J1.5:Using JPagination in your component

The "J1.5" namespace is an archived namespace. This page contains information for a Joomla! version which is no longer supported. It exists only as a historical reference, it will not be improved and its content may be incomplete and/or contain broken links.

Class Overview

The JPagination class, introduced in Joomla! 1.5, allows developers to reliably and consistently add pagination to the Front-end and Back-end display of their components. The file containing the class can be found at /libraries/joomla/html/pagination.php.

Variables

The construct function of the class requires three variables:

• $total - the total number of items in a list,
• $limitstart - the offset of the item at which to start, and
• $limit - the number of items to display per page.

Static Class Methods

getPagesCounter()

	/**
	 * Create and return the pagination pages counter string
	 *
	 * @access	public
	 * @return	string	Pagination pages counter string
	 * @since	1.5
	 */
	function getPagesCounter()

Returns a string containing the current page and total pages as

getResultsCounter()

	/**
	 * Create and return the pagination result set counter string
	 *
	 * @access	public
	 * @return	string	Pagination result set counter string
	 * @since	1.5
	 */
	function getResultsCounter()

Returns a string containing the results currently being displayed as

getPagesLinks()

	/**
	 * Create and return the pagination page list string, ie. Previous, Next, 1 2 3 ... x
	 *
	 * @access	public
	 * @return	string	Pagination page list string
	 * @since	1.0
	 */
	function getPagesLinks()

Returns an HTML string to display the Pages Links as

getListFooter()

	/**
	 * Return the pagination footer
	 *
	 * @access	public
	 * @return	string	Pagination footer
	 * @since	1.0
	 */
	function getListFooter()

Returns a combination of the several page-related elements, including: the Display Limit dropdown, the Pages Links and the Pages Counter. Appearance differs in the Front-end and Back-end due to additional CSS formatting applied with the Khepri template.

Front-end:

Back-end:

getLimitBox()

	/**
	 * Creates a dropdown box for selecting how many records to show per page
	 *
	 * @access	public
	 * @return	string	The html for the limit # input box
	 * @since	1.0
	 */
	function getLimitBox()

Returns an HTML string that will output the Display Limit dropdown as

Examples

with JDatabase

Here is a nice method that uses the strength of mysql who knows pagination too. Really!

Most developers don't use the SQL_CALC_FOUND_ROWS and just double the query without limit. Just don't!! ;-)

$db =& JFactory::getDBO();
$lim	= $mainframe->getUserStateFromRequest("$option.limit", 'limit', 14, 'int'); //I guess getUserStateFromRequest is for session or different reasons
$lim0	= JRequest::getVar('limitstart', 0, '', 'int');
$db->setQuery('SELECT SQL_CALC_FOUND_ROWS x, y, z FROM jos_content WHERE x',$lim0, $lim);
$rL=&$db->loadAssocList();
if (empty($rL)) {$jAp->enqueueMessage($db->getErrorMsg(),'error'); return;}	
else {
////Here the beauty starts
$db->setQuery('SELECT FOUND_ROWS();');  //no reloading the query! Just asking for total without limit
jimport('joomla.html.pagination');
$pageNav = new JPagination( $db->loadResult(), $lim0, $lim );
foreach($rL as $r) {
//your display code here
}
echo $pageNav->getListFooter(  ); //Displays a nice footer

Implementation

Changes to the Model

Declare $_total and $_pagination variables in the model; these will be returned by the functions getTotal() and getPagination(), respectively.

  /**
   * Items total
   * @var integer
   */
  var $_total = null;

  /**
   * Pagination object
   * @var object
   */
  var $_pagination = null;

Add to or create a __construct() function that will establish values for the $limitstart and $limit variables as these are needed by the JPagination class.

  function __construct()
  {
 	parent::__construct();

	$mainframe = JFactory::getApplication();

	// Get pagination request variables
	$limit = $mainframe->getUserStateFromRequest('global.list.limit', 'limit', $mainframe->getCfg('list_limit'), 'int');
	$limitstart = JRequest::getVar('limitstart', 0, '', 'int');

	// In case limit has been changed, adjust it
	$limitstart = ($limit != 0 ? (floor($limitstart / $limit) * $limit) : 0);

	$this->setState('limit', $limit);
	$this->setState('limitstart', $limitstart);
  }

Revise the getData() function, adding the $limitstart and $limit values to the _getList() query. This causes only the needed rows to be returned, rather than all rows.

  function getData() 
  {
 	// if data hasn't already been obtained, load it
 	if (empty($this->_data)) {
 	    $query = $this->_buildQuery();
 	    $this->_data = $this->_getList($query, $this->getState('limitstart'), $this->getState('limit'));	
 	}
 	return $this->_data;
  }

Create a getTotal() function. This function uses the _getListCount() method from JModel to return the total number of rows in the query. The value returned will be used by the getPagination() function.

  function getTotal()
  {
 	// Load the content if it doesn't already exist
 	if (empty($this->_total)) {
 	    $query = $this->_buildQuery();
 	    $this->_total = $this->_getListCount($query);	
 	}
 	return $this->_total;
  }

Create a getPagination() function. The function will create and return a new Pagination object that can be accessed by the View.

  function getPagination()
  {
 	// Load the content if it doesn't already exist
 	if (empty($this->_pagination)) {
 	    jimport('joomla.html.pagination');
 	    $this->_pagination = new JPagination($this->getTotal(), $this->getState('limitstart'), $this->getState('limit') );
 	}
 	return $this->_pagination;
  }

Changes to the View

Revise the View to obtain the pagination object created in the Model and assign it for use in the template.

  ...
  	// Get data from the model
 	$items =& $this->get('Data');	
 	$pagination =& $this->get('Pagination');

	// push data into the template
	$this->assignRef('items', $items);	
	$this->assignRef('pagination', $pagination);
  ...

Changes to the Template

Add a footer area to the display table in the template which holds the pagination object. The method getListFooter() from the JPagination class generates the buttons and their next/previous functionality as shown in the image above. Edit colspan="9" to reflect the number of columns in the table.

  ...
  <tfoot>
    <tr>
      <td colspan="9"><?php echo $this->pagination->getListFooter(); ?></td>
    </tr>
  </tfoot>
  ...

Then you have to put another hidden input in your adminform. in your "default.php" add this to form:

  ...
  <input type="hidden" name="view" value="your_view_name" />
  ...

This is to tell Joomla! to redirect to "your_view_name" view after changing pagination.

Implementing Pagination in Front End

To be able to use Joomla!'s handy JPagination in the front end you need to import Joomla! modellist library into your model first, and extend JModelList class just as you would in the back end

 // import the Joomla modellist library
jimport('joomla.application.component.modellist');

Then extend the JModelList class

class ComponentnameModelModelName extends JModelList
{
	/**
	 * Method to build an SQL query to load the list data.
	 *
	 * @return	string	An SQL query
	 */
	protected function getListQuery()
	{
		// Create a new query object.		
		$db = JFactory::getDBO();
		$query = $db->getQuery(true);
		// Select some fields
		$query->select('*');
		// From the tablename
		$query->from('#__tablename');
		return $query;
	}
}

Most of the hard work is already done for you by Joomla!. You only have to extend the above class and add the getListQuery() method that helps you build the query in which the pagination will be based.

Pagination methods, like getPagination(), getItems() & getListFooter() that will be called later from your view are already defined in the parent class of the subclass above.

view.html.php

// import Joomla view library
jimport('joomla.application.component.view');
 
/**
 * Trainings View
 */
class ComponentNameViewViewName extends JView
{
	/**
	 * 
	 */
	function display($tpl = null) 
	{
		// Get data from the model
		$items = $this->get('Items');
		$pagination = $this->get('Pagination');
 
		// Check for errors.
		if (count($errors = $this->get('Errors'))) 
		{
			JError::raiseError(500, implode('<br />', $errors));
			return false;
		}
		// Assign data to the view
		$this->items = $items;
		$this->pagination = $pagination;
 
 
		// Display the template
		parent::display($tpl);
 
	}

default.php

Assuming that we are using default template for the view, the following code will generate output with pagination ready in the front end;

<?php
// No direct access to this file
defined('_JEXEC') or die('Restricted Access');
// load tooltip behavior
JHtml::_('behavior.tooltip');
?>
<form action="<?php echo JRoute::_('index.php?option=com_ComponentName'); ?>" method="post" name="adminForm">

//	ITEMS FROM THE DATABASE GO HERE!!!!

// PAGINATION GOES HERE
<?php echo $this->pagination->getListFooter(); ?>
</form>

Remember tor wrap the output in a form.