Add Custom Columns To Post Type

Declaring a new admin column in our WordPress admin’s list pages is a common task. Fortunately, we can do it quickly.

To create new columns for a WP post type of custom post type, we need two filters:

• manage_{$post_type}_posts_columns, to add the columns and,
• manage_{$post_type}_posts_custom_column to add the content of the columns.

One usual case is when we create a custom post type and add a custom taxonomy to it. Our taxonomy not appended to the admin columns automatically, so we need to declare it like the following:

// Add the Terms(s) columns to the snippets post type
function set_custom_edit_snippets_columns($columns) {
    $columns['terms'] = __( 'Term(s)', 'pine' );
    return $columns;
}
add_filter( 'manage_snippets_posts_columns', 'set_custom_edit_snippets_columns' );
// Add the data to the snippet's Term(s) column
function custom_snippets_column( $column, $post_id ) {
    switch ( $column ) {
        case 'terms' :
            $terms = get_the_terms( $post_id, 'snippets_category' );
            $links = array();
        
            foreach ( $terms as $term ) {
                $link = get_term_link( $term, 'snippets_category' );
                if ( is_wp_error( $link ) ) {
                    return $link;
                }
                $links[] = '<a href="' . admin_url( 'edit.php?post_type=snippets&snippets_category=' . $term->slug ) . '" rel="tag">' . $term->name . '</a>';
            }
            $terms = join( ', ', $links );
            if ( is_string( $terms ) )
                echo $terms;
            else
                _e( 'No avialable term.', 'pine' );
            break;
    }
}
add_action( 'manage_snippets_posts_custom_column' , 'custom_snippets_column', 10, 2 );