What to use instead of UIScreen.mainScreen().applicationFrame for swift in ios 9.1?

Use

let rect1 = UIScreen.mainScreen().bounds // Returns CGRect
let rect2 = UIScreen.mainScreen().bounds.size // Returns CGSize

I know that UIScreen.mainScreen().bounds is the recommended alternative; however, it's not the exact equivalent to UIScreen.mainScreen().applicationFrame, particularly when your application does NOT occupy the whole screen, which happens with Split View and Slide Over feature on certain iPads.

In that case, this is a good alternative: UIApplication.sharedApplication.keyWindow.frame. (of course keyWindow has to be available, that is, you did invoke makeKeyAndVisible)

As of swift 3 you need to use it like this now.

let SCREEN_WIDTH = UIScreen.main.bounds.size.width
let SCREEN_HEIGHT = UIScreen.main.bounds.size.height