Index.php

<?php
/**
 * Mageplaza
 *
 * NOTICE OF LICENSE
 *
 * This source file is subject to the Mageplaza.com license that is
 * available through the world-wide-web at this URL:
 * https://www.mageplaza.com/LICENSE.txt
 *
 * DISCLAIMER
 *
 * Do not edit or add to this file if you wish to upgrade this extension to newer
 * version in the future.
 *
 * @category    Mageplaza
 * @package     Mageplaza_BannerSlider
 * @copyright   Copyright (c) Mageplaza (https://www.mageplaza.com/)
 * @license     https://www.mageplaza.com/LICENSE.txt
 */

namespace Mageplaza\BannerSlider\Controller\Adminhtml\Slider;

use Magento\Backend\App\Action;
use Magento\Backend\App\Action\Context;
use Magento\Framework\View\Result\Page;
use Magento\Framework\View\Result\PageFactory;

/**
 * Class Index
 * @package Mageplaza\BannerSlider\Controller\Adminhtml\Slider
 */
class Index extends Action
{
    const ADMIN_RESOURCE = 'Mageplaza_BannerSlider::slider';

    /**
     * Page result factory
     *
     * @var PageFactory
     */
    protected $resultPageFactory;

    /**
     * Page factory
     *
     * @var \Magento\Backend\Model\View\Result\Page
     */
    protected $resultPage;

    /**
     * constructor
     *
     * @param PageFactory $resultPageFactory
     * @param Context $context
     */
    public function __construct(
        PageFactory $resultPageFactory,
        Context $context
    ) {
        $this->resultPageFactory = $resultPageFactory;

        parent::__construct($context);
    }

    /**
     * execute the action
     *
     * @return \Magento\Backend\Model\View\Result\Page|Page
     */
    public function execute()
    {
        $resultPage = $this->resultPage = $this->resultPageFactory->create();
        $resultPage->getConfig()->getTitle()->prepend((__('Manage Sliders')));

        return $resultPage;
    }
}