How to keep iPhone screen from reducing backlight..?

My app shows a picture and then an mp3 plays over it, describi开发者_如何学编程ng the picture. The trouble is that the backlight on the screen reduces after 40 seconds or so, if the phone is not interacted with. How do I prevent the fade?...so that my picture doesn't go dark when they are looking at it.

[[UIApplication sharedApplication] setIdleTimerDisabled:YES];

Set UIApplication's idleTimerDisabled property to YES.

For swift the code will be:

UIApplication.sharedApplication().idleTimerDisabled = true