WooCommerce: Get custom field from product variations and display it on the “additional information area”

Question

I\'m trying to add a custom field to product variations, and display the custom field value on products in the \"additional information area\".

I\'m working from \"WooCo

Answer 1

At 'value' => get_post_meta( $variation_id, '_custom_field', true ) you make use of the $variation_id while this is not defined.

So you can make use a foreach loop and $variations->get_children(); instead to add a custom label & value in the "additional information area"

// 4. Display custom field on the additional information area
function display_product_attributes( $product_attributes, $variations ) {
    // Get childIDs in an array
    $children_ids = $variations->get_children();

    foreach ( $children_ids as $child_id ) {
        $value = get_post_meta( $child_id, 'custom_field', true );

        // True
        if ( $value ) {
            // rows
            $product_attributes[ 'custom_field ' . $child_id ] = array(
                'label' => __('custom', 'woocommerce'),
                'value' => $value,
            );
        }
    }

    return $product_attributes;
}
add_filter('woocommerce_display_product_attributes', 'display_product_attributes', 10, 2);