Not working- Passing data from Controller to View in a PHP MVC -

i'm watching tutorial on php, , have problems. everytime call variable in view throws error

notice: trying property of non-object in /opt/lampp/htdocs/talkingspace/topics.php on line 18 

and

notice: undefined variable: totaltopics in /opt/lampp/htdocs/talkingspace/templates/topics.php on line 36 

earlier instead of ,for example, $topic->userid, put $topic['userid'], not working anymore.

here template/topics.php:

<?php include('includes/header.php'); ?>    <ul id="topics">                              <?php  if($topics) :  ?> <?php  foreach ($topics $topic) :  ?>                                 <li class="topic">                                       <div class="row">                                         <div class="col-md-2">                                           <img class="avatar pull-left" src="images/avatars/<?php echo $topic['avatar']; ?> " alt="img">                                         </div>                                        <div class="col-md-10">                                                 <div class="topic-content pull-right">                                                       <h3><a href="topic.php"><?php echo $topic['title']; ?></a></h3>                                                      <div class="topic-info">                                                                     <a href="topics.php?category=<?php echo urlformat($topic['category_id']); ?>"><?php echo $topic['name']; ?></a> >>                                                                      <a href="profile.php?user=<?php echo urlformat($topic['user_id']);?>"><?php echo $topic['username']; ?></a>                                                                   <?php echo formatdate($topic['create_date']);?>                                                                     <span class="badge pull-right"><?php echo replycount($topic['id']); ?></span>                                                     </div>                                                                                          </div>                                           </div>                                     </div>                                  </li>  <?php endforeach; ?>                             </ul> <?php else : ?>   <p>no topics display</p> <?php endif; ?>                                  <h3>forum statistics</h3>                             <ul>                                 <li>total number of users: <strong>4</strong></li>                                 <li>total number of topics: <strong><?php echo $totaltopics; ?></strong></li>                                 <li>total number of categories: <strong><?php echo $totalcategories; ?></strong></li>                             </ul>  <?php include('includes/footer.php'); ?> 

here template class:

<?php   /** * template class * creates template/view object */  class template  {     //path template     protected $template;      //variables passed in     protected $vars = array();      /*     * class constructor     */      public function __construct($template){         $this->template = $template;     }       /*     * template variables     */      public function __get($key) {         return $this->vars[$key];     }      public function __set($key, $value) {         $this->vars[$key] = $value;     }      public function __tostring() {         extract($this->vars);         chdir(dirname($this->template));         ob_start();          include basename($this->template);          return ob_get_clean();     } }  ?> 

here topics.php:

<?php require('core/init.php'); ?>  <?php  $topic = new topic;   //get category url $category = isset($_get['category']) ? $_get['category'] : null;  //get template & assign url $template = new template('templates/topics.php');  //assign template variables  if(isset($category)){      $template->topics = $topic->getbycategory($category);     $template->title = 'posts in "'.$topic->getcategory($category)->name.'"'; }  if(!isset($category)){  $template->topics = $topic->getalltopics(); } //assign variables  $template->totaltopics = $topic->gettotaltopics(); $template->totalcategories = $topic->gettotalcategories();  //display template echo $template;  ?> 

and topic class here

<?php   class topic{     //init db variable     private $db;   //constructor      public function __construct()     {         $this->db = new database;     }  //get topics      public function getalltopics() { $this->db->query("select topics.*, users.username, users.avatar, categories.name topics  inner join users  on topics.user_id = users.id inner join categories on topics.category_id = categories.id order create_date desc  ");  $results = $this->db->resultset();  return $results;     }   public function getbycategory($category_id){ $this->db->query("select topics.*, categories.*, users.username, users.avatar,  categories.name  topics     inner join categories     on topics.category_id = categories.id     inner join users     on topics.user_id = users.id      topics.category_id = :category_id     "); $this->db->bind(':category_id', $category_id);  //assign result set $results = $this->db->resultset();  return $results; }   public function getcategory($category_id){ $this->db->query("select * categories id = :category_id"); $this->db->bind(':category_id', $category_id);  //assign row $row = $this->db->single();  return $row; }  public function gettotaltopics(){      $this->db->query("select * topics");     $rows = $this->db->resultset();      return $this->db->rowcount();  }  public function gettotalcategories(){ $this->db->query('select * categories'); $rows = $this->db->resultset();  return $this->db->rowcount();  }  public function gettotalreplies($topic_id){ $this->db->query('select * replies topic_id = '.$topic_id); $rows = $this->db->resultset();  return $this->db->rowcount(); }  } ?> 

what i'm doing wrong?