Use a conditional statement when creating a form - symfony-forms

Question

I would like to use a conditional statement when creating a form in Symfony.
I am using a choice widget in general case. If the user selects the option "Other", I would like to display an additional text box widget. I suppose this can be done in javascript, but how can I still persist the data from 2 widgets into the same property in my entity?
I have this so far:
$builder->add('menu', 'choice', array(
'choices' => array('Option 1' => 'Option 1', 'Other' => 'Other'),
'required' => false,
));
//How to add text box if choice == Other ????
I was planing to use a DataTransfomer, but on 2 widgets??

Answer 1

I recommend to build a custom type for that, for example ChoiceOrTextType. To this type you add both the choice (named "choice") and the text field (named "text").
use Symfony\Component\Form\AbstractType;
use Symfony\Component\OptionsResolver\OptionsResolverInterface;
class ChoiceOrTextType extends AbstractType
{
public function buildForm(FormBuilderInterface $builder, array $options)
{
$builder
->add('choice', 'choice', array(
'choices' => $options['choices'] + array('Other' => 'Other'),
'required' => false,
))
->add('text', 'text', array(
'required' => false,
))
->addModelTransformer(new ValueToChoiceOrTextTransformer($options['choices']))
;
}
public function setDefaultOptions(OptionsResolverInterface $resolver)
{
$resolver->setRequired(array('choices'));
$resolver->setAllowedTypes(array('choices' => 'array'));
}
}
As you already guessed, you also need a data transformer, which can be quite simple:
use Symfony\Component\Form\DataTransformerInterface;
class ValueToChoiceOrTextTransformer implements DataTransformerInterface
{
private $choices;
public function __construct(array $choices)
{
$this->choices = $choices;
}
public function transform($data)
{
if (in_array($data, $this->choices, true)) {
return array('choice' => $data, 'text' => null);
}
return array('choice' => 'Other', 'text' => $data);
}
public function reverseTransform($data)
{
if ('Other' === $data['choice']) {
return $data['text'];
}
return $data['choice'];
}
}
Now only make the "menu" field a field of that type.
$builder->add('menu', new ChoiceOrTextType(), array(
'choices' => array('Option 1' => 'Option 1', 'Option 2' => 'Option 2'),
'required' => false,
));