Magento 2: How to override Magento\Catalog\Block\Product\View constructor to inject \Magento\Eav\Model\Entity\Attribute\SetFactory

Question

I am attempting to override the __construct method in the Magento\Catalog\block\Product\View block so that I can access the Magento\Eav\Model\Entity\Attribute\SetFactory to get the AttributeSetName of a product in the addtocart.phtml. However, I keep running into a 404 Error.

I created a module and extended the Magento\Catalog\Block\Product\View class.

namespace MyVendor\MyModule\Block\Product;

use Magento\Catalog\Block\Product\View as BaseView;

class View extends BaseView {

    protected $_attributeSetFactory;

    public function __construct(
        \Magento\Catalog\Block\Product\Context $context,
        \Magento\Framework\Url\EncoderInterface $urlEncoder,
        \Magento\Framework\Json\EncoderInterface $jsonEncoder,
        \Magento\Framework\Stdlib\StringUtils $string,
        \Magento\Catalog\Helper\Product $productHelper,
        \Magento\Catalog\Model\ProductTypes\ConfigInterface $productTypeConfig,
        \Magento\Framework\Locale\FormatInterface $localeFormat,
        \Magento\Customer\Model\Session $customerSession,
        ProductRepositoryInterface $productRepository,
        \Magento\Framework\Pricing\PriceCurrencyInterface $priceCurrency,
        \Magento\Eav\Model\Entity\Attribute\SetFactory $attributeSetFactory,
        array $data = []
    ) {
        $this->_attributeSetFactory = $attributeSetFactory;
        parent::__construct(
            $context,
            $urlEncoder,
            $jsonEncoder,
            $string,
            $productHelper,
            $productTypeConfig,
            $localeFormat,
            $customerSession,
            $productRepository,
            $priceCurrency,
            $data
        );
    }

/**
 * Add meta information from product to head block
 *
 * @return \Magento\Catalog\Block\Product\View
 */
protected function _prepareLayout()
{
    parent::_prepareLayout();
}

}

In the Magento\view\frontend\templates\product\view\addtocart.phtml template I wasn't sure if I had to change the line /** @var $block \Magento\Catalog\Block\Product\View */ to reference my block instead of the core block either.

Snippet from MyVendor\MyModule\view\frontend\templates\product\view\addtocart.phtml:

...
/** @var $block \Magento\Catalog\Block\Product\View */
?>
<?php $_product = $block->getProduct(); ?>
<?php echo $block->getAttributeSetName(); ?>
<?php $buttonTitle = __('Add to Cart'); ?>
...

After reading documentation I do not think I am injecting the factory correctly in the construct because before getting the 404 error I was having issues with the order the parameters are passed in the __construct. However, after I cleared the cache I get the 404 error. Any help and direction would greatly be appreciated.

This is my di.xml file:

<?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\Block\Product\View" type="MyVendor\MyModule\Block\Product\View" />
</config>

Answer 1

So after taking everyones suggestions and getting as far as being able to render the product detail page without any errors but the block addtocart.phtml would not appear at all. I ran into this stackoverflow question Overriding Block in Magento 2 and I realized that the accepted answer allowed for my block to be rendered on the page.

Even though my block was overwritten, the template name is determined by module name of a block and the template attribute of the block and therefore needed to add the following method to my block:

protected function _toHtml()
    {
        $this->setModuleName($this->extractModuleName('Magento\Catalog\Block\Product\View'));
        return parent::_toHtml();
    }

To be able to render the template. Still not completely clear on the reason why I need to do this, will have to do more research, but this allowed the block to be overwritten and display the appropriate custom template.

thanks all for the help :)

Answer 2

The order of the constructor parameters must match the order of the original constructor. Extra parameters should come last, before the $data parameter.

So your method should look like this:

public function __construct(
        \Magento\Catalog\Block\Product\Context $context,
        \Magento\Framework\Url\EncoderInterface $urlEncoder,
        \Magento\Framework\Json\EncoderInterface $jsonEncoder,
        \Magento\Framework\Stdlib\StringUtils $string,
        \Magento\Catalog\Helper\Product $productHelper,
        \Magento\Catalog\Model\ProductTypes\ConfigInterface $productTypeConfig,
        \Magento\Framework\Locale\FormatInterface $localeFormat,
        \Magento\Customer\Model\Session $customerSession,
        ProductRepositoryInterface $productRepository,
        \Magento\Framework\Pricing\PriceCurrencyInterface $priceCurrency,
        \Magento\Eav\Model\Entity\Attribute\SetFactory $attributeSetFactory,
        array $data = []
    ) {
        $this->_attributeSetFactory = $attributeSetFactory;
        parent::__construct(
            $context,
            $urlEncoder,
            $jsonEncoder,
            $string,
            $productHelper,
            $productTypeConfig,
            $localeFormat,
            $customerSession,
            $productRepository,
            $priceCurrency,
            $data
        );
    }