How Can i create a conditional questionnaire in Flutter - flutter

Question

I am trying to build a questionnaire within an application
The idea is that the user answers questions
So every answer he gives is in one question
Accordingly he will receive the following question
For example if he answered a question with answer a
Will get one question
If he answered the same question with answer b
Will get another question later
how can i solve this
The code is attached
Thanks
import 'package:flutter/material.dart';
import 'package:gsheets/question_model.dart';
class QuizScreen extends StatefulWidget {
#override
State<QuizScreen> createState() => _QuizScreenState();
}
class _QuizScreenState extends State<QuizScreen> {
//define the datas
List<Question> questionList = getQuestions();
int currentQuestionIndex = 0;
int score = 0;
Answer? selectedAnswer;
int? nextQuestionId;
int? questionId;
#override
Widget build(BuildContext context) {
return Scaffold(
backgroundColor: const Color.fromARGB(255, 5, 50, 80),
body: Container(
margin: const EdgeInsets.symmetric(horizontal: 16, vertical: 32),
child:
Column(mainAxisAlignment: MainAxisAlignment.spaceAround, children: [
const Text(
"Simple Quiz App",
style: TextStyle(
color: Colors.white,
fontSize: 24,
),
),
_questionWidget(),
_answerList(),
_nextButton(),
]),
),
);
}
_questionWidget() {
return Column(
crossAxisAlignment: CrossAxisAlignment.start,
mainAxisAlignment: MainAxisAlignment.center,
children: [
Text(
"Question ${currentQuestionIndex + 1}/${questionList.length.toString()}",
style: const TextStyle(
color: Colors.white,
fontSize: 20,
fontWeight: FontWeight.w600,
),
),
const SizedBox(height: 20),
Container(
alignment: Alignment.center,
width: double.infinity,
padding: const EdgeInsets.all(32),
decoration: BoxDecoration(
color: Colors.orangeAccent,
borderRadius: BorderRadius.circular(16),
),
child: Text(
questionList[currentQuestionIndex].questionText,
style: const TextStyle(
color: Colors.white,
fontSize: 18,
fontWeight: FontWeight.w600,
),
),
)
],
);
}
_answerList() {
return Column(
children: questionList[currentQuestionIndex]
.answerList
.map(
(e) => _answerButton(e),
)
.toList(),
);
}
Widget _answerButton(Answer answer) {
bool isSelected = answer == selectedAnswer;
return Container(
width: double.infinity,
margin: const EdgeInsets.symmetric(vertical: 8),
height: 48,
child: ElevatedButton(
child: Text(answer.answerText),
style: ElevatedButton.styleFrom(
shape: const StadiumBorder(),
primary: isSelected ? Colors.orangeAccent : Colors.white,
onPrimary: isSelected ? Colors.white : Colors.black,
),
onPressed: () {
// if (selectedAnswer == null) {
// if (answer.isCorrect) {
// score++;
// }
setState(() {
selectedAnswer = answer;
});
}
// },
),
);
}
_nextButton() {
// if(answer == )
bool isLastQuestion = false;
if (currentQuestionIndex == questionList.length - 1) {
isLastQuestion = true;
}
return Container(
width: MediaQuery.of(context).size.width * 0.5,
height: 48,
child: ElevatedButton(
child: Text(isLastQuestion ? "Submit" : "Next"),
style: ElevatedButton.styleFrom(
shape: const StadiumBorder(),
primary: Colors.blueAccent,
onPrimary: Colors.white,
),
onPressed: () {
// if(nextQuestionId == questionId)
if (isLastQuestion) {
//display score
showDialog(context: context, builder: (_) => _showScoreDialog());
} else {
//next question
setState(() {
selectedAnswer = null;
currentQuestionIndex++;
});
}
},
),
);
}
_showScoreDialog() {
bool isPassed = false;
if (score >= questionList.length * 0.6) {
//pass if 60 %
isPassed = true;
}
String title = isPassed ? "Passed " : "Failed";
return AlertDialog(
title: Text(
title + " | Score is $score",
style: TextStyle(color: isPassed ? Colors.green : Colors.redAccent),
),
content: ElevatedButton(
child: const Text("Restart"),
onPressed: () {
Navigator.pop(context);
setState(() {
currentQuestionIndex = 0;
score = 0;
selectedAnswer = null;
});
},
),
);
}
}
========================
import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';
import 'package:gsheets/quiz.dart';
class Question {
final String questionText;
final List<Answer> answerList;
final int questionId;
Question(this.questionText, this.answerList, this.questionId);
}
class Answer {
final String answerText;
final int nextQuestionId;
// final bool selectedOption;
Answer(this.answerText, this.nextQuestionId);
}
List<Question> getQuestions() {
List<Question> list = [];
list.add(Question(
"Which school did you learn",
[
Answer("a", 3),
Answer("b", 2),
],
3,
));
list.add(Question(
"what is your age",
[
Answer("18", 3),
Answer("20", 5),
],
2,
));
list.add(Question(
"which car do you drive",
[
Answer("c", 3),
Answer("d", 2),
],
3,
));
return list;
}