如何在symfony2中创建自定义字段类型？

// src/YourBundle/Form/Type/CustomFieldType.php

namespace YourBundle\Form\Type;

use Symfony\Component\Form\AbstractType;
use Symfony\Component\Form\FormBuilderInterface;

class CustomFieldType extends AbstractType
{
    public function buildForm(FormBuilderInterface $builder, array $options)
    {
        $builder->add('custom_field', null, [
            'label' => 'Custom Field',
            'attr' => [
                'class' => 'custom-field-class',
            ],
        ]);
    }

    public function getParent()
    {
        return 'text';
    }

    public function getName()
    {
        return 'custom_field';
    }
}

// src/YourBundle/DependencyInjection/YourBundleExtension.php

namespace YourBundle\DependencyInjection;

use Symfony\Component\DependencyInjection\ContainerBuilder;
use Symfony\Component\DependencyInjection\Extension\Extension;

class YourBundleExtension extends Extension
{
    public function load(array $configs, ContainerBuilder $container)
    {
        $container->registerExtension(new YourBundleExtension());
        $container->register('your_bundle.form.type.custom_field', CustomFieldType::class)
            ->addTag('form.type');
    }
}

// src/YourBundle/Resources/config/services.yml

services:
    your_bundle.form.type.custom_field:
        class: YourBundle\Form\Type\CustomFieldType
        tags:
            - { name: form.type }

// src/YourBundle/Form/YourFormType.php

namespace YourBundle\Form;

use Symfony\Component\Form\AbstractType;
use Symfony\Component\Form\FormBuilderInterface;

class YourFormType extends AbstractType
{
    public function buildForm(FormBuilderInterface $builder, array $options)
    {
        $builder->add('name', 'text')
                ->add('custom_field', 'custom_field');
    }

    public function getName()
    {
        return 'your_form';
    }
}