How to override blocks in v2.1

Override block:

Create your own module under app/code folder.
We can use preference to override the class in Magento 2.

app/code/Vendor/Module/etc/di.xml

<?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\Theme\Block\Html\Topmenu" type="Vendor\Module\Block\Html\Topmenu" />
</config>

app/code/Vendor/Module/Block/Html/Topmenu.php

<?php

namespace Vendor\Module\Block\Html;

class Topmenu extends \Magento\Theme\Block\Html\Topmenu
{

    protected function _addSubMenu($child, $childLevel, $childrenWrapClass, $limit)
    {

    }

}

Temporary solution:
Currently, seem that above steps cannot override the the block completely. We need to create new custom theme. And then, create the default.xml file:

app/design/frontend/Vendor/Theme/Magento_Theme/layout/default.xml

<?xml version="1.0"?>

<page layout="3columns" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:View/Layout/etc/page_configuration.xsd">
    <update handle="default_head_blocks"/>
    <referenceBlock name="catalog.topnav" class="Vendor\Module\Block\Html\Topmenu" template="Magento_Theme::html/topmenu.phtml"/>
</page>

It's may be a Magento bug: Are we forced to rewrite a template in Magento2 when rewritting a block?

[EDIT]

1) We can set the template:

app/code/Vendor/Module/Block/Html/Topmenu.php

public function setTemplate($template)
{
    return parent::setTemplate('Vendor_Module::custom-menu.phtml');
}

2) Set template via Xml:

For example:

app/code/Vendor/Module/view/frontend/layout/checkout_cart_index.xml

<?xml version="1.0"?>
<page xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" layout="1column" xsi:noNamespaceSchemaLocation="urn:magento:framework:View/Layout/etc/page_configuration.xsd">
    <body>
        <referenceBlock name="checkout.cart">
            <action method="setTemplate">
                <argument name="template" xsi:type="string">Magento_Checkout::cart.phtml</argument>
            </action>
        </referenceBlock>
    </body>
</page>

Remember to create registration.php and module.xml.

We create the new module because we're overriding the class of Magento. When we want to override any class, we have to create new module.

The custom theme under app/design/frontend contains:
--layout
--templates
--js
--html templates (Knockout templates)
--less, css
--etc...

Read more here and here.

Autoloading standard and naming convention:

For [Namespace] and [Module], we should read more here:

http://www.php-fig.org/psr/psr-0/
http://www.php-fig.org/psr/psr-4/
http://alanstorm.com/magento_2_autoloader_and_class_generation


For override catalog product ListProduct block.

1) Create di.xml file in Folder Vendor/Module/etc

<?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\Catalog\Model\Product" type="Vendor\Module\Model\Rewrite\Catalog\Product" />
</config>

2) Create ListProduct.php Block file in Folder Vendor/Module/Block/Rewrite/Product

<?php
namespace Vendor\Module\Block\Rewrite\Product;

class ListProduct extends \Magento\Catalog\Block\Product\ListProduct
{
    public function _getProductCollection()
    {
        // Do your code here
    }
}

For override catalog product model.

1) Add preference in di.xml before

<?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\Catalog\Model\Product" type="Vendor\Module\Model\Rewrite\Catalog\Product" />
</config>

2) Create Product.php Model file in Folder Vendor/Module/Model/Rewrite/Catalog

<?php
namespace Vendor\Module\Model\Rewrite\Catalog;

class Product extends \Magento\Catalog\Model\Product
{
    public function isSalable()
    {
        // Do your code here

        return parent::isSalable();
    }

}

For Overriding Controller

1) Add preference in di.xml

2) Create View.php Controller file at Vendor/Module/Controller/Rewrite/Product

class View extends \Magento\Catalog\Controller\Product\View
{
    public function execute()
    {
        // Do your stuff here
        return parent::execute();
    }
}

You can override other block,model and controllers using this same approach.

Tags:

Magento 2.1

Theme

Blocks

Recent Posts