ValidateUserTask

new ValidateUserTask(new TaskListener() {
    /**
     * Called when the username and password have successfully validated.
     */
    @Override
    public void onTaskSuccess() {

    }
 
    /**
     * Called when there was an error attempting to verify the username and password.
     * @param errorMessage - Message describing the error that occurred.
     * @param errorCode - Code for the error that occurred.
     */
    @Override
    public void onTaskError(String errorMessage, int errorCode) {

    }

}).execute(U2F_SERVER_URL, username, password);