Android : Run 2 timers 4 times in a row

I created an Intervall-Countdowntimer-app which starts off with a 30 sec. timer and continues with a second timer (15 sec.)as soon as the first timer ends. But, I want the app to do this 4 times. So, as soon as the second timer (15 sec) is finished the whole process should start again (4 times in a row).

Here´s my code, thank´s in advance.

public class MainActivity extends ActionBarActivity {



    CountDownTimer counter;
    MediaPlayer mp;



    Button btnStart, btnStop;
    TextView textViewTime;
    @Override
    public void onCreate(Bundle savedInstanceState) {


        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        btnStart = (Button)findViewById(R.id.btnStart);
        btnStop = (Button)findViewById(R.id.btnStop);
        textViewTime = (TextView)findViewById(R.id.textViewTime);
        textViewTime.setText("00:00:00");

        mp = MediaPlayer.create(this, R.raw.vuvuneu);
        btnStart = (Button)this.findViewById(R.id.btnStart);



        counter=new CountDownTimer(15000, 1000) {
            @Override
            public void onTick(long millisUntilFinished) {
                long millis = millisUntilFinished;
                String hms = String.format("%02d:%02d:%02d", TimeUnit.MILLISECONDS.toHours(millis),
                        TimeUnit.MILLISECONDS.toMinutes(millis) - TimeUnit.HOURS.toMinutes(TimeUnit.MILLISECONDS.toHours(millis)),
                        TimeUnit.MILLISECONDS.toSeconds(millis) - TimeUnit.MINUTES.toSeconds(TimeUnit.MILLISECONDS.toMinutes(millis)));
                System.out.println(hms);
                textViewTime.setText(hms);

            }

            @Override
            public void onFinish() {

                textViewTime.setText("Done");
                mp.start();


            }
        };




        final CounterClass timer = new CounterClass(30000,1000);
        btnStart.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                timer.start();
                mp.start();

            }
        });
        btnStop.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                timer.cancel();
            }
        });

    }
    @TargetApi(Build.VERSION_CODES.GINGERBREAD)
    @SuppressLint("NewApi")
    public class CounterClass extends CountDownTimer {
        public CounterClass(long millisInFuture, long countDownInterval) {
            super(millisInFuture, countDownInterval);
        }





            @Override
        public void onFinish() {
              counter.start();
                mp.start();



            }


        @SuppressLint("NewApi")
        @TargetApi(Build.VERSION_CODES.GINGERBREAD)
        @Override
        public void onTick(long millisUntilFinished) {

            textViewTime.setText("seconds remaining: " + millisUntilFinished / 1000);


            long millis = millisUntilFinished;
            String hms = String.format("%02d:%02d:%02d", TimeUnit.MILLISECONDS.toHours(millis),
                    TimeUnit.MILLISECONDS.toMinutes(millis) - TimeUnit.HOURS.toMinutes(TimeUnit.MILLISECONDS.toHours(millis)),
                    TimeUnit.MILLISECONDS.toSeconds(millis) - TimeUnit.MINUTES.toSeconds(TimeUnit.MILLISECONDS.toMinutes(millis)));
            System.out.println(hms);
            textViewTime.setText(hms);
        }
    }
}