woocommerce中与购物车相关的新语法是使用**WC()创建的，无需调用global woocommerce;**
因此，您的代码如下所示：

$products_in_cart= array();
$products_post_title_in_cart = array();
$products_ids_in_cart= array();

foreach(WC()->cart->get_cart() as $cart_item) {
    $products_in_cart[] = $cart_item['data']->post;
    $products_post_title_in_cart[] = $cart_item['data']->post->post_title;
    $products_ids_in_cart[] = $cart_item['product_id'];
}

// The first product (or item of the cart)
$_product = $products_in_cart[0]; // product post data
$product_id = $products_ids_in_cart[0]; // product ID
$products_post_title_in_cart[0] // product post title

// The Second product (or item of the cart)
$_product = $products_in_cart[1]; // product post data
$product_id = $products_ids_in_cart[1]; // product ID
$products_post_title_in_cart[1] // product post title

// etc … for all other products you increase the key of the arrays to get the correct values

<?php
    global $woocommerce;
    $items = $woocommerce->cart->get_cart();
    $arr_product=array();
        foreach($items as $item => $values) {             
           $arr_product[]= $_product->post_title;            
        } 
    print_r($arr_product,true); // echo print_r(); thats why get 1
?>

尝试此代码，它返回购物车中的所有名称。

global $woocommerce; 

$cart_item = $woocommerce->cart->get_cart(); 

echo "<pre>";
print_r($cart_item);

exit();

$products_post_title_in_cart = array();
foreach(WC()->cart->get_cart() as $cart_item) {
    $products_post_title_in_cart[] = $cart_item['data']->post->post_title;
}

$产品名称=内爆（“\n”，$产品发布标题在购物车中）;
这是一个非常好的例子.