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J3.x

Developing a MVC Component/Adding categories

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< J3.x:Developing a MVC Component


This is a multiple-article series of tutorials on how to develop a Model-View-Controller Component for Joomla! Version Joomla 3.x.

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

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This is a multiple-article series of tutorials on how to develop a Model-View-Contoller Component for Joomla! Version Joomla 3.4.

Introduction

This tutorial is part of the Developing a MVC Component for Joomla! 3.2 tutorial. You are encouraged to read the previous parts of the tutorial before reading this.

The Joomla framework has implemented the use of categories for all components. Adding categorized ability to a component is fairly simple.

Modifying the SQL

In order to manage categories, we have to change the SQL tables.

With your favorite 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 - 2015 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 favorite 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 - 2015 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  $submenu  The name of the active view.
 *
 * @return  void
 *
 * @since   1.6
 */
abstract class HelloWorldHelper
{
	/**
	 * Configure the Linkbar.
	 */
	public static function addSubmenu($submenu) 
	{
		JSubMenuHelper::addEntry(
			JText::_('COM_HELLOWORLD_SUBMENU_MESSAGES'),
			'index.php?option=com_helloworld',
			$submenu == 'messages'
		);
 
		JSubMenuHelper::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 - 2015 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 fileJLoader::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 - 2015 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'));
	}
}

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" />
	</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 - 2015 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

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="3.2.0" method="upgrade">
 
	<name>COM_HELLOWORLD</name>
	<!-- The following elements are optional and free of formatting constraints -->
	<creationDate>February 2015</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>


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