Android应用中怎么实现一个手机震动功能

import android.app.Activity;import android.app.Service;import android.os.Vibrator;public class TipHelper {  public static void Vibrate(final Activity activity, long milliseconds) {    Vibrator vib = (Vibrator) activity.getSystemService(Service.VIBRATOR_SERVICE);    vib.vibrate(milliseconds);  }  public static void Vibrate(final Activity activity, long[] pattern,booleanisRepeat) {    Vibrator vib = (Vibrator) activity.getSystemService(Service.VIBRATOR_SERVICE);    vib.vibrate(pattern, isRepeat ? 1 : -1);  }}