How do we format custom DateTime as DateTime in Flutter/Dart?

Question

I would like to have my DateTime to always save as the following format: yMMMd

I.e. March 30, 2021

Problem:

When I format my DateTime, it formats as a String. When I try to parse this back into DateTime I get errors and no success.

I'm having issues chasing down a good solution to doing this.

Is this possible or do I have to settle for saving as a String?

EDIT

Tried everything that has been recommended and I tried many other methods which didn't work either. I wonder if the Intl package date format has trouble being parsed back to DateTime? That could be my issue. Anyone?

Please have a look at me print statements and error to see what is successful and isn't.

My date selector where I'm trying this:

  Future<void> _selectDate(BuildContext context) async {
    final DateTime picked = await showDatePicker(
        context: context,
        initialDate: DateTime.now(),
        firstDate: DateTime(2015, 8),
        lastDate: DateTime(2101));
    if (picked != null)
      setState(() {
        print('------ Picked date: $picked');
        var dateString = '';
        final formattedDate = DateFormat.yMMMd().format(picked);
        var parsedDate = DateTime.parse(formattedDate);           // Does not work...
        print('------- Parsed date: $parsedDate');
        dateString = formattedDate;
        print('------ String date: $dateString');
        expenseDate = formattedDate as DateTime;
        print('------ Formatted date: ${formattedDate.toString()}');
      });
  }

Error:

flutter: ------ Picked date: 2021-03-31 00:00:00.000
[VERBOSE-2:ui_dart_state.cc(186)] Unhandled Exception: FormatException: Invalid date format
Mar 31, 2021
#0      DateTime.parse (dart:core/date_time.dart:322:7)
#1      _AddExpenseButtonState._selectDate.<anonymous closure> (package:fp_provider_demo_one/widgets/add_expense_button.dart:48:35)
#2      State.setState (package:flutter/src/widgets/framework.dart:1267:30)
#3      _AddExpenseButtonState._selectDate (package:fp_provider_demo_one/widgets/add_expense_button.dart:44:7)
<asynchronous suspension>

You didn't try to parse the DateTime string at all; you instead tried to cast it (i.e., pretend that the String is a DateTime object, which it isn't). If you want to actually parse it, see convert datetime string to datetime object in dart? — jamesdlin
I’ll check this out tonight, for some reason I believe I was having issues doing this also- hence the seemingly redundant post. I will edit my post to be more detailed as to what I could not do — RobbB
Tried parse, no go. Could this be an issue trying to parse intl formatted string to DateTime? — RobbB
As mentioned in my answer to the linked question, DateTime.parse handles only a small set of date/time formats. Since you formatted the DateTime to a string using DateFormat, you should parse it back with DateFormat too: DateFormat.yMMMd().parse(formattedDate). — jamesdlin
DateTime by definition stores both a date and a time. You're free to ignore the time portion, but you will need to use DateFormat whenever you want to convert it to a String (or back). You could make your own Date class that internally stores a DateTime and whose toString() method uses DateFormat. — jamesdlin

Navaneeth P Navaneeth P · Accepted Answer · 2021-03-17T08:26:07

Use the parse method to get back a DateTime from the string.

final df = DateFormat.yMMMd();
final dateString = df.format(picked);

final expenseDate = df.parse(dateString);

https://pub.dev/documentation/intl/latest/intl/DateFormat/parse.html

How do we format custom DateTime as DateTime in Flutter/Dart?

2 Answers