Okay, I figure it out. Instead of using wp_nav_menu, I use wp_list_categories which has more parameters that we can control. So to not display empty menu, I use: <?php wp_list_categories(array(‘taxonomy’ => ‘custom_tax’,’hide_empty’ => ‘1’,’title_li’ => ”)); ?> the hide_empty do the magic here.
Using custom taxonomies to display hierarchical URLs?
List Posts For Terms Of A Custom Taxonomy For Any Post Type
Display all taxonomy, children and grandchildren with links
How can I unregister a custom taxonomy?
Multi-select field for Taxonomy can’t save the value
Front-End Custom Taxonomy Tag Select
How to get posts which must match both custom taxonomies?
Try hooking into ‘save_post’ action: add_action( ‘save_post’, ‘your_state_term_save’ ); function your_state_term_save( $post_id ){ // Bail if we’re doing an auto save if( defined( ‘DOING_AUTOSAVE’ ) && DOING_AUTOSAVE ) return; //check if they selected your state term $state = isset($_POST[‘tax_input_field_name’]) ? $_POST[‘tax_input_field_name’] : ”; //make sure of what the input name is here… //insert post meta … Read more
Take a look at this plugin. It provides hierarchical URLs for categories, but you can easily adapt to any taxonomy.