async-onprogressupdate

Below is my code my trying to display my progress in Asyntask via onProgressUpdate method but it aint showing in the alert diaalog. Only the initial message is shown. class DownloadFileFromURL extends AsyncTask<String, String, String> { private AlertDialog.Builder alert; private int progress = 0; /** * Before starting background thread Show Progress Bar Dialog */ @Override protected void onPreExecute() { super.onPreExecute(); alert = new AlertDialog.Builder(context); alert.setTitle("Downloading.."); alert.setMessage("1"); alert.setCancelable(false); alert.show(); } /** * Downloading file in