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

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< J2.5:Developing a MVC Component
Revision as of 20:52, 20 November 2010 by Cdemko (Talk | contribs)


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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 are responsible for managing the data. The first function that has to be 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:


// No direct access to this file
defined('_JEXEC') or die('Restricted access');
// import Joomla modelitem library
// 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:


// No direct access to this file
defined( '_JEXEC' ) or die( 'Restricted access' );
// import Joomla view library
// inherit the JView class
class HelloWorldViewHelloWorld extends JView
	// Overwriting JView display method
	function display($tpl = null) 
		// Assign data to the view
		$this->msg = $this->get('Msg');
		// Check for errors.
		if (count($errors = $this->get('Errors'))) {
			JError::raiseError(500, implode("<br />", $errors));
			return false;
		// Display the view

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


<?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>
	<copyright>Copyright Info</copyright>
	<license>License Info</license>
	<description>Description of the Hello World component ...</description>
	<files folder="site">
		<!-- Include the models folder -->
		<menu>Hello World!</menu>
		<files folder="admin">

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!1.6. You can add a menu item of this component using the menu manager in the backend.


Prev: Adding a menu type to the site part Next: Adding a variable request in the menu type


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