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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.
In the Joomla!1.6 framework, third party components authors divide their code into three main parts:
- models They manage the data
- controllers They perform tasks, set and get the states of the models and ask the views to display
- views They display the content according to the type (error, feed, html, json, raw, xml) and the layout chosen by the controllers
Setting the controller
In the core code of Joomla, there is a class able to manage controllers: JController. This class has to be extended to be used in our component. In the file site/helloworld.php (entry point of our Hello World component), put these lines
site/helloworld.php
<?php // No direct access to this file defined('_JEXEC') or die('Restricted access'); // import joomla controller library jimport('joomla.application.component.controller'); // Get an instance of the controller prefixed by HelloWorld $controller = JController::getInstance('HelloWorld'); // Perform the Request task $controller->execute(JRequest::getCmd('task')); // Redirect if set by the controller $controller->redirect();
The getInstance static method of the JController class will create a controller. In the code above, it will create a controller named HelloWorldController using the controller.php file (it's a default behavior)
With your favorite file manager and editor, create a site/controller.php file containing
site/controller.php
<?php // No direct access to this file defined('_JEXEC') or die('Restricted access'); // import Joomla controller library jimport('joomla.application.component.controller'); /** * Hello World Component Controller */ class HelloWorldController extends JController { }
When no task is given in the request variables, the default task will be executed. It's the display task by default. The JController class has such a task. In our example, it will display a view named HelloWorld.
Setting the view
With your favorite file manager and editor, create a file site/views/helloworld/view.html.php able to display the default view and containing
site/views/helloworld/view.html.php
<?php // No direct access to this file defined('_JEXEC') or die('Restricted access'); // import Joomla view library jimport('joomla.application.component.view'); /** * HTML View class for the HelloWorld Component */ class HelloWorldViewHelloWorld extends JView { // Overwriting JView display method function display($tpl = null) { // Assign data to the view $this->msg = 'Hello World'; // Display the view parent::display($tpl); } }
The display method of the JView class is called with the display task of the JController class. In our case, this method will display data using the tmpl/default.php file. With your favorite file manager and editor, create a file site/views/helloworld/tmpl/default.php able to display the default view and containing
site/views/helloworld/tmpl/default.php
<?php // No direct access to this file defined('_JEXEC') or die('Restricted access'); ?> <h1><?php echo $this->msg; ?></h1>
This template file will be included by the JView class. Therefore, here, $this refers to the HelloWorldViewHelloWorld class.
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.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!1.6. You can test this basic component by putting index.php?option=com_helloworld in your browser address.
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>[email protected]</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>0.0.2</version> <!-- The description is optional and defaults to the name --> <description>Description of the Hello World component ...</description> <update> <!-- Runs on update; New in 1.6 --> <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> </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>
Result: You will see by default the message contained in the variable $this->msg in the view.html.php file.