如何在php中创建在线购物车
[英]How to create an online shopping cart in php
问题描述
I am creating a shopping cart which has four buttons continue shopping, clear cart, update cart and place order I am facing a problem with the sessions like when I press the clear cart button it shows the 
我正在创建一个具有四个按钮的购物车，其中四个按钮用于继续购物，清除购物车，更新购物车和下订单我遇到了一些问题，例如当我按下清除购物车按钮时，它显示了
undefined index cart
but the cart comes from the session and when i press the clear cart button 但是购物车来自会话，当我按下清除购物车按钮时
it unsets the session of cart
so where i am doing it wrong ? 那我在哪里做错了？ can anyone help ? 有人可以帮忙吗？ here is my code 这是我的代码
<?php
include("includes/db.php");
include("includes/functions.php");
if($_REQUEST['command']=='delete' && $_REQUEST['pid']>0){
remove_product($_REQUEST['pid']);
}
else if($_REQUEST['command']=='clear'){
unset($_SESSION['cart']);
}
else if($_REQUEST['command']=='update'){
$max=count($_SESSION['cart']);
for($i=0;$i<$max;$i++){
$pid=$_SESSION['cart'][$i]['productid'];
$q=intval($_REQUEST['product'.$pid]);
if($q>0 && $q<=999){
$_SESSION['cart'][$i]['qty']=$q;
}
else{
$msg='Some proudcts not updated!, quantity must be a number between 1 and 999';
}
}
}
?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Shopping Cart</title>
<script language="javascript">
function del(pid){
if(confirm('Do you really mean to delete this item')){
document.form1.pid.value=pid;
document.form1.command.value='delete';
document.form1.submit();
}
}
function clear_cart(){
if(confirm('This will empty your shopping cart, continue?')){
document.form1.command.value='clear';
document.form1.submit();
}
}
function update_cart(){
document.form1.command.value='update';
document.form1.submit();
}
</script>
</head>
<body>
<form name="form1" method="post">
<input type="hidden" name="pid" />
<input type="hidden" name="command" />
<div style="margin:0px auto; width:600px;" >
<div style="padding-bottom:10px">
<h1 align="center">Your Shopping Cart</h1>
<input type="button" value="Continue Shopping" onclick="window.location='products.php'" />
</div>
<div style="color:#F00"><?php echo'' ;?></div>
<table border="0" cellpadding="5px" cellspacing="1px" style="font-family:Verdana, Geneva, sans-serif; font-size:11px; background-color:#E1E1E1" width="100%">
<?php
if(is_array($_SESSION['cart'])){
echo '<tr bgcolor="#FFFFFF" style="font-weight:bold"><td>Serial</td><td>Name</td><td>Price</td><td>Qty</td><td>Amount</td><td>Options</td></tr>';
$max=count($_SESSION['cart']);
for($i=0;$i<$max;$i++){
$pid=$_SESSION['cart'][$i]['productid'];
$q=$_SESSION['cart'][$i]['qty'];
$pname=get_product_name($pid);
if($q==0) continue;
?>
<tr bgcolor="#FFFFFF"><td><?php echo $i+1?></td><td><?php echo $pname?></td>
<td>$ <?php echo get_price($pid)?></td>
<td><input type="text" name="product<?php echo $pid?>" value="<?php echo $q?>" maxlength="3" size="2" /></td>
<td>$ <?php echo get_price($pid)*$q?></td>
<td><a href="javascript:del(<?php echo $pid?>)">Remove</a></td></tr>
<?php
}
?>
<tr><td><b>Order Total: $<?php echo get_order_total()?></b></td><td colspan="5" align="right"><input type="button" value="Clear Cart" onclick="clear_cart()"><input type="button" value="Update Cart" onclick="update_cart()"><input type="button" value="Place Order" onclick="window.location='billing.php'"></td></tr>
<?php
}
else{
echo "<tr bgColor='#FFFFFF'><td>There are no items in your shopping cart!</td>";
}
?>
</table>
</div>
</form>
</body>
</html>
3 个解决方案
解决方案1
1 已采纳 2013-03-23 07:43:21
If you haven't already started populating your cart then the element will be undefined. 如果尚未开始填充购物车，则该元素将为未定义。 When dealing with array elements it's always better to add the additional test array_key_exists(). 处理数组元素时，最好添加额外的测试array_key_exists（）。 However in your case the problem is more about the way you handle your array generally. 但是，在您的情况下，问题更多是与您通常处理数组的方式有关。
PHP is quite forgiving, so you have to enforce your own disciplines on the way you code. PHP相当宽容，因此您必须在编码方式上实施自己的规则。 One piece of very good practice which is worth getting used is to explicitly initialise your variables before you start using them. 值得使用的一种非常好的做法是在开始使用变量之前显式初始化它们。
// somewhere near the top of your code
$_SESSION['cart'] = array_key_exists('cart', $_SESSION)?$_SESSION['cart']:array();
and don't unset it in the clear test ... just set it back to an empty array. 并且不要在明确的测试中取消设置它……只需将其设置回一个空数组即可。
else if($_REQUEST['command']=='clear'){
$_SESSION['cart'] = array();
}
解决方案2
0 2013-03-23 07:17:17
here is Simple PHP Shopping Cart Tutorial 这是简单的PHP购物车教程
$product_id = $_GET['id']; //the product id from the URL
$action = $_GET['action']; //the action from the URL
//if there is an product_id and that product_id doesn't exist display an error message
if($product_id && !productExists($product_id)) {
die("Error. Product Doesn't Exist");
}
switch($action) { //decide what to do
case "add":
$_SESSION['cart'][$product_id]++; //add one to the quantity of the product with id $product_id
break;
case "remove":
$_SESSION['cart'][$product_id]--; //remove one from the quantity of the product with id $product_id
if($_SESSION['cart'][$product_id] == 0) unset($_SESSION['cart'][$product_id]); //if the quantity is zero, remove it completely (using the 'unset' function) - otherwise is will show zero, then -1, -2 etc when the user keeps removing items.
break;
case "empty":
unset($_SESSION['cart']); //unset the whole cart, i.e. empty the cart.
break;
}
?>
解决方案3
0 2013-05-21 02:03:09
switch($action) { //decide what to do
case "add":
$_SESSION['cart'][$product_id]++; //add one to the quantity of the product with id $product_id
break;
case "remove":
$_SESSION['cart'][$product_id]--; //remove one from the quantity of the product with id $product_id
if($_SESSION['cart'][$product_id] == 0) unset($_SESSION['cart'][$product_id]); //if the quantity is zero, remove it completely (using the 'unset' function) - otherwise is will show zero, then -1, -2 etc when the user keeps removing items.
break;
case "empty":
unset($_SESSION['cart']); //unset the whole cart, i.e. empty the cart.
break;
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