private void uploadUserDetails(String registrationId, String instanceId) {

    SharedPreferences sharedPreferences =
        StudentAssistApplication.getAppContext()
            .getSharedPreferences(SAConstants.sharedPreferenceName, 0);

    // setting GCM id to user and storing it into shared preferences
    SharedPreferences.Editor editor = sharedPreferences.edit();
    editor.putString(SAConstants.GCM_ID, registrationId);
    editor.putString(SAConstants.INSTANCE_ID, instanceId);
    editor.commit();

    String fbToken = "";

    if (AccessToken.getCurrentAccessToken() != null
        && !AccessToken.getCurrentAccessToken().isExpired()) {

      fbToken = AccessToken.getCurrentAccessToken().getToken();
    } else {
      Toast.makeText(StudentAssistApplication.getAppContext(), "not registered", Toast.LENGTH_LONG)
          .show();
    }

    UrlInterface urlGen = new UrlGenerator();
    try {

      String url = urlGen.createUser(fbToken, instanceId);

      new NotificationBO(
          new NotificationBI() {
            @Override
            public void onResponse(String response) {

              L.m("successfully created user");
            }
          },
          url);

    } catch (Exception e) {
      ErrorReporting.logReport(e);
    }
  }
  private String getAccessToken() {

    FacebookSdk.sdkInitialize(StudentAssistApplication.getAppContext());

    if (AccessToken.getCurrentAccessToken() != null
        && !AccessToken.getCurrentAccessToken().isExpired()) {
      String fbToken = AccessToken.getCurrentAccessToken().getToken();
      return fbToken;
    }

    return "";
  }