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

如果不想添加另一个库，也可以使用此方法

  DateTime dateTime = DateTime.now();
  String YYYY_MM_DD = dateTime.toIso8601String().split('T').first;
  print(YYYY_MM_DD); //2020-11-23

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}';
      }
    }

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

如果你想将多个日期格式合并为一个，这就是我们使用intl的方法。

DateFormat('yMMMd').addPattern(DateFormat.HOUR24_MINUTE).format(yourDateTime))

无依赖项方法[用于将日期显示为格式化字符串]

如果你想要以日/月/年的形式显示你的DateTime值或任何你喜欢的格式，字符串插值可以很方便:

"${_date.day} / ${_date.month} / ${_date.year}"

示例输出:

It's 23 out of 4 out of 1920

我不想使用任何额外的库，所以我走了这条路。