我有一个DateTime的实例，我想将其格式化为字符串。我怎么做呢?我想把日期转换成一个字符串，类似于“2013-04-20”。
当前回答
您可以使用intl包(安装程序)格式化日期。
对于en_US格式，它非常简单:
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
}
有许多格式化选项。从文档中可以看出:
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，需要显式地加载语言环境。更多信息请参阅DateFormat文档。date_symbol_data_local。Dart包含每个国家/语言的所有格式，如果您想更深入地了解的话。
其他回答
另一种方法，使用intl包。
创建DateTime的扩展:
date_time_extension.dart
import 'package:intl/date_symbol_data_local.dart';
import 'package:intl/intl.dart';
extension DateTimeExtension on DateTime {
String format([String pattern = 'dd/MM/yyyy', String? locale]) {
if (locale != null && locale.isNotEmpty) {
initializeDateFormatting(locale);
}
return DateFormat(pattern, locale).format(this);
}
}
导入你要使用DateTime类型的文件，你可以这样使用它:
DateTime.now().format();
DateTime.now().format('MM/yyyy');
DateTime.now().format('MM/yyyy', 'es');
您可以使用intl包(安装程序)格式化日期。
对于en_US格式，它非常简单:
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
}
有许多格式化选项。从文档中可以看出:
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，需要显式地加载语言环境。更多信息请参阅DateFormat文档。date_symbol_data_local。Dart包含每个国家/语言的所有格式，如果您想更深入地了解的话。
这也会起作用:
DateTime today = new DateTime.now();
String dateSlug ="${today.year.toString()}-${today.month.toString().padLeft(2,'0')}-${today.day.toString().padLeft(2,'0')}";
print(dateSlug);
这就给你提供了社交网络中的日期:[“今天”，“昨天”，“星期的哪一天”，等等。]
void main() {
DateTime now = new DateTime(2018,6,26);
print(date(now));
}
String date(DateTime tm) {
DateTime today = new DateTime.now();
Duration oneDay = new Duration(days: 1);
Duration twoDay = new Duration(days: 2);
Duration oneWeek = new Duration(days: 7);
String month;
switch (tm.month) {
case 1:
month = "january";
break;
case 2:
month = "february";
break;
case 3:
month = "march";
break;
case 4:
month = "april";
break;
case 5:
month = "may";
break;
case 6:
month = "june";
break;
case 7:
month = "july";
break;
case 8:
month = "august";
break;
case 9:
month = "september";
break;
case 10:
month = "october";
break;
case 11:
month = "november";
break;
case 12:
month = "december";
break;
}
Duration difference = today.difference(tm);
if (difference.compareTo(oneDay) < 1) {
return "today";
} else if (difference.compareTo(twoDay) < 1) {
return "yesterday";
} else if (difference.compareTo(oneWeek) < 1) {
switch (tm.weekday) {
case 1:
return "monday";
case 2:
return "tuesday";
case 3:
return "wednesday";
case 4:
return "thursday";
case 5:
return "friday";
case 6:
return "saturday";
case 7:
return "sunday";
}
} else if (tm.year == today.year) {
return '${tm.day} $month';
} else {
return '${tm.day} $month ${tm.year}';
}
}
/// Get date as a string for display.
String getFormattedDate(String date) {
/// Convert into local date format.
var localDate = DateTime.parse(date).toLocal();
/// inputFormat - format getting from api or other func.
/// e.g If 2021-05-27 9:34:12.781341 then format must be yyyy-MM-dd HH:mm
/// If 27/05/2021 9:34:12.781341 then format must be dd/MM/yyyy HH:mm
var inputFormat = DateFormat('yyyy-MM-dd HH:mm');
var inputDate = inputFormat.parse(localDate.toString());
/// outputFormat - convert into format you want to show.
var outputFormat = DateFormat('dd/MM/yyyy HH:mm');
var outputDate = outputFormat.format(inputDate);
return outputDate.toString();
}
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