Why changing the root template doesn't work
Both
Mage_Cms_IndexController::indexAction()
and
Mage_Cms_IndexController::viewAction()
which are responsible for displaying the default homepage and a CMS page respectively call a helper:
Mage::helper('cms/page')->renderPage($this, $pageId)
If you jump into the helper (located at app/code/core/Mage/Cms/Helper/Page.php) and follow renderPage() to the protected method _renderPage() you'll see that Magento is checking two times for a root template (Magento CE 1.7.0.2):
if ($page->getRootTemplate()) {
$handle = ($page->getCustomRootTemplate()
&& $page->getCustomRootTemplate() != 'empty'
&& $inRange) ? $page->getCustomRootTemplate() : $page->getRootTemplate();
$action->getLayout()->helper('page/layout')->applyHandle($handle);
}
and
if ($page->getRootTemplate()) {
$action->getLayout()->helper('page/layout')
->applyTemplate($page->getRootTemplate());
}
Both calls happen after layout handles like "cms_page" and the like are processed, so you are out of luck here.
What you can do to change the root template
There is an event cms_page_render which you can use for adding your own XML layout handle on CMS pages. Create your own extension (I'll spare some details here) and configure the event observer in your config.xml:
<?xml version="1.0"?>
<config>
<modules>
<Emzee_Cms>
<version>0.0.1</version>
</Emzee_Cms>
</modules>
<global>
<events>
<cms_page_render>
<observers>
<emzee_cms_page_render>
<class>emzee_cms/observer</class>
<method>cms_page_render</method>
</emzee_cms_page_render>
</observers>
</cms_page_render>
</events>
<models>
<emzee_cms>
<class>Emzee_Cms_Model</class>
</emzee_cms>
</models>
</global>
</config>
Add your event observer:
<?php
class Emzee_Cms_Model_Observer
{
public function cms_page_render(Varien_Event_Observer $observer)
{
$action = $observer->getEvent()->getControllerAction();
$actionName = strtolower($action->getFullActionName());
$action->getLayout()->getUpdate()
->addHandle($actionName . '_after');
return $this;
}
}
Finally, add your new layout XML handle (e.g. in your local.xml):
<?xml version="1.0"?>
<layout version="0.1.0">
<cms_index_index_after>
<reference name="root">
<action method="setTemplate"><template>page/1column.phtml</template></action>
</reference>
</cms_index_index_after>
</layout>
You can use this method as well to add a cms_page_view_after handle or create page specific handles as cms_page_render passes the $page object to your observer.
Why you can't add a block to the 'reference left'
Are you sure that the template you're using has a left column? This question may sound silly but the default "2 columns with right bar" layout for example only offers a 'content' and a 'right' area. I can add blocks to the right column using cms_page without problems so this could be the problem.
In general, you can only easily add blocks to references and echo them if
- the chosen root template uses the block you're referencing (see
app/design/frontend/base/default/template/page/*.phtml) and
- the block you're referencing either is of type
core/text_list, calls $this->getChildhtml() without arguments or does something else to echo all child blocks.
Without further details, I can't tell you why your blocks are not echo'd in the left or right column.
Best Answer
Not in the way you want it. The problem is that at the time the header is rendered, you can't know if another block will be rendered at a later point. As you already noticed, there are other factors besides the block being part of the layout hierarchy, for example:
getChildHtml()of the parent block be called?So you will need some trickery. A possible workaround is to make the check in another block that is rendered after your block, for example as child of
before_body_endand then move your alternative content to the header with JavaScript.For this to work you must also make a change in your banner block because by default there is no flag that says "the block was rendered".
In Magento 1, you can use the
_afterToHtml()method for that:Then later you can check it like this: