Developing a custom Joomla custom field plugin

custom-joomla-custom-field.md

Anatomy of a custom form field

fields
  |
  -- fieldName.php
language
  |
  -- en-GB
    |
    -- en-GB.plg_fields_fieldName.ini
    -- en-GB.plg_fields_fieldName.sys.ini
media
  |
  -- css
    |
    -- fieldName.css
  -- js
    |
    -- fieldName.js
params
  |
  -- fieldName.xml
tmpl
  |
  -- fieldName.php
fieldName.php
fieldName.xml

• fields/fieldName.php is a custom JForm field. You can add as many custom JForm fields to this directory as you need.
• language/ contains the language definition files are located.
• media/ is an optional directory for supporting media like CSS and JavaScript files.
• params/ contains the form field definitions used when creating a custom field instance in the component configuration.
• tmpl/fieldName.php is the frontend template used for rendering the field.
• fieldName.php is the plugin entry point.
• fieldName.xml is the plugin manifest file used for installation.

Resources

• Custom fields overview at https://docs.joomla.org/J3.x:Adding_custom_fields

• From Create a custom field plugin for Joomla 3.7

The custom field plugin uses the JForm API so the standard Joomla field types as used in an extension's .xml file, are applicable, just written differently, in a .php file.

• You can also add your own JForm fields, see https://docs.joomla.org/Creating_a_custom_form_field_type. A good example of this can be downloaded at https://geodata.solutions/tools/plg_fields_locationlists.zip or check out https://github.com/Digital-Peak/DPFields

File (upload) form field

For a file form field, you need a destination to upload to. Some options:

1. Develop a simple ajax plugin to acept the upload.
2. Add an admin template override add enctype="multipart/form-data" to the form tag. This has the side effect of that field not being available in the jcfields #item object.