Complete Flutter Project for Online Exam

 

import 'package:flutter/material.dart';

void main() => runApp(MyApp());

class MyApp extends StatefulWidget {
  @override
  State<StatefulWidget> createState() {
    return _MyAppState();
  }
}

class _MyAppState extends State<MyApp> {
  final _questions = const [
    {
      'questionText': 'What\'s your favorite color?',
      'answers': [
        {'text': 'Black', 'score': 10},
        {'text': 'Red', 'score': 5},
        {'text': 'Green', 'score': 3},
        {'text': 'White', 'score': 1},
      ],
    },
    {
      'questionText': 'What\'s your favorite animal?',
      'answers': [
        {'text': 'Rabbit', 'score': 3},
        {'text': 'Snake', 'score': 11},
        {'text': 'Elephant', 'score': 5},
        {'text': 'Lion', 'score': 9},
      ],
    },
    {
      'questionText': 'Who\'s your favorite instructor?',
      'answers': [
        {'text': 'Max', 'score': 1},
        {'text': 'Max', 'score': 1},
        {'text': 'Max', 'score': 1},
        {'text': 'Max', 'score': 1},
      ],
    },
  ];
  var _questionIndex = 0;
  var _totalScore = 0;

  void _resetQuiz() {
    setState(() {
      _questionIndex = 0;
      _totalScore = 0;
    });
  }

  void _answerQuestion(int score) {
    _totalScore += score;

    setState(() {
      _questionIndex = _questionIndex + 1;
    });
    print(_questionIndex);
    if (_questionIndex < _questions.length) {
      print('We have more questions!');
    } else {
      print('No more questions!');
    }
  }

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          title: Text('My First App'),
        ),
        body: _questionIndex < _questions.length
            ? QuizWidget( answerQuestion: _answerQuestion,  questionIndex: _questionIndex,  questions: _questions )
            : ResultWidget(_totalScore, _resetQuiz),
      ),
    );
  }
}


class QuizWidget extends StatelessWidget {
  final List<Map<String, Object>> questions;
  final int questionIndex;
  final Function answerQuestion;

  QuizWidget({  @required this.questions, @required this.answerQuestion,  @required this.questionIndex });

  @override
  Widget build(BuildContext context) {
    return Column(
      children: [
        QuestionWidget(
          questions[questionIndex]['questionText'],
        ),
        ...(questions[questionIndex]['answers'] as List).map((_answer) {
          return AnswerWidget(() => answerQuestion(_answer['score']), _answer['text']);
        }).toList()
      ],
    );
  }
}


class QuestionWidget extends StatelessWidget {
  final String questionText;

  QuestionWidget(this.questionText);

  @override
  Widget build(BuildContext context) {
    return Container(
      width: double.infinity,
      margin: EdgeInsets.all(10),
      child: Text(
        questionText,
        style: TextStyle(fontSize: 28),
        textAlign: TextAlign.center,
      ),
    );
  }
}


class AnswerWidget extends StatelessWidget {
  final Function selectHandler;
  final String answerText;

  AnswerWidget(this.selectHandler, this.answerText);

  @override
  Widget build(BuildContext context) {
    return Container(
      width: double.infinity,
      child: RaisedButton(
        color: Colors.blue,
        textColor: Colors.white,
        child: Text(answerText),
        onPressed: selectHandler,
      ),
    );
  }
}


class ResultWidget extends StatelessWidget {
  final int resultScore;
  final Function resetHandler;

  ResultWidget(this.resultScore, this.resetHandler);

  String get resultPhrase {
    String resultText;
    if (resultScore <= 8) {
      resultText = 'You are awesome and innocent!';
    } else if (resultScore <= 12) {
      resultText = 'Pretty likeable!';
    } else if (resultScore <= 16) {
      resultText = 'You are ... strange?!';
    } else {
      resultText = 'You are so bad!';
    }
    return resultText;
  }

  @override
  Widget build(BuildContext context) {
    return Center(
      child: Column(
        children: <Widget>[
          Text(
            resultPhrase,
            style: TextStyle(fontSize: 36, fontWeight: FontWeight.bold),
            textAlign: TextAlign.center,
          ),
          FlatButton(
            child: Text(
              'Restart Quiz!',
            ),
            textColor: Colors.blue,
            onPressed: resetHandler,
          ),
        ],
      ),
    );
  }
}