强制CodeIgniter执行hooks功能?

嗨,我在Codeigniter中遇到一个钩子问题。我已经为 '邮政控制器' 后置控制器 有人可以建议我任何方法来做到这一点。或任何其他方式来呈现自定义404页。

function show_404($page = ''){ // error page logic

    header("HTTP/1.1 404 Not Found");
$heading = "404 Page Not Found";
    $message = "The page you requested was not found ";
$CI =& get_instance();
$metadata[AppContants::META_TITLE] = '404 Page Not Found | Door and Window';
$metadata[AppContants::META_KEYWORDS] = '';
$metadata[AppContants::META_DESCRIPTION] = '';
$CI->setMeta($metadata);
$params['LAYOUT_MAINVIEW']='404_page';
$CI->renderView($params);// this is the function in my controller which sets the parameter for my template.Or it would also be very helpful if i can load the view directly as show below.
$CI->load->view('404_page'); // Loading view directly.

}