title: addToolbar in joomla 3.0
body: <p>Added toolbar in joomla 3.0 html.php file. When the addNew button is clicked it displays </p>
  
  <blockquote>
    <p>An error has occurred.  0 Invalid controller:
    name='Comboscategories', format=''</p>
  </blockquote>
  
  <p>html.php file as follows.</p>
  
  <pre><code>&lt;?php    
  defined( '_JEXEC' ) or die( 'Restricted access' ); 
  
  class ComboscategoriesViewsStatisticsHtml extends JViewHtml
  {
    function render()
    {
      $app = JFactory::getApplication();
  
      //retrieve task list from model
      $model = new ComboscategoriesModelsStatistics();
      $this-&gt;stats = $model-&gt;getStats();
  
      $this-&gt;addToolbar();
      /*$this-&gt;displayComboslist();*/
      //display
      return parent::render();
    } 
  
  
      protected function addToolbar()
      {
          $canDo  = ComboscategoriesHelpersLendr::getActions();
  
          // Get the toolbar object instance
          $bar = JToolBar::getInstance('toolbar');
  
          JToolbarHelper::title(JText::_('Combos Category'));
  
  
               JToolBarHelper::addNew('Comboscategories.add');
             /* JToolbarHelper::preferences('com_comboscategories');*/
              JToolBarHelper::save();
              JToolBarHelper::cancel();
              JToolBarHelper::deleteList();
              JToolBarHelper::publishList();
              JToolBarHelper::unpublishList();
  
      }
  }
  </code></pre>
  
  <p>controller.php(display.php)</p>
  
  <pre><code>&lt;?php 
  
  defined( '_JEXEC' ) or die( 'Restricted access' ); 
  
  class ComboscategoriesControllersDisplay extends JControllerBase
  {
  
    public function execute()
    {
  
      // Get the application
      $app = $this-&gt;getApplication();
  
      // Get the document object.
      $document     = JFactory::getDocument();
  
      $viewName     = $app-&gt;input-&gt;getWord('view', 'statistics');
      $viewFormat   = $document-&gt;getType();
      $layoutName   = $app-&gt;input-&gt;getWord('layout', 'default');
  
      $app-&gt;input-&gt;set('view', $viewName);
  
      // Register the layout paths for the view
      $paths = new SplPriorityQueue;
  
      $paths-&gt;insert(JPATH_COMPONENT . '/views/' . $viewName . '/tmpl', 'normal');
  
      $viewClass  = 'ComboscategoriesViews' . ucfirst($viewName) . ucfirst($viewFormat);
      $modelClass = 'ComboscategoriesModels' . ucfirst($viewName);
  
      $view = new $viewClass(new $modelClass, $paths);
  
      $view-&gt;setLayout($layoutName);
  
      // Render our view.
      echo $view-&gt;render();
  
      return true;
    }
  
  }
  </code></pre>
  
  <p>I searched related to this but i dont find the solution. kindly help me to sort this</p>