Codeigniter自定义404页面，适用于不同的控制器

I need assistance to get the correct method to display a custom 404 error page, for differect controllers. I have home, welcome as my controllers, but default controller is welcome. When the user Logs in, they are redirected to home. I need each of this conrtollers to have their own custom 404 error page.

Set up a custom 404 controller in the application/config/routes.php file.

$route['404_override'] = 'my404controller';

Create a My404controller and handle all the 404 errors in the index() using $this->uri->segment(0).

<?php defined('BASEPATH') OR exit('No direct script access allowed');

  class My404controller extends CI_Controller {

  function __construct() {
    parent::__construct();
  }

  public function index() {

  // $this->uri->segment(1) is *original* controller segment before routing.

  set_status_header(404); // set 404 header

  if ($this->uri->segment(1) == 'home') {
     $this->load->view('home/home404');
     return;
  }

  if ($this->uri->segment(1) == 'admin') {
     $this->load->view('admin/admin404');
     return;
  }

  if ($this->uri->segment(1) == 'blog') {
     $this->load->view('blog/blog404');
     return;
  }

  // If there's no match to existing controller, default to generic 404 page view.
  $this->load->view('default404');

  }
}