HarmonyOS 鸿蒙Next 预览打开相册中的一张图片，预览失败

参考如下代码：

import { filePreview } from '@kit.PreviewKit';

import { promptAction } from '@kit.ArkUI';

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

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

import fileUri from '@ohos.file.fileuri';

let fileName: string = 'tt.jpg';

let context = getContext(this);

let fileDir = context.filesDir; // 获取沙箱路径

let uri = ''; // 获取uri

let pathDir = getContext().filesDir;

@Entry

@Component

struct Index {

  @State message: string = 'Hello World';

  build() {

    Row() {

      Column() {

        Button('1、相册图片写入沙箱')

          .onClick(() => {

            this.picture()

          })

        Button('2、预览')

          .onClick(async () => {

            let result = await filePreview.canPreview(context, uri); // 传入uri，判断是否可预览

            console.log('result:' + result)

            if (result) {

              let previewInfo: filePreview.PreviewInfo = {

                title: fileName,

                uri: uri,

                mimeType: 'image/jpeg'

              }

              filePreview.openPreview(getContext(this), previewInfo)

                .then(() => {

                  console.log('预览成功')

                }); // 打开预览

            } else {

              promptAction.showToast({

                // 不可预览

                message: '文件不可预览'

              });

            }

          })

      }

      .width('100%')

    }

    .height('100%')

  }

  async picture() {

    let PhotoSelectOptions = new photoAccessHelper.PhotoSelectOptions();

    PhotoSelectOptions.MIMEType = photoAccessHelper.PhotoViewMIMETypes.IMAGE_TYPE;

    PhotoSelectOptions.maxSelectNumber = 1;

    let photoPicker = new photoAccessHelper.PhotoViewPicker();

    photoPicker.select(PhotoSelectOptions).then((PhotoSelectResult: photoAccessHelper.PhotoSelectResult) => {

      let photouri: Array<string> = PhotoSelectResult.photoUris

      console.log('photouri[0]:' + photouri[0])

      let file = fs.openSync(photouri[0], fs.OpenMode.READ_ONLY)

      // 图片保存到沙箱

      uri = fileUri.getUriFromPath(pathDir + '/picture2.jpg')

      console.log('uri:'+uri)

      let file2 = fs.openSync(pathDir + '/picture2.jpg', fs.OpenMode.READ_WRITE | fs.OpenMode.CREATE)

      fs.copyFileSync(file.fd, file2.fd)

      fs.closeSync(file);

      fs.closeSync(file2);

    })

  }

}