We told you about the function creation of the news list in the last class. In the last class, we had a paging function under the news list page! So today we will introduce to you the production process of paging implementation!
First we create a php file page.php, in this file we put the code for making paging!
The first step: Same, connect to the database!
// 显示所有的错误
error_reporting(E_ALL & ~E_NOTICE );
// 连接mysql数据库
$link = mysqli_connect('localhost','root', 'root');
if (!$link) {
echo "connect mysql error!";
exit();
}
// 选中数据库 news为数据库的名字
$db_selected = mysqli_select_db($link, 'news');
if (!$db_selected) {
echo "<br>selected db error!";
exit();
}
// 设置mysql字符集 为 utf8
$link->query("set names utf8");The second step: To implement the paging function, we need to query which data table in which list. We are paging news, so our SQL statement must check the news table
// 查询新闻表中的数据 $sql = "select * from new where 1 "; // 查询语句 $sql_count = "select count(*) as amount from new where 1 "; // 统计总记录数 $sql .= "order by id asc";
The next step is to get the total number of records:
// 获取总记录条数 $result_amount = mysqli_query($link, $sql_count); $arr_amount = mysqli_fetch_array(mysqli_query($link, $sql_count), MYSQL_ASSOC); // 总记录条数 $amount = $arr_amount['amount'];
Then set the total number of pages and the total page number
// 每页的记录条数 $page_size = 4; // 总页码 $max_page = ceil( $amount / $page_size );
Everyone knows that there is a formula algorithm for paging. We will calculate the previous page based on this formula. Page, next page, last page!
// 获取当前页码
$page = intval($_GET['page']); // 获取page值，并转成int
if( $page <= 0 || $page > $max_page){ // 如果page值小于0，或是大于最大页码
$page = 1;
}
// 上一页
$pre_page = $page -1;
if( $pre_page < 1 ){ // 如果上一页小于1
$pre_page = 1;
}
// 下一页
$next_page = $page + 1;
if( $next_page > $max_page ){ // 如果下一页大于最大页码
$next_page = $max_page;
}
// 分页计算， 计算分页的offset
$offset = ($page - 1 ) * $page_size;
$sql .= " limit $offset, $page_size ";At this point our paging code is finished, and then we introduce this paging file on the news list page
<?php include_once "../common/page.php"; ?>
Finally find the paging position below the news list page and output the paging
<div class="pagelist">
<a href="new_list.php">首页</a>
<?php
if( $page > 1 ){
?>
<a href="new_list.php?page=<?php echo $pre_page;?>">上一页</a>
<?
}
if( $page < $max_page ){
?>
<a href="new_list.php?page=<?php echo $next_page;?>">下一页</a>
<?
}
?>
<a href="new_list.php?page=<?php echo $max_page;?>">末页</a>
/ 总页码 <font color="red"><?php echo $max_page;?></font>页 当前页码 <font color="red"><?php echo $page;?></font>页
</div>
OK! The pagination is finished!
Note: Mine may be a bit troublesome here. You can also download the paging class from the website and call it directly! But you need to know the principle of paging implementation~
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