How to add custom attribute in product collection

Question

I want to add a custom attribute in product collection

protected function _getProductCollection()
    {
       parent::__construct();

        $products = Mage::getModel('catalog/product')->getCollection()
            ->addAttributeToSort("entity_id","DESC")
            ->addAttributeToSelect('*')
            ->setVisibility(Mage::getSingleton('catalog/product_visibility')->getVisibleInSiteIds())
            ->setPageSize($this->get_prod_count())
            ->addAttributeToSort($this->get_order(), $this->get_order_dir())
            ->setCurPage($this->get_cur_page());

        Mage::getSingleton('catalog/product_status')->addVisibleFilterToCollection($products);
        Mage::getSingleton('catalog/product_visibility')->addVisibleInCatalogFilterToCollection($products);
        Mage::getSingleton('cataloginventory/stock')->addInStockFilterToCollection($products);

        $this->_productCollection = $products;

        return $this->_productCollection;
    }

In this collection will display all new product. But i want to restrict if newproduct_display_homepage = yes then only display. how to add this filter into that

Answer 1

you can add filter like that ->addAttributeToFilter('newproduct_display_homepage', 1)

protected function _getProductCollection()
    {
       parent::__construct();

        $products = Mage::getModel('catalog/product')->getCollection()
            ->addAttributeToSort("entity_id","DESC")
            ->addAttributeToSelect('*')
            ->addAttributeToFilter('newproduct_display_homepage', 1)
            ->setVisibility(Mage::getSingleton('catalog/product_visibility')->getVisibleInSiteIds())
            ->setPageSize($this->get_prod_count())
            ->addAttributeToSort($this->get_order(), $this->get_order_dir())
            ->setCurPage($this->get_cur_page());

        Mage::getSingleton('catalog/product_status')->addVisibleFilterToCollection($products);
        Mage::getSingleton('catalog/product_visibility')->addVisibleInCatalogFilterToCollection($products);
        Mage::getSingleton('cataloginventory/stock')->addInStockFilterToCollection($products);

        $this->_productCollection = $products;

        return $this->_productCollection;
    }