// Function for user login
    // return : JSON array (login : true/false; user_id : if user is loged in)
    public function login() {
        $post = JFactory::getApplication()->input;
        $result = array();
        $username = $post->get('username');
        $password = $post->get('password');

        $credentials = array("username" => $username, "password" => $password);

        $app = JFactory::getApplication('site');
        $result['login'] = $app->login($credentials);

        if($result['login']) {
            $result['user_id'] = JUserHelper::getUserId($username);
        }

        CJoomDroidHelper::postResult($result);
    }

// Function for user login
    // return : JSON array (login : true/false; user_id : if user is loged in)
    public function login() {
        $post = JFactory::getApplication()->input;
        $result = array();
        $username = $post->get('username');
        $password = $post->get('password');

        $credentials = array("username" => $username, "password" => $password);

        $app = JFactory::getApplication('admin');
        $result['login'] = $app->login($credentials);

        if($result['login']) {
            $result['user_id'] = JUserHelper::getUserId($username);
        }

        CJoomDroidHelper::postResult($result);
    }

{"login":true}