How can fixed the codeigniter cart update issue - codeigniter

Question

I am unable to update cart on checkout page. I do not know what is Happen.
Here is my code.
function update_cart()
{
$rowid =$this->input->post('rowid');
$price =$this->input->post('price');
$qty = $this->input->post('qty');
$pr = preg_replace( '/,/', '', $price);
$amount = $pr * $qty;
$data = array(
'rowid' => $rowid,
'price' => $price,
'amount' => $amount,
'qty' => $qty
);
$this->cart->update($data);
redirect('checkout');
}
Here is my car view code .I am trying to update cart value here.No error showing. I unable to solve .Any help .Only update cart is not working . Other functionality is working good .add to cart delete to cart but update to cart does not working . I create session table and also try other suggestion and solution form stack overflow.
<form action="<?=base_url()?>cart/update_cart" method="post">
<div class="panel panel-info">
<div class="panel-heading">
<div class="panel-title">
<div class="row">
<div class="col-xs-6">
<h5><span class="glyphicon glyphicon-shopping-cart"></span> Shopping Cart</h5>
</div>
<div class="col-xs-6">
<a href="<?=base_url()?>">
<button type="button" class="btn btn-primary btn-sm btn-block">
<span class="glyphicon glyphicon-share-alt"></span> Continue shopping
</button>
</a>
</div>
</div>
</div>
</div>
<div class="panel-body">
<?php $i = 1; ?>
<?php
//print_r($this->cart->contents() );
//die;
foreach ($this->cart->contents() as $items): ?>
<?php echo form_hidden($i.'[rowid]', $items['rowid']); ?>
<div class="row">
<div class="col-xs-2">
<img class="img-responsive" src="<?=base_url()?>uploads/product/<?=$items['image'];?>" />
</div>
<div class="col-xs-4">
<h5 class="product-name">
<strong><?php echo $items['name']; ?>
</strong>
<?=$items['options'];?>
</h5>
</div>
<div class="col-xs-6">
<div class="col-xs-6 text-right">
<h6><strong><?= $this->cart->format_number($items['price']); ?>
<span class="text-muted">x</span></strong></h6>
</div>
<div class="col-xs-4">
<?php //echo form_input(array('name' => $i.'[qty]', 'value' => $items['qty'], 'size' => '1')); ?>
<input type="text" name="qty" min="1" value="<?=$items['qty'] ?>" maxlength="1" style="width: 50%;">
<input type="hidden" name="price" value="<?=$items['price'] ?>">
<input type="hidden" name="name" value="<?=$items['name'] ?>">
<input type="hidden" name="description" value="<?=$items['description'] ?>">
</div>
<div class="col-xs-2">
<a href="<?=base_url()?>cart/remove/<?=$items['rowid']?>">
<button type="button" class="btn btn-link btn-xs">
<span class="glyphicon glyphicon-trash" onclick="confirm('Are you sure want to delete')";> </span>
</button>
</a>
</div>
</div>
</div>
<hr>
<?php $i++; ?>
<?php endforeach; ?>

Answer 1

at view .... use only two input
<input type="text" name="qty[]" min="1" value="<?=$items['qty'] ?>" maxlength="1" style="width: 50%;">
<input type="hidden" name="rowid[]" value="<?=$items['rowid'] ?>">
at controller
you only need to change qty if you are going to update a cart
function update_cart()
{
for ($i=0; $i < count($_POST) - 1; $i++) {
$data = array(
'rowid' => $_POST['rowid'][$i],
'qty' => $_POST['qty'][$i]
);
$this->cart->update($data);
}
redirect('checkout');
}