为啥 MainActivity 的黑色保活中AlarmManager被注释?

代码如下:

``` java
/*AlarmManager alarmManager = (AlarmManager) getSystemService(ALARM_SERVICE);
PendingIntent operation = PendingIntent.getBroadcast(this, 123, blackIntent, PendingIntent.FLAG_UPDATE_CURRENT);
alarmManager.set(AlarmManager.RTC, System.currentTimeMillis(), operation);*/
```
