问题
When I press the add to cart button at my product-page the $_SESSION variable --> $_SESSION['shopping-cart']['quantity'] is set in the the input value. It will display 4 quantity's for example. However, if I manually want to decrease this quantity from 4 -> 5 in the shopping-cart page. It won't remember it's changing and will be overwritten by his original $_SESSION['shopping-cart']['quantity'].
My question is: How can this $_SESSION variable remembers his new input and don't get overwritten by the original $_SESSION variable after refreshing the page.
I hope you understand my question.
<td data-th="Price"><input type="number" class="form-control text-center" value="<?php echo $product['quantity']; ?>"> </td>
Shopping cart file code: (The session is already started).
<!-- Shopping Cart Section -->
<div class="container">
<table id="cart" class="table table-hover table-condensed">
<thead>
<tr>
<th style="width:50%">Product</th>
<th style="width:10%">Price</th>
<th style="width:8%">Quantity</th>
<th style="width:22%" class="text-center">Subtotal</th>
<th style="width:10%"></th>
</tr>
</thead>
<tbody>
<tr>
<?php
if(!empty($_SESSION['shopping-cart'])):
$total_payment = 0;
foreach($_SESSION['shopping-cart'] as $key => $product):
?>
<td data-th="Product">
<div class="row">
<!--<div class="col-sm-2 hidden-xs"><img src="http://placehold.it/100x100" alt="..." class="img-responsive"/></div>-->
<div class="col-sm-10">
<h6 class="nomargin"><?php echo $product['product-name']; ?></h6>
</div>
</div>
</td>
<td data-th="Price"><?php echo $product['product-price']; ?></td>
<td data-th="Price">
<input type="number" class="form-control text-center" value="<?php echo $product['quantity']; ?>">
</td>
<td data-th="Subtotal" class="text-center"><?php echo number_format($product['quantity'] * $product['product-price'], 2); ?></td>
<td class="actions" data-th="">
<a href="products/shopping-cart.php"><button class="btn btn-info btn-sm"><i class="fa fa-refresh"></i></button></a>
<a href="includes/shopping-cart.inc.php?action=delete&id=<?php echo $product['id'];?>"><button class="btn btn-danger btn-sm" name="delete-product"><i class="fa fa-trash-o"></i></button></a>
</td>
</tr>
<?php
$total_payment += ($product['quantity'] * $product['product-price']);
endforeach;
endif; ?>
</tbody>
<tfoot>
<tr>
<td><a href="categorie/categorie.php" class="btn btn-warning"><i class="fa fa-angle-left"></i> Continue Shopping</a></td>
<td colspan="2" class="hidden-xs"></td>
<?php if(isset($_SESSION['shopping-cart'])){
if(count($_SESSION['shopping-cart']) > 0){
?>
<td class="hidden-xs text-center"><strong>Total price: <?php echo number_format($total_payment, 2);?></strong></td>
<td><a href="#" class="btn btn-success btn-block">Checkout <i class="fa fa-angle-right"></i></a></td>
<?php }
} ?>
</tr>
</tfoot>
</table>
</div>
<!-- /Shopping Cart Section -->
</main>
<!-- /Main -->
<!-- Footer -->
<?php
include('../structure/footer.php');
?>
<!-- /Footer -->
<!-- Script: Bootstrap CDN, JS -->
<?php
include('../structure/script.php');
?>
Shopping-cart.inc.php file
<?php
$products_in_cart = array();
require('../php/connection.php');
require('../function.php');
//session_destroy();
protect_user();
// Check if Add to Cart button has been submitted
if(isset($_POST['add_to_cart'])){
if(isset($_SESSION['shopping-cart'])){
// Keeps track of how many products in shopping cart
$count = count($_SESSION['shopping-cart']);
// Create array for matching arrays keys to product id's
$products_in_cart = array_column($_SESSION['shopping-cart'], 'id');
if(!in_array(filter_input(INPUT_GET, 'id'), $products_in_cart)){
$_SESSION['shopping-cart'][$count] = array
(
'id' => filter_input(INPUT_GET, 'id'),
'product-name' => $_POST['product-name'],
'product-price' => $_POST['product-price'],
'quantity' => $_POST['quantity']
);
}
else{
for($i = 0; $i < count($products_in_cart); $i++){
if($products_in_cart[$i] == filter_input(INPUT_GET, 'id')){
// Adding item quantity to the existing product in the array
$_SESSION['shopping-cart'][$i]['quantity'] += filter_input(INPUT_POST, 'quantity');
}
}
}
}
else{
$_SESSION['shopping-cart'][0] = array
(
'id' => filter_input(INPUT_GET, 'id'),
'product-name' => $_POST['product-name'],
'product-price' => $_POST['product-price'],
'quantity' => $_POST['quantity']
);
}
header("Location: ../products/shopping-cart.php");
exit();
}
// Check if Delete product in shopping-cart button has been submitted
if(filter_input(INPUT_GET, 'action') == 'delete'){
// Loop through all products until matches the deleted product
foreach($_SESSION['shopping-cart'] as $key => $product){
if($product['id'] == filter_input(INPUT_GET, 'id')){
unset($_SESSION['shopping-cart'][$key]);
}
}
$_SESSION['shopping-cart'] = array_values($_SESSION['shopping-cart']);
header("Location: ../products/shopping-cart.php");
exit();
}
header("Location: ../index.php");
exit();
Quantity after submitting product
adding extra quantity
来源：https://stackoverflow.com/questions/61878646/html-input-variable-overwrite-the-session-variable-php