Flutter Error - how to solve: The constructor being called isn't a const constructor. Try removing 'const' from the constructor invocation

Question

I am new to flutter. I am facing a few issues with the const constructors.

class StartOnboarding extends OnboardingEvent {
  final User user;

  const StartOnboarding({
    this.user = const User(
      id: '',
      name: '',
      age: 0,
      gender: '',
      imageUrls: [],
    
    ),
  });

  @override
  List<Object?> get props => [user];
}

I am getting these two errors:

The default value of an optional parameter must be constant.

The constructor being called isn't a const constructor. Try removing 'const' from the constructor invocation.

Answer 1

On your User constructor, you need to use const in order use const on StartOnboarding

class StartOnboarding extends OnboardingEvent {
  final User user;

  const StartOnboarding({
    this.user = const User(
      id: '',
      name: '',
      age: 0,
      gender: '',
      imageUrls: [],
    ),
  });

  @override
  List<Object?> get props => [user];
}

class User {
  final String id;
  final String name;
  final int age;

  final String gender;
  final List<String> imageUrls;
 const  User({
    required this.id,
    required this.name,
    required this.age,
    required this.gender,
    required this.imageUrls,
  });
}