bagaimana cara membuat pengatur waktu yang dimulai secara otomatis?

Saya sedang mengerjakan kuis Android di aplikasi saya, saya memiliki kelas QuestionActivity. Dalam metode setQuestions() mana teks dari database ditetapkan dalam tampilan teks tombol dan skor disetel ke nol untuk pertama kalinya. Dalam teks berikutnya, pertanyaan berikutnya diberikan dan skor juga diperbarui apakah pertanyaannya salah atau benar. Saya ingin memiliki pengatur waktu otomatis yang dimulai saat kita memasuki aktivitas ini. Dan pada putaran berikutnya dimulai lagi dari beberapa waktu dan terus menurun. saya tahu untuk ini saya harus membuat tampilan teks dalam pertanyaan xml yang terkait dengan panggilan ini. tapi saya tidak tahu di mana dan bagaimana menulis kode di kelas ini. waktu pengatur waktu 30 detik. saya memposting kode kelas ini. tolong seseorang bantu saya.

public class QuestionActivity extends Activity implements OnClickListener{

    private Question currentQ;
    private GamePlay currentGame;


    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.question);
                /**
         * Configure current game and get question
         */
        currentGame = ((CYKApplication)getApplication()).getCurrentGame();
        currentQ = currentGame.getNextQuestion();
        Button nextBtn1 = (Button) findViewById(R.id.answer1);
        nextBtn1.setOnClickListener(this);
        Button nextBtn2 = (Button) findViewById(R.id.answer2);
        nextBtn2.setOnClickListener(this);
        Button nextBtn3 = (Button) findViewById(R.id.answer3);
        nextBtn3.setOnClickListener(this);
        Button nextBtn4 = (Button) findViewById(R.id.answer4);
        nextBtn4.setOnClickListener(this);
        Button nextBtn5 = (Button) findViewById(R.id.answer5);
        nextBtn5.setOnClickListener(this);


        /**
         * Update the question and answer options..
         */
        setQuestions();

    }


    /**
     * Method to set the text for the question and answers from the current games
     * current question
     */
    private void setQuestions() {
        //set the question text from current question
        String question = Utility.capitalise(currentQ.getQuestion());
        TextView qText = (TextView) findViewById(R.id.question);
        qText.setText(question);

        //set the available options
        List<String> answers = currentQ.getQuestionOptions();
        TextView option1 = (TextView) findViewById(R.id.answer1);
        option1.setText(Utility.capitalise(answers.get(0)));

        TextView option2 = (TextView) findViewById(R.id.answer2);
        option2.setText(Utility.capitalise(answers.get(1)));

        TextView option3 = (TextView) findViewById(R.id.answer3);
        option3.setText(Utility.capitalise(answers.get(2)));

        TextView option4 = (TextView) findViewById(R.id.answer4);
        option4.setText(Utility.capitalise(answers.get(3)));

        int score = currentGame.getScore();
        String scr = String.valueOf(score);
        TextView score1 = (TextView) findViewById(R.id.score);
        score1.setText(scr);
        }


    @Override
    public void onClick(View arg0) {
        //Log.d("Questions", "Moving to next question");
        if(arg0.getId()==R.id.answer5)
        {
        new AlertDialog.Builder(this)
        .setMessage("Are you sure?")
        .setCancelable(true)
        .setPositiveButton("Yes",
         new DialogInterface.OnClickListener() {
        public void onClick(DialogInterface dialog,
         int id) {
                finish();
                 }
             }).setNegativeButton("No", null).show();

                }

        else
        {
            if(!checkAnswer(arg0)) return;  

        /**
         * check if end of game
         */
        if (currentGame.isGameOver()){
            //Log.d("Questions", "End of game! lets add up the scores..");
            //Log.d("Questions", "Questions Correct: " + currentGame.getRight());
            //Log.d("Questions", "Questions Wrong: " + currentGame.getWrong());
            Intent i = new Intent(this, EndgameActivity.class);
            startActivity(i);
            finish();
        }
        else{
            Intent i = new Intent(this, QuestionActivity.class);
            startActivity(i);
            finish();
          }
        }
      }



    @Override
    public boolean onKeyDown(int keyCode, KeyEvent event)
    {
        switch (keyCode)
        {
        case KeyEvent.KEYCODE_BACK :
            return true;
        }

        return super.onKeyDown(keyCode, event);
    }


    /**
     * Check if a checkbox has been selected, and if it
     * has then check if its correct and update gamescore
     */
    private boolean checkAnswer(View v) {

        Button b=(Button) v;
        String answer = b.getText().toString();

            //Log.d("Questions", "Valid Checkbox selection made - check if correct");
            if (currentQ.getAnswer().equalsIgnoreCase(answer))
            {
                b.setBackgroundResource(R.drawable.answercolor);
                //Log.d("Questions", "Correct Answer!");
                currentGame.incrementScore();
            }
            else{
                b.setBackgroundResource(R.drawable.answercolorr);
                //Log.d("Questions", "Incorrect Answer!");
                currentGame.decrementScore();
            }
            return true;
        }

}