Set locale in Symfony 2.1 - php

Question

I am trying to have a language switcher on my symfony 2.1 website.
I followed the official documentation, set the translation files but setting the locale with $request->setLocale('en_US'); doesn't seem to work. After some research, I found this question which provides a beginning of an answer with this listener technique.
However, I still don't manage to have it working, I'm not so sure about my listener declaration, is something wrong with it?
My controller:
public function englishAction(Request $request)
{
$this->get('session')->set('_locale', 'en_US');
return $this->redirect($request->headers->get('referer'));
}
Service declaration in config.yml:
services:
my_listener:
class: "FK\MyWebsiteBundle\Listener\LocaleListener"
My routing:
homepage:
pattern: /{_locale}
defaults: { _controller: FKMyWebsiteBundle:Default:index, _locale: en }
requirements:
_locale: en|fr|cn
about:
pattern: /{_locale}/about
defaults: { _controller: FKMyWebsiteBundle:Default:about, _locale: en }
requirements:
_locale: en|fr|cn

Answer 1

The declaration of the LocaleListener in yml (inspired by the current declaration of the new LocaleListener: \vendor\symfony\symfony\src\Symfony\Bundle\FrameworkBundle\Resources\config\web.xml)
services:
my_listener:
class: "FK\MyWebsiteBundle\Listener\LocaleListener"
arguments: [%locale%]
tags:
- { name: kernel.event_subscriber }
Some snippets:
A language switcher in your template:
{% for locale in ['en', 'fr', 'cn'] %}
<li {% if locale == app.request.locale %}class="active"{% endif %}>
{{ locale }}
</li>
{% endfor %}
A redirection with locale change from a controller:
$LocalizedUrl = $this->get('router')->generate(
$request->attributes->get('_route'),
['_locale' => $locale] + $request->attributes->get('_route_params')
);
return new \Symfony\Component\HttpFoundation\RedirectResponse($LocalizedUrl);

Answer 2

You should get the translator instance linked to your symfony kernel container:
$this->container->get('translator')->setLocale('fr');