Notification notification = new Notification(R.drawable.icon, "服務(wù)開(kāi)啟", System.currentTimeMillis());
notification.flags|= Notification.FLAG_NO_CLEAR; 
notification.flags=Notification.FLAG_ONGOING_EVENT;
Intent notificationIntent = new Intent(this, MainActivity.class);
PendingIntent pendingIntent = PendingIntent.getActivity(this, 0, notificationIntent, 0);
notification.setLatestEventInfo(this, "service", "防止服務(wù)被任務(wù)管理器所殺", pendingIntent);
startForeground(ONGOING_NOTIFICATION, notification);

Notification notification = new Notification();
startForeground(1, notification);

public class TestService extends Service {
 private static final Class[] mStartForegroundSignature = new Class[] {
   int.class, Notification.class };
 private static final Class[] mStopForegroundSignature = new Class[] { boolean.class };
 private NotificationManager mNM;
 private Method mStartForeground;
 private Method mStopForeground;
 private Object[] mStartForegroundArgs = new Object[2];
 private Object[] mStopForegroundArgs = new Object[1];
 @Override
 public IBinder onBind(Intent intent) {
  return null;
 }
 @Override
 public void onCreate() {
  super.onCreate();
  mNM = (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
  try {
   mStartForeground = TestService.class.getMethod("startForeground",
     mStartForegroundSignature);
   mStopForeground = TestService.class.getMethod("stopForeground",
     mStopForegroundSignature);
  } catch (NoSuchMethodException e) {
   mStartForeground = mStopForeground = null;
  }
  // 我們并不需要為 notification.flags 設(shè)置 FLAG_ONGOING_EVENT，因?yàn)?
  // 前臺(tái)服務(wù)的 notification.flags 總是默認(rèn)包含了那個(gè)標(biāo)志位
  Notification notification =new Notification();
  // 注意使用 startForeground ，id 為 0 將不會(huì)顯示 notification
  startForegroundCompat(1, notification);
 }
 @Override
 public void onDestroy() {
  super.onDestroy();
  stopForegroundCompat(1);
 }
 // 以兼容性方式開(kāi)始前臺(tái)服務(wù)
 private void startForegroundCompat(int id, Notification n) {
  if (mStartForeground != null) {
   mStartForegroundArgs[0] = id;
   mStartForegroundArgs[1] = n;
   try {
    mStartForeground.invoke(this, mStartForegroundArgs);
   } catch (IllegalArgumentException e) {
    e.printStackTrace();
   } catch (IllegalAccessException e) {
    e.printStackTrace();
   } catch (InvocationTargetException e) {
    e.printStackTrace();
   }
   return;
  }
  mNM.notify(id, n);
 }
 // 以兼容性方式停止前臺(tái)服務(wù)
 private void stopForegroundCompat(int id) {
  if (mStopForeground != null) {
   mStopForegroundArgs[0] = Boolean.TRUE;
   try {
    mStopForeground.invoke(this, mStopForegroundArgs);
   } catch (IllegalArgumentException e) {
    e.printStackTrace();
   } catch (IllegalAccessException e) {
    e.printStackTrace();
   } catch (InvocationTargetException e) {
    e.printStackTrace();
   }
   return;
  }
  // 在 setForeground 之前調(diào)用 cancel，因?yàn)槲覀冇锌赡茉谌∠芭_(tái)服務(wù)之后
  // 的那一瞬間被kill掉。這個(gè)時(shí)候 notification 便永遠(yuǎn)不會(huì)從通知一欄移除
  mNM.cancel(id);
 }
}