无法在会话对象中增加产品的数量

Question

我创建了一个对象，它名为carwash。我创建了一个会话并为会话分配了该对象，如果我输入数量然后按下购买按钮，我有结果（例6）：

  

    

您的购物车包含6件商品。

  

但是当我什么也没输入时，我得到了：

  

    

您的购物车包含商品。

  

我该怎么办？谢谢！这是我的所有代码：

index.php
PHP代码：

<?php 
    session_start();  

    require_once 'carwash.php'; 
    if (isset($_SESSION['encoded_cartopass'])) { 
        // first let's get the variable from the session 
        $encoded_cartopass = $_SESSION['encoded_cartopass']; 

        // now let's unpack it 
        $cartopass = unserialize($encoded_cartopass); 

        // echo quantity 
        echo "Your shopping cart contains {$cartopass->getQuantity()} items. <br /><br />"; 
    } 
    else { 
        echo "Your shopping cart contains 0 items. <br /><br />"; 
    } 
?> 



    <form action="process.php" method="post"> 
    Quantity: <input type="text" name="quantity" id="quantity"/> 
    <input type="submit" value="Buy" name="submit" /> 
    </form>

process.php
PHP代码：

<?php 

    require_once 'carwash.php'; 

    if (isset($_POST['submit'])) { 

        if (!isset($_SESSION['encoded_cartopass'])) { 

            // construct and set quantity 
            $cartopass = new carwash(); 
            $cartopass->setQuantity($_POST['quantity']); 

            // construct and encode session 
            session_register('encoded_cartopass'); 
            $_SESSION['encoded_cartopass'] = serialize($cartopass); 
        } 
        else { 
            // if session is existing, decode it and 
            // increment quantity 
            $encoded_cartopass = $_SESSION['encoded_cartopass']; 

            $cartopass = unserialize($encoded_cartopass); 

            $cartopass->incrementQuantity($_POST['quantity']); 

            // encode class and assign to session and 
            // session is used pass to index.php 
            $_SESSION['encode_cartopass'] = serialize($cartopass); 
        } 

    } 

    echo "<script>window.location.href='index.php'</script>"; 
?>

carwash.php
PHP代码：

<?php 
    class carwash { 

        private $carmake; 
        private $caryear; 
        private $quantity; 

        public function getCarmake() { 
            return $this->carmake; 
        } 

        public function setCarmake($carmake) { 
            $this->carmake = $carmake; 
        } 

        public function getCaryear() { 
            return $this->caryear; 
        } 

        public function setCaryear($caryear) { 
            $this->caryear = $caryear; 
        } 

        public function getQuantity() { 
            return $this->quantity; 
        } 

        public function setQuantity($quantity) { 
            $this->quantity = $quantity; 
        } 

        public function incrementQuantity($quantity = '') { 
            if (empty($quantity)) { 
                $this->quantity++; 
            } 
            else { 
                $this->quantity += $quantity; 
            } 
        } 

        public function washcar() { 
            echo "scruba, dub, dub, scruba, dub, dub <br />"; 
            echo "I'm feelling cleaner, Thank you!"; 
        } 
    } 
?>

Answer 1

编辑:(发现大括号的作用......） 以下任何一种都应该有效：

echo "Your shopping cart contains ".($cartopass->getQuantity() ? $cartopass->getQuantity() : 0)." items. <br /><br />"; 

echo "Your shopping cart contains ", $cartopass->getQuantity() + 0, " items. <br /><br />"; 

Answer 2

有两种可能的解决方案 -

1. 检查会话的值是否为"0"（即使“0”为假，$v = "0"; isset($v)将返回true）。

如果$_POST为"0"，则

2. 销毁会话。

将index.php更改为 -

<?php 
session_start();  

require_once 'carwash.php'; 
if (isset($_SESSION['encoded_cartopass']) && $_SESSION['encoded_cartopass']) { 
    // first let's get the variable from the session 
    $encoded_cartopass = $_SESSION['encoded_cartopass']; 

    // now let's unpack it 
    $cartopass = unserialize($encoded_cartopass); 

    // echo quantity 
    echo "Your shopping cart contains {$cartopass->getQuantity()} items. <br /><br />"; 
} 
else { 
    echo "Your shopping cart contains 0 items. <br /><br />"; 
} 
?> 

或将您的process.php更改为 -

<?php 

require_once 'carwash.php'; 

if (isset($_POST['submit']) && $_POST['quantity']) { 

    if (!isset($_SESSION['encoded_cartopass'])) { 

        // construct and set quantity 
        $cartopass = new carwash(); 
        $cartopass->setQuantity($_POST['quantity']); 

        // construct and encode session 
        session_register('encoded_cartopass'); 
        $_SESSION['encoded_cartopass'] = serialize($cartopass); 
    } 
    else { 
        // if session is existing, decode it and 
        // increment quantity 
        $encoded_cartopass = $_SESSION['encoded_cartopass']; 

        $cartopass = unserialize($encoded_cartopass); 

        $cartopass->incrementQuantity($_POST['quantity']); 

        // encode class and assign to session and 
        // session is used pass to index.php 
        $_SESSION['encode_cartopass'] = serialize($cartopass); 
    } 

} else {
    unset($_SESSION['cartopass']);
    session_destroy();
}

echo "<script>window.location.href='index.php'</script>"; 
?>