未找到Symfony 4 isClicked方法

// 表单类
namespace App\Form;

use Symfony\Component\Form\AbstractType;
use Symfony\Component\Form\FormBuilderInterface;
use Symfony\Component\Form\Extension\Core\Type\SubmitType;

class MyFormType extends AbstractType
{
    public function buildForm(FormBuilderInterface $builder, array $options)
    {
        $builder
            // 添加其他表单字段
            // ...

            // 添加提交按钮
            ->add('submit', SubmitType::class, [
                'label' => 'Submit',
            ]);
    }
}

// 控制器
namespace App\Controller;

use App\Form\MyFormType;
use Symfony\Component\HttpFoundation\Request;
use Symfony\Component\Routing\Annotation\Route;
use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;

class MyController extends AbstractController
{
    /**
     * @Route("/my-form", name="my_form")
     */
    public function myForm(Request $request)
    {
        $form = $this->createForm(MyFormType::class);
        $form->handleRequest($request);

        if ($form->isSubmitted() && $form->isValid()) {
            // 处理表单提交
            // ...

            // 检查按钮是否被点击
            if ($form->get('submit')->isClicked()) {
                // 按钮被点击
                // ...
            }
        }

        return $this->render('my_form.html.twig', [
            'form' => $form->createView(),
        ]);
    }
}