Flutter- Non-nullable instance field 'questionAnswer', 'questionText' must be initialized

Question

I'm learning flutter by following an online course. I'm at the lesson of creating classes. So we have to create a class that has a string and a bool property. Below is this class:

class Question {
  String questionText;
  bool questionAnswer;

  Question({required String q, required bool a}) {
    questionText = q;
    questionAnswer = a;
  }
}

And the error is showing like this:

Non-nullable instance field 'questionText' must be initialized.

Non-nullable instance field 'questionAnswer' must be initialized.

Someone please help

Your online course may create with Flutter 1. Flutter 2 have `Sound null safety` now, so if something can be `null`, you can add a `?`, such as `String? questionText;`. — iwpz, Jul 22 '21 at 05:54
[Use an initializer list](https://stackoverflow.com/q/64546212/). — jamesdlin, Jul 22 '21 at 06:19

score 0 · Answer 1 · answered Jul 22 '21 at 07:02

As per the new null-safety rules, you can't initialise a variable of any datatype without specifying its value or doing a null check. Try this:

class Question {
  String? questionText;
  bool? questionAnswer;

  Question({@required String q,@required bool a}) {
    questionText = q;
    questionAnswer = a;
  }
}

Flutter- Non-nullable instance field 'questionAnswer', 'questionText' must be initialized

1 Answers1