HarmonyOS 鸿蒙Next使用showAssetsCreationDialog保存沙盒图片到相册无效

应该是没读取到沙箱里面的文件，可以参考以下demo，先往沙箱里拷贝一个图片，使用fileUri.getUriFromPath获取沙箱路径再保存

import { common } from '@kit.AbilityKit'
import { BusinessError } from '@kit.BasicServicesKit'
import fs from '@ohos.file.fs';
import { photoAccessHelper } from '@kit.MediaLibraryKit';
import { fileUri } from '@kit.CoreFileKit';
import { buffer } from '@kit.ArkTS';
export function myRawfileCopy(context: common.UIAbilityContext) {
  context.resourceManager.getRawFileContent("background.png", (err: BusinessError, data: Uint8Array) => {
    if (err != null) {
      console.error(`open aaa.txt failed: ${err.message}`)
    } else {
      let buffer = data.buffer
      let sanboxPath = context.filesDir
      console.log('myRawfileCopy path' + sanboxPath)
      let file = fs.openSync(context.filesDir + '/test.png', fs.OpenMode.CREATE | fs.OpenMode.READ_WRITE)
      try {
        fs.writeSync(file.fd, buffer) // 拷贝文件到沙箱，为了简便，这里是直接getrawfilecontent然后写入，当文件过大时内存压力会很大，如需优化，可通过buffer进行读取
        fs.close(file.fd)
      } catch (err) {
        console.log('myRawfileCopy error')
      }
    }
  })
}
let context = getContext(this);
let phAccessHelper = photoAccessHelper.getPhotoAccessHelper(context);
export async function saveImgToPhoto(context: Context) {
  try {
    let phAccessHelper: photoAccessHelper.PhotoAccessHelper = photoAccessHelper.getPhotoAccessHelper(context);
    let photoCreationConfigs: Array<photoAccessHelper.PhotoCreationConfig> = [
      {
        title: 'test2', // 可选
        fileNameExtension:  'png',
        photoType: photoAccessHelper.PhotoType.IMAGE,
        subtype: photoAccessHelper.PhotoSubtype.DEFAULT, // 可选
      }
    ];
    let srcFileUris: Array<string> = [
      fileUri.getUriFromPath(context.filesDir+ '/test.png')
    ];
    let desFileUris: Array<string> = await phAccessHelper.showAssetsCreationDialog(srcFileUris, photoCreationConfigs);
    let file1 = fs.openSync(context.filesDir+ '/test.png', fs.OpenMode.READ_WRITE | fs.OpenMode.CREATE);
    let arrayBuffer = new ArrayBuffer(4096000);
    let readLen = fs.readSync(file1.fd, arrayBuffer);
    let buf = buffer.from(arrayBuffer, 0, readLen);
    console.info(`content of File: ${buf.toString()}`);
    let file2 = fs.openSync(desFileUris[0], fs.OpenMode.READ_WRITE | fs.OpenMode.CREATE);
    let writeLen = fs.writeSync(file2.fd, arrayBuffer);
    fs.closeSync(file2);
    fs.closeSync(file1);
    console.info('showAssetsCreationDialog success, data is ' + desFileUris);
  } catch (err) {
    console.error('showAssetsCreationDialog failed, errCode is ' + err.code + ', errMsg is ' + err.message);
  }
  return false
}
[@Component](/user/Component)
[@Entry](/user/Entry)
struct Index {
  build() {
    Column() {
      Button('拷贝文件到沙箱').onClick(() => {
        myRawfileCopy(getContext(this) as common.UIAbilityContext)
      })
      Button('保存到').onClick(() => {
        saveImgToPhoto(getContext(this) as common.UIAbilityContext)
      })
    }
  }
}