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Adding sortable columns to a table in a component

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Revision as of 22:38, 6 March 2010 by Zola (Talk | contribs)

Article Altered

Hopefully final fix after much head-banging upon desk Zola 03:38, 7 March 2010 (UTC)

Suggested Fix

There is a problem with this example. As reported in many posts, the column headings only allow DESCending sorts. In addition, the grid.sort method called by JHTML doesn't display the sort direction arrow graphic. If you can live without having the final sort column and sort direction stored in the user state for future use, the problem can be fixed as follows. The whole process is shown rather than alterations.

1. Add a new private variable to the MODEL. This is used to store the sort column field name and the sort direction.

var $_order  = array();

2. Add the following lines to the MODEL __construct() function. Values for filter_order and filter_order_Dir are pulled from the $_REQUEST array (if present) or default values substituted. Replace 'fieldName' with the name of the MySQL field name you want to sort by default. Change 'asc' to 'desc' if you want the default sort direction to be descending.

$this->_order[] = JRequest::getVar('filter_order', 'fieldName', 'POST', 'cmd');
$this->_order[] = JRequest::getVar('filter_order_Dir', 'asc', 'POST', 'word');

3. Add a new private function to the MODEL to general the necessary MySQL query suffix. The MODEL will need to call this function and append the result to any existing MySQL query before execution.

function _buildContentOrderBy() {
  return ' ORDER BY '.$this->_order[0].' '.$this->_order[1].' ';

If, for example, the query was stored in a private variable called $_query, the following would need to be added before the query is passed for execution.

$this->_query .= $this->_buildContentOrderBy();

4. Add a new public function to the MODEL so that the ordering field and sort direction can be accessed by the VIEW using the get() method.

function getOrder() {
 return $this->_order;

5. Add the following lines to the display() function in the VIEW (usually view.html.php). This uses the JView::get() method to 'get' a copy of the array containing the ordering field and sort direction from the MODEL. The array is then assigned to the TEMPLATE.

$lists =& $this->get( 'order' );
$this->assignRef( 'lists', $lists );

6. To conform with HTML add the following to the TEMPLATE (usually default.php). This ensures that the Javascript necessary is placed between the the <head></head> tags. Change 'formName' to the name attribute of the <form> used later (see below)

 JFactory::getDocument()->addScriptDeclaration( "
 function tableOrdering( order, dir, task ) {
  var form = document.formName;
  form.filter_order.value = order;
  form.filter_order_Dir.value = dir;
  form.submit( task );

7. Enclose the table to be sorted in <form></form> tags and add two hidden input fields as follows

<form action="index.php?option=com_componentName" method="post" name="formName">
 table goes here
 <input type="hidden" name="filter_order" value="<?php echo $this->lists[0]; ?>" />
 <input type="hidden" name="filter_order_Dir" value="<?php echo $this->lists[1]; ?>" />

Change the <form> action attribute as needed or use the JRoute method if you have the file router.php set up for SEF URLs.

8. For each of the columns you want to sort, replace each of the column headings with the following (enclosed in 'th' and '/th' tags). Change 'columnXName' to the table columns heading text you want and change fieldXName to the corresponding MySQL field names. Leave non-sortable columns unchanged.

 <th><?php echo JHTML::_( 'grid.sort', 'column1Name', 'field1Name', $this->lists[1], $this->lists[0]); ?></th>
 <th><?php echo JHTML::_( 'grid.sort', 'column2Name', 'field2Name', $this->lists[1], $this->lists[0]); ?></th>
 <th><?php echo JText::_( 'unSortableColumnName'); ?></th>
 <th><?php echo JHTML::_( 'grid.sort', 'column3Name', 'field3Name', $this->lists[1], $this->lists[0]); ?></th>

Preserving the state of 'filter_order' and 'filter_order_Dir' could be achieved by altering the MODEL __construct() function.

Fletcher 17:11, 11 October 2009 (UTC)