Magento 2：在订单详情页添加自定义按钮并实现功能

<?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\Sales\Block\Adminhtml\Order\View">
       <plugin name="addCustomButton" type="MG\Dropship\Plugin\Sales\Block\Adminhtml\Order\Button"/>
   </type>
</config>

<?xml version="1.0"?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework/App/etc/routes.xsd">
    <router id="admin">
        <route id="mg_dropship" frontName="mg_dropship">
            <module name="MG_Dropship" />
        </route>
    </router>
</config>

<?php
namespace MG\Dropship\Controller\Adminhtml\Order;

use Magento\Backend\App\Action;
use Magento\Backend\App\Action\Context;
use Magento\Framework\Controller\ResultFactory;
use Magento\Sales\Api\OrderRepositoryInterface;
use Psr\Log\LoggerInterface;

class Index extends Action
{
    /**
     * @var OrderRepositoryInterface
     */
    protected $orderRepository;

    /**
     * @var LoggerInterface
     */
    protected $logger;

    /**
     * @param Context $context
     * @param OrderRepositoryInterface $orderRepository
     * @param LoggerInterface $logger
     */
    public function __construct(
        Context $context,
        OrderRepositoryInterface $orderRepository,
        LoggerInterface $logger
    ) {
        $this->orderRepository = $orderRepository;
        $this->logger = $logger;
        parent::__construct($context);
    }

    /**
     * Execute action
     *
     * @throws \Magento\Framework\Exception\LocalizedException|\Exception
     */
    public function execute()
    {
        $orderId = $this->getRequest()->getParam('order_id');

        $resultRedirect = $this->resultFactory->create(ResultFactory::TYPE_REDIRECT);

        try {
            $order = $this->orderRepository->get($orderId);

            // TODO: Do something with the order
            $this->messageManager->addSuccessMessage(__('We did something!'));
        } catch (\Magento\Framework\Exception\LocalizedException $e) {
            $this->messageManager->addErrorMessage($e->getMessage());
        } catch (\Exception $e) {
            $this->messageManager->addErrorMessage(__('We can\'t process your request' . $e->getMessage()));
            $this->logger->critical($e);
        }

        return $resultRedirect->setPath(
            'sales/order/view',
            [
                'order_id' => $orderId
            ]
        );
    }

    /**
     * @return bool
     */
    protected function _isAllowed()
    {
        return $this->_authorization->isAllowed('MG_Dropship::order_dosomething');
    }
}

<?php
namespace MG\Dropship\Plugin\Sales\Block\Adminhtml\Order;

use Magento\Sales\Block\Adminhtml\Order\View as OrderView;

class Button
{
    public function beforeSetLayout(OrderView $subject)
    {
        if ($subject->getOrder()) {
            $message = __('Are you sure you want to Do Something?');
            $subject->addButton(
                'do_something',
                [
                    'label' => __('Do Something'),
                    'class' => 'do_something',
                    'onclick' => "confirmSetLocation('{$message}', '{$subject->getUrl('mg_dropship/order/index', ['order_id' => $subject->getOrder()->getId()])}')"
                ]
            );
        }
    }
}

php bin/magento cache:clean
php bin/magento setup:upgrade
php bin/magento setup:di:compile
php bin/magento setup:static-content:deploy -f