J3.x:Developing an MVC Component/Adding categories

Joomla! 

3.x

Tutorial

Developing an MVC Component

Articles in This Series

1. Introduction
2. Developing a Basic Component
3. Adding a View to the Site Part
4. Adding a Menu Type to the Site Part
5. Adding a Model to the Site Part
6. Adding a Variable Request in the Menu Type
7. Using the Database
8. Basic Backend
9. Adding Language Management
10. Adding Backend Actions
11. Adding Decorations to the Backend
12. Adding Verifications
13. Adding Categories
14. Adding Configuration
15. Adding ACL
16. Adding an Install/Uninstall/Update Script File
17. Adding a Frontend Form
18. Adding an Image
19. Adding a Map
20. Adding AJAX
21. Adding an Alias
22. Using the Language Filter Facility
23. Adding a Modal
24. Adding Associations
25. Adding Checkout
26. Adding Ordering
27. Adding Levels
28. Adding Versioning
29. Adding Tags
30. Adding Access
31. Adding a Batch Process
32. Adding Cache
33. Adding a Feed
34. Adding an Update Server
35. Adding Custom Fields
36. Upgrading to Joomla4

This is a multiple-article series of tutorials on how to develop a Model-View-Controller Component for Joomla! Version.

Begin with the Introduction, and navigate the articles in this series by using the navigation button at the bottom or the box to the right (the Articles in this series).

Introduction

This tutorial is part of the Developing an MVC Component for Joomla! 3.2 tutorial. You are encouraged to read the previous parts of the tutorial before reading this. You can watch a video associated with this step at Step 12, adding categories.

In this step we will make use of the Joomla Categories functionality to enable us to define a set of categories for use with our Helloworld component, and to allow us to associate each Helloworld greeting with one of those categories. Much of this will be implemented in a similar manner to other components, such as Articles (com_content) and Banners.

There are a number of strands to this:

1. We have to link our Helloworld database table with the Joomla Categories table; this will affect our SQL install and update scripts.
2. We will update our Helloworld Edit form to allow an administrator to associate a category with any of the Helloworld greetings. This will impact the Helloworld Edit form XML definition.
3. Until now when administrators define a menu item of type Helloworld they are asked to select the greeting to display from the list of available greetings. We'll enhance this list to show the associated category in brackets after the greeting, provided that that greeting has a category defined. This will impact our model FieldList code in admin/models/fields/helloworld.php.
4. We will allow the administrator to define the Categories which are associated with our Helloworld component. This is functionality which the Joomla com_categories component provides for us automatically. It generates the form which allows administrators to do this – we just have to provide menu links to this form through the submenu described below and through the Components menu, and in addition we must define the access permissions to this functionality.
5. We will change the Helloworlds form which shows all the Helloworld messages so that the Category associated with each message is displayed. This will impact our model (as we'll have to do a SQL Join with the Categories table in order to get the Category title) and our layout file (where we'll display the associated categories).
6. We will create a submenu which can slide as a Sidebar in from the left, and which will show two items on the submenu:
   • Messages – which will go to our form with all the Helloworld messages
   • Categories – which will go to the form allowing the administrator to define the set of categories for the Helloworld component.

   This will affect our Helloworlds view (where we'll set up the sidebar) and layout (where we'll display the sidebar), as well as defining the sidebar submenu itself in a new Helper file. We'll also add a line to our main admin helloworld.php file telling Joomla to load and run that helper file.

Important Note (with hindsight). This step builds categories into the helloworld component by allowing them to be optional. This is different from the core Joomla components where a category must be always be defined, and by default items have a category of "uncategorised". If you allow categories to be optional you are likely to encounter difficulties later on because some core Joomla library functions assume that they are mandatory. If this tutorial series is updated for later Joomla versions it would be better to include categories in a way that follows the standard Joomla pattern.

Modifying the SQL

In order to manage categories, we have to change the SQL tables. With your favourite editor, modify admin/sql/install.mysql.utf8.sql and put these lines:

admin/sql/install.mysql.utf8.sql

DROP TABLE IF EXISTS `#__helloworld`;

CREATE TABLE `#__helloworld` (
	`id`       INT(11)     NOT NULL AUTO_INCREMENT,
	`greeting` VARCHAR(25) NOT NULL,
	`published` tinyint(4) NOT NULL,
	`catid`	    int(11)    NOT NULL DEFAULT '0',
	PRIMARY KEY (`id`)
)
	ENGINE =MyISAM
	AUTO_INCREMENT =0
	DEFAULT CHARSET =utf8;

INSERT INTO `#__helloworld` (`greeting`) VALUES
('Hello World!'),
('Good bye World!');

admin/sql/updates/mysql/0.0.12.sql

ALTER TABLE `#__helloworld` ADD `catid` int(11) NOT NULL DEFAULT '0';

Modifying the form

A HelloWorld message can now belong to a category. We have to modify the editing form. In the admin/models/forms/helloworld.xml file, put these lines:

admin/models/forms/helloworld.xml

<?xml version="1.0" encoding="utf-8"?>
<form
				addrulepath="/administrator/components/com_helloworld/models/rules"
>
	<fieldset>
		<field
				name="id"
				type="hidden"
				/>
		<field
				name="greeting"
				type="text"
				label="COM_HELLOWORLD_HELLOWORLD_GREETING_LABEL"
				description="COM_HELLOWORLD_HELLOWORLD_GREETING_DESC"
				size="40"
				class="inputbox validate-greeting"
				validate="greeting"
				required="true"
				default=""
				/>
		<field
				name="catid"
				type="category"
				extension="com_helloworld"
				class="inputbox"
				default=""
				label="COM_HELLOWORLD_HELLOWORLD_FIELD_CATID_LABEL"
				description="COM_HELLOWORLD_HELLOWORLD_FIELD_CATID_DESC"
				required="true"
		>
			<option value="0">JOPTION_SELECT_CATEGORY</option>
		</field>
	</fieldset>
</form>

Note that the category can be 0 (representing no category).

Modifying the menu type

The HelloWorld menu type displays a drop down list of all messages. If the message is categorized, we have to add the category in this display.

In the admin/models/fields/helloworld.php file, put these lines:

admin/models/fields/helloworld.php

<?php
/**
 * @package     Joomla.Administrator
 * @subpackage  com_helloworld
 *
 * @copyright   Copyright (C) 2005 - 2018 Open Source Matters, Inc. All rights reserved.
 * @license     GNU General Public License version 2 or later; see LICENSE.txt
 */

// No direct access to this file
defined('_JEXEC') or die('Restricted access');

JFormHelper::loadFieldClass('list');

/**
 * HelloWorld Form Field class for the HelloWorld component
 *
 * @since  0.0.1
 */
class JFormFieldHelloWorld extends JFormFieldList
{
	/**
	 * The field type.
	 *
	 * @var         string
	 */
	protected $type = 'HelloWorld';

	/**
	 * Method to get a list of options for a list input.
	 *
	 * @return  array  An array of JHtml options.
	 */
	protected function getOptions()
	{
		$db    = JFactory::getDBO();
		$query = $db->getQuery(true);
		$query->select('#__helloworld.id as id,greeting,#__categories.title as category,catid');
		$query->from('#__helloworld');
		$query->leftJoin('#__categories on catid=#__categories.id');
		// Retrieve only published items
		$query->where('#__helloworld.published = 1');
		$db->setQuery((string) $query);
		$messages = $db->loadObjectList();
		$options  = array();

		if ($messages)
		{
			foreach ($messages as $message)
			{
				$options[] = JHtml::_('select.option', $message->id, $message->greeting .
				                      ($message->catid ? ' (' . $message->category . ')' : ''));
			}
		}

		$options = array_merge(parent::getOptions(), $options);

		return $options;
	}
}

It will now display the category between parenthesis. Note: We have added a where clause too to filter out unpublished items.

Managing the submenu

The com_categories component allows to set the submenu using a helper file. With your favourite file manager and editor, put a admin/helpers/helloworld.php file containing these lines:

admin/helpers/helloworld.php

<?php
/**
 * @package     Joomla.Administrator
 * @subpackage  com_helloworld
 *
 * @copyright   Copyright (C) 2005 - 2018 Open Source Matters, Inc. All rights reserved.
 * @license     GNU General Public License version 2 or later; see LICENSE.txt
 */

// No direct access to this file
defined('_JEXEC') or die('Restricted access');

/**
 * HelloWorld component helper.
 *
 * @param   string  $submenu  The name of the active view.
 *
 * @return  void
 *
 * @since   1.6
 */
abstract class HelloWorldHelper extends JHelperContent
{
	/**
	 * Configure the Linkbar.
	 *
	 * @return Bool
	 */

	public static function addSubmenu($submenu) 
	{
		JHtmlSidebar::addEntry(
			JText::_('COM_HELLOWORLD_SUBMENU_MESSAGES'),
			'index.php?option=com_helloworld',
			$submenu == 'helloworlds'
		);

		JHtmlSidebar::addEntry(
			JText::_('COM_HELLOWORLD_SUBMENU_CATEGORIES'),
			'index.php?option=com_categories&view=categories&extension=com_helloworld',
			$submenu == 'categories'
		);

		// Set some global property
		$document = JFactory::getDocument();
		$document->addStyleDeclaration('.icon-48-helloworld ' .
										'{background-image: url(../media/com_helloworld/images/tux-48x48.png);}');
		if ($submenu == 'categories') 
		{
			$document->setTitle(JText::_('COM_HELLOWORLD_ADMINISTRATION_CATEGORIES'));
		}
	}
}

NOTE: You MUST use your component name (without com_) for the helper file name, or else your submenus won't show in category view.

To import the helper class, put these lines in the admin/helloworld.php file:

admin/helloworld.php

<?php
/**
 * @package     Joomla.Administrator
 * @subpackage  com_helloworld
 *
 * @copyright   Copyright (C) 2005 - 2018 Open Source Matters, Inc. All rights reserved.
 * @license     GNU General Public License version 2 or later; see LICENSE.txt
 */

// No direct access to this file
defined('_JEXEC') or die('Restricted access');

// Set some global property
$document = JFactory::getDocument();
$document->addStyleDeclaration('.icon-helloworld {background-image: url(../media/com_helloworld/images/tux-16x16.png);}');

// Require helper file
JLoader::register('HelloWorldHelper', JPATH_COMPONENT . '/helpers/helloworld.php');

// Get an instance of the controller prefixed by HelloWorld
$controller = JControllerLegacy::getInstance('HelloWorld');

// Perform the Request task
$input = JFactory::getApplication()->input;
$controller->execute($input->getCmd('task'));

// Redirect if set by the controller
$controller->redirect();

This function will be automatically called by the com_categories component. Note that it will:

• change the submenu
• change some css properties (for displaying icons)
• change the browser title if the submenu is categories
• change the title and add a preferences button

The .icon-48-helloworld css class is now set in the addSubmenu function. We have now to call this function in the hellowords view:

admin/views/helloworlds/view.html.php

<?php
/**
 * @package     Joomla.Administrator
 * @subpackage  com_helloworld
 *
 * @copyright   Copyright (C) 2005 - 2018 Open Source Matters, Inc. All rights reserved.
 * @license     GNU General Public License version 2 or later; see LICENSE.txt
 */

// No direct access to this file
defined('_JEXEC') or die('Restricted access');

/**
 * HelloWorlds View
 *
 * @since  0.0.1
 */
class HelloWorldViewHelloWorlds extends JViewLegacy
{
	/**
	 * Display the Hello World view
	 *
	 * @param   string  $tpl  The name of the template file to parse; automatically searches through the template paths.
	 *
	 * @return  void
	 */

	function display($tpl = null)
	{
		
		// Get application
		$app = JFactory::getApplication();
		$context = "helloworld.list.admin.helloworld";
		// Get data from the model
		$this->items			= $this->get('Items');
		$this->pagination		= $this->get('Pagination');
		$this->state			= $this->get('State');
		$this->filter_order 	= $app->getUserStateFromRequest($context.'filter_order', 'filter_order', 'greeting', 'cmd');
		$this->filter_order_Dir = $app->getUserStateFromRequest($context.'filter_order_Dir', 'filter_order_Dir', 'asc', 'cmd');
		$this->filterForm    	= $this->get('FilterForm');
		$this->activeFilters 	= $this->get('ActiveFilters');

		// Check for errors.
		if (count($errors = $this->get('Errors')))
		{
			JError::raiseError(500, implode('<br />', $errors));

			return false;
		}

		// Set the submenu
		HelloWorldHelper::addSubmenu('helloworlds');

		// Set the toolbar and number of found items
		$this->addToolBar();

		// Display the template
		parent::display($tpl);

		// Set the document
		$this->setDocument();
	}

	/**
	 * Add the page title and toolbar.
	 *
	 * @return  void
	 *
	 * @since   1.6
	 */
	protected function addToolBar()
	{
		$title = JText::_('COM_HELLOWORLD_MANAGER_HELLOWORLDS');

		if ($this->pagination->total)
		{
			$title .= "<span style='font-size: 0.5em; vertical-align: middle;'>(" . $this->pagination->total . ")</span>";
		}

		JToolBarHelper::title($title, 'helloworld');
		JToolBarHelper::addNew('helloworld.add');
		JToolBarHelper::editList('helloworld.edit');
		JToolBarHelper::deleteList('', 'helloworlds.delete');
	}
	/**
	 * Method to set up the document properties
	 *
	 * @return void
	 */
	protected function setDocument() 
	{
		$document = JFactory::getDocument();
		$document->setTitle(JText::_('COM_HELLOWORLD_ADMINISTRATION'));
	}
}

Getting the associated category titles

Update the helloworlds model so that it does a SQL join with the Joomla Categories table to find the associated category title.

admin/models/helloworlds.php

<?php
/**
 * @package     Joomla.Administrator
 * @subpackage  com_helloworld
 *
 * @copyright   Copyright (C) 2005 - 2018 Open Source Matters, Inc. All rights reserved.
 * @license     GNU General Public License version 2 or later; see LICENSE.txt
 */
// No direct access to this file
defined('_JEXEC') or die('Restricted access');

/**
 * HelloWorldList Model
 *
 * @since  0.0.1
 */
class HelloWorldModelHelloWorlds extends JModelList
{
	/**
	 * Constructor.
	 *
	 * @param   array  $config  An optional associative array of configuration settings.
	 *
	 * @see     JController
	 * @since   1.6
	 */
	public function __construct($config = array())
	{
		if (empty($config['filter_fields']))
		{
			$config['filter_fields'] = array(
				'id',
				'greeting',
				'published'
			);
		}

		parent::__construct($config);
	}

	/**
	 * Method to build an SQL query to load the list data.
	 *
	 * @return      string  An SQL query
	 */
	protected function getListQuery()
	{
		// Initialize variables.
		$db    = JFactory::getDbo();
		$query = $db->getQuery(true);

		// Create the base select statement.
		$query->select('a.id as id, a.greeting as greeting, a.published as published')
			  ->from($db->quoteName('#__helloworld', 'a'));

		// Join over the categories.
		$query->select($db->quoteName('c.title', 'category_title'))
			->join('LEFT', $db->quoteName('#__categories', 'c') . ' ON c.id = a.catid');

		// Filter: like / search
		$search = $this->getState('filter.search');

		if (!empty($search))
		{
			$like = $db->quote('%' . $search . '%');
			$query->where('greeting LIKE ' . $like);
		}

		// Filter by published state
		$published = $this->getState('filter.published');

		if (is_numeric($published))
		{
			$query->where('a.published = ' . (int) $published);
		}
		elseif ($published === '')
		{
			$query->where('(a.published IN (0, 1))');
		}

		// Add the list ordering clause.
		$orderCol	= $this->state->get('list.ordering', 'greeting');
		$orderDirn 	= $this->state->get('list.direction', 'asc');

		$query->order($db->escape($orderCol) . ' ' . $db->escape($orderDirn));

		return $query;
	}
}

Updating the Layout

Update the helloworlds layout file to display the sidebar and the category associated with the greeting.

admin/views/helloworlds/tmpl/default.php

<?php
/**
 * @package     Joomla.Administrator
 * @subpackage  com_helloworld
 *
 * @copyright   Copyright (C) 2005 - 2018 Open Source Matters, Inc. All rights reserved.
 * @license     GNU General Public License version 2 or later; see LICENSE.txt
 */

// No direct access to this file
defined('_JEXEC') or die('Restricted Access');

JHtml::_('formbehavior.chosen', 'select');

$listOrder     = $this->escape($this->filter_order);
$listDirn      = $this->escape($this->filter_order_Dir);
?>
<form action="index.php?option=com_helloworld&view=helloworlds" method="post" id="adminForm" name="adminForm">
	<div id="j-sidebar-container" class="span2">
		<?php echo JHtmlSidebar::render(); ?>
	</div>
	<div id="j-main-container" class="span10">
		<div class="row-fluid">
			<div class="span6">
				<?php echo JText::_('COM_HELLOWORLD_HELLOWORLDS_FILTER'); ?>
				<?php
					echo JLayoutHelper::render(
						'joomla.searchtools.default',
						array('view' => $this)
					);
				?>
			</div>
		</div>
		<table class="table table-striped table-hover">
			<thead>
			<tr>
				<th width="1%"><?php echo JText::_('COM_HELLOWORLD_NUM'); ?></th>
				<th width="2%">
					<?php echo JHtml::_('grid.checkall'); ?>
				</th>
				<th width="90%">
					<?php echo JHtml::_('grid.sort', 'COM_HELLOWORLD_HELLOWORLDS_NAME', 'greeting', $listDirn, $listOrder); ?>
				</th>
				<th width="5%">
					<?php echo JHtml::_('grid.sort', 'COM_HELLOWORLD_PUBLISHED', 'published', $listDirn, $listOrder); ?>
				</th>
				<th width="2%">
					<?php echo JHtml::_('grid.sort', 'COM_HELLOWORLD_ID', 'id', $listDirn, $listOrder); ?>
				</th>
			</tr>
			</thead>
			<tfoot>
				<tr>
					<td colspan="5">
						<?php echo $this->pagination->getListFooter(); ?>
					</td>
				</tr>
			</tfoot>
			<tbody>
				<?php if (!empty($this->items)) : ?>
					<?php foreach ($this->items as $i => $row) :
						$link = JRoute::_('index.php?option=com_helloworld&task=helloworld.edit&id=' . $row->id);
					?>
						<tr>
							<td><?php echo $this->pagination->getRowOffset($i); ?></td>
							<td>
								<?php echo JHtml::_('grid.id', $i, $row->id); ?>
							</td>
							<td>
								<a href="<?php echo $link; ?>" title="<?php echo JText::_('COM_HELLOWORLD_EDIT_HELLOWORLD'); ?>">
									<?php echo $row->greeting; ?>
								</a>
								<div class="small">
									<?php echo JText::_('JCATEGORY') . ': ' . $this->escape($row->category_title); ?>
								</div>
							</td>
							<td align="center">
								<?php echo JHtml::_('jgrid.published', $row->published, $i, 'helloworlds.', true, 'cb'); ?>
							</td>
							<td align="center">
								<?php echo $row->id; ?>
							</td>
						</tr>
					<?php endforeach; ?>
				<?php endif; ?>
			</tbody>
		</table>
		<input type="hidden" name="task" value=""/>
		<input type="hidden" name="boxchecked" value="0"/>
		<input type="hidden" name="filter_order" value="<?php echo $listOrder; ?>"/>
		<input type="hidden" name="filter_order_Dir" value="<?php echo $listDirn; ?>"/>
		<?php echo JHtml::_('form.token'); ?>
	</div>
</form>

Adding some ACL

admin/access.xml

<?xml version="1.0" encoding="utf-8" ?>
<access component="com_helloworld">
	<section name="component">
		<action name="core.admin" title="JACTION_ADMIN" description="JACTION_ADMIN_COMPONENT_DESC" />
		<action name="core.manage" title="JACTION_MANAGE" description="JACTION_MANAGE_COMPONENT_DESC" />
		<action name="core.create" title="JACTION_CREATE" description="JACTION_CREATE_COMPONENT_DESC" />
		<action name="core.delete" title="JACTION_DELETE" description="JACTION_DELETE_COMPONENT_DESC" />
		<action name="core.edit" title="JACTION_EDIT" description="JACTION_EDIT_COMPONENT_DESC" />
		<action name="core.edit.state" title="JACTION_EDITSTATE"/>
	</section>
	<section name="category">
		<action name="core.create" title="JACTION_CREATE"/>
		<action name="core.delete" title="JACTION_DELETE"/>
		<action name="core.edit" title="JACTION_EDIT"/>
		<action name="core.edit.state" title="JACTION_EDITSTATE"/>
	</section>
	<section name="message">
		<action name="core.delete" title="JACTION_DELETE" description="COM_HELLOWORLD_ACCESS_DELETE_DESC" />
		<action name="core.edit" title="JACTION_EDIT" description="COM_HELLOWORLD_ACCESS_EDIT_DESC" />
	</section>
</access>

NOTE: If you don't add this file, buttons "New" "Edit" and ... don't show in category view. For more information, read section Adding ACL on top of the page.

Adding some translation strings

Some strings have to be translated. In the admin/language/en-GB/en-GB.com_helloworld.ini file, put these lines:

admin/language/en-GB/en-GB.com_helloworld.ini

; Joomla! Project
; Copyright (C) 2005 - 2018 Open Source Matters. All rights reserved.
; License GNU General Public License version 2 or later; see LICENSE.txt, see LICENSE.php
; Note : All ini files need to be saved as UTF-8

COM_HELLOWORLD_ADMINISTRATION="HelloWorld - Administration"
COM_HELLOWORLD_ADMINISTRATION_CATEGORIES="HelloWorld - Categories"
COM_HELLOWORLD_NUM="#"
COM_HELLOWORLD_HELLOWORLDS_FILTER="Filters"
COM_HELLOWORLD_PUBLISHED="Published"
COM_HELLOWORLD_HELLOWORLDS_NAME="Name"
COM_HELLOWORLD_ID="Id"

COM_HELLOWORLD_HELLOWORLD_CREATING="HelloWorld - Creating"
COM_HELLOWORLD_HELLOWORLD_DETAILS="Details"
COM_HELLOWORLD_HELLOWORLD_EDITING="HelloWorld - Editing"
COM_HELLOWORLD_HELLOWORLD_ERROR_UNACCEPTABLE="Some values are unacceptable"
COM_HELLOWORLD_HELLOWORLD_FIELD_CATID_DESC="The category the messages belongs to"
COM_HELLOWORLD_HELLOWORLD_FIELD_CATID_LABEL="Category"
COM_HELLOWORLD_HELLOWORLD_FIELD_GREETING_DESC="This message will be displayed"
COM_HELLOWORLD_HELLOWORLD_FIELD_GREETING_LABEL="Message"
COM_HELLOWORLD_HELLOWORLD_HEADING_GREETING="Greeting"
COM_HELLOWORLD_HELLOWORLD_HEADING_ID="Id"
COM_HELLOWORLD_MANAGER_HELLOWORLD_EDIT="HelloWorld manager: Edit Message"
COM_HELLOWORLD_MANAGER_HELLOWORLD_NEW="HelloWorld manager: New Message"
COM_HELLOWORLD_MANAGER_HELLOWORLDS="HelloWorld manager"
COM_HELLOWORLD_EDIT_HELLOWORLD="Edit message"
COM_HELLOWORLD_N_ITEMS_DELETED_1="One message deleted"
COM_HELLOWORLD_N_ITEMS_DELETED_MORE="%d messages deleted"
COM_HELLOWORLD_N_ITEMS_PUBLISHED="%d message(s) published"
COM_HELLOWORLD_N_ITEMS_UNPUBLISHED="%d message(s) unpublished"
COM_HELLOWORLD_HELLOWORLD_GREETING_LABEL="Greeting"
COM_HELLOWORLD_HELLOWORLD_GREETING_DESC="Add Hello World Greeting"
COM_HELLOWORLD_SUBMENU_MESSAGES="Messages"
COM_HELLOWORLD_SUBMENU_CATEGORIES="Categories"

Packaging the component

Content of your code directory. Each file link below takes you to the step in the tutorial which has the latest version of that source code file.

• helloworld.xml
• site/helloworld.php
• site/index.html
• site/controller.php
• site/views/index.html
• site/views/helloworld/index.html
• site/views/helloworld/view.html.php
• site/views/helloworld/tmpl/index.html
• site/views/helloworld/tmpl/default.xml
• site/views/helloworld/tmpl/default.php
• site/models/index.html
• site/models/helloworld.php
• site/language/index.html
• site/language/en-GB/index.html
• site/language/en-GB/en-GB.com_helloworld.ini
• admin/index.html
• admin/helloworld.php
• admin/controller.php
• admin/access.xml
• admin/helpers/helloworld.php
• admin/helpers/index.html
• admin/sql/index.html
• admin/sql/install.mysql.utf8.sql
• admin/sql/uninstall.mysql.utf8.sql
• admin/sql/updates/index.html
• admin/sql/updates/mysql/index.html
• admin/sql/updates/mysql/0.0.1.sql
• admin/sql/updates/mysql/0.0.6.sql
• admin/sql/updates/mysql/0.0.12.sql
• admin/models/index.html
• admin/models/fields/index.html
• admin/models/fields/helloworld.php
• admin/models/helloworlds.php
• admin/models/helloworld.php
• admin/models/forms/filter_helloworlds.xml
• admin/models/forms/index.html
• admin/models/forms/helloworld.js
• admin/models/forms/helloworld.xml
• admin/models/rules/greeting.php
• admin/models/rules/index.html
• admin/controllers/helloworld.php
• admin/controllers/helloworlds.php
• admin/controllers/index.html
• admin/views/index.html
• admin/views/helloworld/index.html
• admin/views/helloworld/view.html.php
• admin/views/helloworld/tmpl/index.html
• admin/views/helloworld/tmpl/edit.php
• admin/views/helloworld/submitbutton.js
• admin/views/helloworlds/index.html
• admin/views/helloworlds/view.html.php
• admin/views/helloworlds/tmpl/index.html
• admin/views/helloworlds/tmpl/default.php
• admin/tables/index.html
• admin/tables/helloworld.php
• admin/language/index.html
• admin/language/en-GB/index.html
• admin/language/en-GB/en-GB.com_helloworld.ini
• admin/language/en-GB/en-GB.com_helloworld.sys.ini
• media/index.html
• media/images/index.html
• media/images/tux-16x16.png
• media/images/tux-48x48.png

Create a compressed file of this directory or directly download the archive and install it using the extension manager of Joomla. You can add a menu item of this component using the menu manager in the backend.

helloworld.xml

<?xml version="1.0" encoding="utf-8"?>
<extension type="component" version="3.0" method="upgrade">

	<name>COM_HELLOWORLD</name>
	<!-- The following elements are optional and free of formatting constraints -->
	<creationDate>January 2018</creationDate>
	<author>John Doe</author>
	<authorEmail>john.doe@example.org</authorEmail>
	<authorUrl>http://www.example.org</authorUrl>
	<copyright>Copyright Info</copyright>
	<license>License Info</license>
	<!--  The version string is recorded in the components table -->
	<version>0.0.12</version>
	<!-- The description is optional and defaults to the name -->
	<description>COM_HELLOWORLD_DESCRIPTION</description>

	<install> <!-- Runs on install -->
		<sql>
			<file driver="mysql" charset="utf8">sql/install.mysql.utf8.sql</file>
		</sql>
	</install>
	<uninstall> <!-- Runs on uninstall -->
		<sql>
			<file driver="mysql" charset="utf8">sql/uninstall.mysql.utf8.sql</file>
		</sql>
	</uninstall>
	<update> <!-- Runs on update; New since J2.5 -->
		<schemas>
			<schemapath type="mysql">sql/updates/mysql</schemapath>
		</schemas>
	</update>

	<!-- Site Main File Copy Section -->
	<!-- Note the folder attribute: This attribute describes the folder
		to copy FROM in the package to install therefore files copied
		in this section are copied from /site/ in the package -->
	<files folder="site">
		<filename>index.html</filename>
		<filename>helloworld.php</filename>
		<filename>controller.php</filename>
		<folder>views</folder>
		<folder>models</folder>
	</files>

        <languages folder="site/language">
		<language tag="en-GB">en-GB/en-GB.com_helloworld.ini</language>
        </languages>

	<media destination="com_helloworld" folder="media">
		<filename>index.html</filename>
		<folder>images</folder>
	</media>

	<administration>
		<!-- Administration Menu Section -->
		<menu link='index.php?option=com_helloworld' img="../media/com_helloworld/images/tux-16x16.png">COM_HELLOWORLD_MENU</menu>
		<!-- Administration Main File Copy Section -->
		<!-- Note the folder attribute: This attribute describes the folder
			to copy FROM in the package to install therefore files copied
			in this section are copied from /admin/ in the package -->
		<files folder="admin">
			<!-- Admin Main File Copy Section -->
			<filename>index.html</filename>
			<filename>helloworld.php</filename>
			<filename>controller.php</filename>
			<filename>access.xml</filename>
			<!-- SQL files section -->
			<folder>sql</folder>
			<!-- tables files section -->
			<folder>tables</folder>
			<!-- models files section -->
			<folder>models</folder>
			<!-- views files section -->
			<folder>views</folder>
			<!-- controllers files section -->
			<folder>controllers</folder>
			<!-- helpers files section -->
			<folder>helpers</folder>
		</files>
		<languages folder="admin/language">
        		<language tag="en-GB">en-GB/en-GB.com_helloworld.ini</language>
                        <language tag="en-GB">en-GB/en-GB.com_helloworld.sys.ini</language>
		</languages>
	</administration>

</extension>

Contributors

• Christophe Demko
• Ozgur Aksu
• Anibal Sanchez // Just a fix
• Hans Postema // Just another fix
• Scionescire
• Veronika Patel
• Robbie Jackson

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Next: Adding configuration