Time in Milliseconds Alarm

Okay, So I'm working on having an alarm that gives a notification at, lets say 3:00 PM daily, but I want this to be selectable by the user, between AM/PM, and Hours/Min freely changeable. I will probably use a TimePicker, and this is my code I have so far:

    public void startAlarm() {


            Intent intent = new Intent(currentDay.this, AlarmReceiver.class);
            PendingIntent sender = PendingIntent.getBroadcast(currentDay.this,0, intent,0);

            long firstTime = SystemClock.elapsedRealtime();
            firstTime += 15*1000;


            AlarmManager am = (AlarmManager)getSystemService(ALARM_SERVICE);
            am.setRepeating(AlarmManager.ELAPSED_REALTIME_WAKEUP,firstTime,AlarmManager.INTERVAL_DAY, sender);


        }

So, I figure I'm going to be using something along the lines of:

Calendar cal = Calendar.getInstance();
cal.set(Calendar.HOUR_OF_DAY, 19);
cal.s开发者_Python百科et(Calendar.MINUTE, 45);

and then using

cal.getTimeInMillis()

But this doesn't work, any ideas? Thanks!

EDIT: So, long story short, I know how to get the current time, then add lets say 15 seconds to it, but I want to have a definite time that WORKS for example 5:14 PM, and everything I've tried doesn't work

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As far as I can tell you are getting a Calendar instance with the current date/time and then you are adding 19 hours and 45 minutes to it, NOT setting the time of the Calendar instance explicitly to 19:45. Is that what you are meaning to do? You need to use the Calendar set() method to set an explicit time.

From the API reference for Calendar

Calendar's getInstance method returns a calendar whose locale is based on system settings and whose time fields have been initialized with the current date and time:

    Calendar rightNow = Calendar.getInstance()

public abstract void add (int field, int value)

Since: API Level 1
Adds the specified amount to a Calendar field.
Parameters
    field   the Calendar field to modify.
    value   the amount to add to the field.
    Throws IllegalArgumentException if field is DST_OFFSET or ZONE_OFFSET.

EDIT: To convert local time to UTC...

Calendar cal = Calendar.getInstance();
cal.set(Calendar.HOUR_OF_DAY, 19);
cal.set(Calendar.MINUTE, 45);
int offset = cal.getTimeZone().getOffset(cal.getTimeInMillis());
firstTime = cal.getTimeInMillis() + offset;

NOTE: I haven't tried the above and there may be an easier way but it should work. It's hard for me to test stuff like this as my timezone is GMT/UTC.