Add custom block to existing tab in catalog product edit view

Question

I need to add some content to the top of the images tab in the catalog product edit view. I do not want to add a new tab, i want to include some content (custom block) to the existing one.

I have seen a lot of tutorials on how to add a whole new tab, but nothing on how to edit an existing one.

I have managed to create an observer on the event "core_block_abstract_prepare_layout_after":

<core_block_abstract_prepare_layout_after>
      <observers>
          <edit_images_tab>
              <type>singleton</type>
                  <class>custom_module/observer</class>
                  <method>editImagesTab</method>
          </edit_images_tab>
      </observers>
</core_block_abstract_prepare_layout_after>

and remove and recreate the tab in the same position:

public function editImagesTabs(Varien_Event_Observer $observer) {
    $block = $observer->getEvent()->getBlock();

    if ($block instanceof Mage_Adminhtml_Block_Catalog_Product_Edit_Tabs) {
        $block->removeTab('group_10');

        $block->addTabAfter(
            'group_10',
            array(
                'label'     => 'Upload Product Files',
                'content'   => $block->getLayout()->createBlock('adminhtml/catalog_product_helper_form_gallery_content')->toHtml() . 'custom content'
            ),
            'group_9'
        );
    }
}

Anyway, it seems that $block->getLayout()->createBlock('adminhtml/catalog_product_helper_form_gallery_content')->toHtml() is not enough to recreate the images tab.

Not sure if i'm going in the right direction.

Any hint would be greatly appreciated.

Answer 1

I've found another way to achieve my goal, here is what I did.

I have overridden the method toHtml() of the class "Mage_Adminhtml_Block_Catalog_Product_Helper_Form_Gallery" in that way:

class Custom_Module_Block_Adminhtml_Catalog_Product_Helper_Form_Gallery 
    extends Mage_Adminhtml_Block_Catalog_Product_Helper_Form_Gallery {

    public function toHtml() {

        $myBlock = Mage::getSingleton('core/layout')->createBlock('custom_module/custom_block')->toHtml();

        return $myBlock . parent::toHtml();
    }
}

and added this in the config.xml file:

<global>
    <blocks>
        <adminhtml>
            <rewrite>
               <catalog_product_helper_form_gallery>Custom_Module_Block_Adminhtml_Catalog_Product_Helper_Form_Gallery</catalog_product_helper_form_gallery>
            </rewrite>
        </adminhtml>
    </blocks>
</global>

not sure if this is the best approach but it works.