HarmonyOS 鸿蒙Next如何取出图库视频封面的缩略图

参考demo:

import { common } from '@kit.AbilityKit';
import { picker } from '@kit.CoreFileKit';
import fs from '@ohos.file.fs';
import { photoAccessHelper } from '@kit.MediaLibraryKit';
import { dataSharePredicates } from '@kit.ArkData';
import { image } from '@kit.ImageKit';

let uri:string = '';

@Entry
@Component
struct PhotoPage {
@State imagePath: string = ''
@State pixelMap:image.PixelMap | undefined = undefined
private context = getContext(this) as common.UIAbilityContext;

build() {
Row() {
Column() {
Text('11')
Button('选择视频')
.onClick(() => {
this.selectPhoto()
})
Image(this.pixelMap).width(100).height(100)
}.width('100%')
}.height('100%')
}

selectPhoto() {
const photoSelectOptions = new picker.PhotoSelectOptions();
const photoViewPicker = new picker.PhotoViewPicker();
photoSelectOptions.MIMEType = picker.PhotoViewMIMETypes.VIDEO_TYPE; // 过滤选择媒体文件类型为VIDEO
photoSelectOptions.maxSelectNumber = 1; // 选择媒体文件的最大数目
photoViewPicker.select(photoSelectOptions).then((photoSelectResult: picker.PhotoSelectResult) => {
const fileUri = photoSelectResult.photoUris[0]
uri = fileUri
this.getFileInfo(fileUri)
this.uriGetAssets()
})
}

async getFileInfo(filePathString: string) {
let resFile = fs.openSync(filePathString, fs.OpenMode.READ_ONLY)
const dateStr = (new Date().getTime()).toString()
// 临时文件目录
let newPath = this.context.filesDir + `/${dateStr + resFile.name}`;
// 转化路径
fs.copyFileSync(resFile.fd, newPath);
// 新的路径
let realUri = 'file://' + newPath;
this.imagePath = realUri
console.log(this.imagePath)
}

async uriGetAssets() {
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: [],
fetchColumns: [],
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('getAssets photoAsset.displayName : ' + asset.displayName);
console.info('asset displayName: ', asset.displayName);
asset.getThumbnail((err, pixelMap) => {
if (err == undefined) {
console.info('getThumbnail successful');
this.pixelMap=pixelMap
} else {
console.error('getThumbnail fail', err);
}
})
}
}