Enhance eventtype filtering in eventlistings with a drop-down

This incorporates the simple change in civicrm#68 and adds selection based on
names of event types.

site/elements/civieventtypes.php

@@ -0,0 +1,84 @@
+<?php
+/*
+   +--------------------------------------------------------------------+
+   | CiviCRM version 5                                                  |
+   +--------------------------------------------------------------------+
+   | This file is a part of CiviCRM.                                    |
+   |                                                                    |
+   | CiviCRM is free software; you can copy, modify, and distribute it  |
+   | under the terms of the GNU Affero General Public License           |
+   | Version 3, 19 November 2007 and the CiviCRM Licensing Exception.   |
+   |                                                                    |
+   | CiviCRM is distributed in the hope that it will be useful, but     |
+   | WITHOUT ANY WARRANTY; without even the implied warranty of         |
+   | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.               |
+   | See the GNU Affero General Public License for more details.        |
+   |                                                                    |
+   | You should have received a copy of the GNU Affero General Public   |
+   | License and the CiviCRM Licensing Exception along                  |
+   | with this program; if not, contact CiviCRM LLC                     |
+   | at info[AT]civicrm[DOT]org. If you have questions about the        |
+   | GNU Affero General Public License or the licensing of CiviCRM,     |
+   | see the CiviCRM license FAQ at http://civicrm.org/licensing        |
+   +--------------------------------------------------------------------+
+  */
+
+// Retrieve list of CiviCRM events
+// Active, current or future
+
+// Check to ensure this file is included in Joomla!
+defined('_JEXEC') or die('Restricted access');
+class JFormFieldCiviEventTypes extends JFormField
+{
+
+  /**
+   * Element name
+   *
+   * @access  protected
+   * @var     string
+   */
+  var $type = 'CiviEventTypes';
+
+  protected function getInput()
+  {
+    $value = $this->value;
+    $name = $this->name;
+
+    // Initiate CiviCRM
+    define('CIVICRM_SETTINGS_PATH', JPATH_ROOT . '/' . 'administrator/components/com_civicrm/civicrm.settings.php');
+    require_once CIVICRM_SETTINGS_PATH;
+
+    require_once 'CRM/Core/ClassLoader.php';
+    CRM_Core_ClassLoader::singleton()->register();
+
+    require_once 'CRM/Core/Config.php';
+    $config = CRM_Core_Config::singleton();
+
+    $groupIdForEventTypes = $this->getGroupIdForEventTypes();
+
+    $eventTypeResults = \Civi\Api4\OptionValue::get(TRUE)
+      ->addWhere('option_group_id', '=', $groupIdForEventTypes)
+      ->execute();
+    $eventTypes = iterator_to_array($eventTypeResults);
+
+    $options = array();
+    $options[] = JHTML::_('select.option', '', ''); // Add an empty first option
+    foreach ($eventTypes as $eventType) {
+      $options[] = JHTML::_('select.option', $eventType['value'], $eventType['label']);
+    }
+
+    return JHTML::_('select.genericlist', $options, $name, NULL, 'value', 'text', $value);
+  }
+
+    private function getGroupIdForEventTypes()
+    {
+        $groupIdResults = \Civi\Api4\OptionGroup::get(TRUE)
+          ->addSelect('id')
+          ->addWhere('name', '=', 'event_type')
+          ->execute();
+        $groupIdForEventTypes = current(iterator_to_array($groupIdResults))['id'];
+
+        return $groupIdForEventTypes;
+    }
+}
+

site/views/Events/tmpl/eventlisting.xml

@@ -16,16 +16,15 @@
     <description>List of all active, current, public events.</description>
     <name>Event Listing</name>
 
-    <fields name="request">
+    <fields name="request" addfieldpath="/administrator/components/com_civicrm/civicrm/joomla/site/elements">
       <fieldset name="request">
-        <field name="spacer"
-               type="spacer"
-               class="text"
-               label="The event listing page has no parameter options to configure."
+        <field name="type"
+               type="civieventtypes"
+               label="Filter on event type (leave empty for no filtering)"
           />
         <field name="task"
                type="hidden"
-               default="civicrm/event/ical"
+               default="civicrm/event/list"
                required="true"
           />
         <field name="reset"