Magento 1.9 – Fix Layered Navigation Error on Homepage

As you already know the real category filtering is taking place in app/code/core/Mage/Catalog/Model/Layer/Filter/Category.php, more specifically in _getItemsData(). Let us inspect that method.

<?php
            $categoty   = $this->getCategory();
            $categories = $categoty->getChildrenCategories();

            $this->getLayer()->getProductCollection()
                ->addCountToCategories($categories);

            $data = array();

            foreach ($categories as $category) {
                if ($category->getIsActive() && $category->getProductCount()) {
                    $data[] = array(
                        'label' => Mage::helper('core')->escapeHtml($category->getName()),
                        'value' => $category->getId(),
                        'count' => $category->getProductCount(),
                    );
                }
            }

As you can see, the method loads child categories of $categoty in layered navigation filter. That means we need to set this variable to a parent category in level 2 (Every main categories lies in level 2), according to the current category that we stands.

We can achieve this in many ways. In my method, I dig into the codes further and find the exact position where the category is set for layered navigation.

It resides here app/code/core/Mage/Catalog/Model/Layer.php in getCurrentCategory(). The method look like this.

<?php
 public function getCurrentCategory()
{
    $category = $this->getData('current_category');
    if (is_null($category)) {
        if ($category = Mage::registry('current_category')) {
            $this->setData('current_category', $category);
        }
        else {
            $category = Mage::getModel('catalog/category')->load($this->getCurrentStore()->getRootCategoryId());
            $this->setData('current_category', $category);
        }
    }

    return $category;
}

In short, it loads the current category to the variable $categoty (variable that I mentioned in _getItemsData()) if it set, otherwise loads the root-category to variable categoty. Replace this method with this code

<?php
/**
 * Retrieve current category model
 * If no category found in registry, the root will be taken
 *
 * @return Mage_Catalog_Model_Category
 */
public function getCurrentCategory()
{
    $category = $this->getData('current_category');

    if (is_null($category)) {
        $category = Mage::registry('current_category');
        if ($category) {
            /*
             * Check whether the current category is in level 2.
             * If yes set it as current category.
             * Else check for any parent categories with level 2
             */
            if($category->getLevel() != 2) {
                //gets all parent categories
                $parentCategories = Mage::registry('current_category')->getParentCategories();
                /*
                 * If parent categories exist,search for parent categories in level 2.
                 * If exist set it as current category.
                 *else set root category as current category.
                */
                if(count($parentCategories) > 0)
                {
                    foreach ( $parentCategories as $parentCategory ) {
                        if($parentCategory->getLevel() == 2 ) {
                            $category = Mage::getModel('catalog/category')->load($parentCategory->getId());
                            $this->setData('current_category', $category);
                            break;
                        }
                    }
                }
                else {

                    $category = Mage::getModel('catalog/category')->load($this->getCurrentStore()->getRootCategoryId());
                    $this->setData('current_category', $category);
                }
            }
            else {

                $this->setData('current_category', $category);
            }
        }
        else {

            $category = Mage::getModel('catalog/category')->load($this->getCurrentStore()->getRootCategoryId());
            $this->setData('current_category', $category);
        }
    }

    return $category;
}

What we are doing here is, we get the parent category in level 2 from the current category and set it to $categoty, so that we can see all child categories in layered navigation.

As I already mentioned, you can achieve it in many ways. All you need to do is to set $categoty variable with parent category in level 2. Above I have altered the root files. It is not a good practice. You have to create a module that rewrites the model file app/code/core/Mage/Catalog/Model/Layer.php and then overwrite the method getCurrentCategory().

Hope it helps

So firstly I am making a few assumptions.

1. That you want to remove the normal navigation from the top and move it completely to the left hand-side,
2. That you are going to style it yourself :)

Firstly want you want to do is create a local.xml in your theme so you can change the xml of pages easily.

Then you want to unset the current main navigation.

<reference name="top.menu">
    <action method="unsetChild">
        <name>catalog.topnav</name>
    </action>
</reference>

Now what you want to do is move this into the left column.

<reference name="left">
    <action method="insert">
        <block>catalog.topnav</block>
    </action>
</reference>

Now in the end your complete local.xml file will look as follows.

<?xml version="1.0"?>
<layout version="0.1.0">
    <default>
        <reference name="top.menu">
            <action method="unsetChild">
                <name>catalog.topnav</name>
            </action>
        </reference>
        <reference name="left">
            <action method="insert">
                <block>catalog.topnav</block>
            </action>
        </reference>
    </default>
</layout>

Now one very important thing to think about here is that not all pages have a left column. For instance in a default set-up the homepage and other cms pages do not have this as well as all product pages.