向JFrame的每個JPanel添加滾動條（如果需要）

Question

//這是我的JFrame代碼，然後連接到其他面板。

public class startQuiz extends JFrame { 

     private static final long serialVersionUID = 1L; 
     private JPanel jContentPane = null; 
     private JButton jButtonGQuiz = null; 
     private JFrame myFrame = null; 
     private JLabel jLabelTitle = null; 
     private JLabel jLabelGQuiz = null; 
     private JLabel jLabelCQuiz = null; 
     private JButton jButtonCQuiz = null; 
     private JMenuBar jJMenuBar = null; 
     private JMenu jMenuFile = null; 
     private JMenuItem jMenuItemNew = null; 
     private JMenuItem jMenuItemImport = null; 
     private JScrollPane jScrollPane = null; 
     /** 
     * This method initializes jButtonGQuiz 
     * 
     * @return javax.swing.JButton 
     */ 
     private JButton getJButtonGQuiz() { 
      if (jButtonGQuiz == null) { 
       jButtonGQuiz = new JButton(); 
       jButtonGQuiz.setBounds(new Rectangle(345, 90, 75, 26)); 
       jButtonGQuiz.setText("Start"); 
       jButtonGQuiz.addActionListener(new java.awt.event.ActionListener() { 
        public void actionPerformed(java.awt.event.ActionEvent e) { 
         startButtonClicked(); 
        } 
        public void startButtonClicked() { 
         JPanel panel = new GQuiz(myFrame); 
         myFrame.getContentPane().removeAll(); 
         myFrame.getContentPane().add(panel); 
         myFrame.getContentPane().validate(); 
         myFrame.getContentPane().repaint(); 
        } 
       }); 
      } 
      return jButtonGQuiz; 
     } 

     /** 
     * This method initializes jButtonCQuiz 
     * 
     * @return javax.swing.JButton 
     */ 
     private JButton getJButtonCQuiz() { 
      if (jButtonCQuiz == null) { 
       jButtonCQuiz = new JButton(); 
       jButtonCQuiz.setBounds(new Rectangle(344, 140, 75, 26)); 
       jButtonCQuiz.setText("Start"); 
       jButtonCQuiz.addActionListener(new java.awt.event.ActionListener() { 
        public void actionPerformed(java.awt.event.ActionEvent e) { 
         startButton1Clicked(); 
        } 
        public void startButton1Clicked() { 
         JPanel panel = new CancerQuiz(myFrame); 
         myFrame.getContentPane().removeAll(); 
         myFrame.getContentPane().add(panel); 
         myFrame.getContentPane().validate(); 
         myFrame.getContentPane().repaint(); 

        } 
       }); 
      } 
      return jButtonCQuiz; 
     } 

     /** 
     * This method initializes jJMenuBar  
     * 
     * @return javax.swing.JMenuBar 
     */ 
     private JMenuBar getJJMenuBar() { 
      if (jJMenuBar == null) { 
       jJMenuBar = new JMenuBar(); 
       jJMenuBar.add(getJMenuFile()); 
      } 
      return jJMenuBar; 
     } 

     /** 
     * This method initializes jMenuFile  
     * 
     * @return javax.swing.JMenu  
     */ 
     private JMenu getJMenuFile() { 
      if (jMenuFile == null) { 
       jMenuFile = new JMenu(); 
       jMenuFile.setText("File"); 
       jMenuFile.add(getJMenuItemNew()); 
       jMenuFile.add(getJMenuItemImport()); 
      } 
      return jMenuFile; 
     } 

     /** 
     * This method initializes jMenuItemNew 
     * 
     * @return javax.swing.JMenuItem  
     */ 
     private JMenuItem getJMenuItemNew() { 
      if (jMenuItemNew == null) { 
       jMenuItemNew = new JMenuItem(); 
       jMenuItemNew.setText("New"); 
       jMenuItemNew.addActionListener(new java.awt.event.ActionListener() { 
        public void actionPerformed(java.awt.event.ActionEvent e) { 
         newMenuItemClicked(); 
        } 
        public void newMenuItemClicked() { 
         JPanel panel = new MyTestDatePicker(myFrame); 
         myFrame.getContentPane().removeAll(); 
         myFrame.getContentPane().add(panel); 
         myFrame.getContentPane().validate(); 
         myFrame.getContentPane().repaint(); 
        } 
       }); 
      } 
      return jMenuItemNew; 
     } 

     /** 
     * This method initializes jMenuItemImport 
     * 
     * @return javax.swing.JMenuItem  
     */ 
     private JMenuItem getJMenuItemImport() { 
      if (jMenuItemImport == null) { 
       jMenuItemImport = new JMenuItem(); 
       jMenuItemImport.setText("Import"); 
       jMenuItemImport.addActionListener(new java.awt.event.ActionListener() { 
        public void actionPerformed(java.awt.event.ActionEvent e) { 
         importMenuItemClicked(); 
        } 
        public void importMenuItemClicked() { 
         JPanel panel = new importQuestions(myFrame); 
         myFrame.getContentPane().removeAll(); 
         myFrame.getContentPane().add(panel); 
         myFrame.getContentPane().validate(); 
         myFrame.getContentPane().repaint(); 

        } 
       }); 
      } 
      return jMenuItemImport; 
     } 

     /** 
     * This method initializes jScrollPane 
     * 
     * @return javax.swing.JScrollPane 
     */ 


     /** 
     * @param args 
     */ 
     public static void main(String[] args) { 
      // TODO Auto-generated method stub 
      SwingUtilities.invokeLater(new Runnable() { 
       public void run() { 
        startQuiz thisClass = new startQuiz(); 
        thisClass.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
        thisClass.setVisible(true); 

       } 
      }); 
     } 

     /** 
     * This is the default constructor 
     */ 
     public startQuiz() { 
      super(); 
      initialize(); 
      myFrame = this; 
      this.setVisible(true); 
     } 

     /** 
     * This method initializes this 
     * 
     * @return void 
     */ 
     private void initialize() { 
      this.setSize(680, 320); 
      this.setJMenuBar(getJJMenuBar()); 
      this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
      this.setContentPane(getJContentPane()); 
      this.setTitle("Quiz"); 
      this.setVisible(true); 


     } 

     /** 
     * This method initializes jContentPane 
     * 
     * @return javax.swing.JPanel 
     */ 
     private JPanel getJContentPane() { 
      if (jContentPane == null) { 
       jLabelCQuiz = new JLabel(); 
       jLabelCQuiz.setHorizontalAlignment(SwingConstants.RIGHT); 
       jLabelCQuiz.setLocation(new Point(64, 134)); 
       jLabelCQuiz.setSize(new Dimension(251, 38)); 
       jLabelCQuiz.setText("Cancer Quiz : "); 
       jLabelGQuiz = new JLabel(); 
       jLabelGQuiz.setBounds(new Rectangle(66, 83, 251, 38)); 
       jLabelGQuiz.setHorizontalAlignment(SwingConstants.RIGHT); 
       jLabelGQuiz.setText("General Quiz :"); 
       jLabelTitle = new JLabel(); 
       jLabelTitle.setBounds(new Rectangle(73, 8, 488, 46)); 
       jLabelTitle.setFont(new Font("Dialog", Font.BOLD, 18)); 
       jLabelTitle.setHorizontalAlignment(SwingConstants.CENTER); 
       jLabelTitle.setText("Choose a Quiz !"); 
       jContentPane = new JPanel(); 
       jContentPane.setLayout(null); 
       jContentPane.setBorder(null); 
       jContentPane.add(getJButtonGQuiz(), null); 
       jContentPane.add(jLabelTitle, null); 
       jContentPane.add(jLabelGQuiz, null); 
       jContentPane.add(jLabelCQuiz, null); 
       jContentPane.add(getJButtonCQuiz(), null); 

      } 
      return jContentPane; 
     } 

    } 

//這是我的面板之一，鏈接到以前的JFrame。我在這裏添加了滾動條//但它不起作用。因此，我怎樣才能讓滾動條正常工作。

import java.awt.GridBagLayout; 
    import javax.swing.JPanel; 
    import javax.swing.JScrollBar; 
    import java.awt.Rectangle; 
    import java.awt.Dimension; 

    import javax.swing.JFrame; 
    import javax.swing.JLabel; 
    import javax.swing.JRadioButton; 
    import javax.swing.JButton; 

    import myQuiz.entity.QuizQuestion; 
    import javax.swing.SwingConstants; 
    import javax.swing.JScrollPane; 

    public class GQuiz extends JPanel { 

     private static final long serialVersionUID = 1L; 
     private JLabel jLabelG1 = null; 
     private JRadioButton jRadioButtonTrue = null; 
     private JRadioButton jRadioButtonFalse = null; 
     private JLabel jLabelG2 = null; 
     private JRadioButton jRadioButtonTrue1 = null; 
     private JRadioButton jRadioButtonFalse1 = null; 
     private JButton jButtonSubmit = null; 
     private JFrame myFrame = null; 

     private int questionID; 
     private String username; 
     private String answer; 
     /** 
     * This is the default constructor 
     */ 
     public GQuiz() { 
      super(); 
      initialize(); 
     } 
     public GQuiz (JFrame f){ 
      this(); 
      myFrame = f; 
      } 

     /** 
     * This method initializes this 
     * 
     * @return void 
     */ 
     private void initialize() { 
      jLabelG2 = new JLabel(); 
      jLabelG2.setBounds(new Rectangle(5, 104, 724, 37)); 
      jLabelG2.setText("2. Exercise is a good way to help prevent heart attacks."); 
      jLabelG1 = new JLabel(); 
      jLabelG1.setBounds(new Rectangle(6, 3, 719, 32)); 
      jLabelG1.setHorizontalAlignment(SwingConstants.LEFT); 
      jLabelG1.setText("1. Drinking two glasses of water before meals is a good way to help fill your stomach up which makes you eat less."); 
      this.setSize(733, 359); 
      this.setLayout(null); 
      this.add(jLabelG1, null); 
      this.add(getJRadioButtonTrue(), null); 
      this.add(getJRadioButtonFalse(), null); 
      this.add(jLabelG2, null); 
      this.add(getJRadioButtonTrue1(), null); 
      this.add(getJRadioButtonFalse1(), null); 
      this.add(getJButtonSubmit(), null); 
     } 

     /** 
     * This method initializes jRadioButtonTrue 
     * 
     * @return javax.swing.JRadioButton 
     */ 
     private JRadioButton getJRadioButtonTrue() { 
      if (jRadioButtonTrue == null) { 
       jRadioButtonTrue = new JRadioButton(); 
       jRadioButtonTrue.setBounds(new Rectangle(7, 39, 77, 26)); 
       jRadioButtonTrue.setText("True"); 
      } 
      return jRadioButtonTrue; 
     } 

     /** 
     * This method initializes jRadioButtonFalse  
     * 
     * @return javax.swing.JRadioButton 
     */ 
     private JRadioButton getJRadioButtonFalse() { 
      if (jRadioButtonFalse == null) { 
       jRadioButtonFalse = new JRadioButton(); 
       jRadioButtonFalse.setBounds(new Rectangle(8, 70, 74, 30)); 
       jRadioButtonFalse.setText("False"); 
      } 
      return jRadioButtonFalse; 
     } 

     /** 
     * This method initializes jRadioButtonTrue1  
     * 
     * @return javax.swing.JRadioButton 
     */ 
     private JRadioButton getJRadioButtonTrue1() { 
      if (jRadioButtonTrue1 == null) { 
       jRadioButtonTrue1 = new JRadioButton(); 
       jRadioButtonTrue1.setBounds(new Rectangle(6, 145, 75, 30)); 
       jRadioButtonTrue1.setText("True"); 
      } 
      return jRadioButtonTrue1; 
     } 

     /** 
     * This method initializes jRadioButtonFalse1 
     * 
     * @return javax.swing.JRadioButton 
     */ 
     private JRadioButton getJRadioButtonFalse1() { 
      if (jRadioButtonFalse1 == null) { 
       jRadioButtonFalse1 = new JRadioButton(); 
       jRadioButtonFalse1.setBounds(new Rectangle(6, 177, 77, 31)); 
       jRadioButtonFalse1.setText("False"); 
      } 
      return jRadioButtonFalse1; 
     } 

     /** 
     * This method initializes jButtonSubmit  
     * 
     * @return javax.swing.JButton 
     */ 
     private JButton getJButtonSubmit() { 
      if (jButtonSubmit == null) { 
       jButtonSubmit = new JButton(); 
       jButtonSubmit.setBounds(new Rectangle(284, 287, 83, 32)); 
       jButtonSubmit.setText("Submit"); 


      } 
      return jButtonSubmit; 
     } 

    } 

Answer 1

我沒有看到你在面板中使用的JScrollPane，但基本上這可能不是正確的地方，反正（取決於你想要做什麼）。

通常，將滾動窗格添加到框架而不是面板，並將面板置於滾動窗格中。是這樣的僞代碼：

JFrame frame = new JFrame(); 
JPanel panel = new JPanel(); 
JScrollPane scroll = new JScrollPane(panel); 
frame.add(scroll); 

Answer 2

如果你想爲每一個的JPanel您添加到JFrame中那麼你可以做如下：

1. 創建一個類擴展JFrame類
2. 覆蓋add(component) JFrame的方法
3. 在這個方法中檢查參數組件是否是JPanel。
4. 如果JPanel然後創建一個JScrollPane，添加jPanel到它，然後添加scrollPane到框架。
5. 否則打電話super.add(component);