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This tutorial is for {{JVer|1.6}} {{JVer|1.7}} {{JVer|2.5}}
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{{version/tutor|2.5}}
 
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== Articles in this series ==
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{{Chunk:Developing a Model-View-Controller (MVC) Component for Joomla!2.5 - Contents}}
 
{{Chunk:Developing a Model-View-Controller (MVC) Component for Joomla!2.5 - Contents}}
  
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== Adding a model ==
 
== Adding a model ==
In the Joomla 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:
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In the Joomla 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'' residing in ''site/models/helloworld.php'' is the main model associated to this view.  
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So let's have a quick look at the naming conventions with an example, since the naming convention are the actual magic, that make everything work:
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The class ''HelloWorldView'''HelloWorld''''' resides in ''site/views/'''helloworld'''/view.html.php'' and will make use of the class ''HelloWorldModel'''HelloWorld''''' in the file ''site/models/'''helloworld'''.php''
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So let's just assume we want to use an imaginary view ''fluffy'', you would have to have:
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The class ''HelloWorldView'''Fluffy''''' which resides in ''site/views/'''fluffy'''/view.html.php''. The view will make use of ''HelloWorldModel'''Fluffy''''' in the file ''site/models/'''fluffy'''.php''. Note: the actual screen of the view: ''site/views/'''fluffy'''/tmpl/default.php'' is required as well to make this example work.
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Breaking any of these bold conventions will lead to errors or a blank page.
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So back to the actual implementation of the single classes:
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With your favorite file manager and editor put a ''site/models/helloworld.php'' file containing:
  
 
<span id="site/models/helloworld.php">
 
<span id="site/models/helloworld.php">
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if (count($errors = $this->get('Errors')))  
 
if (count($errors = $this->get('Errors')))  
 
{
 
{
JError::raiseError(500, implode('<br />', $errors));
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JLog::add(implode('<br />', $errors), JLog::WARNING, 'jerror');
 
return false;
 
return false;
 
}
 
}
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Create a compressed file of this directory or directly download the [http://joomlacode.org/gf/download/frsrelease/11394/58228/com_helloworld-1.6-part04.zip archive] and install it using the extension manager of Joomla. You can add a menu item of this component using the menu manager in the backend.
 
Create a compressed file of this directory or directly download the [http://joomlacode.org/gf/download/frsrelease/11394/58228/com_helloworld-1.6-part04.zip archive] and install it using the extension manager of Joomla. You can add a menu item of this component using the menu manager in the backend.
 
== Zips ==
 
Download the zip file for this Part:
 
[http://www.leyar.com/joomlaorg/part04.zip]
 
  
 
== Navigate ==
 
== Navigate ==
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*[[User:cdemko|Christophe Demko]]
 
*[[User:cdemko|Christophe Demko]]
 
*[[User:oaksu|Ozgur Aksu]]
 
*[[User:oaksu|Ozgur Aksu]]
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*[[User:Jossnaz|Lukas Meier]]
  
 
[[Category:Development]]
 
[[Category:Development]]
[[category:Joomla! 1.6]]
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[[Category:Joomla! 1.6]]
[[category:Joomla! 1.7]]
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[[Category:Joomla! 1.7]]
[[category:Joomla! 2.5]]
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[[Category:Joomla! 2.5]]
[[category:Manual]]
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'''Bold text'''
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Latest revision as of 18:13, 31 December 2013


Introduction

This tutorial is part of the Developing a Model-View-Controller (MVC) Component for Joomla!2.5 tutorial. You are encouraged to read the previous parts of the tutorial before reading this.

Adding a model

In the Joomla 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 residing in site/models/helloworld.php is the main model associated to this view.


So let's have a quick look at the naming conventions with an example, since the naming convention are the actual magic, that make everything work:

The class HelloWorldViewHelloWorld resides in site/views/helloworld/view.html.php and will make use of the class HelloWorldModelHelloWorld in the file site/models/helloworld.php


So let's just assume we want to use an imaginary view fluffy, you would have to have:

The class HelloWorldViewFluffy which resides in site/views/fluffy/view.html.php. The view will make use of HelloWorldModelFluffy in the file site/models/fluffy.php. Note: the actual screen of the view: site/views/fluffy/tmpl/default.php is required as well to make this example work.


Breaking any of these bold conventions will lead to errors or a blank page.


So back to the actual implementation of the single classes:

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'))) 
                {
                        JLog::add(implode('<br />', $errors), JLog::WARNING, 'jerror');
                        return false;
                }
                // Display the view
                parent::display($tpl);
        }
}

Note: $this->get() is a member of JView::get which is a proxy to get* methods of the default model where * is populated with the value of the first parameter passed to get()

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="2.5.0" method="upgrade">
 
        <name>Hello World!</name>
        <!-- The following elements are optional and free of formatting constraints -->
        <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>
 
        <update> <!-- Runs on update; New in 2.5 -->
                <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>
                <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>
                        <!-- SQL files section -->
                        <folder>sql</folder>
                </files>
        </administration>
 
</extension>

Packaging the component

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. You can add a menu item of this component using the menu manager in the backend.

Navigate

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