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

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(),
    ]);
});