Extending Community Answers using plugin events

Community Answers is not just full featured but also extendible. There are many plugin events the component triggers which you can use to extend the functionality provided by the component.

Creating a plugin

Please read the following documentation to know about creating a Joomla! plugin. The process is same for any plugin.
https://docs.joomla.org/J2.5:Creating_a_Plugin_for_Joomla

The best way to get started on creating the plugin is to refer to the default Questions plugin provided with the Community Answers package. It is the full featured implementation of most of the plugin events.

Following is the sample class without any plugin events declared. The plugin name is Questions, and the class name is prefixed with PlgCommunityanswers.

<?php
/**
 * @package     corejoomla.administrator
 * @subpackage  com_communityanswers
 *
 * @copyright   Copyright (C) 2009 - 2015 corejoomla.com. All rights reserved.
 * @license     GNU General Public License version 2 or later; see LICENSE.txt
 */
defined('_JEXEC') or die;
 
require_once JPATH_ROOT.'/components/com_cjlib/framework/api.php';
require_once JPATH_ROOT.'/components/com_communityanswers/router.php';
require_once JPATH_ROOT.'/components/com_communityanswers/helpers/route.php';
 
class PlgCommunityanswersQuestions extends JPlugin
{
	public function __construct(& $subject, $config)
	{
		parent::__construct($subject, $config);
		$this->loadLanguage();
		$this->loadLanguage('com_communityanswers', JPATH_ROOT);
	}
}

Plugin Events

Community Answers defines a set of plugin events which you can listen to extend the functionality. The following are the plugin events:

onQuestionBeforeSave

This event will be triggered before saving the question to database. Return false from this event will stops saving the question.

public function onQuestionBeforeSave($context, $question, $isNew)
{
   // do your stuff
   return true;
}

onReplyBeforeSave

This event will be triggered before saving the answer to database. Return false from this event will stops saving the answer.

public function onReplyBeforeSave($context, $reply, $isNew)
{
   // do your stuff
   return true;
}

onQuestionBeforeDelete

This event will be fired before deleting a question.

public function onQuestionBeforeDelete($context, $question)
{
   // do your stuff
   return true;
}

onReplyBeforeDelete

This event will be fired before deleting an answer.

public function onReplyBeforeDelete($context, $answer)
{
   // do your stuff
   return true;
}

onQuestionChangeState

This event will be triggered before any change of the state of a question(s) such as unpublishing, trashing or deleting.

public function onQuestionChangeState($context, $pks, $value)
{
   // do your stuff
   return true;
}

onReplyChangeState

This event will be triggered before any change of the state of answers such as unpublishing, trashing or deleting.

public function onReplyChangeState($context, $pks, $value)
{
   // do your stuff
   return true;
}

onQuestionAfterSave

This event will be fired after saving the question to database.

public function onQuestionAfterSave($context, $question, $isNew)
{
  // do your stuff
}

onReplyAfterSave

This event will be fired after saving the answer to database.

public function onReplyAfterSave($context, $reply, $isNew)
{
  // do your stuff
}

onQuestionAfterLike

This event will be fired after a user likes a question

public function onQuestionAfterLike($context, $rating)
{
  // do your stuff
}

onReplyAfterLike

This event will be fired after a user likes an answer

public function onReplyAfterLike($context, $rating)
{
  // do your stuff
}

onReplyAfterAccepted

This event will be fired after the owner of the question accepted an answer as best answer.

public function onReplyAfterAccepted($context, $reply)
  // do your stuff
}

onQuestionAfterComment

This event fires after a user adds a new comment on a question. Please note that this is a comment not the answer.

public function onQuestionAfterComment($context, $comment)
  // do your stuff
}

onReplyAfterComment

This event fires after a user adds a new comment on an answer.

public function onReplyAfterComment($context, $comment)
  // do your stuff
}

onQuestionAfterDelete

This event will be fired after deleting one or more questions.

public function onQuestionAfterDelete($context, $question)
{
  // do your stuff
}

onReplyAfterDelete

This event will be fired after deleting one or more answers.

public function onReplyAfterDelete($context, $reply)
{
  // do your stuff
}

Plugin installer

Finally you need to have your plugin installer xml file as shown below.

<?xml version="1.0" encoding="utf-8"?>
<extension version="2.5" type="plugin" group="communityanswers" method="upgrade">
    <name>CoreJoomla - YourPlugin</name>
    <creationDate>21-06-2016</creationDate/>/
    <author>Your Name</author>
    <authorEmail>Your email</authorEmail>
    <authorUrl>Your email</authorUrl>
    <copyright>All rights reserved by your company 2003-14.</copyright>
    <license>http://www.gnu.org/licenses/gpl-2.0.html GNU/GPL</license>
    <version>1.0.0</version>
    <description>Some description</description>
    <files>
        <filename>pluginname.xml</filename>
        <filename plugin="pluginname">pluginname.php</filename>
    </files>
 
    <config>
        <fields name="params">
            <fieldset name="basic">
            </fieldset>
        </fields>
    </config>
</extension>