Disabling device sleep / idle timer / auto dim on iOS

Hello!

I’m trying to disable device sleep / auto dim in my Cocos Creator-created iOS app. From my web research, I got the impression that I have to add this

UIApplication.SharedApplication.IdleTimerDisabled = true;

to my App Delegate (which I assume to be the AppDelegate.cpp file generated during build). I’m a bit stuck here, though – where do I add it, and what do I have to adjust to make it fit into my Cocos Creator ecosystem?

Greetings, and thanks!
Fabian