Symfony, oneToMany relationship Invalid argument supplied for foreach() - symfony

Question

I'm adding oneToMany relationship to database, and its working but when i want to view array i get this error :
Warning: Invalid argument supplied for foreach()
this is my User.php
class User implements AdvancedUserInterface, \Serializable
{
// ...
/**
* #ORM\OneToMany(targetEntity="Acme\CityBundle\Entity\City", mappedBy="user")
**/
private $cities;
public function __construct()
{
$this->cities = new ArrayCollection();
}
/**
* #inheritDoc
*/
public function getCities()
{
$c = array();
foreach ($this->cities as $city) {
$c[] = $city->getCity();
}
return $c;
}
/**
* Add cities
*
* #param \Acme\CityBundle\Entity\City $cities
* #return User
*/
public function addCity(\Acme\CityBundle\Entity\City $city)
{
$city->setUser($this);
$this->cities->add($city);
return $this->cities;
}
and City.php
<?php
namespace Acme\CityBundle\Entity;
use Doctrine\ORM\Mapping as ORM;
use Doctrine\Common\Collections\ArrayCollection;
/**
* City
*/
class City
{
/**
* #var integer
*/
private $id;
/**
* #var string
*/
private $name;
/**
* #ManyToOne(targetEntity="Acme\UserBundle\Entity\User", inversedBy="cities")
* #JoinColumn(name="id", referencedColumnName="id")
**/
private $user;
public function setUser($user)
{
$this->user = $user;
return $this;
}
/**
* Get id
*
* #return integer
*/
public function getId()
{
return $this->id;
}
/**
* Set name
*
* #param string $name
* #return City
*/
public function setName($name)
{
$this->name = $name;
return $this;
}
public function getCity()
{
return $this;
}
/**
* Get name
*
* #return string
*/
public function getName()
{
return $this->name;
}
}
Controller
$city=new City();
$em = $this->getDoctrine()->getManager();
$city->setName('Miasto');
$user->addCity($city);
$em->persist($city);
$em->persist($user);
$em->flush();
index controller
public function indexAction()
{
$cities=$this->get('security.context')->getToken()->getUser()->getCities();
return $this->render(
'AcmeUserBundle:User:index.html.twig',array( 'cities'=>$cities));
}
and when i try to show array (cities) in view i get error
Warning: Invalid argument supplied for foreach()
in User.php
foreach ($this->cities as $city)
my table city look (id,name)
Thanks for any help.
EDIT : SOLVED
I have to update my CityBundle\Resources\config\doctrine\City.orm.yml file

Answer 1

In your City class, shouldn't be the relationship something like :
/**
* #ManyToOne(targetEntity="Acme\UserBundle\Entity\User", inversedBy="cities")
* #JoinColumn(name="cityId", referencedColumnName="id")
**/
private $user;
The join column shouldn't be the id of user's table.
And then, of course:
public function getCities()
{
return $this->cities;
}