler used to customize the media asset processing logic in onDataPrepared.

NOTE

The initial APIs of this module are supported since API version 10. Newly added APIs will be marked with a superscript to indicate their earliest API version.

The initial APIs of this interface are supported since API version 11.

Modules to Import

import { photoAccessHelper } from '@kit.MediaLibraryKit';

onDataPrepared¹¹⁺

onDataPrepared(data: T, map?: Map<string, string>): void

Called when the requested media asset is ready. If an error occurs, data returned by the callback is undefined. Each media asset request corresponds to a callback.

T supports the following data types: ArrayBuffer, ImageSource, MovingPhoto, and boolean. ArrayBuffer indicates the image or video asset data, ImageSource indicates the image source, MovingPhoto indicates a moving photo object, and boolean indicates whether the image or video is successfully written to the application sandbox directory.

Information returned by map:

Map Key	Description
'quality'	Image quality. The value high means high quality, and low means poor quality.

System capability: SystemCapability.FileManagement.PhotoAccessHelper.Core

Parameters

Name	Type	Mandatory	Description
data	T	Yes	Data of the image asset that is ready. It is of the generic type and supports the following data types: ArrayBuffer, ImageSource, MovingPhoto, and boolean.
map¹²⁺	Map<string, string>	No	Additional information about the image asset, such as the image quality. Currently, only quality is supported.

Example

import { image } from '@kit.ImageKit';

class MediaHandler implements photoAccessHelper.MediaAssetDataHandler<image.ImageSource> {
  onDataPrepared = (data: image.ImageSource, map: Map<string, string>) => {
    if (data === undefined) {
      console.error('Error occurred when preparing data');
      return;
    }
    // Customize the processing logic for ImageSource.
    console.info('on image data prepared, photo quality is ' + map['quality']);
  }
}

class MediaDataHandler implements photoAccessHelper.MediaAssetDataHandler<ArrayBuffer> {
  onDataPrepared = (data: ArrayBuffer, map: Map<string, string>) => {
    if (data === undefined) {
      console.error('Error occurred when preparing data');
      return;
    }
    // Customize the processing logic for ArrayBuffer.
    console.info('on image data prepared, photo quality is ' + map['quality']);
  }
}

class MovingPhotoHandler implements photoAccessHelper.MediaAssetDataHandler<photoAccessHelper.MovingPhoto> {
  onDataPrepared = (data: photoAccessHelper.MovingPhoto, map: Map<string, string>) => {
    if (data === undefined) {
      console.error('Error occurred when preparing data');
      return;
    }
    // Customize the processing logic for MovingPhoto.
    console.info('on image data prepared, photo quality is ' + map['quality']);
  }
}