Magento – Automatically continue shopping when product is added to cart

I added a similar feature to my site. Instead of looking at the product I set a variable from the URL on the last category page viewed which in most cases would be the category the items was added from.

This is the code added to template->Catalog->Category->view.phtml

<?php
$_helper    = $this->helper('catalog/output');
$_category  = $this->getCurrentCategory();
$currentUrl = $this->helper('core/url')->getCurrentUrl();
$session = Mage::getSingleton("core/session",  array("name"=>"frontend"));
$session->setData("last_category", $currentUrl);?>

Then in template->Checkout->cart.phtml to replace the current button:

<?php if($this->getContinueShoppingUrl()): ?>
    <?php $session = Mage::getSingleton("core/session",  array("name"=>"frontend"));
    $lastUrl = $session->getData("last_category");
    if(empty($lastUrl)):
        $lastUrl = $this->getContinueShoppingUrl();
    endif; ?>
    <button type="button" title="<?php echo $this->__('Continue Shopping') ?>" class="btn btn-primary" onclick="setLocation('<?php echo $lastUrl ?>')"><span><span><?php echo $this->__('Continue Shopping') ?></span></span></button>
<?php endif; ?>

This also checks to make sure they have visited a category before, if not it sends them to the default "continue shopping" location.

I got this solution from somewhere else, can't recall where though.

You need to write a plugin to achieve this. For that define di.xml file in your module.

File: app/code/<Namespace>/<Module>/etc/frontend/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">
    <type name="Magento\Checkout\Block\Cart">
        <plugin disabled="false" name="NamespaceModuleBlockCartBeforePlugin" sortOrder="1" type="Namespace\Module\Plugin\Magento\Checkout\Block\Cart"/>
    </type>
</config>

Then in your plugin class, add the below code:

File: app/code/<Namespace>/<Module>/Plugin/Magento/Checkout/Block/Cart.php

<?php

namespace Namespace\Module\Plugin\Magento\Checkout\Block;

use Magento\Checkout\Block\Cart as CheckoutCart;
use Magento\Checkout\Model\Session;

class Cart
{
    protected $_checkoutSession;

    public function __construct(Session $session) {
        $this->_checkoutSession   = $session;
    }

    public function beforeGetContinueShoppingUrl(CheckoutCart $subject)
    {
        $url = $subject->getData('continue_shopping_url');
        if ($url === null) {
            $url = $this->_checkoutSession->getContinueShoppingUrl(true);
            if (!$url) {
                $url = $this->getCustomUrl();
            }
            $subject->setData('continue_shopping_url', $url);
        }

        return $this;
    }

    public function getCustomUrl()
    {
        //add the logic to get your custom url
        return $customUrl;
    }
}

As you can see, our plugin method is beforeGetContinueShoppingUrl here. The code is similar to the method \Magento\Checkout\Block\Cart::getContinueShoppingUrl(), except that we are setting the default URL with the call $this->getCustomUrl(). In this way, we are respecting the core code and hence an update to the core code logic to generate (in future) continue_shopping_url will not be altered.

Now you need to define the method getCustomUrl() as you needed.

After the changes made, it is good to perform php bin/magento setup:di:compile and php bin/magento cache:flush.

You are done.