整洁2.0平板电脑媒体查询不起作用(Neat 2.0 tablet media query not working)

 在进一步检查后，正在“验证”的项目仍然使用ajax added_to_cart 。 因此，jQuery代码可以在“added_to_cart”委托事件上发送ajax请求时使用相同的逻辑。 在那个请求中，php将获得一个购物车项目被添加到购物篮的尝试次数 ，并将其返回给jQuery。 如果该计数符合条件，则会显示甜言蜜语消息： 
 
 感谢@LoicTheAztec帮助提供部分解决方案。 
 
// remove the filter 
add_filter( 'woocommerce_cart_redirect_after_error', '__return_false'); 

add_action( 'woocommerce_add_to_cart_validation', 'restrict_only_one_item_in_cart' );

 function restrict_only_one_item_in_cart($cart_item_data) {

   global $woocommerce;
   $item_count = $woocommerce->cart->cart_contents_count;

   if($item_count >= 20)
   {
      //WE WILL EXECUTE JAVASCRIPT BELOW INSTEAD
      return false;
   }

   return $cart_item_data;
}

// The Jquery script
add_action( 'wp_footer', 'cart_full' );
function cart_full() {
    ?>
    <script src="https://unpkg.com/sweetalert2@7.20.1/dist/sweetalert2.all.js"></script>
    <script type="text/javascript">
    jQuery( function($){
        // The Ajax function
        $(document.body).on('added_to_cart', function() {
            console.log('event');
            $.ajax({
                type: 'POST',
                url: wc_add_to_cart_params.ajax_url,
                data: {
                    'action': 'checking_cart_items',
                    'added' : 'yes'
                },
                success: function (response) {
                    if( response >= 20 ){
                        swal(
                            'Youve added the max items!',
                            'Change Your box',
                            'error'
                        );
                    }
                }
            });
        });
    });
    </script>
    <?php
}

Upon further inspection, items which are being "validated" are still called with the ajax added_to_cart. Therefore the same logic can be used where jQuery code will send an ajax request on "added_to_cart" delegated event. On that request php will get the number of attempts a cart item has been added to the basket and will return it to jQuery. If that count has met a condition, it will display sweet-alert message:
 
Thanks to @LoicTheAztec for helping provide part of the solution.
 
// remove the filter 
add_filter( 'woocommerce_cart_redirect_after_error', '__return_false'); 

add_action( 'woocommerce_add_to_cart_validation', 'restrict_only_one_item_in_cart' );

 function restrict_only_one_item_in_cart($cart_item_data) {

   global $woocommerce;
   $item_count = $woocommerce->cart->cart_contents_count;

   if($item_count >= 20)
   {
      //WE WILL EXECUTE JAVASCRIPT BELOW INSTEAD
      return false;
   }

   return $cart_item_data;
}

// The Jquery script
add_action( 'wp_footer', 'cart_full' );
function cart_full() {
    ?>
    <script src="https://unpkg.com/sweetalert2@7.20.1/dist/sweetalert2.all.js"></script>
    <script type="text/javascript">
    jQuery( function($){
        // The Ajax function
        $(document.body).on('added_to_cart', function() {
            console.log('event');
            $.ajax({
                type: 'POST',
                url: wc_add_to_cart_params.ajax_url,
                data: {
                    'action': 'checking_cart_items',
                    'added' : 'yes'
                },
                success: function (response) {
                    if( response >= 20 ){
                        swal(
                            'Youve added the max items!',
                            'Change Your box',
                            'error'
                        );
                    }
                }
            });
        });
    });
    </script>
    <?php
}