最近,当我尝试使用 AlarmManager 安排将来运行的活动时,我注意到了奇怪的行为。看下面的代码,第一个活动在 20 秒后启动,而第二个活动在 40 秒内没有启动,而是在 60 秒后才启动。谁能解释为什么第二个意图不安排第二个活动被调用,而是第三个意图。这是否意味着我只能对 AlarmManager 中的活动有一个意图。
//pending intent for morning
    Intent myIntent1 = new Intent(this, Activity1.class);
    pendingIntent1 = PendingIntent.getActivity(this, 0, myIntent1, 0);
    AlarmManager alarmManager1 = (AlarmManager)getSystemService(ALARM_SERVICE);
    Calendar calendar1 = Calendar.getInstance();
    //calendar1.set(Calendar.YEAR, Calendar.MONTH + 1, Calendar.DAY_OF_MONTH, morningTime, 0, 0);
    calendar1.setTimeInMillis(System.currentTimeMillis());
    calendar1.add(Calendar.SECOND, 20);
    alarmManager1.set(AlarmManager.RTC_WAKEUP, calendar1.getTimeInMillis(), pendingIntent1);
    //pending intent for noon
    Intent myIntent2 = new Intent(this, Activity2.class);
    pendingIntent2 = PendingIntent.getActivity(this, 0, myIntent2, 0);
    AlarmManager alarmManager2 = (AlarmManager)getSystemService(ALARM_SERVICE);
    Calendar calendar2 = Calendar.getInstance();
    //calendar2.set(Calendar.YEAR, Calendar.MONTH + 1, Calendar.DAY_OF_MONTH, noonTime, 0, 0);
    calendar2.setTimeInMillis(System.currentTimeMillis());
    calendar2.add(Calendar.SECOND, 40);
    alarmManager2.set(AlarmManager.RTC_WAKEUP, calendar2.getTimeInMillis(), pendingIntent2);
    //pending intent for night
    Intent myIntent = new Intent(this, Activity2.class);
    pendingIntent = PendingIntent.getActivity(this, 0, myIntent, 0);
    AlarmManager alarmManager = (AlarmManager)getSystemService(ALARM_SERVICE);
    Calendar calendar = Calendar.getInstance();
    //calendar.set(Calendar.YEAR, Calendar.MONTH + 1, Calendar.DAY_OF_MONTH, nightTime, 0, 0);
    calendar.setTimeInMillis(System.currentTimeMillis());
    calendar.add(Calendar.SECOND, 60);
    alarmManager.set(AlarmManager.RTC_WAKEUP, calendar.getTimeInMillis(), pendingIntent);'