YII Frameworkラーニングチュートリアル-YIIのページングCPagination-2011-11-23
上ではほぼCComponentクラスを理解しており,CPaginationがCComponentを継承していることを知っている.ここではCPaginationページングコンポーネントについて説明します.CComponentクラスについてもっと深く理解します.
Webアプリケーションでは、データベースに多くの文章があるなど、ページ分けに使用されます.私たちはすべての文章を一度に読むことはできません.これは効率が低すぎるので、多くのデータが使えないことがあります.また,webページに表示され,ページングを行わないとページが冗長になり,ユーザに友好的ではない.そこでページを分けて生まれました.YIIのページングがどのように実現されているかを見てみましょう.
CPagination.phpファイルのコメントでCPaginationの使い方がわかります.
Webアプリケーションでは、データベースに多くの文章があるなど、ページ分けに使用されます.私たちはすべての文章を一度に読むことはできません.これは効率が低すぎるので、多くのデータが使えないことがあります.また,webページに表示され,ページングを行わないとページが冗長になり,ユーザに友好的ではない.そこでページを分けて生まれました.YIIのページングがどのように実現されているかを見てみましょう.
CPagination.phpファイルのコメントでCPaginationの使い方がわかります.
* Example:
*
* Controller action:
* <pre>
* function actionIndex(){
* $criteria = new CDbCriteria();
* $count=Article::model()->count($criteria);
* $pages=new CPagination($count);
*
* // results per page
* $pages->pageSize=10;
* $pages->applyLimit($criteria);
* $models = Post::model()->findAll($criteria);
*
* $this->render('index', array(
* 'models' => $models,
* 'pages' => $pages
* ));
* }
* </pre>
*
* View:
* <pre>
* <?php foreach($models as $model): ?>
* // display a model
* <?php endforeach; ?>
*
* // display pagination
* <?php $this->widget('CLinkPager', array(
* 'pages' => $pages,
* )) ?>
* </pre><?php
/**
* CPagination class file.
*
* @author Qiang Xue <[email protected]>
* @link http://www.yiiframework.com/
* @copyright Copyright © 2008-2011 Yii Software LLC
* @license http://www.yiiframework.com/license/
*/
/**
* CPagination represents information relevant to pagination.
*
* When data needs to be rendered in multiple pages, we can use CPagination to
* represent information such as {@link getItemCount total item count},
* {@link getPageSize page size}, {@link getCurrentPage current page}, etc.
* These information can be passed to {@link CBasePager pagers} to render
* pagination buttons or links.
*
* Example:
*
* Controller action:
* <pre>
* function actionIndex(){
* $criteria = new CDbCriteria();
* $count=Article::model()->count($criteria);
* $pages=new CPagination($count);
*
* // results per page
* $pages->pageSize=10;
* $pages->applyLimit($criteria);
* $models = Post::model()->findAll($criteria);
*
* $this->render('index', array(
* 'models' => $models,
* 'pages' => $pages
* ));
* }
* </pre>
*
* View:
* <pre>
* <?php foreach($models as $model): ?>
* // display a model
* <?php endforeach; ?>
*
* // display pagination
* <?php $this->widget('CLinkPager', array(
* 'pages' => $pages,
* )) ?>
* </pre>
*
* @author Qiang Xue <[email protected]>
* @version $Id: CPagination.php 3249 2011-05-29 11:35:37Z alexander.makarow $
* @package system.web
* @since 1.0
*/
class CPagination extends CComponent
{
/**
* The default page size.
*/
const DEFAULT_PAGE_SIZE=10;
/**
* @var string name of the GET variable storing the current page index. Defaults to 'page'.
*/
public $pageVar='page';
/**
* @var string the route (controller ID and action ID) for displaying the paged contents.
* Defaults to empty string, meaning using the current route.
*/
public $route='';
/**
* @var array of parameters (name=>value) that should be used instead of GET when generating pagination URLs.
* Defaults to null, meaning using the currently available GET parameters.
* @since 1.0.9
*/
public $params;
/**
* @var boolean whether to ensure {@link currentPage} is returning a valid page number.
* When this property is true, the value returned by {@link currentPage} will always be between
* 0 and ({@link pageCount}-1). Because {@link pageCount} relies on the correct value of {@link itemCount},
* it means you must have knowledge about the total number of data items when you want to access {@link currentPage}.
* This is fine for SQL-based queries, but may not be feasible for other kinds of queries (e.g. MongoDB).
* In those cases, you may set this property to be false to skip the validation (you may need to validate yourself then).
* Defaults to true.
* @since 1.1.4
*/
public $validateCurrentPage=true;
private $_pageSize=self::DEFAULT_PAGE_SIZE;
private $_itemCount=0;
private $_currentPage;
/**
* Constructor.
* @param integer $itemCount total number of items.
* @since 1.0.1
*/
public function __construct($itemCount=0)
{
$this->setItemCount($itemCount);
}
/**
* @return integer number of items in each page. Defaults to 10.
*/
public function getPageSize()
{
return $this->_pageSize;
}
/**
* @param integer $value number of items in each page
*/
public function setPageSize($value)
{
if(($this->_pageSize=$value)<=0)
$this->_pageSize=self::DEFAULT_PAGE_SIZE;
}
/**
* @return integer total number of items. Defaults to 0.
*/
public function getItemCount()
{
return $this->_itemCount;
}
/**
* @param integer $value total number of items.
*/
public function setItemCount($value)
{
if(($this->_itemCount=$value)<0)
$this->_itemCount=0;
}
/**
* @return integer number of pages
*/
public function getPageCount()
{
return (int)(($this->_itemCount+$this->_pageSize-1)/$this->_pageSize);
}
/**
* @param boolean $recalculate whether to recalculate the current page based on the page size and item count.
* @return integer the zero-based index of the current page. Defaults to 0.
*/
public function getCurrentPage($recalculate=true)
{
if($this->_currentPage===null || $recalculate)
{
if(isset($_GET[$this->pageVar]))
{
$this->_currentPage=(int)$_GET[$this->pageVar]-1;
if($this->validateCurrentPage)
{
$pageCount=$this->getPageCount();
if($this->_currentPage>=$pageCount)
$this->_currentPage=$pageCount-1;
}
if($this->_currentPage<0)
$this->_currentPage=0;
}
else
$this->_currentPage=0;
}
return $this->_currentPage;
}
/**
* @param integer $value the zero-based index of the current page.
*/
public function setCurrentPage($value)
{
$this->_currentPage=$value;
$_GET[$this->pageVar]=$value+1;
}
/**
* Creates the URL suitable for pagination.
* This method is mainly called by pagers when creating URLs used to
* perform pagination. The default implementation is to call
* the controller's createUrl method with the page information.
* You may override this method if your URL scheme is not the same as
* the one supported by the controller's createUrl method.
* @param CController $controller the controller that will create the actual URL
* @param integer $page the page that the URL should point to. This is a zero-based index.
* @return string the created URL
*/
public function createPageUrl($controller,$page)
{
$params=$this->params===null ? $_GET : $this->params;
if($page>0) // page 0 is the default
$params[$this->pageVar]=$page+1;
else
unset($params[$this->pageVar]);
return $controller->createUrl($this->route,$params);
}
/**
* Applies LIMIT and OFFSET to the specified query criteria.
* @param CDbCriteria $criteria the query criteria that should be applied with the limit
* @since 1.0.1
*/
public function applyLimit($criteria)
{
$criteria->limit=$this->getLimit();
$criteria->offset=$this->getOffset();
}
/**
* @return integer the offset of the data. This may be used to set the
* OFFSET value for a SQL statement for fetching the current page of data.
* @since 1.1.0
*/
public function getOffset()
{
return $this->getCurrentPage()*$this->getPageSize();
}
/**
* @return integer the limit of the data. This may be used to set the
* LIMIT value for a SQL statement for fetching the current page of data.
* This returns the same value as {@link pageSize}.
* @since 1.1.0
*/
public function getLimit()
{
return $this->getPageSize();
}
}