How to block hardware buttons in services (Android)?

Question

Android

There was a need to write an alarm clock application. In this connection, the question arose - is it possible to somehow block the hardware buttons in Android.
Through keyEvent it is possible to block in Activity. And that's not all. Is it possible to block everything without Activity ?

Answer 1

You definitely won’t block all the buttons, why not start an Activity ? All alarm clocks I've seen do this.

Answer 2

Through some manipulations, I still managed to block the Home button.