Adding layered navigation block to custom page

Question

In Magento, the Layered Navigation block works nicely in the product list page.

How can this block be successfully copied to a custom page, where there is a custom list of products?

Note: Just adding the block to the XML, and calling it's getChildHtml('blockname') doesn't do the trick.

Answer 1

Basically what you have to do is extend/overwrite from Mage_Catalog_Block_Product_List (List.php) and rewrite the getProductCollection() method:

protected function _getProductCollection()
{
    if (is_null($this->_productCollection)) {
        // Build collection and set it
        $collection = "...";
        $this->setProductCollection($collection);
    }

    return $this->_productCollection;
}

When that was done I had overwritten both the Mage_Catalog_Model_Layer class and the Mage_Catalog_Model_Category and introduced a new variable:

protected $_customProductCollection;

I have overwritten the getProductCollection() in both classes and I added this in the beginning of the method:

if(isset($this->_customProductCollection)){
    return $this->_customProductCollection;
}

I have also a method that allows me to set this "customProductCollection" inside both these classes. Once It's set, the rest of the data of the layered navigation/category is based on this collection.

Check out the initial question+answer here.

Good luck ;)