Dependant layered navigation filters in Magento

Although not the best method, we wrote a quick and easy means to remove layered navigation filters that are dependant on other filters being enabled. This code should really be in the block and popped into an extension – with the attributes administrable via the backend, but for the purposes of this tutorial – we are just going to hardcode it into the template and let you decide how you want to improve it.

• 1

   

  Open ./app/design/frontend/default/default/template/catalogue/layer/view.phtml

• 2

   

  Add

   <?php /*Create filter dependencies*/
   $_activeFilters[] = array();
   $_filters = Mage::getSingleton('Mage_Catalog_Block_Layer_State')->getActiveFilters();
   $_depends = array(
   "fits product" => array("product manufacturer")
   );
  foreach ($_filters as $_filter):
  $_activeFilters[] = strtolower($_filter->getName());
  endforeach;
  ?>

  just before getStateHtml() ?>

• 3

   

  Replace the contents of

  <dl id="narrow-by-list"> ... </dl>

  with

   <?php $_filters = $this->getFilters() ?>
   <?php foreach ($_filters as $_filter): ?>
   <?php if($_filter->getItemsCount()): ?>
   
   <?php /*Hide filters whose dependencies are not enabled*/
   $_showFilter = true;
   if(isset($_depends[strtolower($_filter->getName())])):
   $_filterDepends = &$_depends[strtolower($_filter->getName())];
   foreach ($_filterDepends as $_filterDepend):
   if (!in_array($_filterDepend,$_activeFilters) && $_showFilter) {
  $_showFilter = false;
   }
   endforeach;
   endif;
   ?>
   
   <?php if($_showFilter): ?>
   <dt><?php echo $this->__($_filter->getName()) ?></dt>
   <dd>
   <?php echo $_filter->getHtml() ?>
   </dd>
   <?php endif; ?>
   
   <?php endif; ?>
   <?php endforeach; ?>

• 4

   

  Change $_depends in step 1 to reflect the names of the attributes that have dependencies on each other.

   $_depends = array(
   "fits product" => array("product manufacturer")
   );

  Ie. In our example, we do not want to display fits product until product manufacturer has been filtered.