Magento custom admin module wysiwyg integration

Question

I've created an admin module based off of the tutorial here. I'm attempting to change two of my form inputs to wysiwyg editors based off of information found here. However, whenever I load the edit page I get an error Call to a member function setCanLoadTinyMce() on a non-object. $this->getLayout()->getBlock('head') var_dumps to false.

Namespace/Slides/Block/Adminhtml/Slide/Edit.php looks as follows

class Namespace_Slides_Block_Adminhtml_Slide_Edit
    extends Mage_Adminhtml_Block_Widget_Form_Container
{
    protected function _prepareLayout() 
    {
        parent::_prepareLayout();
        if (Mage::getSingleton('cms/wysiwyg_config')->isEnabled()) {
            $this->getLayout()->getBlock('head')->setCanLoadTinyMce(true);
        }
    }

    protected function _construct() 
    {
        //... Construction stuff
    }
}

Namespace/Slides/Block/Adminhtml/Slide/Edit/Form.php

class Cfw_Slides_Block_Adminhtml_Slide_Edit_Form
    extends Mage_Adminhtml_Block_Widget_Form
{

    protected function _prepareForm() 
    {
       //...Do some things first, like create the fieldset..


        //Add the editable fields
        $this->_addFieldsToFieldset($fieldset, array(
            'foreground_image' => array(
                'label' => $this->__('Foreground Image'),
                'input' => 'image',
                'required' => false,
            ),
            'background_image' => array(
                'label' => $this->__('Background Image'),
                'input' => 'editor',
                'required' => true,
                'config' => Mage::getSingleton('cms/wysiwyg_config')->getConfig(),
                'wysiwyg' => true,
            ),
            'description' => array(
                'label' => $this->__('Text Overlay'),
                'input' => 'editor',
                'required' => false,
                'config' => Mage::getSingleton('cms/wysiwyg_config')->getConfig(),
                'wysiwyg' => true,
            )
        )); 
        return $this;
    }


    protected function _addFieldsToFieldset(
        Varien_Data_Form_ElementFieldset $fieldset, $fields)
    {
        $requestData = new Varien_Object($this->getRequest()->getPost('slideData'));
        foreach ($fields as $name => $_data) {
            if ($requestValue = $requestData->getData($name)) {
                $_data['value'] = $requestValue;
            }

            //Wrap all fields with slideData group
            $_data['name'] = "slideData[$name]";

            //Generally, label and title are always the same
            $_data['title'] = $_data['label'];

            //If no new value exists, use the existing slide data.
            if (!array_key_exists('value', $_data)) {
                $_data['value'] = $this->_getSlide()->getData($name);
            }

            //Finally, call vanilla funcctionality to add field.
            $fieldset->addField($name, $_data['input'], $_data);
        }
        return $this;
    }


}

I'm not sure if you need it, but here's my file structure as well

Namespace
-Slides
--Block
---Adminhtml
----Slide
-----Edit
------Form.php
-----Edit.php
-----Grid.php
----Slide.php
--controllers
---Adminhtml
----SlideConroller.php
--etc
---config.xml
--Helper
---Data.php
--Model
---Resource
----Slide
-----Collection.php
----Slide.php
---Slide.php
--sql
---namespace_slides_setup
----install-0.0.1.php

Answer 1

I imagine you no longer need a solution for this, but I ran into the same issue using the same tutorial that you did.

The 'head' block (and thus setCanLoadTinyMce()) was unavailable in the Edit.php and the Form.php via the _prepareLayout() function.

The 'head' block was available in the controller(SlideController.php in your case) between $this->loadLayout() and $this->renderLayout within the editAction() function.

In SlideController.php change

$this->loadLayout()
        ->_addContent($brandBlock)
        ->renderLayout();

to

$this->loadLayout() ;               
$this->_addContent($brandBlock);                                        
$this->getLayout()->getBlock('head')->setCanLoadTinyMce(true);
$this->renderLayout();

Answer 2

The issue is that Magento cannot find your head block.

Instead of using:

$this->getLayout()->getBlock('head')->setCanLoadTinyMce(true);

Try calling it like this:

Mage::app()->getLayout()->getBlock('head')->setCanLoadTinyMce(true);

If that doesn't work, it's a different issue but the problem is still that Magento can't find the head block.