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

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);

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))

处理年度季度，从字符串到日期时间，我没有找到合适的解决方案，所以做了这个:

    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;
    }

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