Joomla:onContentAfterSave没有触发

I'm developing a Joomla plugin. Unfortunately, the necessary event is not fired. This means that the following code never gets executed:

public function onContentAfterSave($context, &$article, $isNew)
{
 ....
}

I have developed the plugin as usual. All other used events work fine. Can this be an internal Joomla \ PHP bug or am I missing something?

Apache/2.2.4 (Win32) mod_ssl/2.2.4 OpenSSL/0.9.8k PHP/5.3.3

Joomla! 2.5.4 Stable [ Ember ] 2-April-2012 14:00 GMT

Have you definitely installed and enabled the plugin? It's easy to forget the latter, in particular.

There's probably something not matching between the plugin name in your .xml file and the plugin name in your .php file.

[PluginName].php

<?php

defined('_JEXEC') or die;

jimport('joomla.event.plugin');  // I've also seen joomla.plugin.plugin.
                                 // Perhaps and older version
class plg[PluginGroup][PluginName]
{
    public function onContentAfterSave( $context, &$article, $isNew  )
    {
      // $db = JFactory::GetDBO();
      // etc...
    }
}
?>

[PluginName].xml

<?xml version="1.0" encoding="UTF-8"?>
<extension type="plugin" version="2.5.0" group="[PluginGroup]">
<name>[PluginName]</name>
<version>0.0.1</version>
<author></author>
<creationDate></creationDate>
<copyright></copyright>
<license></license>
<authorEmail></authorEmail>
<authorUrl></authorUrl>
<description></description>
<files>
  <filename plugin="[PluginName]">[PluginName].php</filename>
  <filename>[PluginName].xml</filename>
  <filename>index.html</filename>       
</files>
</extension>

Otherwise, please post more information:

  1. What else in your [pluginname].php and [pluginname].xml files.
  2. Have you installed the plugin correctly?
  3. Have you published the plugin after installation?