Countdowntimer in minutes and seconds

http://developer.android.com/reference/android/os/CountDownTimer.html

TextView _tv = (TextView) findViewById( R.id.textView1 );
new CountDownTimer(30000, 1000) { // adjust the milli seconds here

    public void onTick(long millisUntilFinished) {
    _tv.setText(""+String.format("%d min, %d sec", 
                    TimeUnit.MILLISECONDS.toMinutes( millisUntilFinished),
                    TimeUnit.MILLISECONDS.toSeconds(millisUntilFinished) - 
                    TimeUnit.MINUTES.toSeconds(TimeUnit.MILLISECONDS.toMinutes(millisUntilFinished))));
    }

    public void onFinish() {
       _tv.setText("done!");
    }
 }.start();

Since java 1.5 there is the java.util.concurrent.TimeUnit class

 _tv.setText(""+String.format("%d min, %d sec", 
                    TimeUnit.MILLISECONDS.toMinutes( millisUntilFinished),
                    TimeUnit.MILLISECONDS.toSeconds(millisUntilFinished) - 
                    TimeUnit.MINUTES.toSeconds(TimeUnit.MILLISECONDS.toMinutes(millisUntilFinished))));

http://docs.oracle.com/javase/7/docs/api/java/util/concurrent/TimeUnit.html

A TimeUnit represents time durations at a given unit of granularity and provides utility methods to convert across units, and to perform timing and delay operations in these units.

For Java versions below 1.5 or for systems that do not fully support the TimeUnit class the following equations can be used:

int seconds = (int) (milliseconds / 1000) % 60 ;
int minutes = (int) ((milliseconds / (1000*60)) % 60);
int hours   = (int) ((milliseconds / (1000*60*60)) % 24);

To vibrate

 Vibrator v = (Vibrator) getSystemService(Context.VIBRATOR_SERVICE);
            // Vibrate for 500 milliseconds
            v.vibrate(500);
  <uses-permission android:name="android.permission.VIBRATE"/> // permission in manifest

Edit:

Vibrate at 4 min 55 seconds for 500 milli seconds

 if((TimeUnit.MILLISECONDS.toMinutes( millisUntilFinished)==4) &&
                    TimeUnit.MILLISECONDS.toSeconds(millisUntilFinished) - 
                    TimeUnit.MINUTES.toSeconds(TimeUnit.MILLISECONDS.toMinutes(millisUntilFinished))==55)
            {

            Vibrator v = (Vibrator) getSystemService(Context.VIBRATOR_SERVICE);
            // Vibrate for 500 milliseconds
            v.vibrate(500);
            }