Archived:Developing a MVC Component/Adding a model to the site part

This page has been archived. This page contains information for an unsupported Joomla! version or is no longer relevant. It exists only as a historical reference, it will not be improved and its content may be incomplete and/or contain broken links.

Under Construction

Articles in this series

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. Using the language filter facility
18. Adding an update server
19. Example of a Frontend Update Function
20. Example of Menu Parameters & Stylesheets

Introduction

This tutorial is part of the Developing a Model-View-Controller (MVC) Component for Joomla!1.6 tutorial. You are encouraged to read the previous parts of the tutorial before reading this.

Adding a model

In the Joomla!1.6 framework, models ares responsible for managing the data. The first function that has to written for a model is a get function. It returns data to the caller. In our case, the caller will be the HelloWorldViewHelloWorld view. By default, the model named HelloWorldModelHelloWorld is the main model associated to this view. with your favorite file manager and editor put a site/models/helloworld.php file containing:

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');
// inherit the JModelItem class
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)) 
		{
			$this->msg = 'Hello World!';
		}
		return $this->msg;
	}
}

The HelloWorldViewHelloWorld class asks the model for data using the get method of the JView class:

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');
// inherit the JView class
class HelloWorldViewHelloWorld extends JView {
	protected $msg=null;
	// Overwriting JView display method
	function display($tpl = null) {
		// Assign data to the view
		$this->msg = $this->get('Msg');
		// Display the view
		parent::display($tpl);
	}
}

Also modify your helloworld.xml file to indicate use of models and the new version:

helloworld.xml

<?xml version="1.0" encoding="utf-8"?>
<extension type="component" version="1.6.0" method="upgrade">
	<name>Hello World!</name>
	<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>
	<version>0.0.4</version>
	<description>Description of the Hello World component ...</description>

	<files folder="site">
		<filename>index.html</filename>
		<filename>helloworld.php</filename>
		<filename>controller.php</filename>
		<folder>views</folder>
		<!-- Include the models folder -->
		<folder>models</folder>
	</files>

	<administration>
		<menu>Hello World!</menu>
		<files folder="admin">
			<filename>index.html</filename>
			<filename>helloworld.php</filename>
		</files>		
	</administration>
</extension>

Packaging the component

Content of your code directory

• helloworld.xml
• site/index.html
• site/helloworld.php
• 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

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.

Contributors

• Christophe Demko