Flutter：检查日期是否在两个日期之间

Question

I need to check date is between two dates or not.

I tried to search it but didn't got fruitful results. May be you have seen such scenarios. So, seeking your advise.

Here is my code.

var service_start_date = '2020-10-17';
var service_end_date = '2020-10-23';
var service_start_time = '10:00:00';
var service_end_time = '11:00:00';

DateTime currentDate = new DateTime.now();
DateTime times = DateTime.now();


  @override
  void initState() {
    super.initState();
    test();
  }

 test() {
    String currenttime = DateFormat('HH:mm').format(times);
    String currentdate = DateFormat('yyyy-mm-dd').format(currentDate);
    print(currenttime);    
    print(currentdate);
    
  }

So, basically i have start date and end date. I need to check current date is falling between these two dates or not.

Answer 1

You can check before/after using 'isBefore' and 'isAfter' in 'DateTime' class.

    DateTime startDate = DateTime.parse(service_start_date);
  DateTime endDate = DateTime.parse(service_end_date);
  
  DateTime now = DateTime.now();
  
  print('now: $now');
  print('startDate: $startDate');
  print('endDate: $endDate');
  print(startDate.isBefore(now));
  print(endDate.isAfter(now));

Answer 2

不要忘记检查这一天是否与两个日期之一相同，也可以通过在条件中添加一个 or 来检查： if ( start is before now || (start.month==now.month && start.day ==now.day ...等）

Answer 3

I've made a series of extensions

extension DateTimeExtension on DateTime? {
  
  bool? isAfterOrEqualTo(DateTime dateTime) {
    final date = this;
    if (date != null) {
      final isAtSameMomentAs = dateTime.isAtSameMomentAs(date);
      return isAtSameMomentAs | date.isAfter(dateTime);
    }
    return null;
  }

  bool? isBeforeOrEqualTo(DateTime dateTime) {
    final date = this;
    if (date != null) {
      final isAtSameMomentAs = dateTime.isAtSameMomentAs(date);
      return isAtSameMomentAs | date.isBefore(dateTime);
    }
    return null;
  }

  bool? isBetween(
    DateTime fromDateTime,
    DateTime toDateTime,
  ) {
    final date = this;
    if (date != null) {
      final isAfter = date.isAfterOrEqualTo(fromDateTime) ?? false;
      final isBefore = date.isBeforeOrEqualTo(toDateTime) ?? false;
      return isAfter && isBefore;
    }
    return null;
  }

}

I'm hoping they're self explanatory but obviously you can call them like

DateTime.now().isBefore(yourDate)

DateTime.now().isAfter(yourDate)

DateTime.now().isBetween(fromDate, toDate)