Pear::Pager分頁類簡介

Pear的Pager分頁類是一個很好用的php分頁類,擴展性很強,能夠適應各種分頁情況的需求,至少我在幾年間大大小小的項目裡,基本上沒有為分頁額外寫過代碼,全部都是用的Pager,足見Pager的可用性之強.下面用代碼來看看它的使用范例:

例子1

<?php
require_once 'Pager/Pager.php';
$params = array(
'mode' => 'Jumping',
'perPage' => 3,
'delta' => 2,
'itemData' => array('a','b','c','d','e',[...omissis...],'z')
);
$pager = & Pager::factory($params);
$data = $pager->getPageData();
$links = $pager->getLinks();
//$links is an ordered+associative array with 'back'/'pages'/'next'/'first'/'last'/'all' links
//NB: $links['all'] is the same as $pager->links;
//echo links to other pages:
echo $links['all'];
//Pager can also generate <link rel="first|prev|next|last"> tags
echo $pager->linkTags;
//Show data for current page:
echo 'PAGED DATA: ' ; print_r($data);
//Results from methods:
echo 'getCurrentPageID()...: '; var_dump($pager->getCurrentPageID());
echo 'getNextPageID()......: '; var_dump($pager->getNextPageID());
echo 'getPreviousPageID()..: '; var_dump($pager->getPreviousPageID());
echo 'numItems()...........: '; var_dump($pager->numItems());
echo 'numPages()...........: '; var_dump($pager->numPages());
echo 'isFirstPage()........: '; var_dump($pager->isFirstPage());
echo 'isLastPage().........: '; var_dump($pager->isLastPage());
echo 'isLastPageComplete().: '; var_dump($pager->isLastPageComplete());
echo '$pager->range........: '; var_dump($pager->range);
?>

Pager的使用,只要調整$param數組的參數,就可以應付很多種分頁情況了.代碼中的$links數組包含了一些鏈接,如上一頁/頁碼/下一頁/第一頁/末頁/全部.

例2

如今許多網站為了SEO,把動態頁使用rewrite規則偽造成靜態頁的形式,例如下面這個.htaccess配置:

RewriteEngine on
#Options FollowSymlinks

RewriteBase /
RewriteRule ^articles/([a-z]{1,12})/art([0-9]{1,4})\.html$ /article.php?num=$2&month=$1 [L]

即使在這種情況下,Pager分頁仍然有辦法工作,見下面的code

<?php
require_once 'Pager/Pager.php';
//first pager
$params1 = array(
    'perPage'    => 3,
    'urlVar'     => pageID_articles,  //1st identifier
    'itemData'   => $someArray
);
$pager1 = & Pager::factory($params1);
$data1  = $pager1->getPageData();
$links1 = $pager1->getLinks();
//second pager
$params2 = array(
    'perPage'    => 8,
    'urlVar'     => pageID_news,      //2nd identifier
    'itemData'   => $someOtherArray
);
$pager2 = & Pager::factory($params2);
$data2  = $pager2->getPageData();
$links2 = $pager2->getLinks();
?>

通過配置$param,就能夠把鏈接 "/articles/march/art15.html"對應到鏈接"/article.php?num=15&month=march" ,比較靈活的表現

擴展性

Pager類的擴展性,平心而論,也是不錯的.比如以前寫的path方式的分頁類 - Pager::Pathing(),這個方法就是從Pager上擴展而來,滿足了當時的需求.