Create custom WP_List_Table in post_type

Question

I have a post type named "case". I want to create a "Sub-page" to list only my "cases". And add some custom HTML (search box, some labels, logos, etc..)

Anyone knows how can I do this?

Code to create the post_type.

function my_custom_post_type_case() {
    $labels = array(
        'name'               => _x( 'Cases', 'post type general name' ),
        'singular_name'      => _x( 'Case', 'post type singular name' ),
        'add_new'            => _x( 'Add New', 'case' ),
        'add_new_item'       => __( 'Add New Case' ),
        'edit_item'          => __( 'Edit Case' ),
        'new_item'           => __( 'New Case' ),
        'all_items'          => __( 'All Cases' ),
        'view_item'          => __( 'View Case' ),
        'search_items'       => __( 'Search Cases' ),
        'not_found'          => __( 'No cases found' ),
        'not_found_in_trash' => __( 'No cases found in the Trash' ), 
        'parent_item_colon'  => '',
        'menu_name'          => 'Cases'
    );
    $args = array(
        'labels'              => $labels,
        'description'         => 'Business Cases & Teaching Material',
        'public'              => true,
        'menu_icon'           => 'dashicons-book',
        'menu_position'       => 5,
        'map_meta_cap'        => true,
        'capability_type'     => array('case', 'cases'),
        'capabilities'        => array(
            'edit_post'             => 'edit_case',
            'edit_posts'            => 'edit_cases',
            'edit_others_posts'     => 'edit_other_cases',
            'publish_posts'         => 'publish_cases',
            'edit_publish_posts'    => 'edit_publish_cases',
            'read_post'             => 'read_cases',
            'read_private_posts'    => 'read_private_cases',
            'delete_post'           => 'delete_case'
        ),
        'supports'            => array( 'title', 'editor', 'wpcom-markdown', 'revisions' ),
        'has_archive'         => false
    );
    register_post_type( 'case', $args );    
}
add_action( 'init', 'my_custom_post_type_case' );

Here is the code to add the "Sub-page".

function register_adminMenu(){
    add_submenu_page('edit.php?post_type=case', 'My cases', 'My cases', 'manage_options', 'my_cases', 1);
};

function my_cases(){
    include_once(file_to_script);
}

The "include_once(file_to_script);" should be the script where list the "cases". I think that I have to extend the "WP_List_Table" class, but I'm not sure and I can't find this in Internet.

Thanks a lot

Answer 1

You can use the pre_get_posts filter to modify requested posts, this filter works in the admin area too, so you don't need to go to the trouble of creating a new post list table class

First lets add a query var to the URL of your 'My Cases' page:

function register_adminMenu(){
    add_submenu_page('edit.php?post_type=case&mycases=mine', 'My Cases', 'My Cases', 'manage_options', 'my_cases', 1);
}

Then, if that value is set, add the filter:

if ( !empty( $_GET['mycases'] ) ) {
    add_filter( 'pre_get_posts', function( $query ) {
        if ( is_main_query() && is_post_type_archive('case') && is_admin() ) {
             $query->set( 'author', $your_user_id );
        }
    });
}

Remember to set the user ID!

But wait, you want to show just your cases, aka cases with a specific author? If that's the case we don't even need the filter!

function register_adminMenu(){
    add_submenu_page('edit.php?post_type=case&author='. get_current_user_id(), 'My Cases', 'My Cases', 'manage_options', 'my_cases', 1);
}