Flutter 选项卡 Controller 页面导航错误

Question

I am making an app and I working on the onboarding screen. When the user finishes answering their questions, I want them the screen to navigate to their user dashboard. I am using a tab controller for the onboarding screen setup, and the problem that I am facing is the final screen not navigating when it is pressed.

I receive the following error when I press the button:

[ERROR:flutter/lib/ui/ui_dart_state.cc(198)] Unhandled Exception: 'package:flutter/src/material/tab_controller.dart': Failed assertion: line 181 pos 12: 'value >= 0 && (value < length || length == 0)': is not true.

My code is set up to check if the tab controller index is on the last page. I understand why it is coming up as false; however, I do not know how else to code it to overcome this issue. I appreciate any help given:)

Code for button and tab controller:

class CustomButton extends StatelessWidget {
  final TabController tabController;

  const CustomButton({Key? key,
  required this.tabController}) 
  : super(key: key);

  @override
  Widget build(BuildContext context) {

    return DecoratedBox(
      decoration: BoxDecoration(
        borderRadius: BorderRadius.circular(50),
        color: Colors.white
      ),
      child: ElevatedButton(
        style: ElevatedButton.styleFrom(
          padding: const EdgeInsets.symmetric(
            vertical: 16),
          elevation: 0,
          primary: Colors.transparent
        ),
        onPressed: () async{
          if (tabController.index == 4) {
            Navigator.pushNamed(context, '/dashboard');
          }
          else {
          tabController.animateTo(tabController.index + 1);
          }
          // await context.read<SignupCubit>().signupWithCredentials();

          User user = User(
            id: context.read<SignupCubit>().state.user!.uid, 
            name: '', 
            age: 0, 
            imageUrls: [], 
            Goals: '', 
            Interests: [], 
            Focus: []);
        },
        child: Container(
          width: double.infinity,
          child: Center(
            child: Text('Continue',
            style: GoogleFonts.montserrat(
              color: const Color.fromARGB(255, 20, 83, 106),
              fontSize: 19,
              fontWeight: FontWeight.w600
            ),),
          ),
        )
      ),
    );
    
  }
}

Answer 1

where is your tabbarview? try this steps https://www.woolha.com/tutorials/flutter-using-tabbar-tabbarview-examples

or if you want to understand and implement try this https://youtu.be/apqVp-UjsLg