J2.5:Developing a MVC Component/Adding a model to the site part

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Articles in this series

Developing a Model-View-Controller (MVC) Component  Introduction  Developing a Basic Component  Adding a view to the site part  Adding a menu type to the site part  Adding a model to the site part  Adding a variable request in the menu type  Using the database  Basic backend  Adding language management  Adding backend actions  Adding decorations to the backend  Adding verifications  Adding categories  Adding configuration  Adding ACL  Adding an install/uninstall/update script file  Using the language filter facility  Adding an update server  Example of a Frontend Update Function  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');
// 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.

Navigate

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

Contributors

• Christophe Demko