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3.x

<translate> Tutorial</translate>

<translate> Developing an MVC Component</translate>

{{Chunk:Developing a Model-View-Controller (MVC) Component for Joomla!3.1 - Contents/<translate> en</translate>}} <translate> This is a multiple-article series of tutorials on how to develop a Model-View-Controller Component for Joomla! Version.</translate>

<translate> 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).</translate>

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.

Adding a variable request in the menu type

For the moment, the displayed message is always Hello World!. Joomla!2.5 gives the possibility to add parameters to menu types. In our case, this is done in the site/views/helloworld/tmpl/default.xml file:

site/views/helloworld/tmpl/default.xml

<?xml version="1.0" encoding="utf-8"?>
<metadata>
	<layout title="COM_HELLOWORLD_HELLOWORLD_VIEW_DEFAULT_TITLE">
		<message>COM_HELLOWORLD_HELLOWORLD_VIEW_DEFAULT_DESC</message>
	</layout>
	<fields name="request">
		<fieldset name="request">
			<field
				name="id"
				type="list"
				label="COM_HELLOWORLD_HELLOWORLD_FIELD_GREETING_LABEL"
				description="COM_HELLOWORLD_HELLOWORLD_FIELD_GREETING_DESC"
				default="1">
				<option value="1">Hello World!</option>
				<option value="2">Good bye World!</option>
			</field>
		</fieldset>
	</fields>
</metadata>

Two important things to note:

• the request group of fields indicates mandatory fields
• the name attribute can be passed to the component in the URL. In this case ?option=com_helloworld&id=1 would indicate that you had chosen option 1.

The model has to be modified in order to switch between the two different messages (which is chosen by the user with the field defined above):

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 string msg
	 */
	protected $msg;
 
	/**
	 * Get the message
	 * @return string The message to be displayed to the user
	 */
	public function getMsg() 
	{
		if (!isset($this->msg)) 
		{

			$jinput = JFactory::getApplication()->input;
			$id     = $jinput->get('id', 1, 'INT');

			switch ($id) 
			{
			case 2:
				$this->msg = 'Good bye World!';
			break;
			default:
			case 1:
				$this->msg = 'Hello World!';
			break;
			}
		}
		return $this->msg;
	}
}

Also modify your helloworld.xml file to indicate the new version:

helloworld.xml

<?xml version="1.0" encoding="utf-8"?>
<extension type="component" version="3.2.0" method="upgrade">

	<name>Hello World!</name>
	<!-- The following elements are optional and free of formatting constraints -->
	<creationDate>January 2014</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>0.0.5</version>
	<!-- The description is optional and defaults to the name -->
	<description>Description of the Hello World component ...</description>

	<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>
	</files>

	<administration>
		<!-- Administration Menu Section -->
		<menu>Hello World!</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>
			<!-- SQL files section -->
			<folder>sql</folder>
		</files>
	</administration>

</extension>

You can test this variable request by putting index.php?option=com_helloworld&id=1 or index.php?option=com_helloworld&id=2 in your browser address.

Packaging the component

Content of your code directory

• 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
• admin/index.html
• admin/helloworld.php
• admin/sql/index.html
• admin/sql/updates/index.html
• admin/sql/updates/mysql/index.html
• admin/sql/updates/mysql/0.0.1.sql

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.

J3.x:Developing a MVC Component/Navigate

Contributors

• Christophe Demko
• Ozgur Aksu
• Matt Thomas