Question

I have 3d-party extention that add new tabs while product edit at the backend. Now I want to add one more tab there.

New tab should have “add” button and let user to add new item, In addition It should have the list with added items. First of all, I have looked at extention code. They have added similar tab using

extends Mage_Adminhtml_Block_Widget
implements Varien_Data_Form_Element_Renderer_Interface 

So I try to folow their way and add my one. Code below.

    $this->addTab('cancellpolicy', array(
            'label'     => Mage::helper('catalog')->__('Cancellation Policies'),
            'content'   => $this->_translateHtml($this->getLayout()->createBlock('Apptha_Reservation_Block_Adminhtml_Catalog_Product_Edit_Tab_Cancellationpolicy')->toHtml()),
        )); 

Above I add new tab and then I create new block class below

class Apptha_Reservation_Block_Adminhtml_Catalog_Product_Edit_Tab_Cancellationpolicy 

extends Mage_Adminhtml_Block_Widget
implements Varien_Data_Form_Element_Renderer_Interface 
{

   /**
 * Form element instance
 *
 * @var Varien_Data_Form_Element
 */
protected $_element;

/**
 * Customer Groups cache
 *
 * @var array
 */
protected $_customerGroups;

/**
 * Websites cache
 *
 * @var array
 */
protected $_websites;



public function __construct(){
    $this->setTemplate('reservation/product/edit/tab/cancellationpolicy.phtml');
}

 public function getProduct(){
    return Mage::registry('product');
}
public function render(Varien_Data_Form_Element_Abstract $element){
    $this->setElement($element);
    return $this->toHtml();
}


protected function _prepareLayout()
{
    $this->setChild('add_button',
        $this->getLayout()->createBlock('adminhtml/widget_button')
            ->setData(array(
                'label'     => Mage::helper('catalog')->__('Add Room Type(s)'),
                'onclick'   => 'roomtypesControl.addItem()',
                'class' => 'add'
            )));   

    return parent::_prepareLayout();
}


 /**
 * Set form element instance
 *
 * @param Varien_Data_Form_Element_Abstract $element
 * @return Apptha_Reservation_Block_Adminhtml_Catalog_Product_Edit_Tab_Cancellationpolicy
 */   
public function setElement(Varien_Data_Form_Element_Abstract $element){
    $this->_element = $element;
    return $this;
}



/**
 * Retrieve form element instance
 *
 * @return Apptha_Reservation_Block_Adminhtml_Catalog_Product_Edit_Tab_Cancellationpolicy
 */
public function getElement(){
    return $this->_element;
}    


public function getWebsites()
{

    if (!is_null($this->_websites)) {
        return $this->_websites;
    }
    $websites = array();
    $websites[0] = array(
        'name'      => $this->__('All Websites'),
        'currency'  => Mage::app()->getBaseCurrencyCode()
    );
    if (Mage::app()->isSingleStoreMode() || $this->getElement()->getEntityAttribute()->isScopeGlobal()) {
        return $websites;
    }
    elseif ($storeId = $this->getProduct()->getStoreId()) {
        $website = Mage::app()->getStore($storeId)->getWebsite();
        $websites[$website->getId()] = array(
            'name'      => $website->getName(),
            'currency'  => $website->getConfig(Mage_Directory_Model_Currency::XML_PATH_CURRENCY_BASE),
        );
    }
    else {
        $websites[0] = array(
            'name'      => $this->__('All Websites'),
            'currency'  => Mage::app()->getBaseCurrencyCode()
        );
        foreach (Mage::app()->getWebsites() as $website) {
            if (!in_array($website->getId(), $this->getProduct()->getWebsiteIds())) {
                continue;
            }
            $websites[$website->getId()] = array(
                'name'      => $website->getName(),
                'currency'  => $website->getConfig(Mage_Directory_Model_Currency::XML_PATH_CURRENCY_BASE),
            );
        }
    }
    $this->_websites = $websites;
    return $this->_websites;
}

public function getValues(){
    return Mage::getModel('reservation/roomtypes')->getCollection()
                ->addEntityIdFilter($this->getProduct()->getId())
                ->addStoreIdFilter($this->getProduct()->getStoreId())
                ->getItems();
}

}

And then add reservation/product/edit/tab/cancellationpolicy.phtml template file. A the beginig of template I get

<?php   Mage::log(get_class($this->getElement())); ?>
<?php $_htmlId      = $this->getElement()->getHtmlId() ?>
<?php $_htmlClass   = $this->getElement()->getClass() ?>
<?php $_storeId     = $this->getProduct()->getStoreId() ?>
<?php $_htmlName    = $this->getElement()->getName() ?>
<?php $_readonly    = $this->getElement()->getReadonly() ?>
<?php $_multiWebsite= 0 && !Mage::app()->isSingleStoreMode() ?>

And here I get error:

Fatal error: Call to a member function getHtmlId() on a non-object in /var/www/vhosts/bluning.com/httpdocs/app/design/adminhtml/default/default/template/reservation/product/edit/tab/cancellationpolicy.phtml on line 10

Mage::log(get_class($this->getElement()));

give me “Mage_Core_Block_Template” but why? As per my code getElement() should return “Apptha_Reservation_Block_Adminhtml_Catalog_Product_Edit_Tab_Cancellationpolicy”

So why Magento return wrong class in the .phtml file?

UPDATE
config.xml has section

      <blocks>
        <reservation>
            <class>Apptha_Reservation_Block</class>
        </reservation>

    </blocks>

UPDATE2
I have placed Mage::log inside getElement function and after calling. It returns different values:

inside: Apptha_Reservation_Block_Adminhtml_Catalog_Product_Edit_Tab_Cancellationpolicy
outside: Mage_Core_Block_Template

Crazy

Answer 1

Using debugger I have found issue.

$this->getElement()

It return NULL because It hasnt been set properly. It should be set in the observer. Code is below:

  public function attachPolicyEditor($observer) {
    $form = $observer->getForm();
    if ($policies = $form->getElement('apptha_hotel_cancellationpolicy')) {
        $policies->setRenderer(
            Mage::getSingleton('core/layout')->createBlock('reservation/adminhtml_catalog_product_edit_tab_cancellationpolicy')
        );
    }
}

attachPolicyEditor is called by adminhtml_catalog_product_edit_prepare_form observer.