AudioManager audio = (AudioManager) context.getSystemService(Context.AUdio_SERVICE);
switch( audio.getRingerMode() ){
case AudioManager.RINGER_MODE_NORMAL:
   break;
case AudioManager.RINGER_MODE_SILENT:
   break;
case AudioManager.RINGER_MODE_VIBRATE:
   break;
}

对于Volume更改,有BroadcastReceiver.

public class VolumeKeyReceiver extends BroadcastReceiver {
    @Override
    public void onReceive(Context context,Intent intent) {
       //Implement Logic
    }
}

注册BroadcastReceiver

VolumeKeyReceiver keyReceiver = new VolumeKeyReceiver();
IntentFilter intentFilter = new IntentFilter();
intentFilter.addAction("android.media.VOLUME_CHANGED_ACTION");
registerReceiver(keyReceiver,intentFilter);