Create plugin to edit category form

Question

i'm trying to edit joomla's category form with a plugin following this guide https://docs.joomla.org/Creating_a_profile_plugin

xml file

<extension version="3.1" type="plugin" group="category">
    <name>plg_img_categories</name>     
    <files>
        <filename plugin="categories">categoryimg.php</filename>
        <folder>forms</folder>
    </files>

</extension>

php file

<?php
defined( '_JEXEC' ) or die;

class plgContentCategoryCategories extends JPlugin {
    function onContentPrepareForm($form, $data) {
        echo "Pippo!";
        var_dump($form->getName());
    }
 }
?>

I was expected to see var_dump "$form->getName()" or "Pippo!" inside the administrator category form, however it doesn't.

Any idea why?

Answer 1

There is no plugin group like category, you should use content in this case.

Joomla! relies strongly on naming conventions:

• Class name should be plg[GROUP_NAME][PLUGIN_ATTR_VALUE], resulting in plgContentCategoryImg
• Plugin name in XML should be plg_[GROUP_NAME]_[PLUGIN_ATTR_VALUE], resulting in plg_content_categoryimg.
• Plugin directory name must be [PLUGIN_ATTR_VALUE], resulting in categoryimg

So, your files would look like this:

categoryimg.php

<?php
defined( '_JEXEC' ) or die;

class plgContentCategoryImg extends JPlugin {
    function onContentPrepareForm($form, $data) {
        echo "Pippo!";
        var_dump($form->getName());
    }
 }
?>

categoryimg.xml

<extension version="3.1" type="plugin" group="content">
    <name>plg_content_categoryimg</name>
    <files>
        <filename plugin="categoryimg">categoryimg.php</filename>
    </files>
</extension>

And don't forget, directory name must be categoryimg.

Result as I tested it: