Joomla! Programmers Documentation

The category form field type provides a drop down list of all published categories for a certain extension. If the parameter has a saved value this is selected when the page is first loaded. If not, the default value (if any) is selected. If the show_root attribute is 1, the first option on the list will be a string representing the root category (which is a translatable string) and is given the value 0.

• type (mandatory) must be category.
• name (mandatory) is the unique name of the field.
• label (mandatory) (translatable) is the field html label.
• extension (mandatory) is the name of the extension for which the categories will be retrieved. For example, to list content categories, use the value 'com_content'.
• scope (optional) is an alias for extension.
• show_root (optional) is whether a choice representing the root category will be shown.
• default (optional) is the default category ID number.
• description (optional) (translatable) is the field description.
• class (optional) allows you set a css class for display. If omitted this will default to 'inputbox'
• multiple (optional) if set to true allows multiple items to be selected at the same time. Set to false to allow single selection.

Implemented by: libraries/src/Form/Field/CategoryField.php

Example XML parameter definition¶

<field
        name="mycategory" 
        type="category" 
        extension="com_content" 
        label="Select a category" 
        description=""
/>