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.