A Collection of Custom Post Types Displayed In a Submenu

Question

I have WordPress 4.6.1. I now have experience with creating custom post types and see them stacked up in the admin UI console. But how can I create a stack all of my custom post types in a menu so that when I go to wp-admin, I see on the left, a button called My Post Types, and if I hover over it, it shows me all of my custom post types displayed in a list format.

Answer 1

I'm going to assuming when you say that you "hover over it, it shows custom post types displayed in a list" you mean submenus. The below uses admin_menu to create a blank Parent Menu then we loop through the public post types to display them as submenus:

/**
 * Add an Admin Menu which contains submenus of public post types
 * - https://codex.wordpress.org/Plugin_API/Action_Reference/admin_menu
 * - https://developer.wordpress.org/reference/hooks/admin_menu/
 *
 * @return void
 */
function wpse_q_241760() {

    $post_types = get_post_types( array(
        'public'    => true,
    ), 'objects' );

    if( ! empty( $post_types ) ) {
        add_menu_page(
            'Post Types',           // Page Title ( doesn't matter )
            'Post Types',           // Menu Title
            'edit_posts',           // Capability to view this menu item
            'javascript:void(0);',  // URL ( slug )
            '',                     // Callback Function
            'dashicons-book',       // Dashicon
            24                      // Menu Position
        );

        foreach( $post_types as $type ) {
            add_submenu_page(
                'javascript:void(0);',      // Parent URL Slug
                $type->labels->name,        // Page Title ( doesn't matter in this case )
                $type->labels->name,        // Menu Title
                'edit_posts',               // Cability to view
                "edit.php?post_type={$type->name}"  // URL ( slug )
            );
        }

        remove_submenu_page( 'javascript:void(0);', 'javascript:void(0);' );
    }
}
add_action( 'admin_menu', 'wpse_q_241760' );

The above add_menu_page() needs to be passed some sort of link - since we would have nothing to show at that link ( there's no post_type tied to this page, it's a dummy page ) I've opted to link to javascript:void(0); instead which tells our browser not to navigation anywhere. This allows us to instead hover the menu item and click one of the Post Type links. It also added a submenu of the same name but we don't need it so we remove it at the end of the function call.

The get_post_types() function has a few parameters to filter on if public doesn't work for your case.