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Rvsjoen/tutorial/Developing an MVC Component/Part 06

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< User:Rvsjoen‎ | tutorial/Developing an MVC Component
Revision as of 04:47, 11 July 2011 by Rvsjoen (talk | contribs) (→‎Creating a table)

Using a database[edit]

We would like to store our hello messages in the database, and to allow the admins to choose which message to show using a field in the menu item options. The order order of business is to create some SQL tables.

SQL install/uninstall[edit]

admin/sql/install.mysql.utf8.sql 

DROP TABLE IF EXISTS `#__helloworld`;

CREATE TABLE `#__helloworld` (
  `id` int(11) NOT NULL auto_increment,
  `greeting` varchar(25) NOT NULL,
   PRIMARY KEY  (`id`)
) ENGINE=MyISAM AUTO_INCREMENT=0 DEFAULT CHARSET=utf8;

INSERT INTO `#__helloworld` (`greeting`) VALUES
        ('Hello World!'),
        ('Good bye World!');

admin/sql/uninstall.mysql.utf8.sql 

DROP TABLE IF EXISTS `#__helloworld`;

Creating a table[edit]

site/models/helloworld.php 

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

jimport('joomla.database.table');

class TableHelloWorld extends JTable
{
        function __construct(&$db) 
        {
                parent::__construct('#__helloworld', 'id', $db);
        }
}

Updating the model[edit]

site/models/helloworld.php 

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

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

class HelloWorldModelHelloWorld extends JModelItem
{
        protected $item;

        /**
         * Get the message
         * @return string The message to be displayed to the user
         */
        public function getItem() 
        {
                if (!isset($this->item)) {
                        $id = JRequest::getInt('id');
                        // Get a TableHelloWorld instance
                        $table = $this->getTable();

                        // Load the message
                        $table->load($id);

                        // Assign the message
                        $this->item = $table->greeting;
                }
                return $this->item;
        }
}

Creating a form field[edit]

admin/models/fields/helloworld.php 

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

jimport('joomla.form.helper');

JFormHelper::loadFieldClass('list');

class JFormFieldHelloWorld extends JFormFieldList
{
        protected $type = 'HelloWorld';

        protected function getOptions()
        {
                $db = JFactory::getDBO();
                $query = $db->getQuery(true);
                $query->select('id,greeting');
                $query->from('#__helloworld');
                $db->setQuery((string)$query);
                $messages = $db->loadObjectList();
                $options = array();
                if($messages){
                        foreach($messages as $message){
                                $options[] = JHtml::_('select.option', $message->id, $message->greeting);
                        }
                }
                $options = array_merge(parent::getOptions(), $options);
                return $options;
        }
}

Installation manifest[edit]

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>0.0.6</version>
        <!-- The description is optional and defaults to the name -->
        <description>Description of the Hello World component ...</description>

        <install>
                <sql>
                        <file driver="mysql" charset="utf8">sql/install.mysql.utf8.sql</file>
                </sql>
        </install>
        <uninstall>
                <sql>
                        <file driver="mysql" charset="utf8">sql/uninstall.mysql.utf8.sql</file>
                </sql>
        </uninstall>

        <!-- 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>
                <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>
                        <folder>sql</folder>
                        <folder>tables</folder>
                        <folder>models</folder>
                </files>
        </administration>

</extension>


Testing your component[edit]

For details on how to install the component into your Joomla! site, refer to the information provided in Part 01.

In order to test this component, go to the administrator interface and create a new menu item. In the menu item type selection interface, pick Hello World as the menu item type. In the options of the menu item you will be able to choose which hello message to show from the database, the message you choose should be displayed in the frontend as in the previous part.

File listing[edit]

Download this part[edit]

com_helloworld-part01.zip

Articles in this series[edit]

This tutorial is supported by the following versions of Joomla!

Joomla 2.5

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