Why does my view page not load in Admin Panel?

Question

I need your help to figure out why my form isn't loading in the Admin Panel.

I currently just get the error:

Fatal error: Call to a member function setData() on a non-object in /home/makeyou/public_html/app/code/core/Mage/Adminhtml/Block/Widget/Form/Container.php on line 129.

Here is my current code: in app/code/local/Sean/MasterCreate/etc/adminhtml.xml

<?xml version="1.0"?>
<!DOCTYPE config>

<config>
    <menu>
        <example translate="title" module="mastercreate">
            <title>MasterCreate</title>
            <sort_order>89</sort_order>
            <action>adminhtml/Creation</action>
        </example>
    </menu>
</config>

For those of you unfamiliar with this code, it creates a new navigation panel in the admin panel that looks for the controller I named Create and runs the index function inside. Here is an image:

app/code/local/Sean/MasterCreate/etc/config.xml

<?xml version="1.0"?>
<!DOCTYPE config>

<config>
    <modules>
        <Sean_MasterCreate>
            <version>0.0.0</version>
        </Sean_MasterCreate>
    </modules>
    <global>
        <models>
            <mastercreate>
                <class>Sean_MasterCreate_Model</class>
            </mastercreate>
        </models>
        <blocks>
            <mastercreate>
                <class>Sean_MasterCreate_Block</class>
            </mastercreate>
        </blocks>
        <helpers>
            <mastercreate>
                <class>Sean_MasterCreate_Helper</class>
            </mastercreate>
        </helpers>
    </global>
    <admin>
        <routers>
            <adminhtml>
                <args>
                    <modules>
                        <mastercreate before="Mage_Adminhtml">Sean_MasterCreate_Adminhtml</mastercreate>
                    </modules>
                </args>
            </adminhtml>
        </routers>
    </admin>
    <frontend>
        <routers>
            <mastercreate>
                <use>standard</use>
                <args>
                    <frontName>mastercreate</frontName>
                    <module>Sean_MasterCreate</module>
                </args>
            </mastercreate>
        </routers>
        <layout>
            <updates>
                <mastercreate>
                    <file>mastercreate.xml</file>
                </mastercreate>
            </updates>
        </layout>
    </frontend>
</config>

app/code/local/Sean/MasterCreate/controllers/Adminhtml/CreationController.php

<?php

class Sean_MasterCreate_Adminhtml_CreationController extends Mage_Adminhtml_Controller_Action {
    public function indexAction(){
        $this->loadLayout();

        $this->_addContent(
            $this->getLayout()->createBlock('mastercreate/adminhtml_event_edit')
        );

        $this->renderLayout();
    }
}

app/code/local/Sean/MasterCreate/Block/Adminhtml/Event/Edit.php

<?php

class Sean_MasterCreate_Block_Adminhtml_Event_Edit extends Mage_Adminhtml_Block_Widget_form_Container {

    public function __construct(){

        $this->_objectId = 'event_id';
        $this->_blockGroup = 'mastercreate';
        $this->_controller = 'adminhtml_creation';

        parent::__construct();

    }

    public function getHeaderText(){
        return Mage::helper('mastercreate')->__('New Event');
    }

}

app/code/local/Sean/MasterCreate/Block/Adminhtml/Event/Edit/Form.php

<?php

class Sean_MasterCreate_Block_Adminhtml_Event_Edit_Form extends Mage_Adminhtml_Block_Widget_Form {

    protected function _prepareForm(){
        $form = new Varien_Data_Form(
            array('id' => 'edit_form', 'action' => $this->getUrl('*/*/save'), 'method' => 'post'
            )
        );

        $fieldset = $form->addFieldset('base_fieldset', array('legend' => Mage::helper('mastercreate')->__('General Information'), 'class' => 'fieldset-wide'));

        $fieldset->addField('name', 'text', array(
            'name' => 'name',
            'label' => Mage::helper('mastercreate')->__('Event Name'),
            'title' => Mage::helper('mastercreate')->__('Event Name'),
            'required' => true
        ));

        $form->setUseContainer(true);
        $this->setForm($form);

        return parent::_prepareForm();

    }

}

Answer 1

I found that in my app/code/local/Sean/MasterCreate/Block/Adminhtml/Event/Edit.php

I had to change

public function __construct(){

        $this->_objectId = 'event_id';
        $this->_blockGroup = 'mastercreate';
        $this->_controller = 'adminhtml_creation';

        parent::__construct();

    }

To this:

public function __construct(){

        $this->_objectId = 'event_id';
        $this->_blockGroup = 'mastercreate';
        $this->_controller = 'adminhtml_event';
        $this->_mode = 'edit';

        parent::__construct();

    }

After taking a closer look at how Magento's __construct works it concats blockGroup then controller so in this case the path had to be /mastercreate/adminhtml/event.

Hopefully this helps anyone else with this issue.