How to add custom field to custom taxonomy in 4.4

Question

I have a custom taxonomy for cities, and would like to have this available as a custom field to be able to access it using the iOS Workflow app. Considering the changes in 4.4 what should I do if I want to have a custom field for location to be able to use in the Workflow app?

I found this page titled, "Adding Custom Meta Fields to Taxonomies": https://pippinsplugins.com/adding-custom-meta-fields-to-taxonomies/ which notes:

With WordPress 4.4, there will be a native “terms metadata” table in WordPress, so this is no longer a necessary or valid method of adding customer metadata to terms.

See here for more information: https://make.wordpress.org/core/2015/09/04/taxonomy-term-metadata-proposal/

My custom taxonomy is:

    add_action( 'init', 'loc_taxonomy', 0 );
    function loc_taxonomy() {

    $labels = array(
        'name'                       => _x( 'Locations', 'Taxonomy General Name', 'text_domain' ),
        'singular_name'              => _x( 'Location', 'Taxonomy Singular Name', 'text_domain' ),
        'menu_name'                  => __( 'Locations', 'text_domain' ),
        'all_items'                  => __( 'All Locations', 'text_domain' ),
        'parent_item'                => __( 'Parent Location', 'text_domain' ),
        'parent_item_colon'          => __( 'Parent Location:', 'text_domain' ),
        'new_item_name'              => __( 'New Location Name', 'text_domain' ),
        'add_new_item'               => __( 'Add New Location', 'text_domain' ),
        'edit_item'                  => __( 'Edit Location', 'text_domain' ),
        'update_item'                => __( 'Update Location', 'text_domain' ),
        'separate_items_with_commas' => __( 'Separate locations with commas', 'text_domain' ),
        'search_items'               => __( 'Search locations', 'text_domain' ),
        'add_or_remove_items'        => __( 'Add or remove locations', 'text_domain' ),
        'choose_from_most_used'      => __( 'Choose from the most used locations', 'text_domain' ),
        'not_found'                  => __( 'Not Found', 'text_domain' ),
    );
    $args = array(
        'labels'                     => $labels,
        'hierarchical'               => true,
        'public'                     => true,
        'show_ui'                    => true,
        'show_admin_column'          => true,
        'show_in_nav_menus'          => true,
        'show_tagcloud'              => true,
    );
    register_taxonomy( 'loc', array( 'post' ), $args );

}

Answer 1

You can implement this in two ways to add meta boxes through plugin or wordpress predefined hooks

https://wordpress.org/plugins/taxonomy-metadata/

  **OR**

Add the following code in functions.php in your theme

function mj_taxonomy_add_custom_meta_field() {
        ?>
        <div class="form-field">
            <label for="term_meta[class_term_meta]"><?php _e( 'Add Class', 'MJ' ); ?></label>
            <input type="text" name="term_meta[class_term_meta]" id="term_meta[class_term_meta]" value="">
            <p class="description"><?php _e( 'Enter a value for this field','MJ' ); ?></p>
        </div>
    <?php
    }
add_action( 'product_cat_add_form_fields', 'mj_taxonomy_add_custom_meta_field', 10, 2 );





 function mj_taxonomy_edit_custom_meta_field($term) {

        $t_id = $term->term_id;
        $term_meta = get_option( "taxonomy_$t_id" ); 
       ?>
        <tr class="form-field">
        <th scope="row" valign="top"><label for="term_meta[class_term_meta]"><?php _e( 'Add Class', 'MJ' ); ?></label></th>
            <td>
                <input type="text" name="term_meta[class_term_meta]" id="term_meta[class_term_meta]" value="<?php echo esc_attr( $term_meta['class_term_meta'] ) ? esc_attr( $term_meta['class_term_meta'] ) : ''; ?>">
                <p class="description"><?php _e( 'Enter a value for this field','MJ' ); ?></p>
            </td>
        </tr>
    <?php
    }

add_action( 'product_cat_edit_form_fields','mj_taxonomy_edit_custom_meta_field', 10, 2 );



function mj_save_taxonomy_custom_meta_field( $term_id ) {
        if ( isset( $_POST['term_meta'] ) ) {

            $t_id = $term_id;
            $term_meta = get_option( "taxonomy_$t_id" );
            $cat_keys = array_keys( $_POST['term_meta'] );
            foreach ( $cat_keys as $key ) {
                if ( isset ( $_POST['term_meta'][$key] ) ) {
                    $term_meta[$key] = $_POST['term_meta'][$key];
                }
            }
            // Save the option array.
            update_option( "taxonomy_$t_id", $term_meta );
        }

    }  
add_action( 'edited_product_cat', 'mj_save_taxonomy_custom_meta_field', 10, 2 );  
add_action( 'create_product_cat', 'mj_save_taxonomy_custom_meta_field', 10, 2 );