Magento2 error on injecting customer session in block

Question

I'm trying to inject customer session in my block:

use Magento\Framework\View\Element\Template;
use Magento\Customer\Model\Session;

class Header
extends Template
{
protected $session;

public function __construct(
    Template\Context $context,
    Session $customerSession
)
{
    $this->session = $customerSession;
    parent::__construct($context);
}

public function getBaseUrl(){
    return $this->_storeManager->getStore()->getBaseUrl();
}

public function isCustomerLogged()
{
    if($this->session->isLoggedIn())
        return "yes";
    else
        return "no";
}

public function getLoggedCustomerName(){
    return $this->session->getCustomer()->getFirstName();
}
}

Updated question

$this->session->isLoggedIn() always returns false whereas in controller, it returns true. The Context namespaces are different for both:

use Magento\Framework\App\Action\Context;
use Magento\Framework\View\Element\Template\Context;

Please help

Answer 1

Your constructor is missing the parent call that does a lot more initialisation work. It needs to look like the following;

public function __construct(
    Template\Context $context,
    \Magento\Customer\Model\Session $customerSession,
    array $data = []
) {
    $this->customerSession = $customerSession;
    parent::__construct($context, $data);
}