Vfrdtyky

I'm trying to create an array of times from the current time to a set time, for example; the current time is 15:41, I would like that to be rounded up to the nearest quarter of an hour (15:45) and an array of 15 minute intervals to be created from 15:45 to a specified time lets say 23:30.

I've managed to create an array of times for a 24 hour period in 15 minute intervals and can't seem to get any further forward.

String quarterHours = {"00","15","30","45"};

    String times = new String[24];



    for(int i = 0; i < 24; i++) {

        for(int j = 0; j < 4; j++) {

            String time = i + ":" + quarterHours[j];

            if(i < 10) {

                time = "0" + time;

            }

            times[i] = "Today " + time;

        }

    }

The output from the above in a DialogList view within Android looks as follows:

You're overwriting the time each cycle of the inner loop. You should use a List<String> instead and just append without worrying about indexes, like this:

String quarterHours = {"00","15","30","45"};

List<String> times = new ArrayList<String>; // <-- List instead of array



for(int i = 0; i < 24; i++) {

    for(int j = 0; j < 4; j++) {

        String time = i + ":" + quarterHours[j];

        if(i < 10) {

            time = "0" + time;

        }

        times.add("Today " + time); // <-- no need to care about indexes

    }

}

It would be much easier to work with the built-in Date/Time API, specifically LocalTime:

LocalTime time = LocalTime.now();



int minute = time.getMinute();



if (minute > 45) {

    time = time.plusHours(1L).withMinute(0);

} else {

    time = time.withMinute(minute < 30 ? minute < 15 ? 15 : 30: 45);

}



Stream.iterate(time.truncatedTo(ChronoUnit.MINUTES), t -> t.plusMinutes(15L))

      .limit(5)

      .forEach(System.out::println);

The above code outputs the following:

11:00

11:15

11:30

11:45

12:00

Your job will just be to figure out the math to limit the Stream size.

Try this. Inserting items to array by times[i] is incorrect in this scenario. It will only count the first loop items

public class Main

{

  public static void main(String args)

  {

    String quarterHours = { "00", "15", "30", "45" };

    String times = new String[96];

    int count = 0;



    for (int i = 0; i < 24; i++)

    {

      for (int j = 0; j < 4; j++)

      {

        String time = i + ":" + quarterHours[j];

        if (i < 10)

        {

          time = "0" + time;

        }

        times[count] = "Today " + time;

        count++;

      }

    }



    for (int i = 0; i < times.length; i++)

    {

      System.out.println(times[i]);

    }

  }

}

Problem in the previous approach was that the last minutes-turn wins and overwrites any previous result.

I suggest using a List, it is much easier to handle. You don't need to take care for the size.

    String quarterHours = { "00", "15", "30", "45" };

    List<String> times = new ArrayList<>();



    for (int i = 0; i < 24; i++) {

        for (int j = 0; j < 4; j++) {

            String time = i + ":" + quarterHours[j];

            if (i < 10) {

                time = "0" + time;

            }

            times.add("Today " + time);

        }

    }

    System.out.println(times);

Output:

[Today 00:00, Today 00:15, Today 00:30, Today 00:45, Today 01:00, Today 01:15, Today 01:30, Today 01:45, Today 02:00, Today 02:15, Today 02:30, Today 02:45, Today 03:00, Today 03:15, Today 03:30, Today 03:45, Today 04:00, Today 04:15, Today 04:30, Today 04:45, Today 05:00, Today 05:15, Today 05:30, Today 05:45, Today 06:00, Today 06:15, Today 06:30, Today 06:45, Today 07:00, Today 07:15, Today 07:30, Today 07:45, Today 08:00, Today 08:15, Today 08:30, Today 08:45, Today 09:00, Today 09:15, Today 09:30, Today 09:45, Today 10:00, Today 10:15, Today 10:30, Today 10:45, Today 11:00, Today 11:15, Today 11:30, Today 11:45, Today 12:00, Today 12:15, Today 12:30, Today 12:45, Today 13:00, Today 13:15, Today 13:30, Today 13:45, Today 14:00, Today 14:15, Today 14:30, Today 14:45, Today 15:00, Today 15:15, Today 15:30, Today 15:45, Today 16:00, Today 16:15, Today 16:30, Today 16:45, Today 17:00, Today 17:15, Today 17:30, Today 17:45, Today 18:00, Today 18:15, Today 18:30, Today 18:45, Today 19:00, Today 19:15, Today 19:30, Today 19:45, Today 20:00, Today 20:15, Today 20:30, Today 20:45, Today 21:00, Today 21:15, Today 21:30, Today 21:45, Today 22:00, Today 22:15, Today 22:30, Today 22:45, Today 23:00, Today 23:15, Today 23:30, Today 23:45]