public class MainActivity extends Activity {

    final String LOG_TAG = "myLog";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);


        TelephonyManager TelephonyMgr = (TelephonyManager) getSystemService(Context.TELEPHONY_SERVICE);
        TelephonyMgr.listen(new TeleListener(), PhoneStateListener.LISTEN_CALL_STATE);
    }
    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }


    class TeleListener extends PhoneStateListener {
        public void onCallStateChanged(int state, String incomingNumber) {
            super.onCallStateChanged(state, incomingNumber);
            switch (state) {
                case TelephonyManager.CALL_STATE_IDLE:
                    // CALL_STATE_IDLE;
                    break;
                case TelephonyManager.CALL_STATE_OFFHOOK:
                    // CALL_STATE_OFFHOOK;
                    break;
                case TelephonyManager.CALL_STATE_RINGING:
                    // CALL_STATE_RINGING
                    Log.d(LOG_TAG,"CALL_STATE_RINGING " + incomingNumber);
                    break;
                default:
                    break;
            }
        }

    }
}