在某些Android设备上，SimpleDateFormat的解析日期有所不同

Question

I am parsing the date as:

public class Consts{
public static final SimpleDateFormat DATE_FORMATTER_WITHOUT_TIME_ZONE = new SimpleDateFormat(
            "yyyy-MM-dd HH:mm");
public static final SimpleDateFormat DATE_FORMATTER_2 = new SimpleDateFormat(
            "MM-dd-yyyy HH:mm:ss ZZZZ");
}

        cDate = new GregorianCalendar();
        sDate = new GregorianCalendar();
        eDate = new GregorianCalendar();

        if (mStartTimeTV.getText().toString().equals("Now")) {
            sDate.setTime(cDate.getTime());
        } else {
            sDate.setTime(Consts.DATE_FORMATTER_WITHOUT_TIME_ZONE
                    .parse(mStartTimeTV.getText().toString()));
        }

        if (!mEndTimeTV.getText().toString().equals("")) {
            eDate.setTime(Consts.DATE_FORMATTER_WITHOUT_TIME_ZONE
                    .parse(mEndTimeTV.getText().toString()));
        } else {
            eDate.setTime(sDate.getTime());
            // eDate = sDate;
        }

And then i format the date as below before sending it to the server.:

request.addProperty("StartTime",
                        Consts.DATE_FORMATTER_2.format(sDate.getTime()));
                request.addProperty("EndTime",
                        Consts.DATE_FORMATTER_2.format(eDate.getTime()));

But the thing is that on devices running 4.1.2 it is sending the date as:

Start Date: 03-23-2015 21:17:20 +0500 End Date : 10-23-2015 21:15:00 +0500

which throws exception on the server side.

But on the other devices it is sending dates as:

Start Date: 03-23-2015 21:12:13 GMT+05:00 End Date : 03-23-2015 21:16:00 GMT+05:00

which is required.

Am i doing something wrong? How can i prevent this problem so that all devices sends the same dates. (for example 03-23-2015 21:16:00 GMT+05:00 )

Answer 1

The difference is caused by different locales set up on devices.

To mitigate the locale differences, you should use particular locale while formatting the date string. Here is a sample from my code, solving the same issue:

new SimpleDateFormat(C.FORMAT_DATETIMEZ, Locale.US).format(new Date(time))

Answer 2

You can extend SimpleDateFormat and override its format(...) function as following:

public class ExSimpleDateFormat extends SimpleDateFormat{

    private static final long serialVersionUID = -8275126788734707527L;

    public ExSimpleDateFormat() {

        super();
    }

    public ExSimpleDateFormat(String string, Locale us) {

        super(string, us);
    }

    @Override
    public StringBuffer format(Date date, StringBuffer toAppendTo, java.text.FieldPosition pos)
    {            
        final StringBuffer buf = super.format(date, toAppendTo, pos);
        buf.insert(buf.length() - 2, ':');
        return buf;
    };
}

And execute following code:

Calendar ca = Calendar.getInstance();       
ca.setTimeInMillis(System.currentTimeMillis());
ExSimpleDateFormat exSimpleDateFormat = new ExSimpleDateFormat("dd-MM-yyyy HH:mm:ss 'GMT'Z", Locale.US);
exSimpleDateFormat.setTimeZone(ca.getTimeZone()); //your device timezone which can be GMT+xx:yy or GMT-xx:yy
String desiredTime = exSimpleDateFormat.format(ca.getTime());

Output would be like: 23-03-2015 23:12:52 GMT+05:00

Let me know if it helps. Thanks