编写程序以创建多项选择测验 需要一个基于 GUI 的程序，使人们能够从多项选择题库中进行测试。每个问题包括： 问题文本; 4个可能的答案; 正确答案的数量（1-4，而不是0-3）; 问题按顺序保存在文本文件中，每个问题保存在 6 行上。问题文本文件中的示例条目可能如下所示： 该计划应具有以下特点： 一个包含“打开”和“退出”的菜单，其中“打开”启动 JFileChooser 以选择包含问题的文件，“退出”结束程序。 加载文件后，GUI 应一次显示一个问题及其答案。 用户应该能够选择一个答案，并且应该通知他们是否正确。 应让用户知道正确回答的数量和回答的问题总数。 用户应该只有在回答了当前问题后才能继续下一个问题。 回答完所有问题后，应通知用户他们的总分以及游戏已完成。现在应启用“打开”菜单项以启动新测验。（可选）您可以添加重新启动菜单项以重做当前测验。

这是一个比较复杂的程序，需要用到 Java 的 GUI 编程。以下是一个简单的 Java 代码示例，可以实现上述功能：

import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import java.util.ArrayList;

public class MultipleChoiceQuiz extends JFrame implements ActionListener {

    private JMenuItem openMenuItem, restartMenuItem, exitMenuItem;
    private JFileChooser fileChooser;
    private JLabel questionLabel;
    private JRadioButton answer1RadioButton, answer2RadioButton, answer3RadioButton, answer4RadioButton;
    private ButtonGroup answerButtonGroup;
    private JButton submitButton, nextButton;
    private ArrayList<Question> questions;
    private int currentQuestionIndex, correctAnswers, totalQuestions;

    public MultipleChoiceQuiz() {
        super("Multiple Choice Quiz");

        // Create menu bar
        JMenuBar menuBar = new JMenuBar();
        JMenu fileMenu = new JMenu("File");
        openMenuItem = new JMenuItem("Open...");
        openMenuItem.addActionListener(this);
        restartMenuItem = new JMenuItem("Restart");
        restartMenuItem.addActionListener(this);
        exitMenuItem = new JMenuItem("Exit");
        exitMenuItem.addActionListener(this);
        fileMenu.add(openMenuItem);
        fileMenu.add(restartMenuItem);
        fileMenu.add(exitMenuItem);
        menuBar.add(fileMenu);
        setJMenuBar(menuBar);

        // Create GUI components
        questionLabel = new JLabel();
        answer1RadioButton = new JRadioButton();
        answer2RadioButton = new JRadioButton();
        answer3RadioButton = new JRadioButton();
        answer4RadioButton = new JRadioButton();
        answerButtonGroup = new ButtonGroup();
        answerButtonGroup.add(answer1RadioButton);
        answerButtonGroup.add(answer2RadioButton);
        answerButtonGroup.add(answer3RadioButton);
        answerButtonGroup.add(answer4RadioButton);
        submitButton = new JButton("Submit");
        submitButton.addActionListener(this);
        nextButton = new JButton("Next");
        nextButton.addActionListener(this);

        // Add components to content pane
        Container contentPane = getContentPane();
        contentPane.setLayout(new GridLayout(6, 1));
        contentPane.add(questionLabel);
        contentPane.add(answer1RadioButton);
        contentPane.add(answer2RadioButton);
        contentPane.add(answer3RadioButton);
        contentPane.add(answer4RadioButton);
        contentPane.add(submitButton);
        pack();

        // Create file chooser
        fileChooser = new JFileChooser();

        // Initialize variables
        questions = new ArrayList<Question>();
        currentQuestionIndex = 0;
        correctAnswers = 0;
        totalQuestions = 0;
    }

    public void actionPerformed(ActionEvent e) {
        if (e.getSource() == openMenuItem) {
            int returnVal = fileChooser.showOpenDialog(this);
            if (returnVal == JFileChooser.APPROVE_OPTION) {
                String filename = fileChooser.getSelectedFile().getAbsolutePath();
                try {
                    BufferedReader reader = new BufferedReader(new FileReader(filename));
                    String line;
                    while ((line = reader.readLine()) != null) {
                        String[] parts = line.split(";");
                        if (parts.length == 5) {
                            String questionText = parts[0];
                            String answer1Text = parts[1];
                            String answer2Text = parts[2];
                            String answer3Text = parts[3];
                            String answer4Text = parts[4];
                            Question question = new Question(questionText, answer1Text, answer2Text, answer3Text, answer4Text);
                            questions.add(question);
                        }
                    }
                    reader.close();
                    totalQuestions = questions.size();
                    displayQuestion();
                } catch (IOException ex) {
                    JOptionPane.showMessageDialog(this, "Error reading file: " + ex.getMessage(), "Error", JOptionPane.ERROR_MESSAGE);
                }
            }
        } else if (e.getSource() == restartMenuItem) {
            currentQuestionIndex = 0;
            correctAnswers = 0;
            displayQuestion();
        } else if (e.getSource() == exitMenuItem) {
            System.exit(0);
        } else if (e.getSource() == submitButton) {
            if (answer1RadioButton.isSelected() && questions.get(currentQuestionIndex).isCorrectAnswer(1)) {
                correctAnswers++;
            } else if (answer2RadioButton.isSelected() && questions.get(currentQuestionIndex).isCorrectAnswer(2)) {
                correctAnswers++;
            } else if (answer3RadioButton.isSelected() && questions.get(currentQuestionIndex).isCorrectAnswer(3)) {
                correctAnswers++;
            } else if (answer4RadioButton.isSelected() && questions.get(currentQuestionIndex).isCorrectAnswer(4)) {
                correctAnswers++;
            }
            displayResults();
            nextButton.setEnabled(true);
            submitButton.setEnabled(false);
        } else if (e.getSource() == nextButton) {
            currentQuestionIndex++;
            if (currentQuestionIndex < totalQuestions) {
                displayQuestion();
                nextButton.setEnabled(false);
                submitButton.setEnabled(true);
            } else {
                displayResults();
                nextButton.setEnabled(false);
                submitButton.setEnabled(false);
            }
        }
    }

    private void displayQuestion() {
        Question question = questions.get(currentQuestionIndex);
        questionLabel.setText(question.getQuestionText());
        answer1RadioButton.setText(question.getAnswer1Text());
        answer2RadioButton.setText(question.getAnswer2Text());
        answer3RadioButton.setText(question.getAnswer3Text());
        answer4RadioButton.setText(question.getAnswer4Text());
        answerButtonGroup.clearSelection();
    }

    private void displayResults() {
        int incorrectAnswers = totalQuestions - correctAnswers;
        double score = ((double) correctAnswers / totalQuestions) * 100;
        String message = String.format("You answered %d out of %d questions correctly (%.1f%%).",
                correctAnswers, totalQuestions, score);
        JOptionPane.showMessageDialog(this, message, "Results", JOptionPane.INFORMATION_MESSAGE);
    }

    private static class Question {
        private String questionText;
        private String answer1Text;
        private String answer2Text;
        private String answer3Text;
        private String answer4Text;
        private int numCorrectAnswers;

        public Question(String questionText, String answer1Text, String answer2Text, String answer3Text, String answer4Text) {
            this.questionText = questionText;
            this.answer1Text = answer1Text;
            this.answer2Text = answer2Text;
            this.answer3Text = answer3Text;
            this.answer4Text = answer4Text;
            this.numCorrectAnswers = 1;
        }

        public String getQuestionText() {
            return questionText;
        }

        public String getAnswer1Text() {
            return answer1Text;
        }

        public String getAnswer2Text() {
            return answer2Text;
        }

        public String getAnswer3Text() {
            return answer3Text;
        }

        public String getAnswer4Text() {
            return answer4Text;
        }

        public boolean isCorrectAnswer(int answerNumber) {
            if (answerNumber == 1) {
                return numCorrectAnswers == 1;
            } else if (answerNumber == 2) {
                return numCorrectAnswers == 2;
            } else if (answerNumber == 3) {
                return numCorrectAnswers == 3;
            } else if (answerNumber == 4) {
                return numCorrectAnswers == 4;
            } else {
                return false;
            }
        }
    }

    public static void main(String[] args) {
        MultipleChoiceQuiz quiz = new MultipleChoiceQuiz();
        quiz.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        quiz.setVisible(true);
    }
}

这个程序的主要思路是在 `actionPerformed` 方法中处理各种事件（如菜单项点击、提交按钮点击、下一题按钮点击等）。当用户打开题目文件时，程序会读取文件并将每个问题存储在 `questions` 列表中。程序会跟踪当前题目索引 `currentQuestionIndex`，以及用户答对的题目数量 `correctAnswers` 和题目总数 `totalQuestions`。每次显示一个问题时，程序会将问题文本和答案选项显示在相应的 GUI 组件中，并清除之前的答案选择。当用户提交答案时，程序会检查选择的答案是否正确，并更新 `correctAnswers` 的值。在用户回答完所有的问题后，程序会弹出一个消息框显示用户的得分。