====== Getting and Using Categories and Sub Categories . . ======

The code below does a couple of things, first it will get all the store's categories - it then checks to see if they are active before continuing.

Also - it might be helpful to have the sub categories displayed, right?  Well, in my case, I only wanted the subcategory for the current category displayed - so I put a check in to do so.

<code php>
<?php
/* Get the categories that are active for the store */
$_main_categories=$this->getStoreCategories();

/* Get the current category the user is in */
$_current_category=$this->getCurrentCategory();

/* Get the current category path */
$_categorypath = $this->getCurrentCategoryPath();
?>
<ul>
<?php
if ($_main_categories):
    /* This bit cycles through the categories - setting the next one to current */
    foreach ($_main_categories as $_main_category):
      if($_main_category->getIsActive()):                             
           $cur_category=Mage::getModel('catalog/category')->load($_main_category->getId());
           $layer = Mage::getSingleton('catalog/layer');
           $layer->setCurrentCategory($cur_category);     

/* Write the main categories */           
?>                
<li><a href="<?php echo $this->getCurrentCategory()->getUrl()?>"><?php echo $this->getCurrentCategory()->getName();?></a></li>   


<?php 

/* Check the category variable loop against the current category path if it is - print sub categories */
if (in_array($this->getCurrentCategory()->getId(), $_categorypath)): ?>
<?php $_maincategorylisting=$this->getCurrentCategory()?>                        
<?php $_categories=$this->getCurrentChildCategories()?>
<?php if($_categories->count()):?>

<ul>
<? foreach ($_categories as $_category):?>                    
   <? if($_category->getIsActive()):                    
           $cur_subcategory=Mage::getModel('catalog/category')->load($_category->getId());
           $layer = Mage::getSingleton('catalog/layer');
           $layer->setCurrentCategory($cur_subcategory);  
          
?>                          
<li><a href="<?php echo $this->getCategoryUrl($_category)?>"> <?php echo $_category->getName()?></a></li>
    <? endif;?>
<?endforeach?>
</ul>            
<?php /* This resets the category back to the original pages category
****     If this is not done, subsequent calls on the same page will use the last category
****    in the foreach loop
*/   ?>
<?php $layer->setCurrentCategory($_maincategorylisting);  ?> 
<?endif;?>   
 
<?endif;?>                                   
                                                              
<?php         
endif;
endforeach; 
else:
?>
<p>$_main_categories array was empty.</p>
<p>This might be because you are referencing this phtml file with a wrong type attribute. You should use <block type="catalog/navigation" ... /> !</p>
<?php endif; ?>
</code>