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

main() {
  final String pattern = 'yyyy-MM-dd';
  final String formatted = DateFormat(pattern).format(DateTime.now());
  print(formatted);
}

更改yyyy-MM-dd字符串可以更改日期格式。我用这个模式字符串做了一个应用程序。

你可以在我的应用程序中实验字符串格式。 https://biplobsd.github.io/EpochConverterApp

在这里你可以看到我如何编辑模式和这个效果显示在顶部

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

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}';
      }
    }

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);

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。