一个巧妙的分页方法
显示的页码数是$size, 当前的页数是$page, 总数是$total, 每页显示的条数是$page_size
首先，要获取总页面数是多少：
$total_page = ceil($total/$page_size);
这样的写法是不是更简单一些呢？
其次，我是这样想的， 这个需求最高的需求是要根据当前的页码，找出size个页码数来。
那么就可以转化为： 根据当前的信息， 填充一个size个元素的数组。
最终就可以简单的转化为：根据当前的信息，寻找出size个元素的数组的起始元素是什么？我们假设这个起始元素是:page_start;
$page_start = 1;
$half = intval($size/2);
$page_start = max(1, $page – $half);
$page_end = min($page_start + $size – 1, $total_page);
$page_start = max(1, $page_end – $size + 1);
这样写，是不是也很有技巧呢？
最后就简单了， 根据起始页和结束页， 生成一个数组， 最后foreach这个数组，生成html代码：
$page_numbers = range($page_start, $page_end);
$nav_str = "";
foreach($page_numbers as $num){
//…….
}
源码：
/**
*A pagination generation class
*@class : Pagination
*@version: 1.0.0
*@author : huixinchen at baidu.com
*@useage:
* $pagi = new Pagination($url_prefix, $page_size, $mesgs_count, $pagination_size=10, array $conf);
* $navigation_str = $pagi->generate($current_page_number);
*/
class Pagination{
private $page, $total_page, $total, $page_size, $size;
private $prev_str = "<", $next_str = ">";
private $class, $selected_class = "selected", $prev_class="prev", $next_class="next",
$de_prev_class="de_prev", $de_next_class="de_next";
private $url_prefix="", $split_char="?";
private $para_name = "page", $target = "";
public function Pagination($url_prefix, $page_size, $total, $size=10, $conf=array()){
$this->page = 1;
$this->page_size = $page_size;
$this->total = $total;
$this->total_page = intval(ceil($total/$page_size));
$this->size = $size;
if(!empty($conf)){
$configure = array("prev_str", "next_str", "class", "selected_class");
foreach($conf as $key => $val){
if(in_array($key, $configure)){
$this->$val = $val;
}
}
}
$this->url_prefix = $url_prefix;
if(strstr($url_prefix, ‘?’) !== false){
$this->url_prefix .= "&" . $this->para_name . "=";
}else{
$this->url_prefix .= "?" . $this->para_name . "=";
}
}
public function generate($page){
$this->page = $page;
if(isset($this->page[$page])){
return $this->page_str[$page];
}
$page_start = 1;
$half = intval($this->size/2);
$page_start = max(1, $page – $half);
$page_end = min($page_start + $this->size – 1, $this->total_page);
$page_start = max(1, $page_end – $this->size + 1);
$this->page_str[$page] = $this->build_nav_str($page_start, $page_end);
return $this->page_str[$page];
}
private function build_nav_str($page_start, $page_end){
$page_nums = range($page_start, $page_end);
$target = $this->target? " target=\"{$this->target}\"" : "";
if($this->page == 1){
$page_str = <<<HTML
<span class="{$this->de_prev_class}"> {$this->prev_str} </span>
HTML;
}else{
$page = $this->page – 1;
$page_str = <<<HTML
<span class="{$this->prev_class}"> <a href="{$this->url_prefix}{$page}"{$this->target}>{$this->prev_str}</a></span>
HTML;
}
foreach($page_nums as $p){
$page_str .= ($p == $this->page) ? <<<HTML
<span class="{$this->selected_class}">{$p}</span>
HTML
: <<<HTML
<span class="{$this->class}"><a href="{$this->url_prefix}{$p}"{$this->target}>{$p}</a></span>
HTML;
}
if($this->page == $this->total_page){
$page_str .= <<<HTML
<span class="{$this->de_next_class}"> {$this->next_str} </span>
HTML;
}else{
$page = $this->page + 1;
$page_str .= <<<HTML
<span class="{$this->next_class}"> <a href="{$this->url_prefix}{$page}"{$this->target}>{$this->next_str}</a></span>
HTML;
}
return $page_str;
}
public function tidy_str(){
;//void
}
public function __call($func_name, $arguments){
if(isset($this->$func_name)){
return $this->$func_name;
}
}
public function __destruct(){
unset($this->page_str);
unset($this);
}
}
原文地址:http://www.corange.cn/archives/2010/04/3616.html