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Difference between revisions of "Using JPagination in your component"

From Joomla! Documentation

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(Implementing Pagination in Front End)
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=====getPagesCounter()=====
 
=====getPagesCounter()=====
<pre>
+
<source lang="php">
 
/**
 
/**
 
* Create and return the pagination pages counter string
 
* Create and return the pagination pages counter string
Line 26: Line 26:
 
*/
 
*/
 
function getPagesCounter()
 
function getPagesCounter()
</pre>
+
</source>
  
 
Returns a string containing the current page and total pages as [[image:pagescounter.png]]
 
Returns a string containing the current page and total pages as [[image:pagescounter.png]]
  
 
=====getResultsCounter()=====
 
=====getResultsCounter()=====
<pre>
+
<source lang="php">
 
/**
 
/**
 
* Create and return the pagination result set counter string
 
* Create and return the pagination result set counter string
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*/
 
*/
 
function getResultsCounter()
 
function getResultsCounter()
</pre>
+
</source>
  
 
Returns a string containing the results currently being displayed as [[image:resultscounter.png]]
 
Returns a string containing the results currently being displayed as [[image:resultscounter.png]]
  
 
=====getPagesLinks()=====
 
=====getPagesLinks()=====
<pre>
+
<source lang="php">
 
/**
 
/**
 
* Create and return the pagination page list string, ie. Previous, Next, 1 2 3 ... x
 
* Create and return the pagination page list string, ie. Previous, Next, 1 2 3 ... x
Line 54: Line 54:
 
*/
 
*/
 
function getPagesLinks()
 
function getPagesLinks()
</pre>
+
</source>
  
 
Returns an HTML string to display the Pages Links as [[image:pageslinks.png]]
 
Returns an HTML string to display the Pages Links as [[image:pageslinks.png]]
  
 
=====getListFooter()=====
 
=====getListFooter()=====
<pre>
+
<source lang="php">
 
/**
 
/**
 
* Return the pagination footer
 
* Return the pagination footer
Line 68: Line 68:
 
*/
 
*/
 
function getListFooter()
 
function getListFooter()
</pre>
+
</source>
  
 
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.
 
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.
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=====getLimitBox()=====
 
=====getLimitBox()=====
<pre>
+
<source lang="php">
 
/**
 
/**
 
* Creates a dropdown box for selecting how many records to show per page
 
* Creates a dropdown box for selecting how many records to show per page
Line 86: Line 86:
 
*/
 
*/
 
function getLimitBox()
 
function getLimitBox()
</pre>
+
</source>
  
 
Returns an HTML string that will output the Display Limit dropdown as [[image:limitbox.png]]
 
Returns an HTML string that will output the Display Limit dropdown as [[image:limitbox.png]]
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=====orderDownIcon()=====
 
=====orderDownIcon()=====
  
 +
==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!! ;-)''
 +
<source lang="php">
 +
$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
 +
</source>
  
 
==Implementation==
 
==Implementation==
 
====Changes to the Model====
 
====Changes to the Model====
 
Declare $_total and $_pagination variables in the model; these will be returned by the functions getTotal() and getPagination(), respectively.
 
Declare $_total and $_pagination variables in the model; these will be returned by the functions getTotal() and getPagination(), respectively.
<pre>
+
<source lang="php">
 
   /**
 
   /**
 
   * Items total
 
   * Items total
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   */
 
   */
 
   var $_pagination = null;
 
   var $_pagination = null;
</pre>
+
</source>
  
 
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.
 
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.
<pre>
+
<source lang="php">
 
   function __construct()
 
   function __construct()
 
   {
 
   {
 
  parent::__construct();
 
  parent::__construct();
  
global $mainframe, $option;
+
$mainframe = JFactory::getApplication();
  
 
// Get pagination request variables
 
// Get pagination request variables
 
$limit = $mainframe->getUserStateFromRequest('global.list.limit', 'limit', $mainframe->getCfg('list_limit'), 'int');
 
$limit = $mainframe->getUserStateFromRequest('global.list.limit', 'limit', $mainframe->getCfg('list_limit'), 'int');
$limitstart = $mainframe->getUserStateFromRequest($option.'.limitstart', 'limitstart', 0, 'int');
+
$limitstart = JRequest::getVar('limitstart', 0, '', 'int');
  
 
// In case limit has been changed, adjust it
 
// In case limit has been changed, adjust it
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$this->setState('limitstart', $limitstart);
 
$this->setState('limitstart', $limitstart);
 
   }
 
   }
</pre>
+
</source>
  
 
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.  
 
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.  
<pre>
+
<source lang="php">
 
   function getData()  
 
   function getData()  
 
   {
 
   {
Line 143: Line 166:
 
  return $this->_data;
 
  return $this->_data;
 
   }
 
   }
</pre>
+
</source>
  
 
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.
 
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.
<pre>
+
<source lang="php">
 
   function getTotal()
 
   function getTotal()
 
   {
 
   {
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  return $this->_total;
 
  return $this->_total;
 
   }
 
   }
</pre>
+
</source>
  
 
Create a getPagination() function.  The function will create and return a new Pagination object that can be accessed by the View.
 
Create a getPagination() function.  The function will create and return a new Pagination object that can be accessed by the View.
<pre>
+
<source lang="php">
 
   function getPagination()
 
   function getPagination()
 
   {
 
   {
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  return $this->_pagination;
 
  return $this->_pagination;
 
   }
 
   }
</pre>
+
</source>
 
+
  
 
====Changes to the View====
 
====Changes to the View====
 
Revise the View to obtain the pagination object created in the Model and assign it for use in the template.
 
Revise the View to obtain the pagination object created in the Model and assign it for use in the template.
<pre>
+
<source lang="php">
 
   ...
 
   ...
 
   // Get data from the model
 
   // Get data from the model
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$this->assignRef('pagination', $pagination);
 
$this->assignRef('pagination', $pagination);
 
   ...
 
   ...
</pre>
+
</source>
  
  
 
====Changes to the Template====
 
====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.
 
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.
<pre>
+
<source lang="php">
 
   ...
 
   ...
 
   <tfoot>
 
   <tfoot>
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   </tfoot>
 
   </tfoot>
 
   ...
 
   ...
</pre>
+
</source>
 +
 
 +
Then you have to put another hidden input in your adminform.
 +
in your "default.php" add this to form:
 +
<source lang="php">
 +
  ...
 +
  <input type="hidden" name="view" value="your_view_name" />
 +
  ...
 +
</source>
 +
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
 +
 
 +
<source lang="php">
 +
// import the Joomla modellist library
 +
jimport('joomla.application.component.modellist');
 +
 
 +
 
 +
 +
</source>
 +
 
 +
Then extend the JModelList class
 +
 
 +
<source lang="php">
 +
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.
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$db = JFactory::getDBO();
 +
$query = $db->getQuery(true);
 +
// Select some fields
 +
$query->select('*');
 +
// From the tablename
 +
$query->from('#__tablename');
 +
return $query;
 +
}
 +
}
 +
</source>
 +
 
 +
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===
 +
<source>
 +
// 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);
 +
 +
}
 +
</source>
 +
===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;
 +
<source lang="php">
 +
<?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>
 +
</source>
  
[[Category:Development]]
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Remember tor wrap the output in a form.
 +
[[Category:Component Development]]
 +
[[Category:Tutorials]]

Revision as of 11:00, 13 December 2012