how to catch hardware key press event in service(background) on android .?

I try to implements KeyListener at service, and override on开发者_如何学运维KeyDown method.

but not use above methos...

Generally, you cannot "catch hardware key press event in service(background) on android".

The CAMERA button, if it exists on a device, and the MEDIA button, if it exists on a plugged-in headset, will result in broadcast Intents if the foreground activity does not consume the events.