I've written an Andoid app that uses the hardware Volume buttons for another purpose.
It works fine if the app is running and visible, but when I turn the screen off or let it time out, the button clicks don't get into my handlers.
Does anyone know if there is a way to detect these button clicks when the screen is off?
The only way to keep detecting things like this when the screen is off is to acquire a WakeLock that will allow the screen to turn off, and still let your app function. However, this drains the battery life quite a bit, and should only be used when absolutely necessary.
In this case, you will need a PARTIAL_WAKE_LOCK.