Swift version: 5.0
You can stop the iOS screen sleeping by using the
isIdleTimerDisabled property of your application. When set to true, this means the screen will never dim or go to sleep while your app is running, so be careful – you don't want to waste your user's battery life!
Here's an example:
UIApplication.shared.isIdleTimerDisabled = true
Available from iOS 2.0
This is part of the Swift Knowledge Base, a free, searchable collection of solutions for common iOS questions.