HarmonyOS request 下载文件搭配 savebutton 报13400001

13400001, err.errInfo : set path permission fail

SaveButton({ icon: SaveIconStyle.FULL_FILLED, buttonType: ButtonType.Circle })
  .iconColor(Color.White)
  .iconSize(12)
  .backgroundColor(Color.Transparent)
  .borderStyle(BorderStyle.Solid)
  .borderColor(Color.White)
  .borderWidth(1)
  .padding(12)
  .borderRadius(100)
  .onClick(async (_, result) => { //下载图片
    if (result == SaveButtonOnClickResult.SUCCESS) {
      try {
        const context = getContext(this);
        let helper = photoAccessHelper.getPhotoAccessHelper(context);
        // onClick触发后10秒内通过createAsset接口创建图片文件，10秒后createAsset权限收回。
        let uri = await helper.createAsset(photoAccessHelper.PhotoType.IMAGE, 'jpg');
        let assetChangeRequest: photoAccessHelper.MediaAssetChangeRequest = photoAccessHelper.MediaAssetChangeRequest.createImageAssetRequest(context, fileUri);
        let file = await fs.open(uri, fs.OpenMode.READ_WRITE | fs.OpenMode.CREATE);
        request.downloadFile(context, {
          url: this.pictureData[this.currentIndex].pictureUrl,
          enableMetered: true,
          enableRoaming: true,
          filePath: file.path
        }, (error, result) => {
          if (error) {
            promptAction.showToast({ message: "保存失败" })
            fs.close(file.fd)
            return
          }
          result.on("complete", () => {
            promptAction.showToast({ message: "保存成功" })
            fs.close(file.fd)
          })
          result.on("fail", () => {
            promptAction.showToast({ message: "保存失败" })
            fs.close(file.fd)
          })
        })
      } catch (error) {
        console.error("error is " + JSON.stringify(error));
        promptAction.showToast({ message: "保存失败" })
      }
    } else {
      promptAction.showToast({ message: "获取权限失败" })
    }
  })

以上为示例代码