flutterdaysweekdayintlflutter-intl

Flutter: Get Wrong days of the week


from Monday - Thursday, I get the right days, but from Friday, I get the wrong days. Why?

Code example:

Text(DateFormat('EEEE').format(DateTime(DateTime.friday))),

And i get Saturday. Is that a bug?


Solution

  • It's not a bug, DateTime() default constructor takes year as the first argument:

      DateTime(int year,
          [int month = 1,
          int day = 1,
          int hour = 0,
          int minute = 0,
          int second = 0,
          int millisecond = 0,
          int microsecond = 0])
          : this._internal(year, month, day, hour, minute, second, millisecond,
                microsecond, false);
    

    So this code:

    DateTime date = DateTime(DateTime.friday);
    

    Is essentially constructing a DateTime of the year 5, because DateTime.friday is nothing more than a const int that equals to 5:

      static const int monday = 1;
      static const int tuesday = 2;
      static const int wednesday = 3;
      static const int thursday = 4;
      static const int friday = 5;
      static const int saturday = 6;
      static const int sunday = 7;
      static const int daysPerWeek = 7;
    

    Formatting with DateFormat returns Saturday which happens to be the first day of the year:

    import 'dart:core';
    import 'package:intl/intl.dart';
    
    main() {
      DateTime date = DateTime(DateTime.friday); // creates a DateTime of the year 5
      print(date.year);    // year: 5
      print(date.month);   // month: Jan (default = 1)
      print(date.weekday); // day: Saturday (first day of the year)
      print("${date.year}-${date.month}-${date.day}"); // 5-1-1
    }
    

    DateTime should be used to define a specific Date and Time, for example, Friday 11th Dec 2020, it can't be used to define any Friday.