How to sort the dates from current to old date in Android or Java?

Question

I am in a need of function, user defined, which could sort the dates from current time to old time.

I'm having list of 10 dates which I want to sort these dates starting from last recent date.

Currently I have a logic, in which if we can covert the date in milli-second then comparing it with current-milli-seconds and the least milli-second will be the recent date. That is,

CURRENT_MILLI_SECOND - A_DATE_CONVERTED_TO_MILLI_SECONDS = MILLI-SECONDS

Please suggest me if anyone can help me in this logic or any other logics...!!!

This is the formate which I am getting from server:

Thu Dec 27 11:02:43 GMT+05:30 2012

Answer 1

You can go with Comparator and can sort data by using compare()

Collections.sort(dateList, new Comparator<Date>(){
           public int compare(Date date1, Date date2){
          return date1.after(date2);
        }
      });

Answer 2

Try this:

 Comparator date_comparator = new Comparator() {
    @Override
    public int compare(Date date1, Date date2){
    return date1.compareTo(date2);
    }
    };

Answer 3

You can use Calendar or Date class to do so. Using calendar and Date you can compare two dates like date1.compare(date2) or date.before(date2) or date1.after(date2) such api's are available for your cases.

Answer 4

tl;dr

Collections.reverse(
    new ArrayList<>().add( 
        OffsetDateTime.parse( 
            "Thu Dec 27 11:02:43 GMT+05:30 2012" , 
            DateTimeFormatter.ofPattern( "EEE MMM d HH:mm:ss OOOO uuuu" , Locale.US  ) 
        ) 
    )
)

java.time

The modern approach uses java.time classes.

Define a formatting pattern to match. By the way, this is a terrible format; if you have any control, use standard ISO 8601 formats instead.

String input = "Thu Dec 27 11:02:43 GMT+05:30 2012" ;

DateTimeFormatter f = DateTimeFormatter.ofPattern( "EEE MMM d HH:mm:ss OOOO uuuu" , Locale.US  );

Your input strings specify an offset-from-UTC but not a full time zone. So we parse as an OffsetDateTime.

OffsetDateTime odt = OffsetDateTime.parse( input , f );

odt.toString(): 2012-12-27T11:02:43+05:30

OffsetDateTime objects already know how to sort themselves, as they implement Comparable.

List< OffsetDateTime > odts = new ArrayList<>( 3 ) ;
odts.add( odt ) ;
odts.add( odt.plusMinutes( 7 ) ) ;
odts.add( odt.minusMinutes( 21 ) ) ;

Collections.sort( odts ) ;

You want the most recent at top of the list, so sort in reverse order.

Collections.reverse( odts ) ;  // Reverse-order.

To compare individual java.time objects, call the isBefore, isAfter, and isEqual/equals methods.

thisOdt.isBefore( thatOdt )

---

About java.time

The java.time framework is built into Java 8 and later. These classes supplant the troublesome old legacy date-time classes such as java.util.Date, Calendar, & SimpleDateFormat.

The Joda-Time project, now in maintenance mode, advises migration to the java.time classes.

To learn more, see the Oracle Tutorial. And search Stack Overflow for many examples and explanations. Specification is JSR 310.

Where to obtain the java.time classes?

• Java SE 8, Java SE 9, and later
  • Built-in.
  • Part of the standard Java API with a bundled implementation.
  • Java 9 adds some minor features and fixes.
• Java SE 6 and Java SE 7
  • Much of the java.time functionality is back-ported to Java 6 & 7 in ThreeTen-Backport.
• Android
  • Later versions of Android bundle implementations of the java.time (JSR 310) classes.
  • For earlier Android, the ThreeTenABP project adapts ThreeTen-Backport (mentioned above). See How to use ThreeTenABP….