Question

Why does the alarm set off immediately instead of the specified time?

Intent myIntent = new Intent(Notepad.this, MyAlarmService.class);
PendingIntent pendingIntent = PendingIntent.getService(Notepad.this, 0, myIntent, 0);

AlarmManager alarmManager = (AlarmManager)getSystemService(ALARM_SERVICE);
         Calendar calendar = Calendar.getInstance();
         calendar.setTimeInMillis(System.currentTimeMillis());
         calendar.set(Calendar.YEAR, 2012);
         calendar.set(Calendar.MONTH, 4);
         calendar.set(Calendar.DAY_OF_MONTH, 5);
         calendar.set(Calendar.HOUR_OF_DAY, 10);
         calendar.set(Calendar.MINUTE, 30);
         calendar.set(Calendar.SECOND, 4);
     alarmManager.set(AlarmManager.RTC_WAKEUP, calendar.getTimeInMillis(), pendingIntent);

If I use only calendar.add(Calendar.SECOND, 5);, it sets off after 5 seconds.

SOLUTION based on Nicholas’ answer

        Date dat  = new Date();//initializes to now
        Calendar cal_alarm = Calendar.getInstance();
        Calendar cal_now = Calendar.getInstance();
        cal_now.setTime(dat);
        cal_alarm.setTime(dat);
        cal_alarm.set(Calendar.HOUR_OF_DAY,Integer.valueOf(h));
        cal_alarm.set(Calendar.MINUTE, Integer.valueOf(m));
        cal_alarm.set(Calendar.SECOND,0);

        if(cal_alarm.before(cal_now)){
            cal_alarm.add(Calendar.DATE,1);
        }

Answer 1

To me it seems that you are setting the calendar time and day to the alarm time. Maybe set up two different calendars and have one for the current time and another for the alarm time. Does that make sense?