Today, I was working on a client project and needed to add a little snippet underneath a hierarchical taxonomy form that was registered on a custom post type. Unfortunately, after spending about ten minutes digging through core and googling, I couldn’t find an action hook to use. Luckily, after tracing the output a little further back, I found what I was looking for.
When registering a custom taxonomy, one of the oft forgotten arguments is meta_box_cb, or the callback function used to render the meta box in the admin edit screen. Tracing this back a little further, the default value is set in wp-includes/taxonomy.php on Line 454. Using one of those default functions within our custom callback, we can essentially add as much code before or after the default taxonomy form.
| <?php | |
| register_taxonomy( 'acme_custom_taxonomy', array( 'my_cpt', 'post' ), array( | |
| 'meta_box_cb' => 'acme_metabox_cb', | |
| ) ); | |
| function acme_metabox_cb( $post, $box ){ | |
| // Render the default hierarchical meta box form | |
| post_categories_meta_box( $post, $box ); | |
| // Add all of our new stuff! | |
| echo "<p>This will show up below the checkboxes that you are used to!</p>"; | |
| } |
It’s that simple! If you need to add something to the non-hierarchical taxonomy form, simply swap out line 9 for the post_tags_meta_box() function instead.
