Allow a custom field value to be removable in WooCommerce - php

Question

I added a custom subtitle field for woo-commerce products. When I fill its field from the dashboard it appears in the product. I can update the text but I can't remove its value it appears again when I update the product.
Here the code. I copied from somewhere
<?php
// Display Fields
add_action('woocommerce_product_options_general_product_data',
'woocommerce_product_custom_fields');
// Save Fields
add_action('woocommerce_process_product_meta', 'woocommerce_product_custom_fields_save');
function woocommerce_product_custom_fields()
{
global $woocommerce, $post;
echo '<div class="product_custom_field">';
// Custom Product Text Field
woocommerce_wp_text_input(
array(
'id' => '_custom_product_subtitle',
'placeholder' => 'Custom Product Subtitle',
'label' => __('Custom Product Subtitle', 'woocommerce'),
'desc_tip' => 'true'
)
);
}
function woocommerce_product_custom_fields_save($post_id)
{
// Custom Product Text Field
$woocommerce_custom_product_text_field = $_POST['_custom_product_subtitle'];
if (!empty($woocommerce_custom_product_text_field))
update_post_meta($post_id, '_custom_product_subtitle',
esc_attr($woocommerce_custom_product_text_field));
}
// To show after the title
add_action( 'woocommerce_after_shop_loop_item_title', 'custom_field_display_below_title', 2 );
function custom_field_display_below_title(){
global $product;
// Get the custom field value
$custom_field = get_post_meta( $product->get_id(), '_custom_product_subtitle', true );
// Display
if( ! empty($custom_field) ){
echo '<p class="custom-product-subtitle">'.$custom_field.'</p>';
}
}
This is the result of the code, it also displays where I want to, but I can't make remove the text it appears again when I update

Answer 1

To be able to reset (empty) this custom field, just replace the code line (from your 2nd function):
if( ! empty($woocommerce_custom_product_text_field) ){
by:
if( isset($woocommerce_custom_product_text_field) ){
So now you can remove the field value and save it.
Now since WooCommerce 3, your code is a bit outdated… Also, you should use shorter keys and variable names.
Below is your revisited code (changed the field meta key from '_custom_product_subtitle' to simply '_subtitle', replaced a hook and made some other changes).
// Display a text Field (admin single product)
add_action( 'woocommerce_product_options_general_product_data', 'display_admin_product_custom_text_field' );
function woocommerce_product_custom_fields() {
echo '<div class="product_custom_field">';
woocommerce_wp_text_input( array(
'id' => '_subtitle',
'label' => __('Custom subtitle', 'woocommerce'),
'placeholder' => __('You can add optionally a custom subtitle', 'woocommerce'),
'desc_tip' => 'true'
) );
echo '</div>'; // <== missing
}
// Save Text Field value (admin)
add_action( 'woocommerce_admin_process_product_object', 'save_admin_product_custom_text_field_value' );
function save_admin_product_custom_text_field_value( $product ) {
if ( isset($_POST['_subtitle']) ) {
$product->update_meta_data( '_subtitle', sanitize_text_field($_POST['_subtitle']) );
}
}
// Display product subtitle (front end)
add_action( 'woocommerce_after_shop_loop_item_title', 'custom_field_display_below_title', 2 );
function custom_field_display_below_title(){
global $product;
$value = $product->get_meta('_subtitle'); // Get the custom field value
if( ! empty($value) ){
echo '<p class="product-subtitle">' . $value . '</p>'; // Display
}
}
Code goes in functions.php file of the active child theme (or active theme). Tested and works.