Flutter: Generating routes with auto_route using a Class with named constructors instead of default constructor

Question

I am trying to generate the router.gr.dart file using the auto_route package in flutter. My class has 3 named constructors:

  ProfilePage.a({
    Key? key,
    this.profileType = UserType.a,
    required this.a,
    required this.userProfileId,
  }) : super(key: key);

  ProfilePage.b({
    Key? key,
    this.profileType = UserType.b,
    required this.b,
    required this.userProfileId,
  }) : super(key: key);

  ProfilePage.c({
    Key? key,
    this.profileType = UserType.c,
    required this.c,
    required this.userProfileId,
  }) : super(key: key);

Now, when I try to generate the router.gr.dart file, it gives me an error:

[INFO] Generating build script...
[INFO] Generating build script completed, took 406ms

[INFO] Initializing inputs
[INFO] Reading cached asset graph...
[INFO] Reading cached asset graph completed, took 64ms

[INFO] Checking for updates since last build...
[INFO] Checking for updates since last build completed, took 651ms

[INFO] Running build...
[INFO] 1.1s elapsed, 0/2 actions completed.
[INFO] 2.2s elapsed, 0/2 actions completed.
[INFO] 10.4s elapsed, 0/2 actions completed.
[SEVERE] auto_route_generator:autoRouteGenerator on lib/routes/router.dart:

Null check operator used on a null value
[INFO] Running build completed, took 11.3s

[INFO] Caching finalized dependency graph...
[INFO] Caching finalized dependency graph completed, took 34ms

[SEVERE] Failed after 11.3s
pub finished with exit code 1

The generation works fine for classes with just the default constructor. How do I fix this problem?

Answer 1

Do some refactoring.

class ProfilePageA extends ProfilePage {
  ProfilePageA({
    Key? key,
    UserType profileType = UserType.a,
    required Object a,
    required int userProfileId,
  }) : super(
    key: key,
    profileType: profileType,
    a: a,
    userProfileId: userProfileId,
  );
}

class ProfilePageB extends ProfilePage {
  ProfilePageB({
    Key? key,
    UserType profileType = UserType.b,
    required Object b,
    required int userProfileId,
  }) : super(
    key: key,
    profileType: profileType,
    b: b,
    userProfileId: userProfileId,
  );
}

// etc