Question

I want to create a custom navigation bar to put in my header.phtml file.

For this I need a list of all the categories, i’m hoping that there is a simple function that I can call to get an array?

Answer 1

The following gets the subcategories of a specified category, you should be able to work from here I think:

$layer = Mage::getSingleton('catalog/layer');
$_category = Mage::getModel('catalog/category')->load(3); //this is cat 3, or can use: 
$_category = $layer->getCurrentCategory();
$_categories = $_category->getCollection()
 ->addAttributeToSelect(array('url_key','name','image','all_children','is_anchor','description')) //or whatever fields you want
 ->addAttributeToFilter('is_active', 1)
 ->addIdFilter($_category->getChildren())
 ->setOrder('position', 'ASC')
 ->joinUrlRewrite();

Then something like:

<?php foreach ($_categories as $_category): ?>

etc…

You may also be interested in:

$this->htmlEscape($_category->getImageUrl())
$this->htmlEscape($_category->getName())
$_category->getURL()

Hope that helps point you in the right direction. Clearly the load(3) can just be your root category.