Convert string to date with IST

Question

I am trying to convert string to date inside Asynctask by parsing json string. I referred this link: How to convert "Mon Jun 18 00:00:00 IST 2012" to 18/06/2012?

//String dateStr = "Mon Jun 18 00:00:00 IST 2012";

changedDate = jsonObjectMain.getString("date");
DateFormat formatter = new SimpleDateFormat("E MMM dd HH:mm:ss Z yyyy");
Date date = (Date)formatter.parse(changedDate);
System.out.println(date);        

Calendar cal = Calendar.getInstance();
cal.setTime(date);
String formatedDate = cal.get(Calendar.DATE) + "/" + (cal.get(Calendar.MONTH) + 1) + "/" +         cal.get(Calendar.YEAR);
System.out.println("formatedDate : " + formatedDate);  

When I run this code in android studio, it gives me below exception:

04-14 12:35:53.363 22963-22963/com.trial W/System.err: java.text.ParseException: Unparseable date: "Mon Jun 18 00:00:00 IST 2012" (at offset 20) 04-14 12:35:53.367 22963-22963/com.trial W/System.err: at java.text.DateFormat.parse(DateFormat.java:579) 04-14 12:35:53.367 22963-22963/com.trial W/System.err: at com.trial.Activity.StartActivity.onClick(StartActivity.java:124) 04-14 12:35:53.367 22963-22963/com.trial W/System.err: at android.view.View.performClick(View.java:5210) 04-14 12:35:53.367 22963-22963/com.trial W/System.err: at android.view.View$PerformClick.run(View.java:21183) 04-14 12:35:53.367 22963-22963/com.trial W/System.err: at android.os.Handler.handleCallback(Handler.java:739) 04-14 12:35:53.367 22963-22963/com.trial W/System.err: at android.os.Handler.dispatchMessage(Handler.java:95) 04-14 12:35:53.367 22963-22963/com.trial W/System.err: at android.os.Looper.loop(Looper.java:148) 04-14 12:35:53.367 22963-22963/com.trial W/System.err: at android.app.ActivityThread.main(ActivityThread.java:5438) 04-14 12:35:53.367 22963-22963/com.trial W/System.err: at java.lang.reflect.Method.invoke(Native Method) 04-14 12:35:53.367 22963-22963/com.trialW/System.err: at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:762) 04-14 12:35:53.367 22963-22963/com.trial W/System.err: at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:652)

But when i run same code in eclipse by creating simple program, it runs very well.

I was wondered, I don't know, why is this happen. So, i checked same code in another Activity on button click but not worked.

Thank you. Any help will be appreciated.

Answer 1

I am aware that using the newer java.time classes on Android requires an external dependency (ThreeTenABP), and also that you have a working solution by now. For anyone else reading along that either can use Java 8 or later or are happy with a library dependency, here’s how to do:

String dateStr = "Mon Jun 18 00:00:00 IST 2012";

DateTimeFormatter inputFormat = DateTimeFormatter.ofPattern("EEE MMM d HH:mm:ss z uuuu", Locale.ENGLISH);
LocalDate date = LocalDate.parse(dateStr, inputFormat);

String formattedDate = date.format(DateTimeFormatter.ofPattern("dd/MM/uuuu"));

System.out.println(formattedDate);

If you know in advance that the string contains correct day, month and year, you can ignore the time zone completely.

Link: The java.time classes (of which LocalDate is just one among many helpful) can be used on Android throught the ThreeTenABP. That’s ThreeTen for JSR-310 and ABP for Android Backport.

PS If you want some further validation of your input string, you may for instance check that time part equals the start of the day in the specified time zone:

ZonedDateTime zdt = ZonedDateTime.parse(dateStr, inputFormat);
if (! zdt.equals(zdt.toLocalDate().atStartOfDay(zdt.getZone()))) {
    throw new IllegalArgumentException("Input date was not at midnight");
}

Answer 2

Try changing format to "EEE MMM dd HH:mm:ss yyyy" and set IST timeZone

changedDate = changedDate.replace("IST ", "");
SimpleDateFormat formatter = new SimpleDateFormat("EEE MMM dd HH:mm:ss yyy");
TimeZone timeZone=TimeZone.getTimeZone("IST");
formatter.setTimeZone(timeZone);

Date date = (Date)formatter.parse(changedDate);