Injecting Translator service to FormType

Question

I'm trying to find a the most reusable working option for being able to translate from a FormType.

My first option is to declare a service specifically for each FormType this way:

services.yml

form.enquiry:
    class: Acme\DemoBundle\Form\EnquiryType
    arguments: [@translator]

EnquiryType.php

use Symfony\Component\Translation\Translator;
class EnquiryType extends AbstractType {

    public $translator;
    public function __construct(Translator $translator=null)
    {
        $this->translator = $translator;
    }

public function buildForm(FormBuilderInterface $builder, array $options) {
    $tr= $this->translator;
    $msg=$tr->trans('default_error');
    $builder->add ...

MyController.php

 $form = $this->container->get('form.enquiry')->create();
 return $this->render('AcmeDemoBundle:Home:index.html.twig', array(
     'form' => $form->createView()
 ));

gives this error

FatalErrorException: Error: Call to undefined method Acme\DemoBundle\Form\EnquiryType::create()

I'd like to know how to solve it by changing the code or even better finding a better option that allows me to inject the translator service to any FormType without needing to declare each FormType service individually.

Answer 1

Your EnqurityType must return whole form so inside buildForm You should create whole form

$builder
->setAction('action')
->setMethod('POST')
->add('field', 'field_type')

And in constructor You should type hint for TranslatorInterface its called design by contract

Answer 2

To make it work properly with Dependency Injection you need to tag it as a form.type:

tags:
    - { name: form.type }

also do not get it from container like a usual service, but use controller helper as it was a normal formType:

$this->createForm(...)

Take a look into: http://symfony.com/doc/2.8/form/form_dependencies.html