Magento 2 - How to change number of products per page dynamically?

Question

In Magento 2, I try to change number of products in category pages dynamically.

For exemple categories 1 and 2 will have default number value (10), and category 3 and 4 will have one less product, only 9 products per pages.

I will use a custom module attribute to identify which category need less product per page.

Do you know how can achieve this ?

Thanks

Answer 1

The pagination limit are retrieved using function getAvailableLimit in class Magento\Catalog\Block\Product\ProductList\Toolbar. You can use plugin to define your custom limits for pagination.

etc/frontend/di.xml

<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:ObjectManager/etc/config.xsd">
   <!--Plugins-->
   <type name="Magento\Catalog\Block\Product\ProductList\Toolbar">
      <plugin name="page_limit"
            type="Vendor\Module\Plugin\Toolbar"
            sortOrder="2" disabled="false" />
   </type>
</config>

Plugin Vendor\Module\Plugin\Toolbar

<?php


 namespace Vendor\Module\Plugin;


 class Toolbar
 {
    /**
   * Core registry
   *
   * @var \Magento\Framework\Registry
   */
    protected $_coreRegistry;

    public function __construct(
       \Magento\Framework\Registry $registry
    ) {
       $this->_coreRegistry = $registry;
    }

    public function afterGetAvailableLimit(
      \Magento\Catalog\Block\Product\ProductList\Toolbar $subject,
      $result
   ) {
       $category = $this->_coreRegistry->registry('current_category');

       //just an example, you can replace with your code.
       if ($category->getId() == '5') {
          $result = [];
          for ($i = 9, $k = 0; $k < 5; $i = $i+5, $k++) {
            $result[$i] = $i;
          }
       }

       return $result;
     }
 }

Answer 2

You can create an observer for this and set page limit dynamic according to your requirement

<event name="catalog_block_product_list_collection">
        <observer name="vendor_module_product_list_collection"
          instance="vendor\Module\Observer\ListCollectionObserver" />
</event>

And below are the observer file code ListCollectionObserver. You just need to get current category ID and add your product limit in collection

$observer->getCollection()->setPageSize(15);

ListCollectionObserver

<?php

namespace vendor\module\Observer;

use Magento\Customer\Model\Session;

class ListCollectionObserver implements \Magento\Framework\Event\ObserverInterface

{
    
    protected $_storeManager;  

    public function __construct(
        \Magento\Store\Model\StoreManagerInterface $storeManager,
    ) {
        $this->_storeManager = $storeManager;
    }

    public function execute(\Magento\Framework\Event\Observer $observer)
    {   

        $productCollection = $observer->getCollection();

        if(isset($_GET['product_list_limit']) && $_GET['product_list_limit']!='all'){
            $productCollection->setPageSize($_GET['product_list_limit'])->load();
        }if(isset($_GET['product_list_limit']) && $_GET['product_list_limit']=='all'){
        $productCollection->load();
        }else{
            $productCollection->setPageSize($this->scopeConfig->getValue('catalog/frontend/grid_per_page', \Magento\Store\Model\ScopeInterface::SCOPE_STORE))->load();
        }
        if(isset($_GET['p'])){
            $productCollection->setCurPage($_GET['p'])->load();
        }else{
            $productCollection->setCurPage(1)->load();
        }               
    }
}