displaying a 3 random numbers with delay on the textview when clicking a button in android [требует правки]

I want to make an application. When I click on the Button, I want to display three numbers with a delay on the Textview. Nothing is displayed on the TEXT. Help me find the error. Thank you in advance.

public class MainActivity extends Activity {
    private Button mStartButton, mCancelButton;
    private TextView mCounterTextView, textView;
    private Spinner spinner;
    private Timer mTimer;
    private MyTimerTask mMyTimerTask;
    private MyTimerTask nMyTimerTask;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mStartButton = (Button) findViewById(R.id.buttonStart);
        mCancelButton = (Button) findViewById(R.id.buttonCancel);
        mCounterTextView = (TextView) findViewById(R.id.textViewCounter);
        textView = (TextView)findViewById(R.id.textView);
        spinner = (Spinner)findViewById(R.id.spinner);
        mStartButton.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View arg0) {
                if (mTimer != null) {
                    mTimer.cancel();
                }
                mTimer = new Timer();
                mMyTimerTask = new MyTimerTask();
                nMyTimerTask = new MyTimerTask();
                if (mStartButton.isClickable() ){
                            mTimer.schedule(mMyTimerTask, 0, 1000);
                }
            }
        });
        mCancelButton.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View v) {
                if (mTimer != null) {
                    mTimer.cancel();
                    mTimer = null;
                }
            }
        });
    }
    class MyTimerTask extends TimerTask {

            @Override
            public void run () {
                final Random random = new Random();
                final String number = String.valueOf(random.nextInt());

                runOnUiThread(new Runnable() {
                    @Override
                    public void run() {
                        for (int i=1; i<=3; i++) {
                            mCounterTextView.setText(number);
                        }
                    }
                });
            }

    }
}