Check if customer logged in not working

Question

I have a block to add link at top based on if customer login like this, when i'm at myaccount page the header link show the right one, but when i go to other page it shows the wrong one, here's my code:

<?php

namespace Namespace\Module\Block;

class Link extends \Magento\Framework\View\Element\Html\Link
{

protected function _toHtml()
    {
     if (false != $this->getTemplate()) {
     return parent::_toHtml();
     }
     $objectManager = \Magento\Framework\App\ObjectManager::getInstance();
     $customerSession = $objectManager->get('Magento\Customer\Model\Session');
     if($customerSession->isLoggedIn()) {
       return '<li><a href="/test/loggedin" > Logged In </a></li>' ;
     } else {
       return '<li><a href="/test/notloggedin" > Not Logged In </a></li>';
     }
    }
}

Answer 1

You have to set cacheable="false" your module with xml file like this,

<block class="Namespace\Module\Block\Link" name="customname" cacheable="false">

Remove var/generation and clear cache.

Answer 2

Simple add this block code in cms or block content

{{block class="Magento\Customer\Block\Account\AuthorizationLink" name="authorization-link" template="account/link/authorization.phtml"/}}

it will show you signin or signout