Question

我正在构建产品目录，我希望根据用户设备确定。即，如果Windows设备显示特定产品。我的产品列表绝对正常，但是在实施分页时，我被卡住了。

我想每页只列出6个项目，我有更多结果。然而，第一页显示了更多结果。当我选择下一步时，ID号会改变，以显示它正在显示下一个结果，但它会继续显示相同的页面，所以很明显我错过/在某处与我的代码混淆。我很感激任何建议：

$current_url = $_SERVER['REQUEST_URI'];
$current_url = substr($current_url, 1);
$results = mysqli_query($conn, "SELECT * FROM apps A INNER JOIN device D ON D.DeviceID = A.DeviceID WHERE D.DeviceName = '$os'");    
$foundnum = mysqli_num_rows($results);
            if ($foundnum==0){
        echo "Sorry, there are currently no applications that are compatible with your device. Please try another option.";
    } else {
        echo "$foundnum applications are avaliable for '$os' devices:<p>";
        $per_page = 6;
            $start = $_GET['start'];
        $max_pages = ceil($foundnum / $per_page);

if(!$start)
            $start=0; 
        while($obj = $results->fetch_object()){
        $applicationid=$obj->ApplicationID;
        $start=0; 
        echo "<div class=\"col-4 col-sm-4 col-lg-4\">";
        echo '<form method="post" action="cart_update.php">';
        echo "<div id='product'><a href='appproduct.php?id=$applicationid'><img src='images/app_images/$applicationid.jpg' alt='Product picture'/></div>";
        echo '<h2>'.$obj->ApplicationName.'</h2>';
        echo '<p>'.$obj->ApplicationDescription.'</p>';
        if($obj->App_cost=="0.00"){ 
                echo '<p>Free</p>';
            }else{
               echo '<p>£'.$obj->App_cost.'</p>';
            }
        echo '<button class="add_to_cart">Add To Cart</button>';
        echo '<input type="hidden" name="product_code" value="'.$obj->ApplicationID.'" />';
        echo '<input type="hidden" name="type" value="add" />';
        echo '<input type="hidden" name="return_url" value="'.$current_url.'" />';
        echo '</form><br /><br /></div>';
     }   


//Pagination Starts
    echo "<center>";
    $prev = $start - $per_page;
    $next = $start + $per_page;                     
    $last = $max_pages - 1;
    if($max_pages > 1){   
    //previous button
        if (!($start<=0)) 
            echo "<a href='index.php?os=$os=Search+source+code&start=$prev'>Prev |</a> ";             
            //pages 
        $i = 0;   
        for ($counter = 1; $counter <= $max_pages; $counter++){
            if($i == $start){
            echo " <a href='index.php?os=$os=Search+source+code&start=$i'><b> $counter |</b></a> ";
            }
            else {
                echo " <a href='index.php?os=$os=Search+source+code&start=$i'> $counter |</a> ";
            }  
        $i = $i + $per_page;                 
        }
    }      
//next button
if (!($start >=$foundnum-$per_page))
    echo " <a href='index.php?os=$os=Search+source+code&start=$next'> Next</a> ";    
}   
echo "</center>"
?>

Answer 1

您需要在MySQL查询中使用LIMIT才能一次只获取一页结果。它看起来像LIMIT 0, 6。

Answer 2

更改此行将起作用

$results = mysqli_query($conn, "SELECT * FROM apps A INNER JOIN device D ON D.DeviceID = A.DeviceID WHERE D.DeviceName = '$os' LIMIT $_GET['start'], 6;");

但它并不是进行分页或直接从全局变量中添加变量的最佳方式。我建议你在php中使用leat mysql escape string函数

Answer 3

您应该尝试通过数据库进行分页，而不是急切地加载所有结果。如果您有100000条记录并且只想显示其中的前6条，则需要获取可能不会使用的99994条记录。尝试使用sql的limit。

至于“加粗”当前页码的问题，这里有逻辑错误：

    $i = 0;   
    for ($counter = 1; $counter <= $max_pages; $counter++) {
        if($i == $start){
            echo " <a href='index.php?os=$os=Search+source+code&start=$i'><b> $counter |</b></a> ";
        } else {
            echo " <a href='index.php?os=$os=Search+source+code&start=$i'> $counter |</a> ";
        }  
    $i = $i + $per_page;

根据这个片段，你将$ i与$ start进行比较，其中$ i总是等于0，所以它只会在第一页上加粗。

PHP分页产品仅在一个页面上显示

3 个答案: