How to load phtml file in magento admin - magento

Question

app\code\local\Stw\Tree\Block\Adminhtml\Adminblock.php
<?php
class Stw_Tree_Block_Adminhtml_Adminblock extends Mage_Adminhtml_Block_Template
{
public function __construct()
{
parent::__construct();
}
protected function _prepareLayout()
{
return parent::_prepareLayout();
}
public function getHandleUpdates()
{
Zend_Debug::dump($this->getLayout()->getUpdate()->getHandles());
}
}
app\code\local\Stw\Tree\controllers\Adminhtml\CustomController.php
class Stw_Tree_Adminhtml_CustomController extends Mage_Adminhtml_Controller_Action
{
public function indexAction()
{
$this->loadLayout();
$this->_setActiveMenu('mycustomtab');
$this->renderLayout();
}
}
app\design\adminhtml\default\default\layout\tree.xml
<?xml version="1.0"?>
<layout>
<default>
<reference name="content">
<block type="tree/adminhtml_adminblock" name="tree" template="tree/myform.phtml" />
</reference>
</default>
</layout>
app\code\local\Stw\Tree\etc\config.xml
<?xml version="1.0"?>
<config>
<modules>
<Stw_Tree>
<version>1.0.0</version>
</Stw_Tree>
</modules>
<global>
<helpers>
<stw_tree>
<!-- Helper definition needed by Magento -->
<class>Mage_Core_Helper</class>
</stw_tree>
</helpers>
<blocks>
<stw_tree>
<class>Stw_Tree_Block</class>
</stw_tree>
</blocks>
</global>
<admin>
<routers>
<adminhtml>
<args>
<modules>
<stw_tree before="Mage_Adminhtml">Stw_Tree_Adminhtml</stw_tree>
</modules>
</args>
<layout>
<updates>
<tree>
<file>tree.xml</file>
</tree>
</updates>
</layout>
</adminhtml>
</routers>
</admin>
</config>
I want load myform.phtml in admin section of magento, but nothing is loading. I am not understanding what is wrong in that. please someone tell me changes. myform.phtml contains pure HTML code

Answer 1

As defined block in config.xml as below :-
<blocks>
<stw_tree>
<class>Stw_Tree_Block</class>
</stw_tree>
</blocks>
You need to use same alias to call this block from Layout as below :-
<layout>
<default>
<reference name="content">
<block type="stw_tree/adminhtml_adminblock" name="tree" template="tree/myform.phtml" />
</reference>
</default>
</layout>

Answer 2

I don't believe the layout node should be inside the router note like that in your config.xml file. You should add a new adminhtml node as a sibling to admin, i.e. a direct child of config.
</admin>
<adminhtml>
<layout>
<updates>
<tree>
<file>tree.xml</file>
</tree>
</updates>
</layout>
</adminhtml>
</config>