/**
  * Converts the useranswer object to a valid json object
  *
  * @return a json object with all the necessary data
  * @throws JSONException
  */
 public JSONObject toJSONObject() throws JSONException {
   JSONObject o = new JSONObject();
   o.put(KEY_ANSWER, answer);
   o.put(KEY_WEEK, week);
   o.put(KEY_NUM, num);
   return o;
 }
 /**
  * Converts a json object to an UserAnswer object
  *
  * @param o a valid json object
  * @throws JSONException
  */
 public void fromJSONObject(JSONObject o) throws JSONException {
   answer = o.getString(KEY_ANSWER);
   week = o.getInt(KEY_WEEK);
   num = o.getInt(KEY_NUM);
 }