DownloadManager

DownloadManager downloadManager = (DownloadManager) getSystemService(DOWNLOAD_SERVICE);
DownloadManager.Request request = new DownloadManager.Request(
Uri.parse("http://down.360safe.com/360mobilemgr/360box_web.apk"));
request.allowScanningByMediaScanner();
request.setTitle("Hello world!");
request.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED);
request.setAllowedOverRoaming(true);
long downloadId = downloadManager.enqueue(request);


http://www.trinea.cn/android/android-downloadmanager/