Android: Convert date to milliseconds

Question

I used

SimpleDateFormat formatter = new SimpleDateFormat("dd.MM.yyyy, HH:mm");
String time = formatter.format(new Date());

to get t

Answer 1

java.time and desugaring or ThreeTenABP

I recommend you use java.time, the modern Java date and time API, for your date and time work.

    ZoneId zone = ZoneId.systemDefault();
    DateTimeFormatter formatter = DateTimeFormatter.ofPattern("dd.MM.uuuu, H:mm");
    
    String dateTimeString = "12.03.2012, 17:31";
    
    LocalDateTime dateTime = LocalDateTime.parse(dateTimeString, formatter);
    long milliseconds = dateTime.atZone(zone).toInstant().toEpochMilli();
    
    System.out.println(milliseconds);

When I run this in Europe/Zurich time zone, the output is:

1331569860000

Question: Doesn’t java.time require Android API level 26?

java.time works nicely on both older and newer Android devices. It just requires at least Java 6.

• In Java 8 and later and on newer Android devices (from API level 26) the modern API comes built-in.
• In non-Android Java 6 and 7 get the ThreeTen Backport, the backport of the modern classes (ThreeTen for JSR 310; see the links at the bottom).
• On older Android either use desugaring or the Android edition of ThreeTen Backport. It’s called ThreeTenABP. In the latter case make sure you import the date and time classes from org.threeten.bp with subpackages.

Links

• Oracle tutorial: Date Time explaining how to use java.time.
• Java Specification Request (JSR) 310, where java.time was first described.
• ThreeTen Backport project, the backport of java.time to Java 6 and 7 (ThreeTen for JSR-310).
• Java 8+ APIs available through desugaring
• ThreeTenABP, Android edition of ThreeTen Backport
• Question: How to use ThreeTenABP in Android Project, with a very thorough explanation.