JRadioButton被選中後消失

Question

一直在使用JComponent進行實驗，併爲用戶做了一個簡短的3個問題測驗。由於我找不到代碼搞亂（或我）的確切區域，因此我將代碼放在出現的地方。當我點擊JFrame上的一個按鈕（button1除外），而不是僅僅保持選中狀態，它與其他按鈕一起消失，並顯示sysout。

public class SimpleQuiz implements ActionListener 
{ 
    private JFrame frame; 
    private JLabel label; 
    private JButton button; 
    private JButton buttona; 
    private JButton buttonb; 
    private JMenuBar menubar; 
    private JRadioButton button1; 
    private JRadioButton button2; 
    private JRadioButton button3; 
    private JCheckBox checkBox1; 
    private JCheckBox checkBox2; 
    private JMenuItem start; 
    private JMenuItem exit; 
    private JMenu fileMenu; 
    private ButtonGroup group; 

    public static void main(String[] args) 
    { 
     new SimpleQuiz(); 
    } 

    public SimpleQuiz() 
    { 
     //Creates the frame, label, button, textfield. and menubar. 
       frame = new JFrame("Classwork 10"); 
       label = new JLabel("Q1: What is the airspeed velocity of an unladen swallow?"); 
       button = new JButton("Show Answer"); 
       buttona = new JButton("Show Answer"); 
       buttonb = new JButton("Show Answer"); 
       menubar = new JMenuBar(); 
       button1 = new JRadioButton("24 miles an hour"); 
       button2 = new JRadioButton("17 miles an hour"); 
       button3 = new JRadioButton("32 miles an hour"); 
       fileMenu = new JMenu("File"); 
       exit = new JMenuItem("Exit"); 
       start = new JMenuItem("Start Quiz"); 
       group = new ButtonGroup(); 
       group.add(button1); 
       group.add(button2); 
       group.add(button3); 


       //Setting dimensions and properties for the JFrame 
       frame.setSize(500, 500); 
       frame.setLayout(null); 
       frame.setLocationRelativeTo(null); 
       frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
       frame.getContentPane().setBackground(Color.WHITE); 

       //Setting dimensions and properties for the JButton 
       button.setSize(175,50); 
       button.setLocation(175, 350); 
       button.setActionCommand("exe"); 
       button.addActionListener(this); 
       button.setVisible(false); 

       buttona.setSize(175,50); 
       buttona.setLocation(175, 350); 
       buttona.setActionCommand("b"); 
       buttona.addActionListener(this); 
       buttona.setVisible(false); 

       buttonb.setSize(175,50); 
       buttonb.setLocation(175, 350); 
       buttonb.setActionCommand("c"); 
       buttonb.addActionListener(this); 
       buttonb.setVisible(false); 

       button1.setSize(175,15); 
       button1.setLocation(150, 300); 
       button1.setActionCommand("t"); 
       button1.addActionListener(this); 
       button1.setVisible(false); 

       button2.setSize(175,15); 
       button2.setLocation(150, 275); 
       button2.setActionCommand("v"); 
       button2.addActionListener(this); 
       button2.setVisible(false); 

       button3.setSize(175,15); 
       button3.setLocation(150, 250); 
       button3.setActionCommand("i"); 
       button3.addActionListener(this); 
       button3.setVisible(false); 


       //Setting location and dimensions of the first question 
       label.setSize(500,25); 
       label.setLocation(25, 225); 
       label.setVisible(false); 

       //Setting dimensions and properties of the JMenuBar and subitems. 
       fileMenu.setMnemonic(KeyEvent.VK_F); 
       menubar.setSize(500, 25); 
       menubar.add(fileMenu); 
       fileMenu.add(start); 
       fileMenu.add(exit); 
       start.setActionCommand("start"); 
       start.addActionListener(this); 
       exit.setActionCommand("exit"); 
       exit.addActionListener(this); 
       menubar.setVisible(true); 

       //adding the JComponents to the frame 
       frame.setJMenuBar(menubar); 
       frame.add(button); 
       frame.add(buttona); 
       frame.add(buttonb); 
       frame.add(button1); 
       frame.add(button2); 
       frame.add(button3); 
       frame.add(label); 
       frame.setVisible(true); 
    } 
    @Override 
    public void actionPerformed(ActionEvent e) 
    { 
     if (e.getActionCommand().equals("start")) 
     { 
      start.setEnabled(false); 
      label.setVisible(true); 
      button1.setVisible(true); 
      button2.setVisible(true); 
      button3.setVisible(true); 
      button.setVisible(true); 
     }//End for actioncommand == start. 
     if(e.getActionCommand().equals("exe")) 
     { 
      if (button1.isSelected()) 
      { 
       System.out.println("You are correct."); 
       label.setText("Q2: Both your arms are cut off. Your opponent taunts you. What do you say?"); 
       button1.setVisible(false); 
       button2.setVisible(false); 
       button3.setVisible(false); 
       group.clearSelection(); 
      }//end of if button1 isSelected() 
     }//end of actioncomand == exe 

     if (button2.isSelected()) 
     { 
      System.out.println("You are incorrect. The correct answer is: 24 miles an hour"); 
      button1.setVisible(false); 
      button2.setVisible(false); 
      button3.setVisible(false); 
      group.clearSelection(); 
     }//end of button2.isselected 

     if (button3.isSelected()) 
     { 
      System.out.println("You are incorrect. The correct answer is: 24 miles an hour"); 
      button1.setVisible(false); 
      button2.setVisible(false); 
      button3.setVisible(false); 
      group.clearSelection(); 
     }//end of button3.isselected. 
     if (e.getActionCommand().equals("b")) 
     { 

     } 
    } 


    } 

爲了澄清，我還沒有完成，但是因爲我剛開始在這個項目上，並抓住了這個錯誤，我想我會來尋求幫助:)

PS對不起我英語不好，我來自意大利。

Answer 1

有幾個問題，但解決你的具體問題：當你點擊按鈕，它會觸發一個actionPerformed（）事件。而在你的actionPerformed（）方法，你設置的按鈕爲不可見：從我看到它

if (button3.isSelected()) 
{ 
    System.out.println("You are incorrect. The correct answer is: 24 miles an hour"); 
    button1.setVisible(false);//set button 1 to invisible 
    button2.setVisible(false);//set button 2 invisible 
    button3.setVisible(false);//set button 3 invisible. 
    group.clearSelection(); 
}