J3.x

J3.x:Developing an MVC Component/Adding Associations

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< J3.x:Developing an MVC Component

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Joomla! 
3.x
Tutorial
Developing an MVC Component


This is a multiple-article series of tutorials on how to develop a Model-View-Controller Component for Joomla! VersionJoomla 3.x.

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).



This tutorial is part of the Developing an MVC Component for Joomla! 3.2 tutorial. You are encouraged to read the previous parts of the tutorial before reading this.

In this step we add multilingual associations.

There are 3 videos accompanying this step, covering the Helloworlds view, the Edit and Multilingual Associations functionality, and the Front End changes.

Introduction

In this step we enhance our component to support multilingual associations, which enable us to associate an item in one language with its equivalent in another language. This functionality is useful in a number of respects:

  • Primarily it assists administrators of a multilingual site in maintenance of the data across the different languages. From a practical data management perspective, it's essential to have some mechanism for keeping track of which items are the equivalents of others in different languages, and implementing Joomla associations on your component means that administrators can use the same processes as they would for other Joomla items such as articles, menus and contacts.
  • On the front end a user can click on the symbol within the language switcher to go to the equivalent item in another language.
  • In the html header Joomla outputs links to the equivalent items in other languages using the hreflang attribute. This enables search engines to find these equivalents, which they then use to try to deliver more pertinent search results to users.
  • Translators can use the Joomla Multilingual Associations component to display in a side-by-side view the item in the reference language and its equivalent in the target language, thus aiding the process of translation.

The development of this functionality will involve introducing some of the APIs around the Joomla form class JForm.

Functionality

We enhance our helloworld component to support associations for both helloworld records (items) and helloworld categories.

On the back end we allow administrators to set associations as part of editing helloworld items or categories, and extend the list view to display the defined associations. We also enable the use of the Joomla Multilingual Associations component.

On the front end we provide the ability for users to switch to the associated helloworld item or category whenever they click on a flag symbol within the language switcher. And we ensure that the hreflang links in the html head element are set correctly.

Approach

Global Configuration

To use associations the site must be configured as multilingual, which basically means that the Joomla System Language Filter plugin must be enabled, and this will result in JLanguageMultilang::isEnabled() returning true. Associated with this plugin is an option Item Associations which can be set to Yes or No, and this should control whether we enable association functionality on our component. Joomla provides a function JLanguageAssociations::isEnabled() which returns true if JLanguageMultilang::isEnabled() and the Item Associations option is set to Yes, so we need to check this before displaying associations functionality on the back end.

Database Access

Associations are stored in the Joomla associations table, which has 3 fields

  • context − the type of record to which this association refers, eg com_menus.item, or com_categories.item
  • id - the id of the record to which the association refers, eg the menuitem id, or category id
  • key - a field which allows Joomla to find the other records which are associated with this one, because they all have the same key. (Joomla takes an array of the ids + context of the records which are associated together, JSON-encodes this to form a string, and takes an MD5 hash of the string to form the value of the key which is then stored in each of those records).

Joomla provides a function JLanguageAssociations::getAssociations which enables components to find associated records. You pass it the context and id of your record, and it then finds records in the associations table which have the same key as yours, passing back the results in the form of an associative array, keyed by the language tag. As we will see, it will also return additional information about the resultant records, such as the alias and category id, provided we tell it where we store that data, so that it can add the appropriate SQL JOIN clauses. (Although within its code it does a SQL INNER join with the category table, so it doesn't find associations which don't have a valid category).

(Just be aware we are going to have 2 other functions which are also called getAssociations, one in our com_associations helper file and one in our front end helper file. It's easy to get confused!)

Code for updating and deleting the association records is in the JModelAdmin class, which our own administrator helloworld model inherits from, and to reuse this we just need to specify the $associationsContext we're using for our associations.

Helloworlds Display

We'll add another column in our display for the associations. After obtaining the associations as described above we'll use a standard layout file used by Joomla core components for displaying the associations. Following the example of other components, we'll put this code in a function within a helper file which will be called from our helloworlds layout file, even though with an MVC implementation obtaining the associations details would usually fit within the remit of the model.

Helloworld Edit

In line with other Joomla components we add in our edit.php layout file another bootstrap tab where the administrator can set the associations. On this tab we'll put fields to select an association for each of the other contact languages on our system, but because we don't know how many other languages will be installed we have to add these fields dynamically (in our model) using the JForm APIs, rather than specifying them in an XML file.

When the administrator presses the select button to select the associated record we'll show a modal displaying the helloworld records, just as we did in the previous tutorial step when defining a menuitem, and we'll reuse the modal field definition code which we developed there. However in this case, when the modal is shown, we want to restrict the records displayed to only those with the correct language, and to enable this we use an extra parameter forcedLanguage, which is set to the tag of the content language in question.

As usual, when editing records we need to prefill the form with any existing associations.

Finally, in our model we define the $associationsContext so that the JModelAdmin code can handle looking after the database updates of the associations records.

Enabling the Multilingual Associations component

First of all we need to provide some configuration data (as described in Multilingual Associations / Developers) to enable the Multilingual Associations (com_associations) component to work with our helloworld component. We also need to define a couple of language strings for the drop-down selection box for choosing which record types to work with.

Once the user selects the type of record, the reference and target records can be displayed side-by-side in 2 iframes. In our case the URL for the iframes will be similar to when the administrator clicks on a record in the helloworlds view, namely passing the id of the record with task=helloworld.edit. So we will be reusing our MVC code for editing a helloworld record, but two changes will be necessary to generate the display we need.

Firstly, as these edit forms will be in an iframe, we won't want the Joomla menu headers displayed, so we will adopt the same approach as in the previous step when we added a modal, and use the &tmpl=component URL parameter.

Also com_associations doesn't allow the user to change the language or associations within the iframes, and it implements that by hiding our fields and displaying its own fields which show just the current value, and to display these fields properly we need to include the Chosen library using JHtml::_('formbehavior.chosen', 'select').

Linking to associated records on the front end

When Joomla is generating the hreflang and language switcher links for our helloworld component on the front end it looks for a class HelloworldHelperAssociation in a helper file association.php, and tries to call a getAssociations method of that class, and this is what we have to code. Joomla passes in the view and record id, and we return the id of the associated helloworld record or category.

Enabling Associations for helloworld categories

Joomla comes with all the code to support associations for our helloworld categories. It checks if the front end helper file association.php is present, with the correct class HelloworldHelperAssociation, and if so, it enables the functionality to set category associations on the back end, and to use them on the front end.

Other consequential changes

We're now using our Helloworlds view in 3 different contexts

  1. Displaying a table of our helloworld records when the administrator clicks on Components / Hello World - functionality developed some time ago
  2. Displaying the helloworld records in a modal when the administrator is defining a site menuitem pointing at a helloworld record, and needs to choose the record to be shown - functionality developed in the previous step, Adding a Modal
  3. Displaying the language-specific records in a modal to allow the administrator to select the associated helloworld record - functionality from this step.

With each of these we're displaying the filter/search fields at the top of the form, and as described in the step Adding Decorations to the Backend, whenever an administrator selects eg a filter in one of these fields the information is stored in the user session, so that when the form is redisplayed the same filter is applied. The problem is that currently this information is stored in the same place for all 3 contexts, so for example, if the administrator is choosing a French record for an association, and then clicks on Components / Hello World, then it will show just the French records in the table.

To fix this in our helloworlds model we need to determine which context it is, and set the $context variable differently, as it's this JModelAdmin protected variable which acts as a key for this session information. (Note that this context has nothing to do with the context field in the associations table.)

As well as that, we'll need to make some changes to our helloworld custom router.

Admin Helloworlds MVC

For our administrator helloworlds display there are no changes required to the controller, but the other source files need updated.

In the helloworlds model the changes are as follows:

  • Adding associations into the SQL query. In the model we only determine if a record has an association in the associations table, and we obtain the actual associated records in the helper file further below.
  • Adding 'association' into the array of filter_fields, which is the list of columns for which sorting is allowed.
  • Setting the $context variable to separate the user session information for the different contexts in which the helloworlds display is used.

admin/models/helloworlds.php

<?php
/**
 * @package     Joomla.Administrator
 * @subpackage  com_helloworld
 *
 * @copyright   Copyright (C) 2005 - 2018 Open Source Matters, Inc. All rights reserved.
 * @license     GNU General Public License version 2 or later; see LICENSE.txt
 */
// No direct access to this file
defined('_JEXEC') or die('Restricted access');

/**
 * HelloWorldList Model
 *
 * @since  0.0.1
 */
class HelloWorldModelHelloWorlds extends JModelList
{
	/**
	 * Constructor.
	 *
	 * @param   array  $config  An optional associative array of configuration settings.
	 *
	 * @see     JController
	 * @since   1.6
	 */
	public function __construct($config = array())
	{
		if (empty($config['filter_fields']))
		{
			$config['filter_fields'] = array(
				'id',
				'greeting',
				'author',
				'created',
				'language',
				'association',
				'published'
			);
		}

		parent::__construct($config);
	}

	protected function populateState($ordering = null, $direction = null)
	{
		$app = JFactory::getApplication();

		// Adjust the context to support modal layouts.
		if ($layout = $app->input->get('layout'))
		{
			$this->context .= '.' . $layout;
		}

		// Adjust the context to support forced languages.
		$forcedLanguage = $app->input->get('forcedLanguage', '', 'CMD');
		if ($forcedLanguage)
		{
			$this->context .= '.' . $forcedLanguage;
		}

		parent::populateState($ordering, $direction);
        
		// If there's a forced language then define that filter for the query where clause
		if (!empty($forcedLanguage))
		{
			$this->setState('filter.language', $forcedLanguage);
		}
	}

	/**
	 * Method to build an SQL query to load the list data.
	 *
	 * @return      string  An SQL query
	 */
	protected function getListQuery()
	{
		// Initialize variables.
		$db    = JFactory::getDbo();
		$query = $db->getQuery(true);

		// Create the base select statement.
		$query->select('a.id as id, a.greeting as greeting, a.published as published, a.created as created, 
			  a.image as imageInfo, a.latitude as latitude, a.longitude as longitude, a.alias as alias, a.language as language')
			  ->from($db->quoteName('#__helloworld', 'a'));

		// Join over the categories.
		$query->select($db->quoteName('c.title', 'category_title'))
			->join('LEFT', $db->quoteName('#__categories', 'c') . ' ON c.id = a.catid');
        
		// Join with users table to get the username of the author
		$query->select($db->quoteName('u.username', 'author'))
			->join('LEFT', $db->quoteName('#__users', 'u') . ' ON u.id = a.created_by');

		// Join with languages table to get the language title and image to display
		// Put these into fields called language_title and language_image so that 
		// we can use the little com_content layout to display the map symbol
		$query->select($db->quoteName('l.title', 'language_title') . "," .$db->quoteName('l.image', 'language_image'))
			->join('LEFT', $db->quoteName('#__languages', 'l') . ' ON l.lang_code = a.language');

		// Join over the associations - we just want to know if there are any, at this stage
		if (JLanguageAssociations::isEnabled())
		{
			$query->select('COUNT(asso2.id)>1 as association')
				->join('LEFT', '#__associations AS asso ON asso.id = a.id AND asso.context=' . $db->quote('com_helloworld.item'))
				->join('LEFT', '#__associations AS asso2 ON asso2.key = asso.key')
				->group('a.id');
		}

		// Filter: like / search
		$search = $this->getState('filter.search');

		if (!empty($search))
		{
			$like = $db->quote('%' . $search . '%');
			$query->where('greeting LIKE ' . $like);
		}

		// Filter by published state
		$published = $this->getState('filter.published');

		if (is_numeric($published))
		{
			$query->where('a.published = ' . (int) $published);
		}
		elseif ($published === '')
		{
			$query->where('(a.published IN (0, 1))');
		}

		// Filter by language, if the user has set that in the filter field
		$language = $this->getState('filter.language');
		if ($language)
		{
			$query->where('a.language = ' . $db->quote($language));
		}

		// Add the list ordering clause.
		$orderCol	= $this->state->get('list.ordering', 'greeting');
		$orderDirn 	= $this->state->get('list.direction', 'asc');

		$query->order($db->escape($orderCol) . ' ' . $db->escape($orderDirn));

		return $query;
	}
}

We also have to change the definition of the ordering field within the filter fields XML definition file to allow ordering by the association.

admin/models/forms/filter_helloworlds.xml

<?xml version="1.0" encoding="utf-8"?>
<form>
	<fields name="filter">
		<field
			name="search"
			type="text"
			label="COM_BANNERS_SEARCH_IN_TITLE"
			hint="JSEARCH_FILTER"
			class="js-stools-search-string"
		/>
		<field
			name="published"
			type="status"
			label="JOPTION_SELECT_PUBLISHED"
			description="JOPTION_SELECT_PUBLISHED_DESC"
			onchange="this.form.submit();"
			>
			<option value="">JOPTION_SELECT_PUBLISHED</option>
		</field>
		<field
			name="language"
			type="contentlanguage"
			label="JOPTION_FILTER_LANGUAGE"
			description="JOPTION_FILTER_LANGUAGE_DESC"
			onchange="this.form.submit();"
			>
			<option value="">JOPTION_SELECT_LANGUAGE</option>
			<option value="*">JALL</option>
		</field>
	</fields>
	<fields name="list">
		<field
			name="fullordering"
			type="list"
			label="COM_HELLOWORLD_LIST_FULL_ORDERING"
			description="COM_HELLOWORLD_LIST_FULL_ORDERING_DESC"
			onchange="this.form.submit();"
			default="greeting ASC"
			>
			<option value="">JGLOBAL_SORT_BY</option>
			<option value="greeting ASC">COM_HELLOWORLD_ORDERING_ASC</option>
			<option value="greeting DESC">COM_HELLOWORLD_ORDERING_DESC</option>
			<option value="id ASC">JGRID_HEADING_ID_ASC</option>
			<option value="id DESC">JGRID_HEADING_ID_DESC</option>
			<option value="published ASC">COM_HELLOWORLD_PUBLISHED_ASC</option>
			<option value="published DESC">COM_HELLOWORLD_PUBLISHED_DESC</option>
			<option value="author ASC">COM_HELLOWORLD_AUTHOR_ASC</option>
			<option value="author DESC">COM_HELLOWORLD_AUTHOR_DESC</option>
			<option value="created ASC">COM_HELLOWORLD_CREATED_ASC</option>
			<option value="created DESC">COM_HELLOWORLD_CREATED_DESC</option>
			<option value="language ASC">COM_HELLOWORLD_LANGUAGE_ASC</option>
			<option value="language DESC">COM_HELLOWORLD_LANGUAGE_DESC</option>
			<option value="association ASC">COM_HELLOWORLD_ASSOCIATION_ASC</option>
			<option value="association DESC">COM_HELLOWORLD_ASSOCIATION_DESC</option>
		</field>
		<field
			name="limit"
			type="limitbox"
			class="input-mini"
			default="25"
			label="COM_CONTENT_LIST_LIMIT"
			description="COM_HELLOWORLD_LIST_LIMIT_DESC"
			onchange="this.form.submit();"
		/>
	</fields>
</form>

If we're displaying the helloworlds view so that the administrator can select a record for an association, then we're displaying records of a certain language, and we don't want to allow the administrator to change the language through use of the filter fields. The filter fields are defined from the xml file above, so we use the JForm API to change dynamically the language field in the form so that it's hidden.

The activeFilters property of the view can be used in the searchtools layout, so we unset the language element.

Also we remove the line which previously set the $context variable.

admin/views/helloworlds/view.html.php

<?php
/**
 * @package     Joomla.Administrator
 * @subpackage  com_helloworld
 *
 * @copyright   Copyright (C) 2005 - 2018 Open Source Matters, Inc. All rights reserved.
 * @license     GNU General Public License version 2 or later; see LICENSE.txt
 */

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

/**
 * HelloWorlds View
 *
 * @since  0.0.1
 */
class HelloWorldViewHelloWorlds extends JViewLegacy
{
	/**
	 * Display the Hello World view
	 *
	 * @param   string  $tpl  The name of the template file to parse; automatically searches through the template paths.
	 *
	 * @return  void
	 */
	function display($tpl = null)
	{
		// Get application
		$app = JFactory::getApplication();

		// Get data from the model
		$this->items			= $this->get('Items');
		$this->pagination		= $this->get('Pagination');
		$this->state			= $this->get('State');
		$this->filterForm    	= $this->get('FilterForm');
		$this->activeFilters 	= $this->get('ActiveFilters');
        
		// What Access Permissions does this user have? What can (s)he do?
		$this->canDo = JHelperContent::getActions('com_helloworld');

		// Check for errors.
		if (count($errors = $this->get('Errors')))
		{
			JError::raiseError(500, implode('<br />', $errors));

			return false;
		}
        
		// Set the sidebar submenu and toolbar, but not on the modal window
		if ($this->getLayout() !== 'modal')
		{
			HelloWorldHelper::addSubmenu('helloworlds');
			$this->addToolBar();
		}
		else
		{
			// If it's being displayed to select a record as an association, then forcedLanguage is set
			if ($forcedLanguage = $app->input->get('forcedLanguage', '', 'CMD'))
			{
				// Transform the language selector filter into an hidden field, so it can't be set
				$languageXml = new SimpleXMLElement('<field name="language" type="hidden" default="' . $forcedLanguage . '" />');
				$this->filterForm->setField($languageXml, 'filter', true);

				// Also, unset the active language filter so the search tools is not open by default with this filter.
				unset($this->activeFilters['language']);
			}
		}

		// Display the template
		parent::display($tpl);

		// Set the document
		$this->setDocument();
	}

	/**
	 * Add the page title and toolbar.
	 *
	 * @return  void
	 *
	 * @since   1.6
	 */
	protected function addToolBar()
	{
		$title = JText::_('COM_HELLOWORLD_MANAGER_HELLOWORLDS');

		if ($this->pagination->total)
		{
			$title .= "<span style='font-size: 0.5em; vertical-align: middle;'>(" . $this->pagination->total . ")</span>";
		}

		JToolBarHelper::title($title, 'helloworld');
		if ($this->canDo->get('core.create')) 
		{
			JToolBarHelper::addNew('helloworld.add', 'JTOOLBAR_NEW');
		}
		if ($this->canDo->get('core.edit')) 
		{
			JToolBarHelper::editList('helloworld.edit', 'JTOOLBAR_EDIT');
		}
		if ($this->canDo->get('core.delete')) 
		{
			JToolBarHelper::deleteList('', 'helloworlds.delete', 'JTOOLBAR_DELETE');
		}
		if ($this->canDo->get('core.admin')) 
		{
			JToolBarHelper::divider();
			JToolBarHelper::preferences('com_helloworld');
		}
	}
	/**
	 * Method to set up the document properties
	 *
	 * @return void
	 */
	protected function setDocument() 
	{
		$document = JFactory::getDocument();
		$document->setTitle(JText::_('COM_HELLOWORLD_ADMINISTRATION'));
	}
}

We'll not change our modal layout file to display the associations, but as this layout will be used for selecting a helloworld record as an association, we need to cater for the forcedLanguage parameter.

admin/views/helloworlds/tmpl/modal.php

<?php
/**
 * Layout file for the admin modal display of helloworld records
 *
 */

defined('_JEXEC') or die('Restricted Access');

use Joomla\Registry\Registry;

JHtml::_('behavior.core');
JHtml::_('script', 'com_helloworld/admin-helloworlds-modal.js', array('version' => 'auto', 'relative' => true));

$listOrder     = $this->escape($this->state->get('list.ordering'));
$listDirn      = $this->escape($this->state->get('list.direction'));

$app = JFactory::getApplication();
$function  = $app->input->getCmd('function', 'jSelectHelloworld');
$onclick   = $this->escape($function);
?>
<div class="container-popup">
    
<form action="<?php echo JRoute::_('index.php?option=com_helloworld&view=helloworlds&layout=modal&tmpl=component&function=' . $function . '&' . JSession::getFormToken() . '=1'); ?>" method="post" name="adminForm" id="adminForm" class="form-inline">

	<?php echo JLayoutHelper::render('joomla.searchtools.default', array('view' => $this)); ?>
    
    <div class="clearfix"></div>

        <table class="table table-striped table-hover">
            <thead>
            <tr>
                <th width="3%"><?php echo JText::_('COM_HELLOWORLD_NUM'); ?></th>
                <th width="15%">
                    <?php echo JHtml::_('searchtools.sort', 'COM_HELLOWORLD_HELLOWORLDS_NAME', 'greeting', $listDirn, $listOrder); ?>
                </th>
                <th width="15%">
                    <?php echo JText::_('COM_HELLOWORLD_HELLOWORLDS_POSITION'); ?>
                </th>
                <th width="15%">
                    <?php echo JText::_('COM_HELLOWORLD_HELLOWORLDS_IMAGE'); ?>
                </th>
                <th width="15%">
                    <?php echo JHtml::_('searchtools.sort', 'COM_HELLOWORLD_AUTHOR', 'author', $listDirn, $listOrder); ?>
                </th>
                <th width="15%">
                    <?php echo JHtml::_('searchtools.sort', 'COM_HELLOWORLD_LANGUAGE', 'language', $listDirn, $listOrder); ?>
                </th>
                <th width="15%">
                    <?php echo JHtml::_('searchtools.sort', 'COM_HELLOWORLD_CREATED_DATE', 'created', $listDirn, $listOrder); ?>
                    </th>
                <th width="5%">
                    <?php echo JHtml::_('searchtools.sort', 'COM_HELLOWORLD_PUBLISHED', 'published', $listDirn, $listOrder); ?>
                </th>
                <th width="2%">
                    <?php echo JHtml::_('searchtools.sort', 'COM_HELLOWORLD_ID', 'id', $listDirn, $listOrder); ?>
                </th>
            </tr>
            </thead>
            <tfoot>
                <tr>
                    <td colspan="5">
                        <?php echo $this->pagination->getListFooter(); ?>
                    </td>
                </tr>
            </tfoot>
            <tbody>
                <?php if (!empty($this->items)) : ?>
                    <?php foreach ($this->items as $i => $row) :
                        $row->image = new Registry;
                        $row->image->loadString($row->imageInfo);
                        if ($row->language && JLanguageMultilang::isEnabled())
                        {
                            $tag = strlen($row->language);
                            if ($tag == 5)
                            {
                                $lang = substr($row->language, 0, 2);
                            }
                            elseif ($tag == 6)
                            {
                                $lang = substr($row->language, 0, 3);
                            }
                            else {
                                $lang = '';
                            }
                        }
                        elseif (!JLanguageMultilang::isEnabled())
                        {
                            $lang = '';
                        }
                    ?>
                        <tr>
                            <td><?php echo $this->pagination->getRowOffset($i); ?></td>
                            <td>
                                <?php 
                                $link = 'index.php?option=com_helloworld&view=helloworld&id=' . $row->id;
                                $attribs = 'data-function="' . $this->escape($onclick) . '"'
								. ' data-id="' . $row->id . '"'
								. ' data-title="' . $this->escape(addslashes($row->greeting)) . '"'
								. ' data-uri="' . $link . '"'
								. ' data-language="' . $this->escape($lang) . '"'
                                ;
                                ?>
                                <a class="select-link" href="javascript:void(0)" <?php echo $attribs; ?>>
                                    <?php echo $this->escape($row->greeting); ?>
                                </a>
                                <span class="small break-word">
                                	<?php echo JText::sprintf('JGLOBAL_LIST_ALIAS', $this->escape($row->alias)); ?>
                                </span>
                                <div class="small">
									<?php echo JText::_('JCATEGORY') . ': ' . $this->escape($row->category_title); ?>
								</div>
                            </td>
                            <td align="center">
                                <?php echo "[" . $row->latitude . ", " . $row->longitude . "]"; ?>
                            </td>
                            <td align="center">
                                <?php
                                    $caption = $row->image->get('caption') ? : '' ;
                                    $src = JURI::root() . ($row->image->get('image') ? : '' );
                                    $html = '<p class="hasTooltip" style="display: inline-block" data-html="true" data-toggle="tooltip" data-placement="right" title="<img width=\'100px\' height=\'100px\' src=\'%s\'>">%s</p>';
                                    echo sprintf($html, $src, $caption);  ?>
                            </td>
                            <td align="center">
                                <?php echo $row->author; ?>
                            </td>
                            <td align="center">
                                <?php echo JLayoutHelper::render('joomla.content.language', $row); ?>
                            </td>
                            <td align="center">
                                <?php echo substr($row->created, 0, 10); ?>
                            </td>
                            <td align="center">
                                <?php echo JHtml::_('jgrid.published', $row->published, $i, 'helloworlds.', true, 'cb'); ?>
                            </td>
                            <td align="center">
                                <?php echo $row->id; ?>
                            </td>
                        </tr>
                    <?php endforeach; ?>
                <?php endif; ?>
            </tbody>
        </table>
        <input type="hidden" name="task" value=""/>
        <input type="hidden" name="boxchecked" value="0"/>
        <input type="hidden" name="forcedLanguage" value="<?php echo $app->input->get('forcedLanguage', '', 'CMD'); ?>" />
        <?php echo JHtml::_('form.token'); ?>
</form>
</div>

We do change our default layout to display the associations.

admin/views/helloworlds/tmpl/default.php

<?php
/**
 * @package     Joomla.Administrator
 * @subpackage  com_helloworld
 *
 * @copyright   Copyright (C) 2005 - 2018 Open Source Matters, Inc. All rights reserved.
 * @license     GNU General Public License version 2 or later; see LICENSE.txt
 */

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

use Joomla\Registry\Registry;

JHtml::_('formbehavior.chosen', 'select');

$listOrder     = $this->escape($this->state->get('list.ordering'));
$listDirn      = $this->escape($this->state->get('list.direction'));
$assoc = JLanguageAssociations::isEnabled();
$authorFieldwidth = $assoc ? "10%" : "25%";
JLoader::register('JHtmlHelloworlds', JPATH_ADMINISTRATOR . '/components/com_helloworld/helpers/html/helloworlds.php');
?>
<form action="index.php?option=com_helloworld&view=helloworlds" method="post" id="adminForm" name="adminForm">
	<div id="j-sidebar-container" class="span2">
		<?php echo JHtmlSidebar::render(); ?>
	</div>
	<div id="j-main-container" class="span10">
        <div class="row-fluid">
            <div class="span6">
                <?php echo JText::_('COM_HELLOWORLD_HELLOWORLDS_FILTER'); ?>
                <?php
                    echo JLayoutHelper::render(
                        'joomla.searchtools.default',
                        array('view' => $this)
                    );
                ?>
            </div>
        </div>
        <table class="table table-striped table-hover">
            <thead>
            <tr>
                <th width="1%"><?php echo JText::_('COM_HELLOWORLD_NUM'); ?></th>
                <th width="2%">
                    <?php echo JHtml::_('grid.checkall'); ?>
                </th>
                <th width="15%">
                    <?php echo JHtml::_('searchtools.sort', 'COM_HELLOWORLD_HELLOWORLDS_NAME', 'greeting', $listDirn, $listOrder); ?>
                </th>
                <th width="15%">
                    <?php echo JText::_('COM_HELLOWORLD_HELLOWORLDS_POSITION'); ?>
                </th>
                <th width="15%">
                    <?php echo JText::_('COM_HELLOWORLD_HELLOWORLDS_IMAGE'); ?>
                </th>
                <?php if ($assoc) : ?>
                    <th width="15%">
                        <?php echo JHtml::_('searchtools.sort', 'COM_HELLOWORLD_HELLOWORLDS_ASSOCIATIONS', 'association', $listDirn, $listOrder); ?>
                    </th>
                <?php endif; ?>
                <th width="<?php echo $authorFieldwidth; ?>">
                    <?php echo JHtml::_('searchtools.sort', 'COM_HELLOWORLD_AUTHOR', 'author', $listDirn, $listOrder); ?>
                </th>
                <th width="10%">
                    <?php echo JHtml::_('searchtools.sort', 'COM_HELLOWORLD_LANGUAGE', 'language', $listDirn, $listOrder); ?>
                </th>
                <th width="10%">
                    <?php echo JHtml::_('searchtools.sort', 'COM_HELLOWORLD_CREATED_DATE', 'created', $listDirn, $listOrder); ?>
                </th>
                <th width="5%">
                    <?php echo JHtml::_('searchtools.sort', 'COM_HELLOWORLD_PUBLISHED', 'published', $listDirn, $listOrder); ?>
                </th>
                <th width="2%">
                    <?php echo JHtml::_('searchtools.sort', 'COM_HELLOWORLD_ID', 'id', $listDirn, $listOrder); ?>
                </th>
            </tr>
            </thead>
            <tfoot>
                <tr>
                    <td colspan="5">
                        <?php echo $this->pagination->getListFooter(); ?>
                    </td>
                </tr>
            </tfoot>
            <tbody>
                <?php if (!empty($this->items)) : ?>
                    <?php foreach ($this->items as $i => $row) :
                        $link = JRoute::_('index.php?option=com_helloworld&task=helloworld.edit&id=' . $row->id);
                        $row->image = new Registry;
                        $row->image->loadString($row->imageInfo);
                    ?>
                        <tr>
                            <td><?php echo $this->pagination->getRowOffset($i); ?></td>
                            <td>
                                <?php echo JHtml::_('grid.id', $i, $row->id); ?>
                            </td>
                            <td>
                                <a href="<?php echo $link; ?>" title="<?php echo JText::_('COM_HELLOWORLD_EDIT_HELLOWORLD'); ?>">
                                    <?php echo $row->greeting; ?>
                                </a>
                                <span class="small break-word">
                                	<?php echo JText::sprintf('JGLOBAL_LIST_ALIAS', $this->escape($row->alias)); ?>
                                </span>
                                <div class="small">
                                    <?php echo JText::_('JCATEGORY') . ': ' . $this->escape($row->category_title); ?>
                                </div>
                            </td>
                            <td align="center">
                                <?php echo "[" . $row->latitude . ", " . $row->longitude . "]"; ?>
                            </td>
                            <td align="center">
                                <?php
                                    $caption = $row->image->get('caption') ? : '' ;
                                    $src = JURI::root() . ($row->image->get('image') ? : '' );
                                    $html = '<p class="hasTooltip" style="display: inline-block" data-html="true" data-toggle="tooltip" data-placement="right" title="<img width=\'100px\' height=\'100px\' src=\'%s\'>">%s</p>';
                                    echo sprintf($html, $src, $caption);  ?>
                            </td>
                            <?php if ($assoc) : ?>
                                <td align="center">
                                    <?php if ($row->association) : ?>
                                        <?php echo JHtml::_('helloworlds.association', $row->id); ?>
                                    <?php endif; ?>
                                </td>
                            <?php endif; ?>
                            <td align="center">
                                <?php echo $row->author; ?>
                            </td>
                            <td align="center">
                                <?php echo JLayoutHelper::render('joomla.content.language', $row); ?>
                            </td>
                            <td align="center">
                                <?php echo substr($row->created, 0, 10); ?>
                            </td>
                            <td align="center">
                                <?php echo JHtml::_('jgrid.published', $row->published, $i, 'helloworlds.', true, 'cb'); ?>
                            </td>
                            <td align="center">
                                <?php echo $row->id; ?>
                            </td>
                        </tr>
                    <?php endforeach; ?>
                <?php endif; ?>
            </tbody>
        </table>
        <input type="hidden" name="task" value=""/>
        <input type="hidden" name="boxchecked" value="0"/>
        <?php echo JHtml::_('form.token'); ?>
    </div>
</form>

Following the approach of core Joomla components which use associations, the detailed display of the associations is delegated to a helper file which is put into a new html subdirectory under our existing admin helpers directory. This then displays the associations using a layout file in joomla/content/associations.php, in the same way as the other components do.

admin/helpers/html/helloworlds.php

<?php
/**
 * Helper file for outputting html associated with the helloworld administrator functionality
 */

defined('_JEXEC') or die;

JLoader::register('HelloworldHelper', JPATH_ADMINISTRATOR . '/components/com_helloworld/helpers/helloworld.php');

class JHtmlHelloworlds
{
	/**
	 * Render the list of associated items
	 *
	 * @param   integer  $id  The id of the helloworld record
	 *
	 * @return  string  The language HTML
	 *
	 * @throws  Exception
	 */
	public static function association($id)
	{
		// Defaults
		$html = '';

		// Get the associations
		if ($associations = JLanguageAssociations::getAssociations('com_helloworld', '#__helloworld', 'com_helloworld.item', (int)$id))
		{
			foreach ($associations as $tag => $associated)
			{
				$associations[$tag] = (int) $associated->id;
			}

			// get the relevant category titles and languages, for the tooltip
			$db = JFactory::getDbo();
			$query = $db->getQuery(true)
				->select('h.*')
				->select('l.sef as lang_sef')
				->select('l.lang_code')
				->from('#__helloworld as h')
				->select('cat.title as category_title')
				->join('LEFT', '#__categories as cat ON cat.id=h.catid')
				->where('h.id IN (' . implode(',', array_values($associations)) . ')')
				->join('LEFT', '#__languages as l ON h.language=l.lang_code')
				->select('l.image')
				->select('l.title as language_title');
			$db->setQuery($query);

			try
			{
				$items = $db->loadObjectList('id');
			}
			catch (RuntimeException $e)
			{
				throw new Exception($e->getMessage(), 500, $e);
			}

			if ($items)
			{
				foreach ($items as &$item)
				{
					$text    = $item->lang_sef ? strtoupper($item->lang_sef) : 'XX';
					$url     = JRoute::_('index.php?option=com_helloworld&task=helloworld.edit&id=' . (int) $item->id);

					$tooltip = htmlspecialchars($item->greeting, ENT_QUOTES, 'UTF-8') . '<br />' . JText::sprintf('JCATEGORY_SPRINTF', $item->category_title);
					$classes = 'hasPopover label label-association label-' . $item->lang_sef;

					$item->link = '<a href="' . $url . '" title="' . $item->language_title . '" class="' . $classes
						. '" data-content="' . $tooltip . '" data-placement="top">'
						. $text . '</a>';
				}
			}

			JHtml::_('bootstrap.popover');

			$html = JLayoutHelper::render('joomla.content.associations', $items);
		}

		return $html;
	}
}

Admin Helloworld (edit) MVC

The helloworld controllers do not require changing, but the other files do. Our model has a number of changes:

  1. We need to change our edit form dynamically to include the fields for capturing the associations. After we load our form, Joomla calls a callback function preprocessForm and it's there that we put our code to add those fields, and we use the JForm APIs to modify the form. Note that we add fields for all of the content languages, including the current language of the record being edited. Joomla includes some javascript code which hides the association field for the current language, and cleverly changes the fields displayed if we change the value in the language field.
  2. In the case of editing an existing record we need to prepopulate the associations data. The callback function in this case is loadFormData, and from there we call getItem if we need to prepopulate the form data from the database, so that's where we need to add our code for getting the associations.
  3. As mentioned above, the JModelAdmin code handles the database updates of the association data, provided we set the protected variable $associationsContext appropriately.

admin/models/helloworld.php

<?php
/**
 * @package     Joomla.Administrator
 * @subpackage  com_helloworld
 *
 * @copyright   Copyright (C) 2005 - 2018 Open Source Matters, Inc. All rights reserved.
 * @license     GNU General Public License version 2 or later; see LICENSE.txt
 */

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

use Joomla\Registry\Registry;

/**
 * HelloWorld Model
 *
 * @since  0.0.1
 */
class HelloWorldModelHelloWorld extends JModelAdmin
{
	// JModelAdmin needs to know this for storing the associations 
	protected $associationsContext = 'com_helloworld.item';

	/**
	 * Method to override getItem to allow us to convert the JSON-encoded image information
	 * in the database record into an array for subsequent prefilling of the edit form
	 * We also use this method to prefill the associations
	 */
	public function getItem($pk = null)
	{
		$item = parent::getItem($pk);
		if ($item AND property_exists($item, 'image'))
		{
			$registry = new Registry($item->image);
			$item->imageinfo = $registry->toArray();
		}

		// Load associated items
		if (JLanguageAssociations::isEnabled())
		{
			$item->associations = array();

			if ($item->id != null)
			{
				$associations = JLanguageAssociations::getAssociations('com_helloworld', '#__helloworld', 'com_helloworld.item', (int)$item->id);

				foreach ($associations as $tag => $association)
				{
					$item->associations[$tag] = $association->id;
				}
			}
		}
		return $item; 
	}

	/**
	 * Method to get a table object, load it if necessary.
	 *
	 * @param   string  $type    The table name. Optional.
	 * @param   string  $prefix  The class prefix. Optional.
	 * @param   array   $config  Configuration array for model. Optional.
	 *
	 * @return  JTable  A JTable object
	 *
	 * @since   1.6
	 */
	public function getTable($type = 'HelloWorld', $prefix = 'HelloWorldTable', $config = array())
	{
		return JTable::getInstance($type, $prefix, $config);
	}

	/**
	 * Method to get the record form.
	 *
	 * @param   array    $data      Data for the form.
	 * @param   boolean  $loadData  True if the form is to load its own data (default case), false if not.
	 *
	 * @return  mixed    A JForm object on success, false on failure
	 *
	 * @since   1.6
	 */
	public function getForm($data = array(), $loadData = true)
	{
		// Get the form.
		$form = $this->loadForm(
			'com_helloworld.helloworld',
			'helloworld',
			array(
				'control' => 'jform',
				'load_data' => $loadData
			)
		);

		if (empty($form))
		{
			return false;
		}

		return $form;
	}

	/**
	 * Method to preprocess the form to add the association fields dynamically
	 *
	 * @return     none
	 */
	protected function preprocessForm(JForm $form, $data, $group = 'helloworld')
	{
		// Association content items
		if (JLanguageAssociations::isEnabled())
		{
			$languages = JLanguageHelper::getContentLanguages(false, true, null, 'ordering', 'asc');

			if (count($languages) > 1)
			{
				$addform = new SimpleXMLElement('<form />');
				$fields = $addform->addChild('fields');
				$fields->addAttribute('name', 'associations');
				$fieldset = $fields->addChild('fieldset');
				$fieldset->addAttribute('name', 'item_associations');

				foreach ($languages as $language)
				{
					$field = $fieldset->addChild('field');
					$field->addAttribute('name', $language->lang_code);
					$field->addAttribute('type', 'modal_helloworld');
					$field->addAttribute('language', $language->lang_code);
					$field->addAttribute('label', $language->title);
					$field->addAttribute('translate_label', 'false');
				}

				$form->load($addform, false);
			}
		}
		parent::preprocessForm($form, $data, $group);
	}

	/**
	 * Method to get the script to be included on the form
	 *
	 * @return string	Script files
	 */
	public function getScript() 
	{
		return 'administrator/components/com_helloworld/models/forms/helloworld.js';
	}

	/**
	 * Method to get the data that should be injected in the form.
	 *
	 * @return  mixed  The data for the form.
	 *
	 * @since   1.6
	 */
	protected function loadFormData()
	{
		// Check the session for previously entered form data.
		$data = JFactory::getApplication()->getUserState(
			'com_helloworld.edit.helloworld.data',
			array()
		);

		if (empty($data))
		{
			$data = $this->getItem();
		}

		return $data;
	}
	/**
	 * Method to override the JModelAdmin save() function to handle Save as Copy correctly
	 *
	 * @param   The helloworld record data submitted from the form.
	 *
	 * @return  parent::save() return value
	 */
	public function save($data)
	{
		$input = JFactory::getApplication()->input;

		JLoader::register('CategoriesHelper', JPATH_ADMINISTRATOR . '/components/com_categories/helpers/categories.php');

		// Validate the category id
		// validateCategoryId() returns 0 if the catid can't be found
		if ((int) $data['catid'] > 0)
		{
			$data['catid'] = CategoriesHelper::validateCategoryId($data['catid'], 'com_helloworld');
		}

		// Alter the greeting and alias for save as copy
		if ($input->get('task') == 'save2copy')
		{
			$origTable = clone $this->getTable();
			$origTable->load($input->getInt('id'));

			if ($data['greeting'] == $origTable->greeting)
			{
				list($greeting, $alias) = $this->generateNewTitle($data['catid'], $data['alias'], $data['greeting']);
				$data['greeting'] = $greeting;
				$data['alias'] = $alias;
			}
			else
			{
				if ($data['alias'] == $origTable->alias)
				{
					$data['alias'] = '';
				}
			}
			// standard Joomla practice is to set the new record as unpublished
			$data['published'] = 0;
		}

		return parent::save($data);
	}
	/**
	 * Method to check if it's OK to delete a message. Overrides JModelAdmin::canDelete
	 */
	protected function canDelete($record)
	{
		if( !empty( $record->id ) )
		{
			return JFactory::getUser()->authorise( "core.delete", "com_helloworld.helloworld." . $record->id );
		}
	}
}

In the model file above we have added to our helloworld edit form an XML element which contains a number of <field> tags, one for each of the modal_helloworld input fields for capturing an association. We previously defined this modal_helloworld field to capture in a modal a helloworld record for a helloworld menuitem. Comparing the code above with the XML definition of the menuitem form (in the site helloworld view layout directory) the key difference is that there is an additional language attribute above. In our php file defining this modal_helloworld field we use the presence of this parameter to set the forcedLanguage parameter, so that the modal displays records only of this language.

admin/models/fields/modal/helloworld.php

<?php

defined('JPATH_BASE') or die;

/**
 * Supports a modal for selecting a helloworld record
 *
 */
class JFormFieldModal_Helloworld extends JFormField
{
	/**
	 * Method to get the html for the input field.
	 *
	 * @return  string  The field input html.
	 */
	protected function getInput()
	{
		// Load language
		JFactory::getLanguage()->load('com_helloworld', JPATH_ADMINISTRATOR);

		// $this->value is set if there's a default id specified in the xml file
		$value = (int) $this->value > 0 ? (int) $this->value : '';
        
		// $this->id will be jform_request_xxx where xxx is the name of the field in the xml file
		// or jform_associations_xx_yy where xx_yy is the language code (hyphen replaced by underscore) for associations
		$modalId = 'Helloworld_' . $this->id;

		// Add the modal field script to the document head.
		JHtml::_('jquery.framework');
		JHtml::_('script', 'system/modal-fields.js', array('version' => 'auto', 'relative' => true));

		// our callback function from the modal to the main window:
		JFactory::getDocument()->addScriptDeclaration("
			function jSelectHelloworld_" . $this->id . "(id, title, catid, object, url, language) {
				window.processModalSelect('Helloworld', '" . $this->id . "', id, title, catid, object, url, language);
			}
			");

		// if a default id is set, then get the corresponding greeting to display it
		if ($value)
		{
			$db    = JFactory::getDbo();
			$query = $db->getQuery(true)
				->select($db->quoteName('greeting'))
				->from($db->quoteName('#__helloworld'))
				->where($db->quoteName('id') . ' = ' . (int) $value);
			$db->setQuery($query);

			try
			{
				$title = $db->loadResult();
			}
			catch (RuntimeException $e)
			{
				JError::raiseWarning(500, $e->getMessage());
			}
		}
        
		// display the default greeting or "Select" if no default specified
		$title = empty($title) ? JText::_('COM_HELLOWORLD_MENUITEM_SELECT_HELLOWORLD') : htmlspecialchars($title, ENT_QUOTES, 'UTF-8');
		$html  = '<span class="input-append">';
		$html .= '<input class="input-medium" id="' . $this->id . '_name" type="text" value="' . $title . '" disabled="disabled" size="35" />';

		// html for the Select button
		$html .= '<a'
			. ' class="btn hasTooltip' . ($value ? ' hidden' : '') . '"'
			. ' id="' . $this->id . '_select"'
			. ' data-toggle="modal"'
			. ' role="button"'
			. ' href="#ModalSelect' . $modalId . '"'
			. ' title="' . JHtml::tooltipText('COM_HELLOWORLD_MENUITEM_SELECT_BUTTON_TOOLTIP') . '">'
			. '<span class="icon-file" aria-hidden="true"></span> ' . JText::_('JSELECT')
			. '</a>';

		// html for the Clear button
		$html .= '<a'
			. ' class="btn' . ($value ? '' : ' hidden') . '"'
			. ' id="' . $this->id . '_clear"'
			. ' href="#"'
			. ' onclick="window.processModalParent(\'' . $this->id . '\'); return false;">'
			. '<span class="icon-remove" aria-hidden="true"></span>' . JText::_('JCLEAR')
			. '</a>';

		$html .= '</span>';

		// url for the iframe
		$linkHelloworlds = 'index.php?option=com_helloworld&amp;view=helloworlds&amp;layout=modal&amp;tmpl=component&amp;' . JSession::getFormToken() . '=1';
		$urlSelect = $linkHelloworlds . '&amp;function=jSelectHelloworld_' . $this->id;
        
		// title to go in the modal header
		$modalTitle    = JText::_('COM_HELLOWORLD_MENUITEM_SELECT_MODAL_TITLE');

		// if the form definition has a 'language' field then it's for the association
		// add the forcedLanguage parameter to the URL, and add the language to the modal title
		if (isset($this->element['language']))
		{
			$urlSelect .= '&amp;forcedLanguage=' . $this->element['language'];
			$modalTitle .= ' &#8212; ' . $this->element['label'];
		}

		// html to set up the modal iframe
		$html .= JHtml::_(
			'bootstrap.renderModal',
			'ModalSelect' . $modalId,
			array(
				'title'       => $modalTitle,
				'url'         => $urlSelect,
				'height'      => '400px',
				'width'       => '800px',
				'bodyHeight'  => '70',
				'modalWidth'  => '80',
				'footer'      => '<a role="button" class="btn" data-dismiss="modal" aria-hidden="true">' . JText::_('JLIB_HTML_BEHAVIOR_CLOSE') . '</a>',
			)
		);

		// class='required' for client side validation.
		$class = $this->required ? ' class="required modal-value"' : '';

		// hidden input field to store the helloworld record id
		$html .= '<input type="hidden" id="' . $this->id . '_id" ' . $class 
			. ' data-required="' . (int) $this->required . '" name="' . $this->name
			. '" data-text="' . htmlspecialchars(JText::_('COM_HELLOWORLD_MENUITEM_SELECT_HELLOWORLD', true), ENT_COMPAT, 'UTF-8') 
			. '" value="' . $value . '" />';

		return $html;
	}

	/**
	 * Method to get the html for the label field.
	 *
	 * @return  string  The field label html.
	 */
	protected function getLabel()
	{
		return str_replace($this->id, $this->id . '_id', parent::getLabel());
	}
}

The view file does not require modification, but the edit.php layout file has the following changes

  1. Include the Associations tab to allow the administrator to edit these. As mentioned above, this should be shown only if associations in general are enabled via the system language filter plugin.
  2. If the page is launched from the com_associations component, then &tmpl=component will have been set to avoid displaying the Joomla menus. In this case the same parameter must be added to the form target url.
  3. Include the chosen library so that the fields generated by com_associations display correctly.

The display of the associations fields is handled by a common layout file joomla/edit/associations, and it's from here that the system/associations-edit.js javascript code is included (which hides the association field for the current language, etc, as mentioned above).

admin/views/helloworld/tmpl/edit.php

<?php
/**
 * @package     Joomla.Administrator
 * @subpackage  com_helloworld
 *
 * @copyright   Copyright (C) 2005 - 2018 Open Source Matters, Inc. All rights reserved.
 * @license     GNU General Public License version 2 or later; see LICENSE.txt
 */

// No direct access
defined('_JEXEC') or die('Restricted access');
JHtml::_('behavior.formvalidator');

// The following is to enable setting the permission's Calculated Setting 
// when you change the permission's Setting. 
// The core javascript code for initiating the Ajax request looks for a field
// with id="jform_title" and sets its value as the 'title' parameter to send in the Ajax request
JFactory::getDocument()->addScriptDeclaration('
	jQuery(document).ready(function() {
        greeting = jQuery("#jform_greeting").val();
		jQuery("#jform_title").val(greeting);
	});
');

// Required for proper display of fields generated by com_associations
JHtml::_('formbehavior.chosen', 'select');

// if &tmpl=component used on first invocation, ensure it's on subsequent ones too
$input = JFactory::getApplication()->input;
$tmpl = $input->getCmd('tmpl', '') === 'component' ? '&tmpl=component' : '';
?>
<form action="<?php echo JRoute::_('index.php?option=com_helloworld&layout=edit' . $tmpl . '&id=' . (int) $this->item->id); ?>"
    method="post" name="adminForm" id="adminForm" class="form-validate">
    
    <input id="jform_title" type="hidden" name="helloworld-message-title"/>
    
    <div class="form-horizontal">

    <?php echo JHtml::_('bootstrap.startTabSet', 'myTab', array('active' => 'details')); ?>
    <?php echo JHtml::_('bootstrap.addTab', 'myTab', 'details', 
        empty($this->item->id) ? JText::_('COM_HELLOWORLD_TAB_NEW_MESSAGE') : JText::_('COM_HELLOWORLD_TAB_EDIT_MESSAGE')); ?>
        <fieldset class="adminform">
            <legend><?php echo JText::_('COM_HELLOWORLD_LEGEND_DETAILS') ?></legend>
            <div class="row-fluid">
                <div class="span6">
                    <?php echo $this->form->renderFieldset('details');  ?>
                </div>
            </div>
        </fieldset>
    <?php echo JHtml::_('bootstrap.endTab'); ?>

    <?php echo JHtml::_('bootstrap.addTab', 'myTab', 'image', JText::_('COM_HELLOWORLD_TAB_IMAGE')); ?>
        <fieldset class="adminform">
            <legend><?php echo JText::_('COM_HELLOWORLD_LEGEND_IMAGE') ?></legend>
            <div class="row-fluid">
                <div class="span6">
                    <?php echo $this->form->renderFieldset('image-info');  ?>
                </div>
            </div>
        </fieldset>
    <?php echo JHtml::_('bootstrap.endTab'); ?>

    <?php echo JHtml::_('bootstrap.addTab', 'myTab', 'params', JText::_('COM_HELLOWORLD_TAB_PARAMS')); ?>
        <fieldset class="adminform">
            <legend><?php echo JText::_('COM_HELLOWORLD_LEGEND_PARAMS') ?></legend>
            <div class="row-fluid">
                <div class="span6">
                    <?php echo $this->form->renderFieldset('params');  ?>
                </div>
            </div>
        </fieldset>
    <?php echo JHtml::_('bootstrap.endTab'); ?>

    <?php if (JLanguageAssociations::isEnabled()) : ?>
        <?php echo JHtml::_('bootstrap.addTab', 'myTab', 'associations', JText::_('COM_HELLOWORLD_TAB_ASSOCIATIONS')); ?>
            <fieldset class="adminform">
                <legend><?php echo JText::_('COM_HELLOWORLD_LEGEND_ASSOCIATIONS') ?></legend>
                <div class="row-fluid">
                    <div class="span12">
                        <?php echo JLayoutHelper::render('joomla.edit.associations', $this);  ?>
                    </div>
                </div>
            </fieldset>
        <?php echo JHtml::_('bootstrap.endTab'); ?>
    <?php endif; ?>

    <?php echo JHtml::_('bootstrap.addTab', 'myTab', 'permissions', JText::_('COM_HELLOWORLD_TAB_PERMISSIONS')); ?>
        <fieldset class="adminform">
            <legend><?php echo JText::_('COM_HELLOWORLD_LEGEND_PERMISSIONS') ?></legend>
            <div class="row-fluid">
                <div class="span12">
                    <?php echo $this->form->renderFieldset('accesscontrol');  ?>
                </div>
            </div>
        </fieldset>
    <?php echo JHtml::_('bootstrap.endTab'); ?>
    <?php echo JHtml::_('bootstrap.endTabSet'); ?>

    </div>
    <input type="hidden" name="task" value="helloworld.edit" />
    <?php echo JHtml::_('form.token'); ?>
</form>

Enabling com_associations

To enable the Multilingual Associations component, as described here we need to include the helper file below, and add 2 strings to the system language file, as well as the other formatting aspects already covered above.

The helper file needs to have the $fields and $support arrays defined because com_associations undertakes some aspects upon our behalf, such as joining to our helloworld to provide additional information, and also updating records, so it needs to know how to SQL JOIN to our database table and what capability we support regarding access control and locking. The function getFieldsTemplate() sets up default valules in the $fields array, for example specifying that the alias will be found in a database field called 'alias', and category id in field called 'catid', so we really need to specify only the exceptions, like finding the title in the 'greeting' database field. And similarly getSupportTemplate() for the $support array.

(If in your component you want to support setting ACLs at an individual helloworld record or category level, then you will need an additional function in the file below: public function allowEdit($typeName, $recordId), similar to what you would have in a controller, but this is really outside the scope of this tutorial).

admin/helpers/associations.php

<?php
/**
 * The Helloworld helper file for Multilingual Associations
 */

defined('_JEXEC') or die;

JTable::addIncludePath(__DIR__ . '/../tables');

class HelloworldAssociationsHelper extends JAssociationExtensionHelper
{
	/**
	 * The extension name
	 */
	protected $extension = 'com_helloworld';

	/**
	 * Array of item types which have associations
	 */
	protected $itemTypes = array('helloworld', 'category');

	/**
	 * Has the extension association support
	 */
	protected $associationsSupport = true;

	/**
	 * Get the associated items for an item
	 *
	 * @param   string  $typeName  The item type, either 'helloworld' or 'category'
	 * @param   int     $id        The id of item for which we need the associated items
	 *
	 */
	public function getAssociations($typeName, $id)
	{
		$type = $this->getType($typeName);

		$context    = $this->extension . '.item';
		$catidField = 'catid';

		if ($typeName === 'helloworld')
		{
			$context    = 'com_helloworld.item';
			$catidField = 'catid';
		}
        elseif ($typeName === 'category')
		{
			$context    = 'com_categories.item';
			$catidField = '';
		}
        else
        {
            return null;
        }

		// Get the associations.
		$associations = JLanguageAssociations::getAssociations(
			$this->extension,
			$type['tables']['a'],
			$context,
			$id,
			'id',
			'alias',
			$catidField
		);

		return $associations;
	}

	/**
	 * Get item information
	 *
	 * @param   string  $typeName  The item type
	 * @param   int     $id        The id of item for which we need the associated items
	 *
	 * @return  JTable object associated with the record id passed in
	 */
	public function getItem($typeName, $id)
	{
		if (empty($id))
		{
			return null;
		}

		$table = null;

		switch ($typeName)
		{
			case 'helloworld':
				$table = JTable::getInstance('Helloworld', 'HelloworldTable');
				break;

			case 'category':
				$table = JTable::getInstance('Category');
				break;
		}

		if (empty($table))
		{
			return null;
		}

		$table->load($id);

		return $table;
	}

	/**
	 * Get information about the type
	 *
	 * @param   string  $typeName  The item type
	 *
	 * @return  array  Array of item types
	 */
	public function getType($typeName = '')
	{
		$fields  = $this->getFieldsTemplate();
		$tables  = array();
		$joins   = array();
		$support = $this->getSupportTemplate();
		$title   = '';

		if (in_array($typeName, $this->itemTypes))
		{
			switch ($typeName)
			{
				case 'helloworld':
					$fields['title'] = 'a.greeting';
                    $fields['ordering'] = '';
                    $fields['access'] = '';
                    $fields['state'] = 'a.published';
                    $fields['created_user_id'] = '';
                    $fields['checked_out'] = '';
                    $fields['checked_out_time'] = '';

					$support['state'] = true;
					$support['acl'] = false;
					$support['category'] = true;

					$tables = array(
						'a' => '#__helloworld'
					);

					$title = 'helloworld';
					break;

				case 'category':
					$fields['created_user_id'] = 'a.created_user_id';
					$fields['ordering'] = 'a.lft';
					$fields['level'] = 'a.level';
					$fields['catid'] = '';
					$fields['state'] = 'a.published';

					$support['state'] = true;
					$support['acl'] = true;
					$support['checkout'] = true;
					$support['level'] = true;

					$tables = array(
						'a' => '#__categories'
					);

					$title = 'category';
					break;
			}
		}

		return array(
			'fields'  => $fields,
			'support' => $support,
			'tables'  => $tables,
			'joins'   => $joins,
			'title'   => $title
		);
	}
}

admin/language/en-GB/en-GB.com_helloworld.sys.ini

; Joomla! Project
; Copyright (C) 2005 - 2018 Open Source Matters. All rights reserved.
; License GNU General Public License version 2 or later; see LICENSE.txt, see LICENSE.php
; Note : All ini files need to be saved as UTF-8

COM_HELLOWORLD="Hello World!"
COM_HELLOWORLD_DESCRIPTION="This is the Hello World description"
COM_HELLOWORLD_HELLOWORLD_VIEW_DEFAULT_TITLE="Hello World"
COM_HELLOWORLD_HELLOWORLD_VIEW_DEFAULT_DESC="This view displays a selected message"
COM_HELLOWORLD_ADD_VIEW_TITLE="Hello World form"
COM_HELLOWORLD_ADD_VIEW_DESC="This displays a form to allow the user to enter a new message"
COM_HELLOWORLD_CATEGORY_VIEW_TITLE="Category List"
COM_HELLOWORLD_CATEGORY_VIEW_DESC="This displays the messages in the selected category"
COM_HELLOWORLD_INSTALL_TEXT="HelloWorld Install script"
COM_HELLOWORLD_MENU="Hello World!"
COM_HELLOWORLD_POSTFLIGHT_DISCOVER_INSTALL_TEXT="HelloWorld postflight discover install script"
COM_HELLOWORLD_POSTFLIGHT_INSTALL_TEXT="HelloWorld postflight install script"
COM_HELLOWORLD_POSTFLIGHT_UNINSTALL_TEXT="HelloWorld postflight uninstall script"
COM_HELLOWORLD_POSTFLIGHT_UPDATE_TEXT="HelloWorld postflight update script"
COM_HELLOWORLD_PREFLIGHT_DISCOVER_INSTALL_TEXT="HelloWorld preflight discover install script"
COM_HELLOWORLD_PREFLIGHT_INSTALL_TEXT="HelloWorld preflight install script"
COM_HELLOWORLD_PREFLIGHT_UNINSTALL_TEXT="HelloWorld preflight uninstall script"
COM_HELLOWORLD_PREFLIGHT_UPDATE_TEXT="HelloWorld preflight update script"
COM_HELLOWORLD_UNINSTALL_TEXT="HelloWorld Uninstall script"
COM_HELLOWORLD_UPDATE_TEXT="HelloWorld Update script. HelloWorld now updated to version %s."
; Using the Multilingual Associations component
COM_HELLOWORLD_HELLOWORLDS="Greetings"
COM_HELLOWORLD_CATEGORIES="Categories"

Front End

The front end associations code is fairly standard across the Joomla components and comprises the helper file below. Joomla calls our getAssociations method with the id and view under consideration, and it must return information about the associated records, in particular the language and URL of each. If the view is 'helloworld' the id relates to the helloworld record id. If the view is 'category' the id relates to the helloworld category id.

The presence of this file enables the associations functionality of com_categories on the back end, allowing the administrator to set up associations on the helloworld categories.

site/helpers/association.php

<?php
/**
 * Helper file for Helloworld Associations (on the site part)
 */

defined('_JEXEC') or die;

JLoader::register('CategoryHelperAssociation', JPATH_ADMINISTRATOR . '/components/com_categories/helpers/association.php');

/**
 * Helloworld Component Association Helper
 *
 */
abstract class HelloworldHelperAssociation extends CategoryHelperAssociation
{
	/**
	 * Method to get the associations for a given item
	 *
	 * @param   integer  $id    Id of the item (helloworld id or catid, depending on view)
	 * @param   string   $view  Name of the view ('helloworld' or 'category')
	 *
	 * @return  array   Array of associations for the item
	 */
	public static function getAssociations($id = 0, $view = null)
	{
		$input = JFactory::getApplication()->input;
		$view = $view === null ? $input->get('view') : $view;
		$id = empty($id) ? $input->getInt('id') : $id;

		if ($view === 'helloworld')
		{
			if ($id)
			{
				$associations = JLanguageAssociations::getAssociations('com_helloworld', '#__helloworld', 'com_helloworld.item', $id);

				$return = array();

				foreach ($associations as $tag => $item)
				{
					$link = 'index.php?option=com_helloworld&view=helloworld&id=' . $item->id . '&catid=' . $item->catid;
					if ($item->language && $item->language !== '*' && JLanguageMultilang::isEnabled())
					{
						$link .= '&lang=' . $item->language;
					}
					$return[$tag] = $link;
				}

				return $return;
			}
		}

		if ($view === 'category' || $view === 'categories')
		{
			return self::getCategoryAssociations($id, 'com_helloworld');
		}

		return array();
	}
}

Custom Router

There are several changes required to our custom router code. Previously we were dealing with URLs which were all related to the same language. Now in our language switcher and hreflang links to associated records we have to support URLs which relate other languages as well.

Firstly note that in providing parameters for the associated URLs in our site association helper file

  • we have included a lang parameter to indicate the language of the associated record
  • we haven't included any Itemid parameter to indicate the target menuitem.

Hence these URLs will be formed using the Itemid of the menuitem which the site user is currently on, and that menuitem is obviously related to the current language. However, we want to point to a menuitem of the appropriate language of the associated record instead, which means changing the 'Itemid' within the $query array. We do that in the custom router preprocess() function, which gets called before build() for each helloworld-related link on the page. The strategy we'll adopt is that we will

  • check if the URL lang and Itemid parameters match from a language perspective - in this case we don't have to do anything, otherwise
  • see if the current menuitem has an associated menuitem in the target language, and if so, use it
  • if not, then use the home page of the target language.

(The preprocess() function is called multiple times for each web page, so we'll use a static variable to speed up the checking in the normal case, ie the URL doesn't relate to an association).

Secondly in our build() function we have to remove the check that the target URL is in the same language as the current page.

The third issue relates to having to build the URL on top of the target language home page. By default the home page contains featured articles, and so its related component is com_content. We're using it to display a com_helloworld view, so we're overriding the component, and when we do that we get a URL of the form .../component/helloworld/... This isn't in itself a problem, but a side effect of this is that on this page we don't get an active menuitem, so we have to be prepared to handle that, particularly in our parse() function, removing the check that it isn't set.

site/router.php

<?php

defined('_JEXEC') or die;

class HelloworldRouter implements JComponentRouterInterface
{

	public function build(&$query)
	{
		$segments = array();

		if (!JLanguageMultilang::isEnabled() || !isset($query['view']))
		{
			return $segments;
		}

		$lang = JFactory::getLanguage()->getTag();
		$app  = JFactory::getApplication();
        
		// get the menu item that this call to build() relates to
		if (!isset($query['Itemid']))
		{
			return $segments;
		}
		$sitemenu = $app->getMenu();
		$thisMenuitem = $sitemenu->getItem($query['Itemid']);
        
		if ($thisMenuitem->note == "Ajax")
		{   
			// We're on the /message menuitem.
			// Check we've got the right parameters then set url segment = id : alias
			if ($query['view'] == "helloworld" && isset($query['id']))
			{
				// we'll support the passed id being in the form id:alias
				$segments[] = $query['id'];

				unset($query['id']);
				unset($query['catid']);
			}
		}
		else
		{
			// assume we're on the /messages menuitem or have /component type of url
			if (($query['view'] == "category") && isset($query['id']))
			{
				// set this part of the url to be of the form /subcat1/subcat2/...
				$pathSegments = $this->getCategorySegments($query['id']);
				if ($pathSegments)
				{
					$segments = $pathSegments;
					unset($query['id']);
				}
			}
			elseif ($query['view'] == "helloworld" && isset($query['catid']) && isset($query['id']))
			{
				// set this part of the url to be of the form /subcat1/subcat2/.../hello-world 
				$pathSegments = $this->getCategorySegments($query['catid']);
				if ($pathSegments)
				{
					$segments = $pathSegments;
				}

				$segments[] = $query['id'];

				unset($query['id']);
				unset($query['catid']);
			}
		}

		unset($query['view']);
		return $segments;
	}

	/*
	 * This function take a category id and finds the path from that category to the root of the category tree
	 * The path returned from getPath() is an associative array of key = category id, value = id:alias
	 * If no valid category is found from the passed-in category id then null is returned. 
	 */
     
	private function getCategorySegments($catid)
	{
		$categories = JCategories::getInstance('Helloworld', array());
		$categoryNode = $categories->get($catid);
		if ($categoryNode)
		{
			$path = $categoryNode->getPath();

			return $path;
		}
		else
		{
			return null;
		}
	}

	public function parse(&$segments)
	{
		$vars = array();
		$nSegments = count($segments);
        
		$app  = JFactory::getApplication();
		$sitemenu = $app->getMenu();
		$activeMenuitem = $sitemenu->getActive();
        
		if (isset($activeMenuitem) && $activeMenuitem->note == "Ajax")
		{
			// Expect 1 segment of the form id:alias for the helloworld record
			if ($nSegments == 1)
			{
				$vars['id'] = $segments[0];
				$vars['view'] = 'helloworld';
			}
		}
		else
		{
			// Try to match the categories in the segments, starting at the root
			$categories = JCategories::getInstance('Helloworld', array());
			$matchingCategory = $categories->get('root');
            
			// Go through the category tree, try to get a match between each segment
			// and the id:alias of one of the children
			// The last segment may be a category id:alias or a helloworld record id:alias
			for ($i=0; $i < $nSegments; $i++)
			{
				$children = $matchingCategory->getChildren();
				$matchingCategory = $this->match($children, $segments[$i]);
				if ($matchingCategory)
				{
					$catid = $matchingCategory->id;
					if ($i == $nSegments - 1)    // we're done, all segments are categories
					{
						$vars['view'] = 'category';
						$vars['id'] = $catid;
					}
				}
				else
				{
					if ($i == $nSegments - 1)   // all but last segment are categories
					{
						$vars['id'] = $segments[$i];
						$vars['view'] = 'helloworld';
					}
					else   // something went wrong - didn't get a match at this level
					{
						break;
					}
				}
			}
		}

		return $vars;
	}

	/*
	 * This function takes an array of categoryNode elements and a url segment
	 * It goes through the categoryNodes looking for the one whose id:alias matches the passed-in segment
	 *   and returns the matching categoryNode, or null if not found
	 */
	private function match($categoryNodes, $segment)
	{
		foreach ($categoryNodes as $categoryNode)
		{
			if ($segment == $categoryNode->id . ':' . $categoryNode->alias)
			{
				return $categoryNode;
			}
		}
		return null;
	}

	public function preprocess($query)
	{
		static $currentLang = null;
		if (JLanguageAssociations::isEnabled())
		{
			$app  = JFactory::getApplication();
			$sitemenu = $app->getMenu();
			$lang = $query['lang'];

			if (!isset($query['lang']) || ($query['lang'] == $currentLang))
			{
				return $query;
			}

			if (!isset($query['Itemid']))  // we're currently on /component type of URL
			{
				// use the home page for the URL's language
				$home = $sitemenu->getItems(array('language','home'), array($lang, true));
				if ($home)
				{
					$query['Itemid'] = $home[0]->id;
				}
				return $query;
			}

			$itemid = $query['Itemid'];

			// ensure the menuitem for Itemid has the correct language
			$thismenuitem = $sitemenu->getItem($itemid);
			$thismenuitemLang = $thismenuitem->language;
			if ($thismenuitemLang == $lang)
			{
				$currentLang = $thismenuitemLang;
			}
			if ($thismenuitemLang == $lang || $thismenuitemLang == '*')
			{
				return $query;
			}
            
			// if not, try to find an associated menuitem with the correct language
			$associations = JLanguageAssociations::getAssociations('com_menus', '#__menu', 'com_menus.item', $itemid, 'id', '', '');
			if (isset($associations[$lang]))
			{
				$query['Itemid'] = (int) $associations[$lang]->id;
				return $query;
			}
			else // use the home page for that language (if it's set)
			{
				$home = $sitemenu->getItems(array('language','home'), array($lang, true));
				if ($home)
				{
					$query['Itemid'] = $home[0]->id;
				}
			}
		}
		return $query;
	}
}

Updated Language Strings

admin/language/en-GB/en-GB.com_helloworld.ini

; Joomla! Project
; Copyright (C) 2005 - 2018 Open Source Matters. All rights reserved.
; License GNU General Public License version 2 or later; see LICENSE.txt, see LICENSE.php
; Note : All ini files need to be saved as UTF-8

COM_HELLOWORLD_ADMINISTRATION="HelloWorld - Administration"
COM_HELLOWORLD_ADMINISTRATION_CATEGORIES="HelloWorld - Categories"
COM_HELLOWORLD_NUM="#"
COM_HELLOWORLD_HELLOWORLDS_FILTER="Filters"
COM_HELLOWORLD_AUTHOR="Author"
COM_HELLOWORLD_LANGUAGE="Language"
COM_HELLOWORLD_CREATED_DATE="Created"
COM_HELLOWORLD_PUBLISHED="Published"
COM_HELLOWORLD_HELLOWORLDS_NAME="Name"
COM_HELLOWORLD_HELLOWORLDS_POSITION="Position"
COM_HELLOWORLD_HELLOWORLDS_IMAGE="Image"
COM_HELLOWORLD_HELLOWORLDS_ASSOCIATIONS="Associations"
COM_HELLOWORLD_ID="Id"

COM_HELLOWORLD_HELLOWORLD_CREATING="HelloWorld - Creating"
COM_HELLOWORLD_HELLOWORLD_DETAILS="Details"
COM_HELLOWORLD_HELLOWORLD_EDITING="HelloWorld - Editing"
COM_HELLOWORLD_HELLOWORLD_ERROR_UNACCEPTABLE="Some values are unacceptable"
COM_HELLOWORLD_HELLOWORLD_FIELD_CATID_DESC="The category the messages belongs to"
COM_HELLOWORLD_HELLOWORLD_FIELD_CATID_LABEL="Category"
COM_HELLOWORLD_HELLOWORLD_FIELD_GREETING_DESC="This message will be displayed"
COM_HELLOWORLD_HELLOWORLD_FIELD_GREETING_LABEL="Message"
COM_HELLOWORLD_HELLOWORLD_FIELD_SHOW_CATEGORY_LABEL="Show category"
COM_HELLOWORLD_HELLOWORLD_FIELD_SHOW_CATEGORY_DESC="If set to Show, the title of the message&rsquo;s category will show."
COM_HELLOWORLD_HELLOWORLD_FIELD_LATITUDE_LABEL="Latitude"
COM_HELLOWORLD_HELLOWORLD_FIELD_LATITUDE_DESC="Enter the position latitude, between -90 and +90 degrees"
COM_HELLOWORLD_HELLOWORLD_FIELD_LONGITUDE_LABEL="Longitude"
COM_HELLOWORLD_HELLOWORLD_FIELD_LONGITUDE_DESC="Enter the position longitude, between -180 and +180 degrees"
COM_HELLOWORLD_HELLOWORLD_FIELD_LANGUAGE_DESC="Select the appropriate language"
COM_HELLOWORLD_IMAGE_FIELDS="Image details"
COM_HELLOWORLD_HELLOWORLD_FIELD_IMAGE_LABEL="Select image"
COM_HELLOWORLD_HELLOWORLD_FIELD_IMAGE_DESC="Select an image from the library, or upload a new one"
COM_HELLOWORLD_HELLOWORLD_FIELD_ALT_LABEL="Alt text"
COM_HELLOWORLD_HELLOWORLD_FIELD_ALT_DESC="Alternative text (if image cannot be displayed)"
COM_HELLOWORLD_HELLOWORLD_FIELD_CAPTION_LABEL="Caption"
COM_HELLOWORLD_HELLOWORLD_FIELD_CAPTION_DESC="Provide a caption for the image"
COM_HELLOWORLD_HELLOWORLD_HEADING_GREETING="Greeting"
COM_HELLOWORLD_HELLOWORLD_HEADING_ID="Id"
COM_HELLOWORLD_MANAGER_HELLOWORLD_EDIT="HelloWorld manager: Edit Message"
COM_HELLOWORLD_MANAGER_HELLOWORLD_NEW="HelloWorld manager: New Message"
COM_HELLOWORLD_MANAGER_HELLOWORLDS="HelloWorld manager"
COM_HELLOWORLD_EDIT_HELLOWORLD="Edit message"
COM_HELLOWORLD_N_ITEMS_DELETED_1="One message deleted"
COM_HELLOWORLD_N_ITEMS_DELETED_MORE="%d messages deleted"
COM_HELLOWORLD_N_ITEMS_PUBLISHED="%d message(s) published"
COM_HELLOWORLD_N_ITEMS_UNPUBLISHED="%d message(s) unpublished"
COM_HELLOWORLD_HELLOWORLD_GREETING_LABEL="Greeting"
COM_HELLOWORLD_HELLOWORLD_GREETING_DESC="Add Hello World Greeting"
COM_HELLOWORLD_SUBMENU_MESSAGES="Messages"
COM_HELLOWORLD_SUBMENU_CATEGORIES="Categories"
COM_HELLOWORLD_CONFIGURATION="HelloWorld Configuration"
COM_HELLOWORLD_CONFIG_GREETING_SETTINGS_LABEL="Messages settings"
COM_HELLOWORLD_CONFIG_GREETING_SETTINGS_DESC="Settings that will be applied to all messages by default"
COM_HELLOWORLD_HELLOWORLD_FIELD_CAPTCHA_LABEL="Captcha"
COM_HELLOWORLD_HELLOWORLD_FIELD_CAPTCHA_DESC="Select Captcha to use on front end form"
COM_HELLOWORLD_HELLOWORLD_FIELD_USER_TO_EMAIL_LABEL="User to email"
COM_HELLOWORLD_HELLOWORLD_FIELD_USER_TO_EMAIL_DESC="Select user to email when a new message is entered on front end"
COM_HELLOWORLD_FIELDSET_RULES="Message Permissions"
COM_HELLOWORLD_FIELD_RULES_LABEL="Permissions"
COM_HELLOWORLD_ACCESS_DELETE_DESC="Is this group allowed to edit this message?"
COM_HELLOWORLD_ACCESS_DELETE_DESC="Is this group allowed to delete this message?"
COM_HELLOWORLD_TAB_NEW_MESSAGE="New Message"
COM_HELLOWORLD_TAB_EDIT_MESSAGE="Message Details"
COM_HELLOWORLD_TAB_PARAMS="Parameters"
COM_HELLOWORLD_TAB_ASSOCIATIONS="Associations"
COM_HELLOWORLD_TAB_PERMISSIONS="Permissions"
COM_HELLOWORLD_TAB_IMAGE="Image"
COM_HELLOWORLD_LEGEND_DETAILS="Message Details"
COM_HELLOWORLD_LEGEND_PARAMS="Message Parameters"
COM_HELLOWORLD_LEGEND_ASSOCIATIONS="Message Associations"
COM_HELLOWORLD_LEGEND_PERMISSIONS="Message Permissions"
COM_HELLOWORLD_LEGEND_IMAGE="Image info"
; Column ordering in the Helloworlds view
COM_HELLOWORLD_ORDERING_ASC="Greeting ascending"
COM_HELLOWORLD_ORDERING_DESC="Greeting descending"
COM_HELLOWORLD_AUTHOR_ASC="Author ascending"
COM_HELLOWORLD_AUTHOR_DESC="Author descending"
COM_HELLOWORLD_CREATED_ASC="Creation date ascending"
COM_HELLOWORLD_CREATED_DESC="Creation date descending"
COM_HELLOWORLD_PUBLISHED_ASC="Unpublished first"
COM_HELLOWORLD_PUBLISHED_DESC="Published first"
COM_HELLOWORLD_LANGUAGE_ASC="Language ascending"
COM_HELLOWORLD_LANGUAGE_DESC="Language descending"
COM_HELLOWORLD_ASSOCIATION_ASC="Association ascending"
COM_HELLOWORLD_ASSOCIATION_DESC="Association descending"
; Helloworld menuitem - selecting a greeting via modal
COM_HELLOWORLD_MENUITEM_SELECT_MODAL_TITLE="Select greeting"
COM_HELLOWORLD_MENUITEM_SELECT_HELLOWORLD="Select"
COM_HELLOWORLD_MENUITEM_SELECT_BUTTON_TOOLTIP="Select a helloworld greeting"

Packaging the Component

Contents of your code directory. Each file link below takes you to the step in the tutorial which has the latest version of that source code file.

helloworld.xml

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

	<name>COM_HELLOWORLD</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>0.0.23</version>
	<!-- The description is optional and defaults to the name -->
	<description>COM_HELLOWORLD_DESCRIPTION</description>

	<!-- Runs on install/uninstall/update; New in 2.5 -->
	<scriptfile>script.php</scriptfile>

	<install> <!-- Runs on install -->
		<sql>
			<file driver="mysql" charset="utf8">sql/install.mysql.utf8.sql</file>
		</sql>
	</install>
	<uninstall> <!-- Runs on uninstall -->
		<sql>
			<file driver="mysql" charset="utf8">sql/uninstall.mysql.utf8.sql</file>
		</sql>
	</uninstall>
	<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>
		<filename>router.php</filename>
		<folder>controllers</folder>
		<folder>views</folder>
		<folder>models</folder>
		<folder>helpers</folder>
	</files>

		<languages folder="site/language">
			<language tag="en-GB">en-GB/en-GB.com_helloworld.ini</language>
			<language tag="fr-FR">fr-FR/fr-FR.com_helloworld.ini</language>
		</languages>

	<media destination="com_helloworld" folder="media">
		<filename>index.html</filename>
		<folder>images</folder>
		<folder>js</folder>
		<folder>css</folder>
	</media>

	<administration>
		<!-- Administration Menu Section -->
		<menu link='index.php?option=com_helloworld' img="../media/com_helloworld/images/tux-16x16.png">COM_HELLOWORLD_MENU</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>config.xml</filename>
			<filename>helloworld.php</filename>
			<filename>controller.php</filename>
			<filename>access.xml</filename>
			<!-- SQL files section -->
			<folder>sql</folder>
			<!-- tables files section -->
			<folder>tables</folder>
			<!-- models files section -->
			<folder>models</folder>
			<!-- views files section -->
			<folder>views</folder>
			<!-- controllers files section -->
			<folder>controllers</folder>
			<!-- helpers files section -->
			<folder>helpers</folder>
		</files>
		<languages folder="admin/language">
			<language tag="en-GB">en-GB/en-GB.com_helloworld.ini</language>
			<language tag="en-GB">en-GB/en-GB.com_helloworld.sys.ini</language>
			<language tag="fr-FR">fr-FR/fr-FR.com_helloworld.ini</language>
			<language tag="fr-FR">fr-FR/fr-FR.com_helloworld.sys.ini</language>
		</languages>
	</administration>

</extension>

Contributors