// Get instance of Vibrator from current Context
Vibrator v = (Vibrator) getSystemService(Context.VIBRATOR_SERVICE);

// Start without a delay
// Vibrate for 100 milliseconds
// Sleep for 1000 milliseconds
long[] pattern = {0, 100, 1000};

// The '0' here means to repeat indefinitely
// '0' is actually the index at which the pattern keeps repeating from (the start)
// To repeat the pattern from any other point, you could increase the index, e.g. '1'
v.vibrate(pattern, 0);