HarmonyOS 鸿蒙Next photoAccessHelper.PhotoAsset.getThumbnail是否需要受限权限才可以使用？

1）getThumbnail 需要 ohos.permission.READ_IMAGEVIDEO权限，参考链接：https://developer.huawei.com/consumer/cn/doc/harmonyos-references-V5/js-apis-photoaccesshelper-V5#getthumbnail 2）对于未申请’ohos.permission.READ_IMAGEVIDEO’权限的应用，可以通过picker的方式调用该接口来请求图片资源数据，详情请参考开发指南。

https://developer.huawei.com/consumer/cn/doc/harmonyos-guides-V5/photoaccesshelper-photoviewpicker-V5#指定uri获取图片或视频资源

获取缩略图，可以参考下这个demo：

import media from '@ohos.multimedia.media';

import image from '@ohos.multimedia.image';

import { BusinessError } from '@ohos.base';

import picker from '@ohos.file.picker';

import fs from '@ohos.file.fs';

import photoAccessHelper from '@ohos.file.photoAccessHelper';

@Entry

@Component

struct Index {

  // pixelMap对象声明，用于图片显示

  @State pixelMap: image.PixelMap | string | undefined = undefined;

  build() {

    Column() {

      Button() {

        Text('select').fontSize(20).fontWeight(FontWeight.Bold)

      }.margin({ top: 20 }).width(100).height(40).onClick(() => this.showPicker())

      // Button('点击')

      // .onClick(() => {

      // this.showPicker()

      // })

      Image(this.pixelMap).width(300).height(300).margin({ top: 20 })

    }.width('100%').height('100%')

  }

  showPicker() {

    // 创建图库选择器对象实例

    const photoViewPicker = new photoAccessHelper.PhotoViewPicker();

    // 图库选项配置，类型与数量

    let selectOptions = new photoAccessHelper.PhotoSelectOptions();

    selectOptions.MIMEType = photoAccessHelper.PhotoViewMIMETypes.VIDEO_TYPE;

    selectOptions.maxSelectNumber = 1;

    //调用select()接口拉起图库界面进行文件选择,文件选择成功后，返回PhotoSelectResult结果集

    photoViewPicker.select(selectOptions)

      .then((photoSelectResult: picker.PhotoSelectResult) => {

        //用一个全局变量存储返回的uri

        if (photoSelectResult.photoUris?.[0]) {

          this.testFetchFrameByTime(photoSelectResult.photoUris[0])

        }

      }).catch((err: BusinessError) => {

      console.error(`Invoke photoViewPicker.select failed, code is ${err.code}, message is ${err.message}`);

    })

  }

  // 获取缩略图

  async testFetchFrameByTime(filePath: string) {

    // 创建AVImageGenerator对象

    let avImageGenerator: media.AVImageGenerator = await media.createAVImageGenerator()

    let file = fs.openSync(filePath, fs.OpenMode.READ_ONLY);

    let avFileDescriptor: media.AVFileDescriptor = { fd: file.fd };

    avImageGenerator.fdSrc = avFileDescriptor;

    // 初始化入参

    let timeUs = 0

    let queryOption = media.AVImageQueryOptions.AV_IMAGE_QUERY_NEXT_SYNC

    let param: media.PixelMapParams = {

      width: 300,

      height: 400,

    }

    // 获取缩略图（promise模式）

    this.pixelMap = await avImageGenerator.fetchFrameByTime(timeUs, queryOption, param)

    // 释放资源（promise模式）

    avImageGenerator.release()

    console.info(`release success.`)

    fs.closeSync(file);

  }

}