Detect if iPhone screen is on/off

Question

Is there any way to detect if an iPhone's screen is on or off? For example, when the phone's screen lock button is pressed.

I've been using (void)applicationWillResignActive:(UIApplication *)application; to prepare for such events (which works fine for the most part), but this method is also fired for incoming calls, texts, etc.

As far as I can tell, there is no documented method to determine this.

I've been playing with some workarounds, like checking if screen resolution changed, checking if the orientation is unknown, or getting the brightness of the device. Nothing has panned out yet.

Does anyone have any creative/workaround solutions for this?

Answer 1

Yes, there is no definitive method. UIApplication has a property protectedDataAvailable which will return YES when screen is unlocked and NO if locked only when user enables content protection. So this is the closest but unreliable I can think of. In such case, you can even listen to UIApplicationProtectedDataDidBecomeAvailable and UIApplicationProtectedDataWillBecomeUnavailable notifications.