Revision as of 09:40, 10 July 2011

Adding a view to the frontend[edit]

In order to create a basic view for the frontend, we first need to have some logic in our previously created entry point site/helloworld.php that decides how to handle requests which are passed to the component. We will manage this my having the entry point load up a controller and execute it, so the first order of business is creating a controller.

Creating a controller[edit]

In the core code of Joomla, the class that implements a controller is named JController. In order to save ourselves a lot of work, and prevent having to reinvent the wheel, this class can be extended to be used in our component.

In the file site/helloworld.php put the following code

site/helloworld.php

<?php
// No direct access to this file
defined('_JEXEC') or die;

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 static getInstance 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 in the same location as the entry point. This means that we have to create this controller so that it has something to load.

With your favorite editor, create the following file

site/controller.php

<?php
// No direct access to this file
defined('_JEXEC') or die;

jimport('joomla.application.component.controller');

class HelloWorldController extends JController
{

}

Yes really, that is it. We do not have to provide any code in our controller except for this. This is because the default behavior of JController is to call the display task if not other task is given, and the display task will look for the name of the view to load in the view request variable. If no view name is given, it will load the view with the same name as the component, namely helloworld.

Setting the view[edit]

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[edit]

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 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 constraints -->
	<creationDate>June 2011</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 stored 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>

	<!-- 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>
		<menu>Hello World!</menu>
		<!-- 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">
			<filename>index.html</filename>
			<filename>helloworld.php</filename>
		</files>
	</administration>

</extension>

Result: You will see by default the message contained in the variable $this->msg in the view.html.php file.

Download this part[edit]

com_helloworld-part01.zip

Articles in this series[edit]

This tutorial is supported by the following versions of Joomla!

@@ Line 28: / Line 28: @@
 </span>
-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)
+The static ''getInstance'' 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 in the same location as the entry point. This means that we have to create this controller so that it has something to load.
-With your favorite file manager and editor, create a ''site/controller.php'' file containing
+With your favorite editor, create the following file
 <span id="site/controller.php">
-''site/controller.php''
+'''<tt>site/controller.php</tt>'''
 <source lang="php">
 <?php
 // No direct access to this file
-defined('_JEXEC') or die('Restricted access');
+defined('_JEXEC') or die;
-// import Joomla controller library
 jimport('joomla.application.component.controller');
-/**
- * Hello World Component Controller
- */
 class HelloWorldController extends JController
 {
 }
 </source>
 </span>
-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''.
+Yes really, that is it. We do not have to provide any code in our controller except for this. This is because the default behavior of JController is to call the '''display''' task if not other task is given, and the '''display''' task will look for the name of the view to load in the '''view''' request variable. If no view name is given, it will load the view with the same name as the component, namely '''helloworld'''.
 == Setting the view ==

User

Difference between revisions of "Rvsjoen/tutorial/Developing an MVC Component/Part 02"

From Joomla! Documentation

< User:Rvsjoen‎ | tutorial/Developing an MVC Component