How do you add a settings page to another menu?

Question

I created a settings page that's being displayed in the options menu like this:

add_options_page(
    'ATB Event Options',
    'ATB Event Options',
    'manage_options',
    'atb-event-options',
    'atb_event_options_display'
);

Instead, I'd like to display it as a menu item under another parent menu with the slug 'mvc_events':

add_submenu_page(
    'mvc_events',
    'ATB Event Options',
    'ATB Event Options',
    'manage_options',
    'atb-event-options',
    'atb_event_options_display'
);

While that does add "ATB Event Options" to my mvc_events menu, it overwrites the first menu item I had there, and the link doesn't even work. The link is generated as blah.dev/wp-admin/atb-event-options.

Any idea what I'm doing wrong?

Answer 1

You'd need to create the top-level menu page, and then the sub-menu after that.

Here's an example:

function my_menu() {
  add_menu_page ( 
    'MVC Events',      // $page_title
    'MVC Events',      // $menu_title
    'manage_options',  // $capability
    'mvc-events',      // $menu_slug
    'mvc-options'      // $function
    );
  add_submenu_page (
    'mvc-events',         // $parent_slug
    'ATB Event Options',  // $page_title
    'ATB Event Options',  // $menu_title
    'manage_options',     // $capability
    'atb-event-options',  // $menu_slug
    'atb-options'         // $function
    );
  }
add_action( 'admin_menu', 'my_menu' );

Here's the pertinent WP codex file, and one particularly on sub-menus.