how to vibrate android java
import android.os.Vibrator;
...
Vibrator v = (Vibrator) getSystemService(Context.VIBRATOR_SERVICE);
// Vibrate for 500 milliseconds
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
v.vibrate(VibrationEffect.createOneShot(500, VibrationEffect.DEFAULT_AMPLITUDE));
} else {
//deprecated in API 26
v.vibrate(500);
}