Is it possible to detect when screen will turn off and catch it? I want to set timer for 15 seconds in global settings of Android. I am trying to find some information how to catch wake-lock mode.
Just register your app for the actions Intent.ACTION_SCREEN_OFF and Intent.ACTION_SCREEN_ON and do what you want when these events are broadcasted.
Create a dedicated BroadcastReceiver class (and add it to the manifest) or register a BroadcastReceiver at runtime.