请尝试用下面的代码段替换现有代码段。此代码段的详细信息在this article中描述。如果可以改进，请告诉我。

add_filter('woocommerce_package_rates', 'xa_hide_shipping_rates_when_free_is_available', 10, 2);

function xa_hide_shipping_rates_when_free_is_available($rates, $package)
{
    global $woocommerce;
    $version = "2.6";
    if (version_compare($woocommerce->version, $version, ">=")) {
        foreach($rates as $key => $value) {
            $key_part = explode(":", $key);
            $method_title = $key_part[0];
            if ('free_shipping' == $method_title) {
                $free_shipping = $rates[$key];
                // Unset all rates.
                $rates = array();
                // Restore free shipping rate.
                $rates[$key] = $free_shipping;
                return $rates;
            }
        }
    }
    else {
        if (isset($rates['free_shipping'])) {
          // Below code is for unsetting single shipping method/option.
            // unset($rates['flat_rate']);
            $free_shipping = $rates['free_shipping'];
            // Unset all rates.
            $rates = array();
            // Restore free shipping rate.
            $rates['free_shipping'] = $free_shipping;
        }
    }

    return $rates;
}

如果您已经删除了旧的送货方式（送货方式必须使用新的送货区设置），您可以使用以下代码片段来删除免费送货时的所有其他送货方式。（WooCommerce 2.6+）：

/**
   * Hide shipping rates when free shipping is available.
   * Updated to support WooCommerce 2.6 Shipping Zones.
   *
   * @param array $rates Array of rates found for the package.
   * @return array
   */
  function my_hide_shipping_when_free_is_available( $rates ) {
    $free = array();
    foreach ( $rates as $rate_id => $rate ) {
      if ( 'free_shipping' === $rate->method_id ) {
        $free[ $rate_id ] = $rate;
        break;
      }
    }
    return ! empty( $free ) ? $free : $rates;
  }
  add_filter( 'woocommerce_package_rates', 'my_hide_shipping_when_free_is_available', 100 );

从updated docs

好了，下面的代码将允许本地拾取与免费送货：

// ##### WOOCOMMERCE - HIDE OTHER SHIPPING METHODS WHEN FREE SHIPPING IS AVAILABLE #####
add_filter('woocommerce_package_rates', 'hide_shipping_when_free_is_available', 10, 2);
function hide_shipping_when_free_is_available($rates, $package) {
    $free_yn = 0;
    $pickup_yn = 0;
    foreach($rates as $key => $value) {
        $key_part = explode(":", $key);
        $method_title = $key_part[0];
        if ('free_shipping' == $method_title) {
            // check if free shipping rate exists
            $free_yn = 1;
            $free_shipping = $rates[$key];
            $free_key = $key;
        }
        if ('local_pickup' == $method_title) {
            // check if local pickup rate exists
            $pickup_yn = 1;
            $local_pickup = $rates[$key];
            $pickup_key = $key;
        }
    }
    if ($free_yn == 1) {
        // Unset all rates.
        $rates = array();
        // Restore free shipping rate.
        $rates[$free_key] = $free_shipping;
        if ($pickup_yn == 1) {
            // Restore local pickup rate.
            $rates[$pickup_key] = $local_pickup;
        }
        return $rates;
    }
    return $rates;
}