Archived:How to override the output from the Joomla! core

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There may be occasions where you would like to change the way a Joomla! Extension (such as a Component or Module, whether from the Joomla! core or produced by a third party) is displayed on your site. Of course, you could recode the Extension from scratch, but that may be a bit ambitious for you! Thankfully, there is another way.

The standard output from any Joomla! Module or Component can be overridden by adding code to the html directory of your template. It is also possible to override two aspects of core functionality: Module chrome, and pagination.

As of overrides can be created using the Template manager Creating Overrides

Getting a head-start with overrides

If you are new to Joomla! development, then it is probably easiest to start with an existing view, and try modifying it to get what you want. To do this, you should make a copy of the existing view in the html directory of your template, and then modify the copy.

The directory structure you need is:

TEMPLATE_NAME/html/EXTENSION_NAME/VIEW_NAME/FILE_NAME.php

For example, if you want to change the way that the 'Article' view displays a com_content article, then you should copy the file at :

PATH_TO_JOOMLA/components/com_content/views/article/tmpl/default.php
to
TEMPLATE_NAME/html/com_content/article/default.php

(note the slight difference in directory structure)

Similarly, if you want to change how the mod_login Module is displayed, then you should copy :

PATH_TO_JOOMLA/modules/mod_login/tmpl/default.php
to
TEMPLATE_NAME/html/mod_login/default.php

Joomla! comes pre-packaged with a frontend template called Beez. Beez utilizes template overrides to produce a table-less layout for faster, smoother, and semantically correct markup. To see how it's done, locate your Joomla! installation's template directory, and you'll notice the Beez template. Inside the Beez template directory, you'll find a directory named html.

The entire directory structure is as follows:

/your_joomla/templates/Beez/html/

If you want to try modifying the overrides used in Beez, you could simply copy and paste the Beez html directory into your own template's main directory. However you choose to make your override files, you will need to ensure that they are correctly installed with your template. To do this, you should add the following code to your template's templateDetails.xml file (in between the <files> and </files> tags):

<folder>html</folder>

The above code in essence lets the Joomla! package installer know that there are files to extract, and that they are part of the template as a whole.

Further tips

You can override Joomla's core images that are stored in the /media/ folder. Put an alternative image with the same name in your template folder. For example, the Breadcrumbs Module uses an orange arrow that is retrieved from /media/system/images/arrow.png. Joomla will use your override version if you put it at /templates/your_template_name/images/system/arrow.png.

Template overrides are almost limitless. They allow you to add, edit, and remove the components of the Joomla! core output. The Template Manager can be used to create override files ready for editing.

Note: For the FireFox web browser, an extension called Firebug is available, which is useful for browsing a page's HTML source and matching it up with the PHP code used in template overrides. For more information, please watch the free video tutorial on using Firebug with Joomla. Now firebug is also available for IE called Firebug Lite.

More information is available from the following resources:

• The article Understanding Output Overrides explains the theory behind template overrides.
• The preferred way of changing text output is by using translations in your template.
• A downloadable tutorial is also available.
• Example in github how to override layout of view without override the view, but extending it.