How to remove empty fields from bootstrap collection?

Question

symfony

Can you please tell me how to delete empty fields when using bootstrap collection? The delete empty option is enabled.

class HostType extends BaseType
{
    public function buildForm(FormBuilderInterface $builder,array $options)
    {
        $builder->add('username','text',array('label'=>'Name'))
                ->add('email','text')
                ->add('about',null,array('label'=>'About host'))
                ->add('picture','iphp_file')
                ->add('videos','bootstrap_collection',array(
                                'type'=>new HostVideoType(),
                                'allow_add'=>true,
                                'allow_delete'=>true,
                                'cascade_validation' => true,
                                'delete_empty'=>true,
                                'add_button_text'    => 'Add video to host',
                                'delete_button_text' => 'Delete video from host',
                ));
    }

    public function setDefaultOptions(OptionsResolverInterface $resolver)
    {
        $resolver->setDefaults(array(
           'data_class' => 'iCliqueLive\HostBundle\Entity\Host',
           'validation_groups' => array('addHost'),
           'cascade_validation'=>true,
        ));
    }

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

Answer 1

Set by_reference to false and write methods addVideo, removeVideo instead of setVideos