HarmonyOS鸿蒙Next中下载提示下载完成无错误状态找不到下载的文件

当前网络资源文件仅支持下载至应用文件目录，是无法直接查看的。 您可以使用FilePicker来实现文件保存到本地系统管理，FilePicker对应的官网链接： https://developer.huawei.com/consumer/cn/doc/harmonyos-guides-V5/save-user-file-V5

问题处理思路：可以先通过picker获取到要选择或者保存文件的公共路径，然后通过fs.copyFile进行文件复制，下载完成后可选择保存位置和保存名称

import { BusinessError } from '@kit.BasicServicesKit';
import fs, { ListFileOptions, Filter } from '@ohos.file.fs';
import request from '@ohos.request';
import { picker } from '@kit.CoreFileKit';
import { common } from '@kit.AbilityKit';

@Entry
@Component
struct Index {
  @State message: string = 'Hello World';

  download() {
    const context = getContext(this);
    const downloadUrl = 'https://xxxxxxxxxxxx.zip';
    try {
      request.downloadFile(context, {
        enableMetered: true,
        url: downloadUrl,
        filePath: context.filesDir + '/aaaaaa.zip'
      }).then((downloadTask: request.DownloadTask) => {
        downloadTask.on('fail', (err: number) => {
          console.error(`Failed to download the task. Code: ${err}`);
        });
        downloadTask.on('progress', (receivedSize: number, totalSize: number) => {
          console.log('download', "receivedSize:" + (receivedSize / 1024) + " totalSize:" + (totalSize / 1024));
        });
        downloadTask.on('complete', () => {
          //将文件复制到文件夹中
          const documentSaveOptions = new picker.DocumentSaveOptions(); // 创建文件管理器保存选项实例
          documentSaveOptions.newFileNames = ["aaa.zip"]; // 保存文件名（可选）

          const documentViewPicker = new picker.DocumentViewPicker;
          documentViewPicker.save(documentSaveOptions)
            .then(async (documentSaveResult) => {
              let uri = documentSaveResult[0];
              console.info('pub uri:' + uri)
              // 沙箱路径文件
              let sanFile = fs.openSync(context.filesDir+ '/aaaaaa.zip', fs.OpenMode.READ_WRITE | fs.OpenMode.CREATE)
              let pubFile = fs.openSync(uri, fs.OpenMode.READ_WRITE | fs.OpenMode.CREATE)
              // 将文件从沙箱路拷贝到公共路径
              fs.copyFileSync(sanFile.fd, pubFile.fd)
              console.log("-------")
            })

          console.log('下载完成')
        })
        .catch((err: BusinessError) => {
          console.error(`Invoke downloadTask failed, code is ${err.code}, message is ${err.message}`);
        });
    } catch (error) {
      let err: BusinessError = error as BusinessError;
      console.error(`Invoke downloadFile failed, code is ${err.code}, message is ${err.message}`);
    }

  }

  build() {
    RelativeContainer() {
      Column() {
        Button('下载')
          .onClick(() => {
            this.download()
          })
      }
      .height('100%')
      .width('100%')
      .alignItems(HorizontalAlign.Center)
      .justifyContent(FlexAlign.Center)
    }
  }
}