在WooComerce产品设置页面中添加自定义字段可用于比较功能

Question

我添加了此代码：

    // Add custom fields to product shipping tab
    add_action( 'woocommerce_product_options_shipping', 'add_custom_shipping_option_to_products');
    function add_custom_shipping_option_to_products(){
        global $product_object;

        $product_id = method_exists( $product_object, 'get_id' ) ? $product_object->get_id() : $product_object->id;

        echo '</div><div class="options_group">'; // New option group

        woocommerce_wp_text_input( array(
            'id'          => 'custom_text_field1',
            'label'       => __( 'Weight without Foam', 'woocommerce' ),
            'placeholder' => 'something',
            'desc_tip'    => 'true',
            'description' => __( 'Weight in decimal form.', 'woocommerce' ),
            'value'       => get_post_meta($product_id, '_custom_meta_field1', true),
        ) );

        woocommerce_wp_text_input( array(
            'id'          => 'custom_text_field2',
            'label'       => __( 'Volume', 'woocommerce' ),
            'placeholder' => 'something',
            'desc_tip'    => 'true',
            'description' => __( 'Volume in decimal form.', 'woocommerce' ),
            'value'       => get_post_meta($product_id, '_custom_meta_field2', true),
        ) );

        woocommerce_wp_text_input( array(
            'id'          => 'custom_text_field3',
            'label'       => __( 'Buoyancy', 'woocommerce' ),
            'placeholder' => 'something',
            'desc_tip'    => 'true',
            'description' => __( 'Buoyancy in decimal form.', 'woocommerce' ),
            'value'       => get_post_meta($product_id, '_custom_meta_field3', true),
        ) );

    }

    // Save the custom fields values as meta data
    add_action( 'woocommerce_process_product_meta', 'save_custom_shipping_option_to_products' );
    function save_custom_shipping_option_to_products( $post_id ){

        $custom_text_field1 = $_POST['custom_text_field1'];
        if( !empty( $custom_text_field1 ) )
            update_post_meta( $post_id, '_custom_meta_field1', esc_attr( $custom_text_field1 ) );

        $custom_text_field2 = $_POST['custom_text_field2'];
        if( !empty( $custom_text_field2 ) )
            update_post_meta( $post_id, '_custom_meta_field2', esc_attr( $custom_text_field2 ) );

        $custom_text_field3 = $_POST['custom_text_field3'];
        if( !empty( $custom_text_field3 ) )
            update_post_meta( $post_id, '_custom_meta_field3', esc_attr( $custom_text_field3 ) );

    }

// Add variation external "dimentions" fields
add_action( 'woocommerce_product_options_shipping','add_variation_options_built_dimensions', 10, 3 );
function add_variation_options_built_dimensions( $loop, $variation_data, $variation ){

    $variation_built_lenght = get_post_meta($variation->ID,"_built_lenght", true );
    if( ! $variation_built_lenght ) $variation_built_lenght = "";

    $variation_built_width = get_post_meta($variation->ID,"_built_width", true );
    if( ! $variation_built_width ) $variation_built_width = "";

    $variation_built_height = get_post_meta($variation->ID,"_built_height", true );
    if( ! $variation_built_height ) $variation_built_height = "";

    ?>
    <p class="form-field dimensions_field">
        <label for="product_built_length"><?php printf( __( 'Ext. dimensions (%s)', 'woocommerce' ), get_option( 'woocommerce_dimension_unit' ) ); ?></label> 

        <span class="wrap">
            <input id="product_built_length" placeholder="<?php esc_attr_e( 'Built length', 'woocommerce' ); ?>" class="input-text wc_input_decimal" size="6" type="text" name="built_lenght_<?php echo $loop; ?>" value="<?php echo esc_attr( $variation_built_lenght ); ?>" />
            <input placeholder="<?php esc_attr_e( 'Built width', 'woocommerce' ); ?>" class="input-text wc_input_decimal" size="6" type="text" name="built_width_<?php echo $loop; ?>" value="<?php echo esc_attr( $variation_built_width ); ?>" />
            <input placeholder="<?php esc_attr_e( 'Built height', 'woocommerce' ); ?>" class="input-text wc_input_decimal last" size="6" type="text" name="built_height_<?php echo $loop; ?>" value="<?php echo esc_attr( $variation_built_height ); ?>" />
        </span>
        <?php echo wc_help_tip( __( 'LxWxH in decimal form.', 'woocommerce' ) ); ?>

    </p>
    <?php

}

    //Save variation custom "dimentions" fields
add_action( 'woocommerce_save_product_variation','save_variation_options_built_dimensions', 10 ,2 );
function save_variation_options_built_dimensions( $variation_id, $loop ){

    $built_lenght = $_POST["built_lenght_$loop"];
    if(!empty($built_lenght))
        update_post_meta( $variation_id, '_built_lenght', sanitize_text_field($built_lenght) );

    $built_width = $_POST["built_width_$loop"];
    if(!empty($built_width))
        update_post_meta( $variation_id, '_built_width', sanitize_text_field($built_width) );

    $built_height = $_POST["built_height_$loop"];
    if(!empty($built_height))
        update_post_meta( $variation_id, '_built_height', sanitize_text_field($built_height) );
} `

到WooCommerce产品页面的后端，我需要这个新添加的字段和参数将由比较功能自动使用。我使用YITH WooCommerce Compare插件来比较产品。现在我只能在那里使用尺寸和重量从bak-end产品发货标签和所有属性，但我需要在那里使用新添加的字段。如果可能，这个新数据应该显示为默认的woocommerce维度参数，该参数已经显示在比较表中。

可以看到该网站HERE。

感谢。