从Android上的DownloadManager队列下载的图像

我有这段代码可以下载图像，但由于某种原因，图像在我的下载中是“排队”的，而不是下载

        String url = file.public_url;

        getContext();
        DownloadManager manager = (DownloadManager) getContext().getSystemService(Context.DOWNLOAD_SERVICE);
        Uri uri = Uri.parse(url);

        DownloadManager.Request request = new DownloadManager.Request(uri);

        request.setTitle(file.filename);
        request.setDescription(file.filename + " description.");
        request.allowScanningByMediaScanner();
        request.setAllowedOverRoaming(true);
        request.setAllowedNetworkTypes(DownloadManager.Request.NETWORK_WIFI | DownloadManager.Request.NETWORK_MOBILE);
        request.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED);
        request.setDestinationInExternalPublicDir(Environment.DIRECTORY_DOWNLOADS, file.filename + file.file_extension);

        manager.enqueue(request);

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我已成功下载了此不使用DownloadManager的异步版本的映像

如果删除setAllowedNetworkTypes调用，该怎么办？@MateusGondim这并不能解决问题。