Profile Edit doesn't accept a text input as a date - php

Question

I'm using Symfony 2 and FOS User Bundle to create a website that handles user information.
I tried to create the edit page to change an existing profile.
My problem is that I want the birthdate to be an input text (because I'm using a Jquery Datapicker). It perfectly works on my register page but when I try to do the same for the profile/edit page, I have a 500 error saying "The form's view data is expected to be of type scalar, array or an instance of \ArrayAccess, but is an instance of class DateTime. You can avoid this error by setting the "data_class" option to "DateTime" or by adding a view transformer that transforms an instance of class DateTime to scalar, array or an instance of \ArrayAccess.".
Here is how I wrote my User (User.php entity) birthdate parameter:
/**
* #ORM\Column(name="birthdate", type="date")
* #Assert\NotBlank(groups={"Registration", "Profile"})
* #Assert\Date()
*/
protected $birthdate;
In my RegistrationFormType.php (that is working fine):
public function buildForm(FormBuilderInterface $builder, array $options)
{
...
$builder->add('givenname');
$builder->add('familyname');
$builder->add('birthdate', 'text');
...
}
When I try to copy paste this code, I got an error.
The only solution is to do the following:
$builder->add('birthdate', 'date', array('input' => 'datetime'));
This solution does work but is not what I want (it generates three select inputs, I would rather have a text input that uses my Jquery datepicker with my Jquery validation).
Do you have any idea why my error occurs on the edit page and not on the registration page?
Thank you!

Answer 1

I think you need to set the widget option of your date field to text. It's by default set to choice.
From the documentation:
text: renders a three field input of type text (month, day, year).
Example,
$builder->add('birthdate', 'date', array(
'input' => 'datetime',
'widget' => 'text'
));
You can also set it to single_text, which allows you to validate the user's input based on the format option.
Example,
$builder->add('birthdate', 'date', array(
'widget' => 'single_text',
// this is actually the default format for single_text
'format' => 'yyyy-MM-dd',
));
To let it work through a Date Picker, you've then to add the right class to your field.