当我在GUI中的actionListener中按下按钮时，图像无法打开？

Question

我试图让PlaySci按钮被按下时打开图像，所以我把图像放在PlaySci动作监听器中，但是只有当按下退出按钮时它才会打开？

我已经看了几个小时，仍然不明白为什么，我试图摆脱退出按钮alltogether，但然后图像根本不显示。

我所造的像成JLabel顶部：

ImageIcon scis1 = new ImageIcon("scis.jpg"); 

private JLabel picture = new JLabel(scis1); 

这里是我的PlaySci按钮ActonListener代码：

class PlaySciHandler implements ActionListener { 
    public void actionPerformed(ActionEvent event) { 

     String computerRand = sps.computerChoice(); 
     txtComputerRand.setText(computerRand); 
     String result = sps.play(Sps.SCISSORS); 
     txtResult.setText(result); 
     picture.setBounds(60, 200, 400, 400);// this is the image I want displayed when the PlaySci button is pressed 
     panel.add(picture); 
    } 
} 

这是退出按钮的ActionListener（由于某种原因是显示图像的唯一方式）：

class exitHandler implements ActionListener{ 
    public void actionPerformed(ActionEvent e) { 
     int n = JOptionPane.showConfirmDialog(frame, //when this button is pressed the image comes up? 
       "Are you sure you want to exit?", 
       "Exit?", 
       JOptionPane.YES_NO_OPTION); 
     if(n == JOptionPane.YES_OPTION){ 
      System.exit(0); 
     } 
    } 
} 

这是co创建按钮并添加ActionListener：

   btnPlaySci = new JButton ("Scissors!"); 
     btnPlaySci.setBounds(180, 40, 110, 20); 
     btnPlaySci.addActionListener(new PlaySciHandler()); 
     panel.add (btnPlaySci); 
     btnPlaySci.setForeground(Color.MAGENTA); 

任何帮助，将不胜感激。

Answer 1

不要加在class PlaySciHandler implements ActionListener的JLabel block.Add它在你createForm()方法，使其隐形：picture.setVisible(false); ，当你想有一个按钮，点击后显示，使其可见：picture.setVisible(true);

Answer 2

你应该添加图片后重新绘制面板。请参阅PlaySciHandleractionPerformed方法的代码。

class PlaySciHandler implements ActionListener { 
     public void actionPerformed(ActionEvent event) { 

      String computerRand = sps.computerChoice(); 
      txtComputerRand.setText(computerRand); 
      String result = sps.play(Sps.SCISSORS); 
      txtResult.setText(result); 
      picture.setBounds(60, 200, 400, 400);// this is the image I want displayed when the PlaySci button is pressed 
      panel.add(picture); 
      panel.repaint();//Must repaint the panel . 
     } 
    } 

注：作为一个方面说明我会建议你从来不使用null Layout为JPanel。使用由Swing提供的内置Layouts。您可以在此official site获得有关布局使用情况的更多信息。另一个是始终坚持使用java命名约定。 exitHandler应改为ExitHandler。要了解更多，请看official site。