@Override
    protected String doInBackground(Void... params) {
        String url = "http://limesurvey-dev.bdwarf.org/index.php/uploader/index/mode/upload/sid/surveyId/preview/0/fieldname/mFieldName/";
        JSONObject json = new JSONObject();
        try {
            json.put("sSessionKey", sessionKey);
            json.put("uploadfile",file);

            String rr = jsonwebservice.httpConnection(json.toString(),url);
            Log.v("result ", ""+rr);
        } catch (JSONException e) {
            e.printStackTrace();
        }
        return null;
    }