Joomla! Documentation™

Joomla! 

3.x

Tutorial

Developing an MVC Component

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. Adding a Frontend Form
18. Adding an Image
19. Adding a Map
20. Adding AJAX
21. Adding an Alias
22. Using the Language Filter Facility
23. Adding a Modal
24. Adding Associations
25. Adding Checkout
26. Adding Ordering
27. Adding Levels
28. Adding Versioning
29. Adding Tags
30. Adding Access
31. Adding a Batch Process
32. Adding Cache
33. Adding a Feed
34. Adding an Update Server
35. Adding Custom Fields
36. Upgrading to Joomla4

This is a multiple-article series of tutorials on how to develop a Model-View-Controller Component for Joomla! Version.

Begin with the Introduction, and navigate the articles in this series by using the navigation button at the bottom or the box to the right (the Articles in this series).

Note

• This tutorial is part of the Developing a MVC Component for Joomla! 3.x tutorial. You are encouraged to read the previous parts of the tutorial before reading this.

• You can follow the steps below to add a menu item to the Hello World! component, or you can directly download the archive

• You can watch a video associated with this step in the tutorial at Step 3, Adding a Menu Part.

Adding a Menu Item to Hello World

In this article we will cover how to add a menu item to a basic Joomla! component. For this example we will be continuing our work on the Hello World! component.

There are several ways to update a Joomla! component. As with the last tutorial, we will focus option 2.

1	Manually add the files into <path_to_joomla>/
2	Update using the Joomla! Extension Manager and the original directory, non-compressed, used for the component install
3	Update using the Joomla! Extension Manager and an Update Server

To add a menu item you will need to navigate to com_helloworld, which is the original directory we made for our component. You must use the updated directory structure from the last tutorial. Using your preferred file manager, create or update the following files; as you create or update the files, add the source code for each file which is found in File Details.

1	Create: default.xml	<path_to_com_helloworld/site/views/helloworld/tmpl/default.xml
2	Update: helloworld.xml	<path_to_com_helloworld/helloworld.xml

Updating the Hello World! Component

To update the Hello World! Component in the Joomla! website, please follow the same steps for the original installation.

After the component has been updated, we will be able to add a Menu Item to it. This will allow us to access our component a menu rather than having to remember what to type into the address bar. We'll do this using the Menu Manager of Joomla!.

• Using your preferred web browser, navigate to the Administrator panel of your Joomla! site. The address would be <yoursite>/joomla/administrator/index.php. For this example we will navigate to localhost/joomla/administrator/index.php.
• Add a new menu item by clicking on Menu  →  <existing menu>  →  Add New Menu Item. A new screen will appear.
• In the "Menu Title" field, enter "Hello World!"
• In the "Menu Type" field, click on the "Select" button and choose Hello World!  →  Hello World from the selection screen.
• Click Save & Close

You should now be able to access the component through the menu that you just created.

File Details

site/views/helloworld/tmpl/default.xml

<?xml version="1.0" encoding="utf-8"?>
<metadata>
	<layout title="COM_HELLOWORLD_HELLOWORLD_VIEW_DEFAULT_TITLE">
		<message>COM_HELLOWORLD_HELLOWORLD_VIEW_DEFAULT_DESC</message>
	</layout>
</metadata>

helloworld.xml

<?xml version="1.0" encoding="utf-8"?>
<extension type="component" version="3.0" method="upgrade">

	<name>Hello World!</name>
	<!-- The following elements are optional and free of formatting constraints -->
	<creationDate>January 2018</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>0.0.3</version>
	<!-- The description is optional and defaults to the name -->
	<description>Description of the Hello World component ...</description>

	<update> <!-- Runs on update; New since J2.5 -->
		<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 link='index.php?option=com_helloworld'>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>

Code Explanation

In case you were curious as to why this works the way it does.

default.xml

Note - For the moment the strings won't be translated in the administrator interface. We will see in a later article how translation is performed.

helloworld.xml

<version>0.0.3</version>

Updates the version number.

Component Contents

At this point in the tutorial, your component should contain the following files:

1	helloworld.xml	this is an XML (manifest) file that tells Joomla! how to install our component.
2	site/helloworld.php	this is the site entry point to the Hello World! component
3	site/index.html	prevents web server from listing directory content
4	site/controller.php	file representing the controller
5	site/views/index.html	prevents web server from listing directory content
6	site/views/helloworld/index.html	prevents web server from listing directory content
7	site/views/helloworld/view.html.php	file representing the view
8	site/views/helloworld/tmpl/index.html	prevents web server from listing directory content
9	site/views/helloworld/tmpl/default.php	the default view
10	site/views/helloworld/tmpl/default.xml	file that adds menu item
11	admin/index.html	prevents web server from listing directory content
12	admin/helloworld.php	this is the administrator entry point to the Hello World! component
13	admin/sql/index.html	prevents web server from listing directory content
14	admin/sql/updates/index.html	prevents web server from listing directory content
15	admin/sql/updates/mysql/index.html	prevents web server from listing directory content
16	admin/sql/updates/mysql/0.0.1.sql	file allowing to initialise schema version of the com_helloworld component.

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