Skip to content

Instantly share code, notes, and snippets.

Embed
What would you like to do?
java/android date time helper
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.TimeZone;
import android.util.Log;
/**
* Utility class for parsing and formatting dates and times.
*
* @author Tom Dignan
*/
public final class DateTimeHelper {
private static final SimpleDateFormat DATE_FORMATTER =
new SimpleDateFormat("yyyy-MM-dd");
private static final SimpleDateFormat TIME_FORMATTER =
new SimpleDateFormat("hh:mm a");
private static final SimpleDateFormat VERBOSE_LOCALE_DATE_FORMATTER =
new SimpleDateFormat("MMM dd',' yyyy");
private static final SimpleDateFormat VERBOSE_LOCALE_TIME_FORMATTER =
new SimpleDateFormat("hh:mm a z");
private static final SimpleDateFormat VERBOSE_LOCALE_DATE_TIME_FORMATTER =
new SimpleDateFormat("MMM dd',' yyyy hh:mm a z");
private static final SimpleDateFormat ISO_8601_FORMATTER = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss.SS");
private static final SimpleDateFormat ALMOST_ISO_8601_FORMATTER = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SS");
public static Date parseAlmostISO8601DateTimeWithTSeparator(String datetime) {
Log.d(TAG, "datetime="+ datetime);
try {
return ALMOST_ISO_8601_FORMATTER.parse(datetime);
} catch (ParseException e) {
Log.e(TAG, "caught ParseException", e);
return null;
}
}
/**
* Parses an ISO8601 formatted datetime and returns a
* java.util.Date object for it, or NULL if parsing
* the date fails.
*
* @param String datetime
* @return Date|null
*/
public static Date parseFromISO8601(String datetime) {
Log.d(TAG, "datetime="+ datetime);
try {
return ISO_8601_FORMATTER.parse(datetime);
} catch (ParseException e) {
Log.e(TAG, "caught ParseException", e);
return null;
}
}
public static String formatToIS08601(Date date) {
return ISO_8601_FORMATTER.format(date);
}
public static Date parseOnlyDate(String date) {
Log.d(TAG, "date="+ date);
try {
return DATE_FORMATTER.parse(date);
} catch (ParseException e) {
Log.e(TAG, "caught ParseException", e);
return null;
}
}
/**
* Tries to parse most date times that it is passed, using
* some heuristics.
*
* @param string
* @return
*/
public static Date parseDateTime(String datetime) {
if (datetime.contains("T")) {
Log.d(TAG, "parseDateTime(): Trying ISO8601 with a T separator");
return parseAlmostISO8601DateTimeWithTSeparator(datetime);
} else if (datetime.length() == 10 && datetime.contains("-")) {
Log.d(TAG, "parseDateTime(): Trying just yyyy-MM-dd date");
return parseOnlyDate(datetime);
} else {
Log.d(TAG, "parseDateTime(): Trying regular ISO8601");
return parseFromISO8601(datetime);
}
}
public static Date parseTime(String time) {
try {
return TIME_FORMATTER.parse(time);
} catch (ParseException e) {
Log.d(TAG, "parseTime() caught ParseException", e);
e.printStackTrace();
return null;
}
}
public static Date parseDate(String date) {
try {
return DATE_FORMATTER.parse(date);
} catch (ParseException e) {
Log.d(TAG, "parseDate() caught ParseException", e);
e.printStackTrace();
return null;
}
}
public static Date parseDateAndTime(String strDate, String strTime) {
Date date = parseDate(strDate);
Date time = parseTime(strTime);
long dateMillis = date.getTime();
long timeMillis = time.getTime();
return new Date(dateMillis + timeMillis);
}
public static String pad(int value) {
if (value < 10) {
return "0" + value;
} else {
return "" + value;
}
}
public static String toLocaleDateTime(Date date) {
return VERBOSE_LOCALE_DATE_TIME_FORMATTER.format(date);
}
public static String toLocaleDate(Date date) {
return VERBOSE_LOCALE_DATE_FORMATTER.format(date);
}
public static String toLocaleTime(Date date) {
return VERBOSE_LOCALE_TIME_FORMATTER.format(date);
}
public static Date toLocalTime(Date date) {
long millisUTC = date.getTime();
TimeZone tz = TimeZone.getDefault();
int tzOffset = tz.getOffset(millisUTC);
if (tz.inDaylightTime(new Date(millisUTC))) {
millisUTC -= tz.getDSTSavings();
}
return new Date(millisUTC + tzOffset);
}
public static long toLocalTime(long millisUTC) {
// TODO: Refactor this and save it. Perfect DST code.
TimeZone tz = TimeZone.getDefault();
int tzOffset = tz.getOffset(millisUTC);
if (tz.inDaylightTime(new Date(millisUTC))) {
millisUTC -= tz.getDSTSavings();
}
return millisUTC + tzOffset;
}
}
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
You can’t perform that action at this time.