How to render a checkbox that is checked by default with the symfony2 Form Builder?

Question

I have not found any easy way to accomplish to simply check a Checkbox by default. That can not be that hard, so what am i missing?

Answer 1

Setting the 'data' option works for me. I'm creating a non entity based form:

$builder->add('isRated','checkbox', array(
    'data' => true
));

Answer 2

In TWIG

If you wish to do this in the template directly:

{{ form_widget(form.fieldName, { 'attr': {'checked': 'checked'} }) }}

Answer 3

As per documentation: http://symfony.com/doc/current/reference/forms/types/checkbox.html#value

To make a checkbox or radio button checked by default, use the data option.

Answer 4

You should make changes to temporary object where entity is stored before displaying it on form. Something like next:

<?php

namespace KPI\AnnouncementsBundle\Form;

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

class AnnouncementType extends AbstractType
{
    public function buildForm(FormBuilderInterface $builder, array $options)
    {  
        // ...        

        if ($options['data']->getDisplayed() === null) {
            $options['data']->setDisplayed(true);
        }

        // ...

        $builder
            ->add('displayed', 'checkbox', array(
                'required' => false
            ));
    }
}

Answer 5

To complete a previous answer, with a multiple field you can do that to check all choices :

   'choice_attr' => function ($val, $key, $index) {
       return array('checked' => true);
   }

https://symfony.com/doc/3.3/reference/forms/types/choice.html#choice-attr

Answer 6

I had the same problem as you and here is the only solution I found:

$builder->addEventListener(FormEvents::PRE_SET_DATA, function (FormEvent $event) {
    $entity= $event->getData();
    $form = $event->getForm();
    $form->add('active', CheckboxType::class, [
        'data' => is_null($entity) ? true : $entity->isActive(),
    ]);
});