Question

I’ve been working on getting a new form in the adminhtml for my Magento module. I’m running into a serious issue with actually loading blocks, however. I can load a test block (using a phtml layout) using this code I found in a different stack overflow question (I implement this in the adminhtml controller):

    $block = $this->getLayout()->createBlock('coupsmart_coupon/adminhtml_forms');
    error_log('The block:' . var_export($block, true));
    if($block)
    {
        $block->setTemplate('test/test.phtml');
        error_log(var_export($block->getTemplate(), true));
        error_log('The HTML:');
        error_log(var_export($block->toHtml(),true));   
    }

Using a test block, I get back the correct html (found in my adminhtml/default/default/template folder).

However, when I instantiate a grid_container block, it it doesn’t run the if($block){} portion, because the block is false. But in my block class for the grid_container, I have a __constructor() method where I log an output, so it is running the constructor, which means my class instantiation (and naming) is correct.

What can cause a constructor to run on a block but have it still return false, for an Mage_Adminhtml_Block_Widget_Grid_Container class?

If any more code is needed (controller, grid_container block, grid block, config, etc.) is needed, let me know, and I’ll post it up. I just didn’t want to overwhelm with a code overflow that may dilute the question.

EDIT: Grid Container

class Coupsmart_Coupon_Block_Adminhtml_Forms extends
Mage_Adminhtml_Block_Widget_Grid_Container
{       
    public function __construct()
    {
        error_log('adminhtml forms (parent) construct');
        $this->_controller = 'adminhtml_forms';
        $this->_blockGroup = 'coupsmart_coupon';
        $this->_headerText = Mage::helper('forms')->__('Coupon Manager');
        $this->_addButtonLabel = Mage::helper('forms')->__('Edit Coupon');
        parent::__construct();
    }
}

The error log in the container above shows up when I instantiate the block.

Answer 1

The returned block can be false if an exception is thrown while it’s instantiated. In your code, this may certainly come from this part : Mage::helper('forms').
In the config.xml file of your module, have you defined the helpers like this ? :

<global>
    <helpers>
        <forms><class>Coupsmart_Coupon_Helper</class></forms>
    </helpers>
</global>

Else, replace forms by the other code you used in the calls to Mage::helper('forms') (from what it seems, this should probably rather looks like this : Mage::helper('coupsmart_coupon'))