Additional field on Custom Post Type’s Taxonomy

I’ve now figured out how to add a field to ALL tags, including the taxonomy I created. But how do I make it only apply to a single taxonomy associated with a single Custom Post Type?

Here’s the code I’ve got so far in functions.php:

add_action ( 'edit_tag_form_fields', 'your_input_box');
function your_input_box($tag) {

	// Get all themes - the hide_empty argument enables you to get all the terms in your 'theme' taxonomy even the empty ones
	$themes = get_terms('theme', 'hide_empty=0'); 

?>
<tr class="form-field">
	<th scope="row" valign="top"><label for="category_theme"><?php _e('Additional Tag Field') ?></label></th>
	<td>
    <select name='category_theme' id='category_theme'>
	<option class='theme-option' value='one'>One</option>
	</select>
	 </td>
</tr>

<?php
}

Hmm… is it maybe possible to do this with an If statement?

Please. Anyone. I’m begging. How do I get it to ONLY apply to this single taxonomy on this single Post Type?

I’ve now discovered edit_{$taxonomy}_{$field}

But I can’t figure out how to implement it. Please help?

https://adambrown.info/p/wp_hooks/hook/edit_%7B$taxonomy%7D_%7B$field%7D

Is this even the right tag? Anyone?

instead of using get_terms() which retrieves ALL terms, use this instead:

$theme = get_the_terms($post->ID, ‘theme’);

$theme is of type Array()

in order to get the value, use this:

echo $theme[0]->name;