我如何获得总价并将其显示在同一页面上PHP

Question

我正在使用php，我有一个产品列表页面，该页面从数据库中获取产品并将其显示给用户。然后，用户选择数量。

问题是我不知道如何在同一页面上显示总价。下一页是计算总价的页面。

有人可以帮助我吗？

我面临的主要问题是，当我更改数量时，它正在重置页面，因此数量变为0。由于需要在另一个页面中进行计算，因此我需要过帐。

include 'Accessories.php';
include_once 'Database.php';
session_start();

$db = new Accessories();
$accessories = $db->getAllAccessories();

echo 'second time';
       
echo '<br>';
echo '<br>';
echo '<br>';
echo '<form action=" '?> <?php $_SERVER['PHP_SELF']?>  <?php  echo'"  method="post">';
echo '<div class="row"><div class="col-md-1"></div><div class="col-md-10"><input type="submit" name="submited" value="Procced" class="btn btn-block btn-primary"></div></div>';
echo '<div class="container">';



    foreach ($accessories as $ac) {

        echo 
        
        
        '<div class = "form-group">
                    
                <label for="qty_list[' . $ac->taskID . "-" . $ac->taskID . ']">'.$ac->taskName . " " . " " . $ac->description . " " . $ac->price . " BHD".'</label>';
                         echo '
 <input id="" type="number" min="0" onchange="this.form.submit()"  class="form-control" name="qty_list[' . $ac->taskID . "-" . $ac->taskID . ']" value="' ?> <?php $_POST['qty_list']   ?> <?php echo'" placeholder="">';
                    echo'</div>';
       
        echo'<br>';
    }


    '</div>
        </div>
    </div>';
  

    

echo '</form>';

<?php

session_start();
include_once 'Database.php';
include 'Ac_car_res.php';
include 'Accessories.php';
include 'Reservation.php';
$reserved = false;
//$dateFrom = $_SESSION['dateFrom'];
//$dateTo = $_SESSION['dateTo'];
//echo $dateFrom;




foreach ($_POST['qty_list'] as $key => $qty) {
 $r = 102;
    //$_SESSION['resId'] = $r;
  
    $qty;
    $acAdd = new Ac_car_res();
   // session_start();
    $resId = $r;

    $index = strrpos($key, "-");
    $sCarId = substr($key, $index + 1);
    $acId = substr($key, 0, $index);
    $acAdd->initWith($acId, $resId, $sCarId, $qty);
    $acAdd->addAcCarRes();
}

$db = Database::getInstance();
$access = new Accessories();
$res1 = new Reservation();

//echo $Id;
echo "<br>";
$r = 102;
$sql = "select * from ac_car_res where resId=" . $r;
$a = $db->multiFetch($sql);
foreach ($a as $m) {
    $access->initWithAcId($m->acId);
    $res1->initWithResId($m->resId);
    echo "accessories" . $access->getPrice() . "qty" . $m->qty;
    echo "<br>";
    $totalPriceForRes = ($res1->getTotalPrice() + $access->getPrice() * $m->qty);
    $res1->setTotalPrice($totalPriceForRes);
    echo $res1->getTotalPrice();
    echo "<br>";
    $res1->updateReservation();
}

?>

<?php

session_start();
include_once 'Database.php';
include 'Ac_car_res.php';
include 'Accessories.php';
include 'Reservation.php';
$reserved = false;
//$dateFrom = $_SESSION['dateFrom'];
//$dateTo = $_SESSION['dateTo'];
//echo $dateFrom;




foreach ($_POST['qty_list'] as $key => $qty) {
 $r = 102;
    //$_SESSION['resId'] = $r;
  
    $qty;
    $acAdd = new Ac_car_res();
   // session_start();
    $resId = $r;

    $index = strrpos($key, "-");
    $sCarId = substr($key, $index + 1);
    $acId = substr($key, 0, $index);
    $acAdd->initWith($acId, $resId, $sCarId, $qty);
    $acAdd->addAcCarRes();
}

$db = Database::getInstance();
$access = new Accessories();
$res1 = new Reservation();

//echo $Id;
echo "<br>";
$r = 102;
$sql = "select * from ac_car_res where resId=" . $r;
$a = $db->multiFetch($sql);
foreach ($a as $m) {
    $access->initWithAcId($m->acId);
    $res1->initWithResId($m->resId);
    echo "accessories" . $access->getPrice() . "qty" . $m->qty;
    echo "<br>";
    $totalPriceForRes = ($res1->getTotalPrice() + $access->getPrice() * $m->qty);
    $res1->setTotalPrice($totalPriceForRes);
    echo $res1->getTotalPrice();
    echo "<br>";
    $res1->updateReservation();
}

?>