我有一个实例,DateTime
我想将其格式化为字符串。我怎么做?我想将日期转换为字符串,例如“ 2013-04-20”。
我有一个实例,DateTime
我想将其格式化为字符串。我怎么做?我想将日期转换为字符串,例如“ 2013-04-20”。
Answers:
对于en_US
格式,这非常简单:
import 'package:intl/intl.dart';
main() {
final DateTime now = DateTime.now();
final DateFormat formatter = DateFormat('yyyy-MM-dd');
final String formatted = formatter.format(now);
print(formatted); // something like 2013-04-20
}
格式化有很多选项。从文档:
ICU Name Skeleton
-------- --------
DAY d
ABBR_WEEKDAY E
WEEKDAY EEEE
ABBR_STANDALONE_MONTH LLL
STANDALONE_MONTH LLLL
NUM_MONTH M
NUM_MONTH_DAY Md
NUM_MONTH_WEEKDAY_DAY MEd
ABBR_MONTH MMM
ABBR_MONTH_DAY MMMd
ABBR_MONTH_WEEKDAY_DAY MMMEd
MONTH MMMM
MONTH_DAY MMMMd
MONTH_WEEKDAY_DAY MMMMEEEEd
ABBR_QUARTER QQQ
QUARTER QQQQ
YEAR y
YEAR_NUM_MONTH yM
YEAR_NUM_MONTH_DAY yMd
YEAR_NUM_MONTH_WEEKDAY_DAY yMEd
YEAR_ABBR_MONTH yMMM
YEAR_ABBR_MONTH_DAY yMMMd
YEAR_ABBR_MONTH_WEEKDAY_DAY yMMMEd
YEAR_MONTH yMMMM
YEAR_MONTH_DAY yMMMMd
YEAR_MONTH_WEEKDAY_DAY yMMMMEEEEd
YEAR_ABBR_QUARTER yQQQ
YEAR_QUARTER yQQQQ
HOUR24 H
HOUR24_MINUTE Hm
HOUR24_MINUTE_SECOND Hms
HOUR j
HOUR_MINUTE jm
HOUR_MINUTE_SECOND jms
HOUR_MINUTE_GENERIC_TZ jmv
HOUR_MINUTE_TZ jmz
HOUR_GENERIC_TZ jv
HOUR_TZ jz
MINUTE m
MINUTE_SECOND ms
SECOND s
对于非en_US
日期,您需要显式加载语言环境。有关更多信息,请参阅DateFormat
文档。date_symbol_data_local.dart
如果您想更深入地了解,则其中包含每种国家/地区/语言的所有格式。
您还可以指定日期格式,如前所述:https : //pub.dartlang.org/documentation/intl/latest/intl/DateFormat-class.html
import 'package:intl/intl.dart';
String formatDate(DateTime date) => new DateFormat("MMMM d").format(date);
产生: March 4
如果有人想要将字符串格式的日期转换为其他字符串格式,请先使用DateTime.parse(“ 2019-09-30”),然后将其传递给DateFormat(“ date pattern”)。format()
dateFormate = DateFormat("dd-MM-yyyy").format(DateTime.parse("2019-09-30"));
DateFormat
但您的文本说DateTime.format()
这样,您就可以在社交网络中找到日期:[“今天”,“昨天”,“星期几”等。
void main() {
DateTime now = new DateTime(2018,6,26);
print(date(now));
}
String date(DateTime tm) {
DateTime today = new DateTime.now();
Duration oneDay = new Duration(days: 1);
Duration twoDay = new Duration(days: 2);
Duration oneWeek = new Duration(days: 7);
String month;
switch (tm.month) {
case 1:
month = "january";
break;
case 2:
month = "february";
break;
case 3:
month = "march";
break;
case 4:
month = "april";
break;
case 5:
month = "may";
break;
case 6:
month = "june";
break;
case 7:
month = "july";
break;
case 8:
month = "august";
break;
case 9:
month = "september";
break;
case 10:
month = "october";
break;
case 11:
month = "november";
break;
case 12:
month = "december";
break;
}
Duration difference = today.difference(tm);
if (difference.compareTo(oneDay) < 1) {
return "today";
} else if (difference.compareTo(twoDay) < 1) {
return "yesterday";
} else if (difference.compareTo(oneWeek) < 1) {
switch (tm.weekday) {
case 1:
return "monday";
case 2:
return "tuesday";
case 3:
return "wednesday";
case 4:
return "thursday";
case 5:
return "friday";
case 6:
return "saturday";
case 7:
return "sunday";
}
} else if (tm.year == today.year) {
return '${tm.day} $month';
} else {
return '${tm.day} $month ${tm.year}';
}
}
pubspec.yaml:
dependencies:
intl:
main.dart:
import 'package:intl/intl.dart'; // for date format
import 'package:intl/date_symbol_data_local.dart'; // for other locales
void main() {
var now = DateTime.now();
print(DateFormat().format(now)); // This will return date using the default locale
print(DateFormat('yyyy-MM-dd hh:mm:ss').format(now));
print(DateFormat.yMMMMd().format(now)); // print long date
print(DateFormat.yMd().format(now)); // print short date
print(DateFormat.jms().format(now)); // print time
initializeDateFormatting('es'); // This will initialize Spanish locale
print(DateFormat.yMMMMd('es').format(now)); // print long date in Spanish format
print(DateFormat.yMd('es').format(now)); // print short date in Spanish format
print(DateFormat.jms('es').format(now)); // print time in Spanish format
}
结果:
May 31, 2020 5:41:42 PM
2020-05-31 05:41:42
May 31, 2020
5/31/2020
5:41:42 PM
31 de mayo de 2020
31/5/2020
17:41:42
import 'package:intl/intl.dart';
main() {
var formattedDate = new DateTime.Format('yyyy-MM-dd').DateTime.now();
print(formattedDate); // something like 2020-04-16
}
有关更多详细信息,请参阅DateFormat文档。
处理年度季度,从字符串到DateTime,我没有找到合适的解决方案,所以这样做:
List<String> dateAsList = 'Q1 2001'.split(' ');
DateTime dateTime = DateTime.now();
String quarter = dateAsList[0];
int year = int.parse(dateAsList[1]);
switch(quarter) {
case "Q1": dateTime = DateTime(year, 1);
break;
case "Q2": dateTime = DateTime(year, 4);
break;
case "Q3": dateTime = DateTime(year, 7);
break;
case "Q4": dateTime = DateTime(year, 10);
break;
}