Form collection symfony2 showing empty div

Question

I have this two forms:

public function buildForm(FormBuilderInterface $builder, array $options)
{
    $builder
        ->add('nome')
        ->add('fotos', 'collection', array(
            'type' => new GaleriaFotoType,
            'allow_add' => true,
            'allow_delete' => true,
            'by_reference' => false
        ));
}

public function buildForm(FormBuilderInterface $builder, array $options)
{
    $builder
        ->add('caminho', 'file', array(
            'required' => false,
            'data_class' => null
        ));
}

If my collection is not empty, for example when I'm editing, it renders normal. But when I'm adding an new entry the form_end(form) renders this at the end of the html:

<div>
    <label class="required">Fotos</label>
    <div id="galeria_fotos" data-prototype=""></div>
</div>

This is my form html for the collection:

{{ form_label(form.fotos) }}
<ul id="galeria_foto" data-prototype="{{ form_widget(form.fotos.vars.prototype)|e }}">
    {% for foto in form.fotos %}
        <li>{{ form_widget(foto) }}</li>
    {% endfor %}
</ul>

{{ form_errors(form.fotos) }}

Controller:

<?php

namespace DasArtes\AdminBundle\Controller;

use DasArtes\AdminBundle\Entity\Galeria;
use DasArtes\AdminBundle\Form\GaleriaType;
use Symfony\Bundle\FrameworkBundle\Controller\Controller;
use Symfony\Component\HttpFoundation\Request;
use Doctrine\Common\Collections\ArrayCollection;

class GaleriasFotosController extends Controller
{
    public function indexAction()
    {
        $galerias = $this->getDoctrine()->getRepository('DasArtesAdminBundle:Galeria')->findAll();

        return $this->render('@DasArtesAdmin/galerias-de-fotos/index.html.twig', array(
            'galerias' => $galerias
        ));
    }

    public function adicionarAction(Request $request)
    {
        $galeria = new Galeria;

        $form = $this->createForm(new GaleriaType, $galeria);
        $form->handleRequest($request);

        if ($form->isValid()) {
            // autor
            $usuario_logado = $this->get('security.context')->getToken()->getUser();
            $galeria->setAutor($usuario_logado);

            // upload fotos
            $uploadableManager = $this->get('stof_doctrine_extensions.uploadable.manager');

            foreach ($form->get('fotos')->getData() as $foto) {
                $uploadableManager->markEntityToUpload($foto, $foto->getCaminho());
            }

            $manager = $this->getDoctrine()->getManager();
            $manager->persist($galeria);
            $manager->flush();

            $this->get('session')->getFlashBag()->add('alert-success', 'Galeria adicionada com sucesso');

            return $this->redirect($this->generateUrl('das_artes_admin_galerias_de_fotos'));
        }

        return $this->render('@DasArtesAdmin/galerias-de-fotos/form.html.twig', array(
            'form' => $form->createView(),
            'tipo' => 'adicionar'
        ));
    }

    public function editarAction(Galeria $galeria, Request $request)
    {
        // salva as fotos originais para comparar depois com as fotos enviadas pelo form
        $fotos = new ArrayCollection;

        foreach ($galeria->getFotos() as $foto) {
            $fotos->add($foto);
        }

        $form = $this->createForm(new GaleriaType, $galeria);
        $form->handleRequest($request);

        if ($form->isValid()) {
            // autor
            $usuario_logado = $this->get('security.context')->getToken()->getUser();
            $galeria->setAutor($usuario_logado);

            // upload fotos
            $uploadableManager = $this->get('stof_doctrine_extensions.uploadable.manager');

            foreach ($form->get('fotos')->getData() as $foto) {
                if (!is_string($foto->getCaminho())) {
                    $uploadableManager->markEntityToUpload($foto, $foto->getCaminho());
                }
            }

            $manager = $this->getDoctrine()->getManager();

            // compara as fotos enviadas pelo form com as originais e remove se necessário
            foreach ($fotos as $foto) {
                if (!$galeria->getFotos()->contains($foto)) {
                    $galeria->getFotos()->removeElement($foto);
                    $manager->remove($foto);
                }
            }

            $manager->flush();

            $this->get('session')->getFlashBag()->add('alert-success', 'Galeria editada com sucesso');

            return $this->redirect($this->generateUrl('das_artes_admin_galerias_de_fotos'));
        }

        return $this->render('@DasArtesAdmin/galerias-de-fotos/form.html.twig', array(
            'form' => $form->createView(),
            'tipo' => 'editar'
        ));
    }

    public function removerAction(Galeria $galeria)
    {
        $manager = $this->getDoctrine()->getManager();
        $manager->remove($galeria);
        $manager->flush();

        // flash message
        $this->get('session')->getFlashBag()->add('alert-success', 'Artista removido com sucesso');

        return $this->redirect($this->generateUrl('das_artes_admin_galerias_de_fotos'));
    }
}

Answer 1

You have to create an object and associate it to your form in your controller. See this example from the documentation:

class TaskController extends Controller
{
    public function newAction(Request $request)
    {
        $task = new Task();

        // dummy code - this is here just so that the Task has some tags
        // otherwise, this isn't an interesting example
        $tag1 = new Tag();
        $tag1->name = 'tag1';
        $task->getTags()->add($tag1);
        $tag2 = new Tag();
        $tag2->name = 'tag2';
        $task->getTags()->add($tag2);
        // end dummy code

        $form = $this->createForm(new TaskType(), $task);

        $form->handleRequest($request);

        if ($form->isValid()) {
            // ... maybe do some form processing, like saving the Task and Tag objects
        }

        return $this->render('AcmeTaskBundle:Task:new.html.twig', array(
            'form' => $form->createView(),
        ));
    }
}

So you will have to create a GaleriaFotoType object and add it to the fotos collection:

public function adicionarAction(Request $request)
{
    $galeria = new Galeria;

    $galeria->getFotos()->add(new Foto());

    $form = $this->createForm(new GaleriaType, $galeria);
    $form->handleRequest($request);
    [...]