HarmonyOS 鸿蒙Next image.createPixelMap返回undefined的问题

参考此demo：

import { picker } from '@kit.CoreFileKit';
import fs from '@ohos.file.fs';
import { BusinessError } from '@kit.BasicServicesKit';
import { image } from '@kit.ImageKit';
import util from '@ohos.util';

@Entry
@Component
struct pickImg {
  uri: string = '';
  resultBase64Str: string = ''
  pixelMap?: image.PixelMap = undefined;
  selectUris: Array<string> = [];
  @State pixelStr: string = '';
  build() {
    Column() {
      Image(this.pixelMap).width(200).height(200)
      Button('打开相册').onClick(() => {
        const photoViewPicker = new picker.PhotoViewPicker();
        photoViewPicker.select().then(async (photoSelectResult: picker.PhotoSelectResult) => {
          this.selectUris = photoSelectResult.photoUris;
          console.info('photoViewPicker.select to file succeed and uris are:' + this.selectUris);
          let file = fs.openSync(this.selectUris[0], fs.OpenMode.READ_ONLY);
          console.info('file fd: ' + file.fd);
          const imageSource: image.ImageSource = image.createImageSource(file.fd);
          fs.closeSync(file);
          let decodingOptions: image.DecodingOptions = { editable: true, desiredPixelFormat: 3, }
          imageSource.createPixelMap(decodingOptions).then(async (pixelMap1: image.PixelMap) => {
            this.pixelMap = pixelMap1;
          });
        }).catch((err: BusinessError) => {
          console.error(`Invoke photoViewPicker.select failed, code is ${err.code}, message is ${err.message}`);
        })
      })
      Button('转base64')
        .onClick(() => {
          const imagePackerApi = image.createImagePacker();
          const packOptions: image.PackingOption = { format: 'image/jpeg', quality: 10 }
          imagePackerApi.packing(this.pixelMap, packOptions).then(async (data: ArrayBuffer) => {
            let arrayBuffer = data;
            console.log('arrayBuffer', arrayBuffer)
            let base64 = new util.Base64Helper();
            let uint8Arr = new Uint8Array(arrayBuffer)
            this.pixelStr = base64.encodeToStringSync(uint8Arr)
          }).catch((error: BusinessError) => {
            console.error('Failed to pack the image. And the error is: ' + error);
          })
        })
      Image('data:image/png;base64,'+this.pixelStr)
        .height('50%')
        .width('50%')
    }
  }
}