.setBackground() 方法不适用于 JRadioButton

Question

我正在编写一个包含测验元素的程序，当用户回答错误时，会给出反馈。问题 JFrame 由具有实际问题的 JLabel 和具有不同选项（名为 rad1、rad2、rad3、rad4）的 4 个 JRadioButton 组成。我想做的是，如果用户回答错误，则具有正确答案背景颜色的单选按钮变为绿色，而具有用户给出的背景答案的单选按钮变为红色。

这是我用来确定哪个答案正确的 FOR 循环：

private void btnSubmitActionPerformed(java.awt.event.ActionEvent evt) {                                          
    System.out.println("Submit Clicked");
    //figures out what choice the user selected
    String correctAnswer = questions.get(current).getAnswer();
    int numChoice = -1;
    String choice = "";
    boolean answered = false;

    if (rad1.isSelected()) {
        numChoice = 0;
        answered = true;
        choice = rad1.getText();
    } else if (rad2.isSelected()) {
        numChoice = 1;
        answered = true;
        choice = rad2.getText();
    } else if (rad3.isSelected()) {
        numChoice = 2;
        answered = true;
        choice = rad3.getText();
    } else if (rad4.isSelected()) {
        numChoice = 3;
        answered = true;
        choice = rad4.getText();
    } else { //user didn't pick a choice
        JOptionPane.showMessageDialog(null, "You didn't answer the question, try again!");
    }

    if (choice.equals(correctAnswer)) {
        score++;
        System.out.println("score++");
    } else {
        //figures out which of the answers was correct
        rad1.setBackground(Color.RED);
        for (int i = 0; i < 4; i++) {
            if (questions.get(current).getChoices()[i].equals(correctAnswer)) {
                System.out.println(correctAnswer);
                System.out.println(i);
                //me trying to see if it will change if I put it outside the switch
                //confirmed that it will not.
                rad1.setBackground(Color.RED);
                switch (i) {
                    case 0:
                        rad1.setBackground(new Color(51, 204, 51));
                        break;
                    case 1:
                        rad2.setBackground(new Color(51, 204, 51));
                        break;
                    case 2:
                        rad3.setBackground(new Color(51, 204, 51));
                        break;
                    case 3:
                        rad4.setBackground(new Color(51, 204, 51));
                        break;
                }
                break;
            }

        }
        switch (numChoice) {
            case 0:
                rad1.setBackground(new Color(153, 0, 0));
                break;
            case 1:
                rad2.setBackground(new Color(153, 0, 0));
                break;
            case 2:
                rad3.setBackground(new Color(153, 0, 0));
                break;
            case 3:
                rad4.setBackground(new Color(153, 0, 0));
                break;
        }
    }
    //loads next question


    //loads the next question
    if (current < 10) {
        updateFrame();
    } else {
        //ends the quiz
    }
}

我使用 .setBackground() 方法有一段时间了，如果我将打印语句放在 case 块中，它们会执行，但不会发生着色。有什么我想念的愚蠢的东西吗？

谢谢

编辑：添加了更多代码以查看 FOR 循环在 btnSubmitActionPerformed() 方法中。当用户点击按钮时，判断他们的答案，改变单选按钮的颜色。

Answer 1

两件事立即跳入脑海：

您发布的代码是从哪里调用的？在 Swing 工作线程之外进行 UI 更改有点不确定。有时正确的事情会发生，有时不会。
我从未尝试在单选按钮上设置颜色，但它们似乎没有背景。

尝试设置一些其他属性，例如尺寸，看看是否能得到结果。如果是这样，那么问题是单选按钮没有背景，您将不得不想出另一种设计。如果没有任何反应，那么可能是第一个问题。

Answer 2

您的代码看起来过于复杂且不必要。我自己，我会尝试 "OOP-ify" 来降低圈复杂度并

一个非 GUI 问题 class、
问题文本有一个字符串字段，
使用 correctAnswer 的字符串字段，
带有 List<String> 的错误答案。
我会给它一个方法，比如 public List<String> getShuffledAnswers() 到 return 一个包含所有答案的字符串列表，正确的和不正确的，在他们自己的列表中洗牌，
testAnswer(String test) 的布尔方法，并且 return 测试的真值等于正确的答案。

然后我会创建一个名为 QuestionPanel 的 JPanel

有问题字段
显示单个问题对象的信息，包括 JLabel 中的问题文本和 JRadioButtons 中的所有随机答案。
它将具有获取 selected JRadioButton 和获取问题的方法，
以及一种在需要时通过调用 `setOpaque(false) 设置使 JRadioButtons 背景不透明的方法
以及允许调用代码将 select JRadioButtons 的背景设置为正确答案颜色或错误答案颜色的方法。

例如：

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

import javax.swing.AbstractAction;
import javax.swing.BorderFactory;
import javax.swing.ButtonGroup;
import javax.swing.ButtonModel;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JRadioButton;
import javax.swing.SwingUtilities;

@SuppressWarnings("serial")
public class TestQuestions extends JPanel {
    private static final Question TEST_QUESTION = new Question("Select the Correct Answer", "This answer is correct", 
            "Incorrect Answer 1", "Incorrect Answer 2", "Incorrect Answer 3");
    private QuestionPanel questionPanel = new QuestionPanel();

    public TestQuestions() {
        questionPanel.setQuestion(TEST_QUESTION);
        JButton testAnswerBtn = new JButton(new AbstractAction("Test Answer") {

            @Override
            public void actionPerformed(ActionEvent e) {
                boolean isCorrect = questionPanel.isCorrectAnswerSelected();
                String message = "";
                if (isCorrect) {
                    message = "Correct answer selected!";
                } else {
                    message = "Incorrect answer selected!";                    
                }
                JOptionPane.showMessageDialog(TestQuestions.this, message);
                questionPanel.displayCorrectWrongAnswers();
            }
        });
        JButton clearAllBtn = new JButton(new AbstractAction("Clear All") {

            @Override
            public void actionPerformed(ActionEvent e) {
                questionPanel.clearAll();
                questionPanel.clearSelection();
            }
        });

        JPanel btnPanel = new JPanel(new GridLayout(1, 0, 5, 5));
        btnPanel.add(testAnswerBtn);
        btnPanel.add(clearAllBtn);

        setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5));
        setLayout(new BorderLayout(5, 5));
        add(questionPanel, BorderLayout.CENTER);
        add(btnPanel, BorderLayout.PAGE_END);
    }

    private static void createAndShowGui() {
        JFrame frame = new JFrame("TestQuestions");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.getContentPane().add(new TestQuestions());
        frame.pack();
        frame.setLocationRelativeTo(null);
        frame.setVisible(true);
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                createAndShowGui();
            }
        });
    }
}

@SuppressWarnings("serial")
class QuestionPanel extends JPanel {
    private static final Color CORRECT_ANSWER_SELECTED_COLOR = new Color(151, 255, 151);
    private static final Color CORRECT_ANSWER_NOT_SELECTED_COLOR = new Color(151,151, 255);
    private static final Color INCORRECT_ANSWER_SELECTED_COLOR = new Color(255, 151, 151);
    private Question question;
    private JLabel questionTextLabel = new JLabel();
    private List<JRadioButton> answerButtonList = new ArrayList<>();
    private JPanel answerPanel = new JPanel(new GridLayout(0, 1));
    private ButtonGroup buttonGroup = new ButtonGroup();

    public QuestionPanel() {
        setLayout(new BorderLayout());
        add(questionTextLabel, BorderLayout.PAGE_START);
        add(answerPanel, BorderLayout.CENTER);
    }

    public void setQuestion(Question question) {
        this.question = question;
        questionTextLabel.setText(question.getQuestionText());

        answerPanel.removeAll();
        answerButtonList.clear();
        buttonGroup = new ButtonGroup();

        for (String answer : question.getShuffledAnswers()) {
            JRadioButton rBtn = new JRadioButton(answer);
            rBtn.setActionCommand(answer);
            answerButtonList.add(rBtn);
            buttonGroup.add(rBtn);
            answerPanel.add(rBtn);
        }
    }

    public boolean isCorrectAnswerSelected() {
        ButtonModel model = buttonGroup.getSelection();
        if (model == null) {
            return false; // nothing selected
        } else {
            return question.checkAnswer(model.getActionCommand());
        }
    }

    public void clearAll() {
        for (JRadioButton jRadioButton : answerButtonList) {
            jRadioButton.setOpaque(false);
            jRadioButton.setBackground(null);
        }
    }

    public void clearSelection() {
        buttonGroup.clearSelection();
    }

    public void displayCorrectWrongAnswers() {
        clearAll();
        for (JRadioButton jRadioButton : answerButtonList) {
            if (jRadioButton.isSelected()) {
                jRadioButton.setOpaque(true);
                if (question.checkAnswer(jRadioButton.getActionCommand())) {
                    jRadioButton.setBackground(CORRECT_ANSWER_SELECTED_COLOR);
                } else {
                    jRadioButton.setBackground(CORRECT_ANSWER_NOT_SELECTED_COLOR);
                }
            } else if (question.checkAnswer(jRadioButton.getActionCommand())) {
                jRadioButton.setOpaque(true);
                jRadioButton.setBackground(INCORRECT_ANSWER_SELECTED_COLOR);
            }
        }
    }

}

class Question {
    private String questionText;
    private String correctAnswer;
    private List<String> incorrectAnswerList = new ArrayList<>();
    public Question(String questionText, String correctAnswer, String... incorrectAnswers) {
        this.questionText = questionText;
        this.correctAnswer = correctAnswer;
        for (String incorrectAnswer : incorrectAnswers) {
            incorrectAnswerList.add(incorrectAnswer);
        }
    }

    public String getQuestionText() {
        return questionText;
    }

    public String getCorrectAnswer() {
        return correctAnswer;
    }

    public List<String> getShuffledAnswers() {
        List<String> answers = new ArrayList<>(incorrectAnswerList);
        answers.add(correctAnswer);
        Collections.shuffle(answers);
        return answers;
    }

    public boolean checkAnswer(String test) {
        return correctAnswer.equalsIgnoreCase(test);
    }

}

.setBackground() 方法不适用于 JRadioButton

.setBackground() method is not working for JRadioButton

java

swing

jradiobutton