This topics show you, how you can disable layout

to disable layout use this line:

$this->_helper->layout->disableLayout();

php zend layout helper

This topics show you, how you can change a default layout

to change layout use this line:

 $this->_helper->layout->setLayout('admin');

php zend layout helper

This example show you how we can check if a use logged in

 $auth = Zend_Auth::getInstance();
 if (!$auth->hasIdentity()) {
     if ('login' != $this->getRequest()->getActionName()) {
         $this->_helper->getHelper('Redirector')->setGotoRoute(array(), 'MYROUTE');
     }
 }

php zend_auth zend