How can I checked if play/pause button in my headset is clicked? After that can I implement some method that could change typical action (play/pause) for my own action (shut down etc.) ?
If you are trying to listen for this from an activity in the foreground, use onKeyDown() and watch for KEYCODE_MEDIA_PLAY_PAUSE.
Use a BroadcastReceiver for ACTION_MEDIA_BUTTON if you are trying to listen for this event from the background (e.g., a service playing music).