Products Google for Education Blockly Reference Blockly Framework Reference DropdownViewDelegate public protocol DropdownViewDelegate: class Delegate for events that occur on DropdownView. dropDownDidReceiveTap() Event that is called when the user has tapped on the dropdown. Declaration Swift func dropDownDidReceiveTap() Except as otherwise noted, the content of this page is licensed under the Creative Commons Attribution 3.0 License, and code samples are licensed under the Apache 2.0 License. For details, see our Site Policies. Java is a registered trademark of Oracle and/or its affiliates. Last updated December 1, 2017.