Android DatePicker and Java's Date

Question

I was bitten by the problem described here: Android DatePicker year problem . In a nutshell, Android's DatePicker expects years to be specified in years (2011 is 2011), while Java's Date class starts at 1900 (so 2011 is actually 111).

Is there a better way to intermix Date and DatePickers, other than adding and substracting 1900 when doing the conversions?

Itay.

This is one of many reasons to never use the terrible legacy classes `Date`, `Calendar`, `SimpleDateFormat`, and such. Use only *java.time* classes. See the modern solution in [Answer by Avinash](https://stackoverflow.com/a/68398163/642706). — Basil Bourque, Jul 15 '21 at 20:56

score 2 · Accepted Answer · answered Dec 11 '11 at 09:38

Yes - don't use the deprecated methods in Date to work with day/month/year values. Date just represents an instant in time - you should use Calendar if you want to translate that into some appropriate human breakdown into days, months, years etc - and to apply time zones.

score 1 · Answer 2 · answered Jul 15 '21 at 17:15

java.time

The java.util Date-Time API and their formatting API, SimpleDateFormat are outdated and error-prone. It is recommended to stop using them completely and switch to the modern Date-Time API^*.

Solution using java.time, the modern Date-Time API:

import java.time.LocalDate;
import java.time.format.DateTimeFormatter;
import java.util.Locale;

public class Main {
    public static void main(String[] args) {
        int dpYear = 2010, dpMonth = 1, dpDayOfMonth = 15;

        // In DatePicker, the month is indexed starting at 0. Check
        // https://stackoverflow.com/a/4467894/10819573 to learn more.
        dpMonth++;

        LocalDate date = LocalDate.of(dpYear, dpMonth, dpDayOfMonth);
        System.out.println(date);

        // Formatted output
        DateTimeFormatter dtf = DateTimeFormatter.ofPattern("EEE MMMM dd uuuu", Locale.ENGLISH);
        String formatted = dtf.format(date);
        System.out.println(formatted);
    }
}

Output:

2010-02-15
Mon February 15 2010

ONLINE DEMO

Learn more about the modern Date-Time API from Trail: Date Time.

^{* For any reason, if you have to stick to Java 6 or Java 7, you can use ThreeTen-Backport which backports most of the java.time functionality to Java 6 & 7. If you are working for an Android project and your Android API level is still not compliant with Java-8, check Java 8+ APIs available through desugaring and How to use ThreeTenABP in Android Project.}

Android DatePicker and Java's Date

2 Answers2

java.time