HarmonyOS 鸿蒙Next沙箱中的视频怎么获取时长和缩略图

可以用选择视频的uri来获得对应的PhotoAsset对象，读取视频的部分信息，可以参考如下代码

async function uriGetAssets(uri: string) {
  try {
    let phAccessHelper = photoAccessHelper.getPhotoAccessHelper(this.context);
    let predicates: dataSharePredicates.DataSharePredicates = new dataSharePredicates.DataSharePredicates();
    // 配置查询条件，使用PhotoViewPicker选择图片返回的uri进行查询
    predicates.equalTo('uri', uri);
    let fetchOption: photoAccessHelper.FetchOptions = {
      fetchColumns: ['duration'],
      predicates: predicates
    };
    let fetchResult: photoAccessHelper.FetchResult<photoAccessHelper.PhotoAsset> = await phAccessHelper.getAssets(fetchOption);
    // 得到uri对应的PhotoAsset对象，读取文件的部分信息
    const asset: photoAccessHelper.PhotoAsset = await fetchResult.getFirstObject();
    console.info('asset displayName: ', asset.displayName);
    console.info('asset uri: ', asset.uri);
    console.info('asset photoType: ', asset.photoType);
    // 获取时长
    let duration: photoAccessHelper.PhotoKeys = photoAccessHelper.PhotoKeys.DURATION;
    let photoAssetDuration: photoAccessHelper.MemberType = asset.get(duration.toString());
    console.info('asset duration: ', photoAssetDuration);
    // 获取缩略图
    asset.getThumbnail((err, pixelMap) => {
      if (err == undefined) {
        console.info('getThumbnail successful ' + JSON.stringify(pixelMap));
      } else {
        console.error('getThumbnail fail', err);
      }
    });
  } catch (error) {
    console.error('uriGetAssets failed with err: ' + JSON.stringify(error));
  }
}