HarmonyOS 鸿蒙Next 切图之后保存为图片文件，开发应可通过id获取资源，但目前无法获取id 图标库

参考下这个demo：

import { common } from '[@kit](/user/kit).AbilityKit';
import { BusinessError, request } from '[@kit](/user/kit).BasicServicesKit';
import fs from '[@ohos](/user/ohos).file.fs';
import { fileUri } from '[@kit](/user/kit).CoreFileKit';
import { joinPicture } from '../../utils/JoinPicture'
import { photoAccessHelper } from '[@kit](/user/kit).MediaLibraryKit';
import { image } from '[@kit](/user/kit).ImageKit';

[@Entry](/user/Entry)
[@Component](/user/Component)
struct Index {
 [@State](/user/State) imageUri: string = '';
 [@State](/user/State) combineImageUri: string = '';
 context = getContext(this) as common.UIAbilityContext;
 filePath = this.context.filesDir + '/test.jpg';
 combinePath = this.context.filesDir + '/combine.jpg';
 saveButtonOptions: SaveButtonOptions = {
   icon: SaveIconStyle.FULL_FILLED,
   text: SaveDescription.SAVE_IMAGE,
   buttonType: ButtonType.Capsule
 } // 设置安全控件按钮属性

 onPageShow(): void {
   this.checkImageExist()
 }

 checkImageExist(notExistCallback?: Function) {
   fs.access(this.filePath).then((res: boolean) => {
     if (res) {
       console.info("PictureJoinTogether file exists");
       this.imageUri = fileUri.getUriFromPath(this.filePath);
     } else {
       console.info("PictureJoinTogether file not exists");
       if (notExistCallback) {
         notExistCallback()
       }
     }
   }).catch((err: BusinessError) => {
     console.info("PictureJoinTogether access failed with error message: " + err.message + ", error code: " + err.code);
   });
 }

 // 只是为了分享图片，随便找个图片下载
 downloadFile(callback: Function) {
   this.checkImageExist(() => {
     request.downloadFile(this.context, {
       url: 'https://image.baidu.com/search/down?tn=download&word=download&ie=utf8&fr=detail&url=http%3A%2F%2Fpic1.win4000.com%2Fwallpaper%2F2019-11-22%2F5dd7afa7df0fc.jpg&thumburl=https%3A%2F%2Fimg1.baidu.com%2Fit%2Fu%3D2205810988%2C4283060315%26fm%3D253%26fmt%3Dauto%26app%3D138%26f%3DJPEG%3Fw%3D800%26h%3D500',
       filePath: this.filePath,
       background: true
     }).then((downloadTask: request.DownloadTask) => {
       downloadTask.on('progress', (receivedSize: number, totalSize: number) => {
         console.info("PictureJoinTogether download receivedSize:" + receivedSize + " totalSize:" + totalSize);
       });

       downloadTask.on('complete', () => {
         console.info('PictureJoinTogether download complete');
         callback()
       })
     }).catch((err: BusinessError) => {
       console.error(`PictureJoinTogether Invoke downloadTask failed, code is ${err.code}, message is ${err.message}`);
     });
   })
 }

 build() {
   Column({space: 10}) {
     Button('下载图片')
       .onClick(() => {
         if (this.imageUri !== '') {
           return;
         }
         this.downloadFile(() => {
           this.imageUri = fileUri.getUriFromPath(this.filePath);
         })
       })

     Image(this.imageUri)
       .width(200)
       .height(200)
       .backgroundColor(Color.Gray)

     Button('合并图片并保存到应用内')
       .onClick(() => {
         joinPicture.join([this.filePath, this.filePath], this.combinePath, () => {
           this.combineImageUri = fileUri.getUriFromPath(this.combinePath);
         })
       })

     Image(this.combineImageUri)
       .width(400)
       .height(200)
       .backgroundColor(Color.Gray)

     // 通过安全控件保存应用图片到图库
     SaveButton(this.saveButtonOptions)
       .onClick(async (event, result: SaveButtonOnClickResult) => {
         if (result === SaveButtonOnClickResult.SUCCESS) {
           try {
             const context = getContext();
             const phAccessHelper = photoAccessHelper.getPhotoAccessHelper(context);
             const uri = await phAccessHelper.createAsset(photoAccessHelper.PhotoType.IMAGE, 'jpg');
             console.info('createAsset successfully, uri: ' + uri);
             const file = await fs.open(uri, fs.OpenMode.READ_WRITE);
             const imageSource = image.createImageSource(this.combinePath);
             const imageInfo = await imageSource.getImageInfo();
             const opts: image.DecodingOptions = {
               editable: true,
               // 注意和拼接图片时的格式统一
               desiredPixelFormat: image.PixelMapFormat.BGRA_8888,
               desiredSize: { width: imageInfo.size.width, height: imageInfo.size.height }
             };
             // 需要通过packing打包图片，直接获取buffer并写入会导致图库中图片无法显示
             const pixelMap = await imageSource.createPixelMap(opts);
             const imagePackerApi: image.ImagePacker = image.createImagePacker();
             let packOpts: image.PackingOption = { format: "image/jpeg", quality: 100 };
             const packingArrayBuffer = await imagePackerApi.packing(pixelMap, packOpts);
             console.info('packing succeeded.');
             fs.writeSync(file.fd, packingArrayBuffer, { offset: 0 })
             fs.closeSync(file.fd)
           } catch (err) {
             console.error('createAsset failed, message = ', err);
           }
         } else {
           console.error('SaveButtonOnClickResult createAsset failed');
         }
       })
   }
   .width('100%')
   .height('100%')
   .justifyContent(FlexAlign.Center)
 }
}