Mryntu

I want to show the button in my custom module (admin page)

but I am getting an error

I want to add a button and how I add action process for that button

i already tried this answer(https://magento.stackexchange.com/a/212656/73525 )

GenericButton.php

 <?php
/**
 * Copyright © 2016 Magento. All rights reserved.
 * See COPYING.txt for license details.
 */
namespace WebkulMpquotesystemBlockAdminhtmlManagequotesEdit;

use MagentoBackendBlockWidgetContext;
//use FMENewsApiNewsRepositoryInterface;
use MagentoFrameworkExceptionNoSuchEntityException;

/**
 * Class GenericButton
 */
class GenericButton

 /**
 * @var Context
 */
 protected $context;

 /**
 * @var BlockRepositoryInterface
 */
 protected $blockRepository;

 /**
 * @param Context $context
 * @param BlockRepositoryInterface $blockRepository
 */
 public function __construct(
 Context $context
 ) 
 $this->context = $context;
 //$this->blockRepository = $blockRepository;
 

 /**
 * Return CMS block ID
 *
 * @return int

SaveandContinuebutton.php

<?php

namespace WebkulMpquotesystemBlockAdminhtmlManagequotesEdit;

use MagentoFrameworkViewElementUiComponentControlButtonProviderInterface;

/**
 * Class SaveAndContinueButton
 */
class SaveAndContinueButton extends GenericButton implements ButtonProviderInterface


 public function getButtonData()
 
 return [
 'label' => __('ADmin pproval'),
 'class' => 'save',
 'on_click' => 'location.reload();',
 'sort_order' => 30
 ];
 

view/adminhtml/uicomponent/custommodule_edit.xml

<?xml version="1.0"?>
<!-- /**
 * Webkul Software
 *
 * @category Webkul
 * @package Webkul_Mpquotesystem
 * @author Webkul
 * @copyright Copyright (c) 2010-2018 Webkul Software Private Limited (https://webkul.com)
 * @license https://store.webkul.com/license.html
 */ -->
<form xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:module:Magento_Ui:etc/ui_configuration.xsd">
 <argument name="data" xsi:type="array">

 <item name="buttons" xsi:type="array">
 <item name="save_and_continue" xsi:type="string">WebkulMpquotesystemBlockAdminhtmlManagequotesEditSaveAndContinueButton</item>
 </item>

 </argument>
</form>

when clicking that admin custom module page

Fatal error: Method MagentoUiTemplateEngineXhtmlResult::__toString() must not throw an exception, caught Error: Call to a member function getRequestFieldName() on null in /var/www/html/equpo2/vendor/magento/module-ui/Component/Wrapper/UiComponent.php on line