How to add a Category Attribute
Category attributes were automatically displayed in the admin panel of Magento 1. In Magento 2, it is necessary to explicitly render it with a UI Component. This is quite easy to do and provides a great degree of control over the form input. In the code examples below, replace
Your Category Attribute Name with your own values.
Step #1: Create the Attribute
The following is a full example of an install script that creates a category attribute. If you already have a category attribute, it is not necessary.
Step #2: Display the Attribute
The category UI Component is rendered with configuration from the
category_form.xml file. All files with that name are merged together. As a result, you can add a field by creating a
category_form.xml file in the
view/adminhtml/ui_component directory in your module.
Here is a full example of adding a field under the “Display Settings” group. It is important to note that
attribute_id should match the ID of the attribute that you created in the install script.
Step #3: Upgrade and Run
How it works
UI Component configuration is merged. When you add a new file, Magento will merge that with the base UI Component configuration file. In the example above, that is
category_form.xml. The nodes inside of that reflect the structure of the base file. There are only two nodes necessary in this case before the custom field is added:
<fieldset>. Inside of that, the
<field> node is used to add a field with a name that matches the id of the attribute you want to render.
<field> node is declared originally in
vendor/magento/module-ui/view/base/ui_component/etc/definition.xml. If you open that file and look for
<field>, you will notice that there is only a PHP class referenced—nothing particularly helpful. This is where the
config elements in the example above come in important. Notice the value of
<item name="formElement"> (
checkbox)? Now, if you look in
definition.xml, you will find a
<checkbox> node that has some configuration values. In the PHP class that the
<field> element references, it looks up the
formElement to use and loads that. As a result,
<checkbox> is the node. In this case, that has the information that we are looking for.
One of those elements is particularly useful when determining what XML you need to provide for your field:
vendor/magento/module-ui/view/base/web/js/form/element/single-checkbox.js. If you open that file, there is a
defaults object which contains values that can be modified through the XML above. For example, notice:
defaults.prefer: 'checkbox'. In the XML above, we declared
This opens up the opportunity for you to customize nearly anything about the UI Component. It also should provide you with a basis of how to determine what configuration is available for you to set through XML.