Nougat出现问题，Oreo DownloadManager无法下载文件

Question

我正在使用下载管理器通过url下载文件 牛轧糖和oreo的较低版本放置问题无法正常工作，请不要帮助

代码在这里：

> DownloadManager.Request request = new
> DownloadManager.Request(Uri.parse(url)); request.setTitle(name);
> request.setAllowedNetworkTypes(DownloadManager.Request.NETWORK_WIFI |
> DownloadManager.Request.NETWORK_MOBILE);
> request.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED);
> String nameofFile = URLUtil.guessFileName(url, null,
> MimeTypeMap.getFileExtensionFromUrl(url));
> request.setDestinationInExternalPublicDir(Environment.DIRECTORY_DOWNLOADS,
> "/MCA/AISC/AISC-ALL/" + "/" + allinone + ".pdf"); downloadManager =
> (DownloadManager) getSystemService(Context.DOWNLOAD_SERVICE); Long
> refid = downloadManager.enqueue(request);

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