Magento calling a block with getChildHtml

blocklayoutmagento

Please follow the code bellow, which is taken from my Magento Commerce theme:

extract from layout/page.xml

<block type="page/html_header" name="header" as="header">
    <block type="page/template_links" name="top.links" as="topLinks"/>
    <block type="page/switch" name="store_language" as="store_language" template="page/switch/languages.phtml"/>
    <block type="page/switch" name="store_switcher" as="store_switcher" template="page/switch/stores.phtml"/>
    <block type="directory/currency" name="store_currency_selector" as="store_currency_selector" template="directory/currency_top.phtml"/>
    <block type="core/text_list" name="top.menu" as="topMenu" translate="label">
        <label>Navigation Bar</label>
        <block type="page/template_links" name="top.links.mobile" as="topLinksMobile"/>
        <block type="checkout/cart_sidebar" name="cart_sidebar_mobile" as="cartSidebarMobile" template="checkout/cart/topbar.phtml"/>
    </block>
    <block type="page/html_wrapper" name="top.container" as="topContainer" translate="label">
        <label>Page Header</label>
        <action method="setElementClass"><value>top-container</value></action>
    </block>
    <block type="checkout/cart_sidebar" name="cart_sidebar" as="topcart" template="checkout/cart/topbar.phtml"/>
</block>

extract from template/catalog/navigation/top.phtml

<li class="level0 nav-2 active level-top first parent">
    <a href="javascript:;">ACCOUNT</a>
    <?php echo $this->getParentBlock()->getChildHtml('topLinksMobile'); ?>
</li>
<li class="level0 nav-3 active level-top first parent">
    <a href="javascript:;">CART</a>
    <?php echo $this->getChildHtml('cartSidebarMobile'); ?>
</li>

Basically, what I'm trying to do, is create two sub-blocs inside the "topMenu" block, and than print them into the template by using "getChildHtml" function.

Unfortunately, my function call fails, while the two blocks are loaded before my top.phtml generated content.

Please give me some advice about what am I doing wrong.

Many thanks in advance.

Best Answer

I've advanced a bit.

By reading: Magento - display block but only show when I call it with getChildHtml

and: Understanding Magento Block and Block Type

I understood that core/text_list automatically prints the content, so I've changed the type to "page/html_wrapper".

Problem is that now the content of those two elements are duplicated. Once before the content of top.phtml, and the second when getChildHtml is called.

Any ideas would be much appreciated.

Related Solutions

Magento – Understanding Magento Block and Block Type

For understanding more about magento block types following are some built-in block types which are widely used in layout.

core/template: This block renders a template defined by its template attribute. The majority of blocks defined in the layout are of type or subtype of core/template.
page/html: This is a subtype of core/template and defines the root block. All other blocks are child blocks of this block.
page/html_head: Defines the HTML head section of the page which contains elements for including JavaScript, CSS etc.
page/html_header: Defines the header part of the page which contains the site logo, top links, etc.
page/template_links: This block is used to create a list of links. Links visible in the footer and header area use this block type.
core/text_list: Some blocks like content, left, right etc. are of type core/text_list. When these blocks are rendered, all their child blocks are rendered automatically without the need to call thegetChildHtml() method.
page/html_wrapper: This block is used to create a wrapper block which renders its child blocks inside an HTML tag set by the action setHtmlTagName. The default tag is <div> if no element is set.
page/html_breadcrumbs: This block defines breadcrumbs on the page.
page/html_footer: Defines footer area of page which contains footer links, copyright message etc.
core/messages: This block renders error/success/notice messages.
page/switch: This block can be used for the language or store switcher.

This is a list of only commonly used block types. There are many other block types which are used in advanced theme implementations.

Php – Understanding getChildHtml in Magento

If we're discussing the frontend of the website, the particular line you've asked about....

<?php echo $this->getChildHtml('content') ?>

is added to the Magento layout XML in app/design/frontend/base/default/layout/page.xml. In Magento version 1.8, you'll find it defined in lines 92-94.

<block type="core/text_list" name="content" as="content" translate="label">
    <label>Main Content Area</label>
</block>

By looking at the "type" attribute of this block tag, we can know what object class this section of the layout is. It comes from the "Core" module, and is of the block type Text List. The class name for this Mage_Core_Block_Text_List. (app/code/core/Mage/Core/Block/Text/List.php). Text Lists are simply block containers which purpose is to store additional child blocks inside them. You can add any number of child blocks to the text list and they will be rendered out either in the order they were added or the order they've been assigned.

So, to answer your question, there is no view script (.phtml file) that renders the contents of $this->getChildHtml('content'). The blocks which have been added to this block, may themselves have view scripts associated with them. To find out what view scripts those are, you'd have to find the layout XML which has added the block.

For example, if I had the following layout file added to the frontend of my website's theme:

<?xml version="1.0"?>
<layout>
    <default>
        <reference name="content">
            <block type="core/template" name="my_view_script" template="hello/world.phtml" />
        </reference>
    </default>
</layout>

The code above, would add the block with an object class of Mage_Core_Block_Template to the block with the name 'content' (which happens to be the one you asked about). Magento will then look for the view script in the following locations, in this order:

app/design/frontend/PACKAGE_NAME/THEME_NAME/template/hello/world.phtml
app/design/frontend/PACKAGE_NAME/default/template/hello/world.phtml
app/design/frontend/base/default/template/hello/world.phtml

First one that is found, is the one it will use. If no view script is found Magento will log an error in var/logs/system.log (default log file setting) stating that the view script was not found. No output from the block will occur.

Note that depending on your settings in System -> Configuration -> (General) Design, there may be additional package/theme locations Magento will look in. There are also other scenarios such as if the "Custom Theme" is field is changed for individual CMS Pages, Catalog Categories, or Catalog Products, these individual model's view page may have an additional view script location (that will match the selected theme) that takes precedence over your site's default settings.

Magento will follow this same fallback logic when looking for translation files as well as layout XML files.

Please note, that it is perfectly acceptable to copy individual view scripts (avoid copying entire directories, copy over only view scripts you actually intend to modify) from app/design/frontend/base/default/template/ to your local theme, and customize them for the purposes of your website's theme. However, in order to have an upgrade compatible site, layout files should not be copied from base to your local theme. Doing so, does not follow upgrade compatible practices. Instead, XML Layout updates for your theme should be contained in app/design/frontend/PACKAGE_NAME/THEME_NAME/layout/local.xml. There is no layout instructions from app/design/frontend/base/default/layout/*, that cannot be removed/added-to/changed, what-have-you, with the proper XML instructions in local.xml.

Best Answer

Related Solutions

Magento – Understanding Magento Block and Block Type

Php – Understanding getChildHtml in Magento

Related Topic