Creating a database-generated menu on every page in CodeIgniter?

I'm using CodeIgniter and have a menu on the site that needs to read a list of cities from the database. This is simple to do if it's just on one or two pages - I load the model and call a function from the controller, a开发者_开发技巧nd pass the data into the view.

But if I want it on every page, that means I have to keep copying the same code to every single controller function and pass the data into the view. (Note, I'm using a separate "header" view that contains the menu.)

What's the best way to automatically load some data on every page load and have it available to my view?

Create a new root controller class like MY_Controller.

You can read how here: https://www.codeigniter.com/user_guide/general/core_classes.html

Then make all your controllers extend that class.

Add a function in MY_Controller like this:

function show_view_with_menu($view_name, $data) {
   $menu_data = $this->menu_model->get_menu(); // load your menu data from the db
   $this->load->view('header', $menu_data); // display your header by giving it the menu
   $this->load->view($view_name, $data); // the actual view you wanna load
   $this->load->view('footer'); // footer, if you have one
}

Whenever you normally do load a view, instead do this:

$this->show_view_with_menu('view_for_this_controller', $data);

You define your own Application_Controller, which extends CI_Controller. All of your own controllers then extend your Application_Controller rather than the CI_Controller.

In the __construct() of your Application_Controller you'll introduce the code you've been copying and pasting everywhere previously.

My solution was just to create a display class that handles these things. A simplified version:

class Display
{
    public function load_pages($name, $data = array()) {
        $CI =& get_instance();

        // Top and header templates
        $CI->load->view('header.php', $data);

        // Default to loading the one template file
        $CI->load->view($name, $data);

        // Footer template
        $CI->load->view('footer.php');
    }   
}

I have it doing fancier stuff, such as setting default values (page title, meta tags) and loading js/css, etc. It works just like a shortcut to having to copy/paste the regular templates that I load but also allows me to define a custom template setup if I need to, unlike if you have it do so automatically be extending your controller class.

I haven't had the need to but you can also specify different functions within this class to load different sections of the site, such as load_admin_pages() or some such. In my case I handle that just by setting a prefix parameter that gets prepended to the file paths and that's gotten what I need for my current project.