How it works

Extend one of the following classes:

• GFAddon
• GFFeedAddon
• GFPaymentAddon

GFAddon Class

For add-ons that are very simple
or don't fit into one of the more specialised cases

https://www.gravityhelp.com/documentation/article/gfaddon/

GFFeedAddon Class

For add-ons that allow users to create form feeds

• Easily add feed settings UI, conditional processing
• Eg. MailChimp add-on

https://www.gravityhelp.com/documentation/article/gffeedaddon/

GFPaymentAddon Class

For add-ons that collect payments. Handles:

• Payments via 3rd party websites (eg PayPal Standard)
• Credit card payments behind the scenes (eg Stripe)

https://www.gravityhelp.com/documentation/article/gfpaymentaddon/

Simple example

https://github.com/rocketgenius/simpleaddon

Bootstrap / plugin file:

/*
...
*/

define( 'GF_SIMPLE_ADDON_VERSION', '2.0' );
add_action( 'gform_loaded', array( 'GF_Simple_AddOn_Bootstrap', 'load' ), 5 );
class GF_Simple_AddOn_Bootstrap {
    public static function load() {
        if ( ! method_exists( 'GFForms', 'include_addon_framework' ) ) {
            return;
        }
        require_once( 'class-gfsimpleaddon.php' );
        GFAddOn::register( 'GFSimpleAddOn' );
    }
}
function gf_simple_addon() {
    return GFSimpleAddOn::get_instance();
}

Add-on class (class-gfsimpleaddon.php):

GFForms::include_addon_framework();

class GFSimpleAddOn extends GFAddOn {
  protected $_version = GF_SIMPLE_ADDON_VERSION;
  protected $_min_gravityforms_version = '1.9';
  protected $_slug = 'simpleaddon';
  protected $_path = 'simpleaddon/simpleaddon.php';
  protected $_full_path = __FILE__;
  protected $_title = 'Gravity Forms Simple Add-On';
  protected $_short_title = 'Simple Add-On';
  private static $_instance = null;

  /**
   * Get an instance of this class.
   *
   * @return GFSimpleAddOn
   */
  public static function get_instance() {
    if ( self::$_instance == null ) {
      self::$_instance = new GFSimpleAddOn();
    }
    return self::$_instance;
  }

  ...

Simple example

Scripts...

/**
 * Return the scripts which should be enqueued.
 *
 * @return array
 */
public function scripts() {
  $scripts = array(
    array(
      'handle'  => 'my_script_js',
      'src'     => $this->get_base_url() . '/js/my_script.js',
      'version' => $this->_version,
      'deps'    => array( 'jquery' ),
      'strings' => array(
        'foo'  => esc_html__( 'Foo', 'simpleaddon' ),
        'bar' => esc_html__( 'Bar', 'simpleaddon' )
      ),
      'enqueue' => array(
        array(
          'admin_page' => array( 'form_settings' ),
          'tab'        => 'simpleaddon'
        )
      )
    ),
  );
  return array_merge( parent::scripts(), $scripts );
}

Styles...

/**
 * Return the stylesheets which should be enqueued.
 *
 * @return array
 */
public function styles() {
  $styles = array(
    array(
      'handle'  => 'my_styles_css',
      'src'     => $this->get_base_url() . '/css/my_styles.css',
      'version' => $this->_version,
      'enqueue' => array(
        array( 'field_types' => array( 'poll' ) )
      )
    )
  );
  return array_merge( parent::styles(), $styles );
}

Plugin page...

/**
 * Creates a custom page for this add-on.
 */
public function plugin_page() {
  echo 'This page appears in the Forms menu';
}

Plugin page...

Add-on settings...

/**
 * Configures the settings which should be rendered on the add-on settings tab.
 *
 * @return array
 */
public function plugin_settings_fields() {
  return array(
    array(
      'title'  => esc_html__( 'Simple Add-On Settings', 'simpleaddon' ),
      'fields' => array(
        array(
          'name'              => 'mytextbox',
          'tooltip'           => esc_html__( 'This is the tooltip', 'simpleaddon' ),
          'label'             => esc_html__( 'This is the label', 'simpleaddon' ),
          'type'              => 'text',
          'class'             => 'small',
          'feedback_callback' => array( $this, 'is_valid_setting' ),
        )
      )
    )
  );
}

Extract value with

$this->get_plugin_setting('mytextbox')

Add-on settings...

Form settings...

/**
 * Configures the settings which should be rendered 
 * on the Form Settings > Simple Add-On tab.
 *
 * @return array
 */
public function form_settings_fields( $form ) {
  return array(
    array(
      'title'  => esc_html__( 'Simple Form Settings', 'simpleaddon' ),
      'fields' => array(
        array(
          'label'             => esc_html__( 'My Text Box', 'simpleaddon' ),
          'type'              => 'text',
          'name'              => 'mytext',
          'tooltip'           => esc_html__( 'This is the tooltip', 'simpleaddon' ),
          'class'             => 'medium',
          'feedback_callback' => array( $this, 'is_valid_setting' ),
        ),
        array(
          'label'   => esc_html__( 'My Text Area', 'simpleaddon' ),
          'type'    => 'textarea',
          'name'    => 'mytextarea',
          'tooltip' => esc_html__( 'This is the tooltip', 'simpleaddon' ),
          'class'   => 'medium merge-tag-support mt-position-right',
        ),
      ),
    ),
  );
}

Form settings...