Magento – How to override product view page in magento 2

You can do this without changing core files, you need to create an observer that will create a new layout handle based on the attribute. Then you can create a layout update for that handle to change the template used for the product view page.

The following code is based on the article from http://magebase.com/magento-tutorials/creating-custom-layout-handles/

Module init file app/etc/modules/Example_AttributeHandle.xml

<?xml version="1.0" encoding="UTF-8"?>
<config>
    <modules>
        <Example_AttributeHandle>
            <active>true</active>
            <codePool>local</codePool>
        </Example_AttributeHandle>
    </modules>
</config>

Module configuration: app/code/local/Example/AttributeHandle/etc/config.xml

<?xml version="1.0" encoding="UTF-8"?>
<config>
    <modules>
        <Example_AttributeHandle>
            <version>0.1.0</version>
        </Example_AttributeHandle>
    </modules>
    <global>
        <events>
            <controller_action_layout_load_before>
                <observers>
                    <attributesethandle>
                        <class>Example_AttributeHandle_Model_Observer</class>
                        <method>addAttributeHandle</method>
                    </attributesethandle>
                </observers>
            </controller_action_layout_load_before>
        </events>
    </global>
</config>

Observer file: app/code/local/Example/AttributeHandle/Model/Observer.php

<?php
class Example_AttributeHandle_Model_Observer
{
    /**
     * Converts attribute value of current product to nice name ([a-z0-9_]+).
     * Adds layout handle PRODUCT_ATTRIBUTE_<attribute>_<value> after
     * PRODUCT_TYPE_<product_type_id> handle
     *
     * Event: controller_action_layout_load_before
     *
     * @param Varien_Event_Observer $observer
     */
    public function addAttributeHandle(Varien_Event_Observer $observer)
    {
        $product = Mage::registry('current_product');

        /**
         * Return if it is not product page
         */
        if (!($product instanceof Mage_Catalog_Model_Product)) {
            return;
        }

        $attributeName = 'myattribute';
        /**
         * Convert attribute value to alphanumeric + underscore string
         */
        $niceName = str_replace('-', '_', $product->formatUrlKey($product->getData($attributeName)));

        /* @var $update Mage_Core_Model_Layout_Update */
        $update = $observer->getEvent()->getLayout()->getUpdate();
        $update->addHandle('PRODUCT_ATTRIBUTE_'.$attributeName.'_' . $niceName);
    }
}

Replace the $attributeName value with the attribute that you would like to use. When the attribute is dropdown, it will use the numeric value of the selected option. Also this will not work for multiselect attributes.

Now you can change the product view template with the following code in your local.xml to select an other template when the product attribute myattribute has the value demotxt:

<PRODUCT_ATTRIBUTE_myattribute_demotxt>
    <reference name="product.info">
      <action method="setTemplate"><template>my/custom/product/view.phtml</template></action>
    </reference>
</PRODUCT_ATTRIBUTE_myattribute_demotxt>

Hope that this info is helpful, I did not had the option to test it completly.

In Magento, the renderers are defined under checkout_cart_item_renderers.xml, there's several of them:

• app/code/Magento/Checkout/view/frontend/layout/checkout_cart_item_renderers.xml for default and simple products renderers
• app/code/Magento/Bundle/view/frontend/layout/checkout_cart_item_renderers.xml for bundle products renderers
• app/code/Magento/Catalog/view/frontend/layout/checkout_cart_item_renderers.xml for virtual products renderers
• app/code/Magento/ConfigurableProduct/view/frontend/layout/checkout_cart_item_renderers.xml for configurable products renderers
• app/code/Magento/Grouped/view/frontend/layout/checkout_cart_item_renderers.xml for grouped products renderers
• app/code/Magento/GiftMessage/view/frontend/layout/checkout_cart_item_renderers.xml this one is special as it adds extra block for the gift message feature to the different renderers
• app/code/Magento/Wishlist/view/frontend/layout/checkout_cart_item_renderers.xml this one is special too as it adds extra block for the wishlist feature to the different renderers

After checking those renderers, you can find which renderer you want to override.

As you said, you want to override the simple product renderer which is a Magento\Checkout\Block\Cart\Item\Renderer.

If you want to override the entire block you should use the Magento 2 preferences:

In your module, you can create a di.xml file under the etc folder with the following content:

<?xml version="1.0"?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:ObjectManager/etc/config.xsd">
    <preference for="Magento\Checkout\Block\Cart\Item\Renderer" type="Vendor\ModuleName\Block\Checkout\Cart\Item\Renderer" />  
</config>

Then you need to create the app/code/Vendor/Module/Block/Checkout/Cart/Item/Renderer.php class with the following content:

<?php
namespace Vendor\Module\Block\Checkout\Cart\Item;
class Renderer extends \Magento\Checkout\Block\Cart\Item\Renderer
{
    public function theFunctionYouWantToRewrite()
    {
        // Do your custom stuff
    }
}

However, if you want to work on the method levels and not on the entire class level, you should use plugins

As it can be very specific, it's hard for me to give you an example but you can find useful resources about plugins here:

• http://devdocs.magento.com/guides/v2.0/extension-dev-guide/plugins.html
• http://alanstorm.com/magento_2_object_manager_plugin_system