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

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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 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:

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)) 
		{
			$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');

/**
 * 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->msg = $this->get('Msg');

		// Check for errors.
		if (count($errors = $this->get('Errors'))) 
		{
			JError::raiseError(500, implode('<br />', $errors));
			return false;
		}
		// Display the view
		parent::display($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>
	<!-- The following elements are optional and free of formatting conttraints -->
	<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>0.0.4</version>
	<!-- The description is optional and defaults to the name -->
	<description>Description of the Hello World component ...</description>

	<!-- 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>
		</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.

Navigate

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

Contributors

• Christophe Demko

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