Joomla 4.x Tutorial - Extension Development - Layout

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Sometimes it is necessary to design the display differently in the frontend. This is basically the responsibility of the template. A component is responsible for the output of content, no more and no less. The template ensures a uniform appearance. Nevertheless, there are use cases for different layouts. How you incorporate them for a view is the topic of the following article.

For impatient people: View the changed program code in the Diff Viewgithub.com/astridx/boilerplate/compare/t19...t20 and copy these changes into your development version.

Step by step

We already use layouts. The empty state Layout (administrator/components/com_foos/tmpl/foos/emptystate.php)https://github.com/astridx/boilerplate/blob/t6b/src/administrator/components/com_foos/tmpl/foos/emptystate.php is an example. This part of the text is about looking at all the steps to integrate a layout as a whole.

New files

components/com_foos/ tmpl/foo/withhead.php

components/com_foos/ tmpl/foo/withhead.php

<?php
// https://raw.githubusercontent.com/astridx/boilerplate/t24/src/components/com_foos/tmpl/foo/withhead.php

\defined('_JEXEC') or die;

use Joomla\CMS\Language\Text;

echo "<hr>Hier kannst du einen Headertext anzeigen.<hr>";

if ($this->item->params->get('show_name')) {
	if ($this->Params->get('show_foo_name_label')) {
		echo Text::_('COM_FOOS_NAME') . $this->item->name;
	} else {
		echo $this->item->name;
	}
}

echo $this->item->event->afterDisplayTitle;
echo $this->item->event->beforeDisplayContent;
echo $this->item->event->afterDisplayContent;

components/com_foos/ tmpl/foo/withhead.xml

components/com_foos/ tmpl/foo/withhead.xml

<!-- https://raw.githubusercontent.com/astridx/boilerplate/t24/src/components/com_foos/tmpl/foo/withhead.xml -->

<?xml version="1.0" encoding="utf-8"?>
<metadata>
	<layout title="COM_FOOS_FOO_VIEW_WITHHEAD_TITLE">
		<message>
			<![CDATA[COM_FOOS_FOO_VIEW_WITHHEAD_DESC]]>
		</message>
	</layout>
	<!-- Add fields to the request variables for the layout. -->
	<fields name="request">
		<fieldset name="request"
			addfieldprefix="FooNamespace\Component\Foos\Administrator\Field"
		>
			<field
				name="id"
				type="modal_foo"
				label="COM_FOOS_SELECT_FOO_LABEL"
				required="true"
				select="true"
				new="true"
				edit="true"
				clear="true"
			/>
		</fieldset>
	</fields>
</metadata>

components/com_foos/ tmpl/foo/withheadandfoot.php

components/com_foos/ tmpl/foo/withheadandfoot.php

// https://raw.githubusercontent.com/astridx/boilerplate/t24/src/components/com_foos/tmpl/foo/withheadandfoot.php

<?php

\defined('_JEXEC') or die;

use Joomla\CMS\Language\Text;

echo "<hr>Hier kannst du einen Headertext anzeigen.<hr>";

if ($this->item->params->get('show_name')) {
	if ($this->Params->get('show_foo_name_label')) {
		echo Text::_('COM_FOOS_NAME') . $this->item->name;
	} else {
		echo $this->item->name;
	}
}

echo "<hr>Hier kannst du eine Fußzeile anzeigen.<hr>";

echo $this->item->event->afterDisplayTitle;
echo $this->item->event->beforeDisplayContent;
echo $this->item->event->afterDisplayContent;

Modified files

administrator/components/ com_foos/ forms/foo.xml

In the form of the element we add a field to select the layout.

administrator/components/com_foos/ forms/foo.xml

 				<option value="0">JHIDE</option>
 				<option value="1">JSHOW</option>
 			</field>

			<field
				name="foos_layout"
				type="componentlayout"
				label="JFIELD_ALT_LAYOUT_LABEL"
				class="custom-select"
				extension="com_foos"
				view="foo"
				useglobal="true"
			/>
 		</fieldset>
 	</fields>
 </form>

components/com_foos/ src/Model/FooModel.php

This is what happens during development. Basically we would not have to change the file components/com_foos/src/Model/FooModel.php. In this chapter I noticed that a use entry is missing. Therefore a change is made after all.

components/com_foos/ src/Model/FooModel.php

 use Joomla\CMS\Factory;
 use Joomla\CMS\MVC\Model\BaseDatabaseModel;
use Joomla\CMS\Language\Text;

 /**
  * Foo model for the Joomla Foos component.

components/com_foos/ src/View/Foo/HtmlView.php

In the case of a menu item, I find it important that it - or the content - is always displayed consistently. Therefore we query the active menu item. For example, if elements are displayed via a category view, then a uniform layout is possible. If the content is displayed as a single element, a different layout can be used.

components/com_foos/ src/View/Foo/HtmlView.php

 		$temp->merge($itemparams);
 		$item->params = $temp;

		$active = Factory::getApplication()->getMenu()->getActive();

		// Override the layout only if this is not the active menu item
		// If it is the active menu item, then the view and item id will match
		if ((!$active) || ((strpos($active->link, 'view=foo') === false) || (strpos($active->link, '&id=' . (string) $this->item->id) === false)))
		{
			if (($layout = $item->params->get('foos_layout')))
			{
				$this->setLayout($layout);
			}
		}
		elseif (isset($active->query['layout']))
		{
			// We need to set the layout in case this is an alternative menu item (with an alternative layout)
			$this->setLayout($active->query['layout']);
		}

 		Factory::getApplication()->triggerEvent('onContentPrepare', array ('com_foos.foo', &$item));

 		// Store the events for later

Test your Joomla component

  1. perform a new installation. To do this, uninstall your previous installation and copy all files again. In a freshly installed system the explanation of the layouts is more uncomplicated.

Copy the files in the administrator folder into the administrator folder of your Joomla 4 installation.
Copy the files in the components folder into the components folder of your Joomla 4 installation.

Install your component as described in part one, after copying all the files.

  1. set a special layout for an item. I set withhead at the item with ID 2.

Joomla Layouts

  1. look at the output in the frontend. Enter the URL JOOMLA4/?option=com_foos&id=2&view=foo in the address bar of your browser. You will see the selected layout. Make sure that typing JOOMLA4/?option=com_foos&id=1&view=foo calls the default layout - if no special one is set.
  2. this layout is also controllable by menu item.

Joomla Layouts

An item without XML file is not selectable in the administration area. Nevertheless such layouts are useful! In the program code it is possible to assign it at any place: $this->setLayout('withheadandfoot');

Since the view is expected to be uniform when controlling via a menu item, the layout set in the menu item is preferred.

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