# init(startTime:duration:parameter:) Constructs an event definition. ``` init(startTime: TimeInterval, duration: TimeInterval, parameter: ActionEventDefinition.EventParameterType? = nil) ``` ## Parameters `startTime` The time when the event becomes active. `duration` The duration of the event. `parameter` The event parameter to return to the event handler when the event occurs. --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)