Developing a MVC Component/Adding configuration

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Introduction[edit]

This tutorial is part of the Developing a Model-View-Controller (MVC) Component for Joomla!2.5 tutorial. You are encouraged to read the previous parts of the tutorial before reading this.

Adding configuration parameters[edit]

The Joomla framework allows the use of parameters stored in each component. With your favorite file manager and editor, put a file admin/config.xml file containing these lines:

admin/config.xml

<?xml version="1.0" encoding="utf-8"?>
<config>
	<fieldset
		name="greetings"
		label="COM_HELLOWORLD_CONFIG_GREETING_SETTINGS_LABEL"
		description="COM_HELLOWORLD_CONFIG_GREETING_SETTINGS_DESC"
	>
		<field
			name="show_category"
			type="radio"
			label="COM_HELLOWORLD_HELLOWORLD_FIELD_SHOW_CATEGORY_LABEL"
			description="COM_HELLOWORLD_HELLOWORLD_FIELD_SHOW_CATEGORY_DESC"
			default="0"
		>
			<option value="0">JHIDE</option>
			<option value="1">JSHOW</option>
		</field>
	</fieldset>
</config>

This file will be read by the com_config component of the Joomla core. For the moment, we defined only one parameter: is the category title displayed or not in the frontend?.

The best way to set the parameters is to put a Preferences button in a toolbar.

With your favorite editor, put these lines in admin/views/helloworlds/view.html.php

admin/views/helloworlds/view.html.php

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

// import Joomla view library
jimport('joomla.application.component.view');

/**
 * HelloWorlds View
 */
class HelloWorldViewHelloWorlds extends JView
{
	/**
	 * HelloWorlds view display method
	 * @return void
	 */
	function display($tpl = null) 
	{
		// Get data from the model
		$items = $this->get('Items');
		$pagination = $this->get('Pagination');

		// Check for errors.
		if (count($errors = $this->get('Errors'))) 
		{
			JError::raiseError(500, implode('<br />', $errors));
			return false;
		}
		// Assign data to the view
		$this->items = $items;
		$this->pagination = $pagination;

		// Set the toolbar
		$this->addToolBar();

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

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

	/**
	 * Setting the toolbar
	 */
	protected function addToolBar() 
	{
		JToolBarHelper::title(JText::_('COM_HELLOWORLD_MANAGER_HELLOWORLDS'), 'helloworld');
		JToolBarHelper::deleteListX('', 'helloworlds.delete');
		JToolBarHelper::editListX('helloworld.edit');
		JToolBarHelper::addNewX('helloworld.add');
		JToolBarHelper::preferences('com_helloworld');
	}
	/**
	 * Method to set up the document properties
	 *
	 * @return void
	 */
	protected function setDocument() 
	{
		$document = JFactory::getDocument();
		$document->setTitle(JText::_('COM_HELLOWORLD_ADMINISTRATION'));
	}
}

Using configuration parameters as default value[edit]

We want to define this parameter individually on all HelloWorld data. With your favorite editor, put these lines into the admin/models/forms/helloworld.xml

admin/models/forms/helloworld.xml

<?xml version="1.0" encoding="utf-8"?>
<form
	addrulepath="/administrator/components/com_helloworld/models/rules"
>
	<fieldset name="details">
		<field
			name="id"
			type="hidden"
		/>
		<field
			name="greeting"
			type="text"
			label="COM_HELLOWORLD_HELLOWORLD_FIELD_GREETING_LABEL"
			description="COM_HELLOWORLD_HELLOWORLD_FIELD_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>
	<fields name="params">
		<fieldset
			name="params"
			label="JGLOBAL_FIELDSET_DISPLAY_OPTIONS"
		>
			<field
				name="show_category"
				type="list"
				label="COM_HELLOWORLD_HELLOWORLD_FIELD_SHOW_CATEGORY_LABEL"
				description="COM_HELLOWORLD_HELLOWORLD_FIELD_SHOW_CATEGORY_DESC"
				default=""
			>
				<option value="">JGLOBAL_USE_GLOBAL</option>
				<option value="0">JHIDE</option>
				<option value="1">JSHOW</option>
			</field>
		</fieldset>
	</fields>
</form>

We define the same parameter for each message with an additional value: Use global.

Modifying the SQL[edit]

Data now contains a new parameter: params. The SQL structure has to be modified.

With your favorite editor, put these lines into admin/sql/install.mysql.utf8.sql:

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,
  `catid` int(11) NOT NULL DEFAULT '0',
  `params` TEXT NOT NULL DEFAULT '',
   PRIMARY KEY  (`id`)
) ENGINE=MyISAM AUTO_INCREMENT=0 DEFAULT CHARSET=utf8;
 
INSERT INTO `#__helloworld` (`greeting`) VALUES
        ('Hello World!'),
        ('Good bye World!');

With your favorite editor, put these lines into admin/sql/updates/mysql/0.0.13.sql:

admin/sql/updates/mysql/0.0.13.sql

ALTER TABLE `#__helloworld` ADD `params` VARCHAR(1024) NOT NULL DEFAULT '';

The TableHelloWorld has to be modified in order to deal with these parameters: they will be stored in a JSON format and get in a JParameter class. We have to overload the bind and the load method. With your favorite editor, put these lines into admin/tables/helloworld.php

admin/tables/helloworld.php

<?php
// No direct access
defined('_JEXEC') or die('Restricted access');

// import Joomla table library
jimport('joomla.database.table');

/**
 * Hello Table class
 */
class HelloWorldTableHelloWorld extends JTable
{
	/**
	 * Constructor
	 *
	 * @param object Database connector object
	 */
	function __construct(&$db) 
	{
		parent::__construct('#__helloworld', 'id', $db);
	}
	/**
	 * Overloaded bind function
	 *
	 * @param       array           named array
	 * @return      null|string     null is operation was satisfactory, otherwise returns an error
	 * @see JTable:bind
	 * @since 1.5
	 */
	public function bind($array, $ignore = '') 
	{
		if (isset($array['params']) && is_array($array['params'])) 
		{
			// Convert the params field to a string.
			$parameter = new JRegistry;
			$parameter->loadArray($array['params']);
			$array['params'] = (string)$parameter;
		}
		return parent::bind($array, $ignore);
	}

	/**
	 * Overloaded load function
	 *
	 * @param       int $pk primary key
	 * @param       boolean $reset reset data
	 * @return      boolean
	 * @see JTable:load
	 */
	public function load($pk = null, $reset = true) 
	{
		if (parent::load($pk, $reset)) 
		{
			// Convert the params field to a registry.
			$params = new JRegistry;                 
                       // loadJSON is @deprecated    12.1  Use loadString passing JSON as the format instead.
                       // $params->loadString($this->item->params, 'JSON');
                       // "item" should not be present.
                       $params->loadJSON($this->params);

			$this->params = $params;
			return true;
		}
		else
		{
			return false;
		}
	}
}

Modifying the backend[edit]

The backend edit view has to display the options to the administrator. With your favorite editor, put these lines into the admin/views/helloworld/tmpl/edit.php file:

admin/views/helloworld/tmpl/edit.php

<?php
// No direct access
defined('_JEXEC') or die('Restricted access');
JHtml::_('behavior.tooltip');
JHtml::_('behavior.formvalidation');
$params = $this->form->getFieldsets('params');
?>
<form action="<?php echo JRoute::_('index.php?option=com_helloworld&layout=edit&id='.(int) $this->item->id); ?>"
      method="post" name="adminForm" id="helloworld-form" class="form-validate">

	<div class="width-60 fltlft">
		<fieldset class="adminform">
			<legend><?php echo JText::_( 'COM_HELLOWORLD_HELLOWORLD_DETAILS' ); ?></legend>
			<ul class="adminformlist">
<?php                      foreach($this->form->getFieldset('details') as $field): ?>
				<li><?php echo $field->label;echo $field->input;?></li>
<?php                      endforeach; ?>
			</ul>
		</fieldset>
	</div>

	<div class="width-40 fltrt">
<?php        echo JHtml::_('sliders.start', 'helloworld-slider');
             foreach ($params as $name => $fieldset):
                echo JHtml::_('sliders.panel', JText::_($fieldset->label), $name.'-params');
                if (isset($fieldset->description) && trim($fieldset->description)): ?>
    	        	<p class="tip"><?php echo $this->escape(JText::_($fieldset->description));?></p>
<?php           endif;?>
		<fieldset class="panelform" >
			<ul class="adminformlist">
<?php                        foreach ($this->form->getFieldset($name) as $field) : ?>
				<li><?php echo $field->label; ?><?php echo $field->input; ?></li>
<?php                        endforeach; ?>
			</ul>
		</fieldset>
<?php        endforeach; ?>

		<?php echo JHtml::_('sliders.end'); ?>
	</div>

	<div>
		<input type="hidden" name="task" value="helloworld.edit" />
		<?php echo JHtml::_('form.token'); ?>
	</div>
</form>

Modifying the frontend[edit]

The frontend has to be modified according to the new show_category parameter.

We have to modify the model:

it has to merge global parameters and individual parameters
it has to provide the category

With your favorite editor, put these lines into the site/models/helloworld.php file:

site/models/helloworld.php

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

// import Joomla modelitem library
jimport('joomla.application.component.modelitem');

/**
 * HelloWorld Model
 */
class HelloWorldModelHelloWorld extends JModelItem
{
	/**
	 * @var object item
	 */
	protected $item;

	/**
	 * Method to auto-populate the model state.
	 *
	 * This method should only be called once per instantiation and is designed
	 * to be called on the first call to the getState() method unless the model
	 * configuration flag to ignore the request is set.
	 *
	 * Note. Calling getState in this method will result in recursion.
	 *
	 * @return	void
	 * @since	2.5
	 */
	protected function populateState() 
	{
		$app = JFactory::getApplication();
		// Get the message id
		$input = JFactory::getApplication()->input;
		$id = $input->getInt('id');
		$this->setState('message.id', $id);

		// Load the parameters.
		$params = $app->getParams();
		$this->setState('params', $params);
		parent::populateState();
	}

	/**
	 * Returns a reference to the a Table object, always creating it.
	 *
	 * @param	type	The table type to instantiate
	 * @param	string	A prefix for the table class name. Optional.
	 * @param	array	Configuration array for model. Optional.
	 * @return	JTable	A database object
	 * @since	2.5
	 */
	public function getTable($type = 'HelloWorld', $prefix = 'HelloWorldTable', $config = array()) 
	{
		return JTable::getInstance($type, $prefix, $config);
	}

	/**
	 * Get the message
	 * @return object The message to be displayed to the user
	 */
	public function getItem() 
	{
		if (!isset($this->item)) 
		{
			$id = $this->getState('message.id');
			$this->_db->setQuery($this->_db->getQuery(true)
				->from('#__helloworld as h')
				->leftJoin('#__categories as c ON h.catid=c.id')
				->select('h.greeting, h.params, c.title as category')
				->where('h.id=' . (int)$id));
			if (!$this->item = $this->_db->loadObject()) 
			{
				$this->setError($this->_db->getError());
			}
			else
			{
				// Load the JSON string
				$params = new JRegistry;
                                // loadJSON is @deprecated    12.1  Use loadString passing JSON as the format instead.
				//$params->loadString($this->item->params, 'JSON');
                                $params->loadJSON($this->item->params);
				$this->item->params = $params;

				// Merge global params with item params
				$params = clone $this->getState('params');
				$params->merge($this->item->params);
				$this->item->params = $params;
			}
		}
		return $this->item;
	}
}

The view has to ask the model for the category. With your favorite editor, put these lines into the site/views/helloworld/view.html.php

site/views/helloworld/view.html.php

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

// import Joomla view library
jimport('joomla.application.component.view');

/**
 * HTML View class for the HelloWorld Component
 */
class HelloWorldViewHelloWorld extends JView
{
	// Overwriting JView display method
	function display($tpl = null) 
	{
		// Assign data to the view
		$this->item = $this->get('Item');

		// Check for errors.
		if (count($errors = $this->get('Errors'))) 
		{
			JError::raiseError(500, implode('<br />', $errors));
			return false;
		}
		// Display the view
		parent::display($tpl);
	}
}

The layout can now display correctly the category or not. With your favorite editor, put these lines into site/views/helloworld/tmpl/default.php

site/views/helloworld/tmpl/default.php

<?php
// No direct access to this file
defined('_JEXEC') or die('Restricted access');
?>
<h1><?php echo $this->item->greeting.(($this->item->category and $this->item->params->get('show_category'))
                                      ? (' ('.$this->item->category.')') : ''); ?>
</h1>

Adding some translation strings[edit]

Some strings have to be added in the admin/language/en-GB/en-GB.com_helloworld.ini file

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

COM_HELLOWORLD="Hello World!"
COM_HELLOWORLD_ADMINISTRATION="HelloWorld - Administration"
COM_HELLOWORLD_ADMINISTRATION_CATEGORIES="HelloWorld - Categories"
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_FIELD_SHOW_CATEGORY_LABEL="Show category"
COM_HELLOWORLD_HELLOWORLD_FIELD_SHOW_CATEGORY_DESC="If set to Show, the title of the message&rsquo;s category will show."
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_N_ITEMS_DELETED_1="One message deleted"
COM_HELLOWORLD_N_ITEMS_DELETED_MORE="%d messages deleted"
COM_HELLOWORLD_SUBMENU_MESSAGES="Messages"
COM_HELLOWORLD_SUBMENU_CATEGORIES="Categories"
COM_HELLOWORLD_CONFIGURATION="HelloWorld Configuration"
COM_HELLOWORLD_CONFIG_GREETING_SETTINGS_LABEL="Messages settings"
COM_HELLOWORLD_CONFIG_GREETING_SETTINGS_DESC="Settings that will be applied to all messages by default"

Packaging the component[edit]

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!1.6. 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="2.5.0" method="upgrade">

	<name>COM_HELLOWORLD</name>
	<!-- The following elements are optional and free of formatting constraints -->
	<creationDate>November 2009</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>0.0.13</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 in 2.5 -->
		<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>
		<folder>language</folder>
	</files>

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

	<administration>
		<!-- Administration Menu Section -->
		<menu 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>config.xml</filename>
			<filename>helloworld.php</filename>
			<filename>controller.php</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 tag="en-GB">language/en-GB/en-GB.com_helloworld.ini</language>
			<language tag="en-GB">language/en-GB/en-GB.com_helloworld.sys.ini</language>
		</languages>
	</administration>

</extension>

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