根据WooCommerce中的其他购物车项目计数，自动将特定产品添加到购物车

Question

我正在尝试根据购物车中的产品数量向购物车添加一个名为（送货费）的产品。

购物车示例：
产品A（数量5）
产品B（数量2）
产品C（数量4）
送货费（数量3）**这是3，因为这是添加送货费产品之前添加到购物车中的应计数的行项目总数。

我的代码有问题：

/* Function to get total Products (line items) not qty of each */
function count_item_in_cart() {
    global $woocommerce; 
    $counter = 0; 

    foreach ($woocommerce->cart->get_cart() as $cart_item_key => $cart_item) {
        $counter++;
    }
    return $counter;
}

/* Add DC (Delivery Charge Product) to Cart based on qty */ 
add_action( 'template_redirect', 'delivery_charge_add_product_to_cart' ); 
function delivery_charge_add_product_to_cart() {
    /* Establish Product Delivery Charge Product ID */
    global $woocommerce;
    $product_id = 4490;  /* Product ID to add to cart */
    $quantity = count_item_in_cart(); 

    if ($quantity > 0) {
        WC()->cart->add_to_cart( $product_id, $quantity); 
    }
}

它总是返回一个更高的数字。我认为这是计算每个产品的数量，而不是实际的产品项目。

任何帮助都将不胜感激！

Answer 1

以下代码将在每次将产品添加到购物车时自动添加/更新您的附加产品“送货费”到购物车，并将处理所有可能的情况：

add_action( 'woocommerce_before_calculate_totals', 'add_delivery_charge_to_cart', 10, 1 );
function add_delivery_charge_to_cart( $cart ) {
    if ( is_admin() && ! defined( 'DOING_AJAX' ) )
        return;

    if ( did_action( 'woocommerce_before_calculate_totals' ) >= 2 )
        return;

    $dcharge_id  = 4490; // Product Id "Delivery charge" to be added to cart
    $items_count = 0;  // Initializing

    // Loop through cart items
    foreach ( $cart->get_cart() as $cart_item_key => $cart_item ) {
        // Check if "Delivery charge" product is already in cart
        if( $cart_item['data']->get_id() == $dcharge_id ) {
            $dcharge_key = $cart_item_key;
            $dcharge_qty = $cart_item['quantity'];
        }
        // Counting other items than "Delivery charge"
        else {
            $items_count++;
        }
    }

    // If product "Delivery charge" is in cart, we check the quantity to update it if needed
    if ( isset($dcharge_key) && $dcharge_qty != $items_count ) {
        $cart->set_quantity( $dcharge_key, $items_count );
    }
    // If product "Delivery charge" is not in cart, we add it
    elseif ( ! isset($dcharge_key) && $items_count > 0 ) {
        $cart->add_to_cart( $dcharge_id, $items_count );
    }
}

代码进入活动子主题（或活动主题）的functions.php文件。测试和工作。