Admin submenu does not call function to load the page

I found my solution.

Problem of hrefs

when the wordpress core did not find the function callback or it’s empty for the functions add_menu_page() and add_submenu_page() the href wil be generated like this : http(s)://my-site.org/wp-admin/my-slug-page, otherwise the href is in this format : http(s)://my-site.org/wp-admin/admin.php?page=my-slug-page

So In my case, I had to be sure the functions callback are called.

Problem to bind the menus with page and load only the current page

I had to call a static public function in add_submenu_page() which is located inside my page classes.

• Any page classes extends Page.php.

• Any sub pages classes extends SubPage.php.

• The static function to init any page/sub page is the same for all.

So I made PageTrait.php which is used in Page.php and SubPage.php.

This is the code :

SubMenu.php

class SubMenu { 

    public $parent_slug;

    public $page_title;

    public $menu_title;

    public $capability;

    public $menu_slug;

    protected $subpage_class; //<-- new argument used for the submenu function callbak

    public $priority;


    public function __construct( $parent_slug, $page_title, $menu_title, $capability, $menu_slug, $subpage_class, $priority = 10 ) {
         $this->parent_slug = $parent_slug;
         $this->page_title = $page_title;
         $this->menu_title = $menu_title;
         $this->capability = $capability;
         $this->menu_slug = $menu_slug;
         $this->subpage_class = $subpage_class;
         $this->priority = $priority;

         // Initialize the component
         add_action( 'admin_menu', array( $this, 'add_submenu' ), $this->priority );
    }


    public function add_submenu() {

         $page_hook = add_submenu_page(
             $this->parent_slug, 
             _x( $this->page_title, "page_title", PLUGIN_DOMAIN ), 
             _x( $this->menu_title, "menu_title", PLUGIN_DOMAIN ), 
             $this->capability, 
             $this->menu_slug, 
             array( $this->subpage_class, "init_page" ) 
         );

    }
}

PageTrait.php

trait PageTrait {

      public static function init_page(){
          //Code to init the right page
          //1.Get data for the constructor
          ...
          //2.Get the class path
          ...
          new $classPath( $data );
      }
}

Page.php

class Page {

    use PageTrait;
    ....
}

SubPage.php

class SubPage{

    use PageTrait;
    ....
}