向 GridBagLayout 添加滚动窗格

Question

我正在尝试使用 GridBagLayout 在 JPanel 中添加两个滚动窗格以及一个标签和一个按钮。而第一个滚动窗格包含一个 JList，第二个滚动窗格包含一个 JTable。下面是代码：

    JPanel capabilityPanel = new JPanel(new GridBagLayout());
    GridBagConstraints constraints = new GridBagConstraints();

    JScrollPane capabilityScrollPane = new JScrollPane(cbList,
            ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS,
            ScrollPaneConstants.HORIZONTAL_SCROLLBAR_ALWAYS);


    JScrollPane capabilityTableScrollPane = new JScrollPane(table,
            ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS,
            ScrollPaneConstants.HORIZONTAL_SCROLLBAR_ALWAYS);

    JButton saveButton = new JButton("Save Table Values");

    JLabel capabilityLabel = new JLabel("Boolean Capability List");
    constraints.fill = GridBagConstraints.HORIZONTAL;
    constraints.gridx = 0;
    constraints.gridy = 0;
    capabilityPanel.add(capabilityLabel, constraints);

    constraints.gridx = 1;
    constraints.gridy = 0;
    capabilityPanel.add(capabilityScrollPane,constraints);

    constraints.gridx = 0;
    constraints.gridy = 1;
    capabilityPanel.add(saveButton, constraints);

    constraints.gridx = 1;
    constraints.gridy = 1;
    capabilityPanel.add(capabilityTableScrollPane, constraints);

问题是当我直接在面板中添加表格而不是相应的滚动窗格时，它在屏幕上正确显示。但是当我添加滚动窗格时，只显示三个元素，表格根本没有显示。我希望表格可以滚动显示。

你能帮我解决一下这种情况吗？

Answer 1

它将创建一个外部面板
两个内板
一个用于列表
一个用于表格
布局

打包新包；

public class NewJFrame extends javax.swing.JFrame {

/**
 * Creates new form NewJFrame
 */
public NewJFrame() {
    initComponents();
}

/**
 * This method is called from within the constructor to initialize the form.
 * WARNING: Do NOT modify this code. The content of this method is always
 * regenerated by the Form Editor.
 */
@SuppressWarnings("unchecked")
// <editor-fold defaultstate="collapsed" desc="Generated Code">                          
private void initComponents() {

    outerPanel = new javax.swing.JPanel();
    listPanel = new javax.swing.JPanel();
    jLabel1 = new javax.swing.JLabel();
    jScrollPane1 = new javax.swing.JScrollPane();
    jList1 = new javax.swing.JList();
    tablePanel = new javax.swing.JPanel();
    jScrollPane2 = new javax.swing.JScrollPane();
    jTable1 = new javax.swing.JTable();
    jButton1 = new javax.swing.JButton();

    setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);

    outerPanel.setLayout(new java.awt.BorderLayout());

    jLabel1.setText("Boolean Capability List");

    jList1.setModel(new javax.swing.AbstractListModel() {
        String[] strings = { "Item 1", "Item 2", "Item 3", "Item 4", "Item 5", "Item 1", "Item 2", "Item 3", "Item 4", "Item 5", "Item 1", "Item 2", "Item 3", "Item 4", "Item 5", " " };
        public int getSize() { return strings.length; }
        public Object getElementAt(int i) { return strings[i]; }
    });
    jScrollPane1.setViewportView(jList1);

    javax.swing.GroupLayout listPanelLayout = new javax.swing.GroupLayout(listPanel);
    listPanel.setLayout(listPanelLayout);
    listPanelLayout.setHorizontalGroup(
        listPanelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(listPanelLayout.createSequentialGroup()
            .addComponent(jLabel1)
            .addGap(0, 177, Short.MAX_VALUE))
        .addComponent(jScrollPane1)
    );
    listPanelLayout.setVerticalGroup(
        listPanelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(listPanelLayout.createSequentialGroup()
            .addComponent(jLabel1)
            .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
            .addComponent(jScrollPane1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
            .addGap(0, 15, Short.MAX_VALUE))
    );

    outerPanel.add(listPanel, java.awt.BorderLayout.NORTH);

    jTable1.setModel(new javax.swing.table.DefaultTableModel(
        new Object [][] {
            {null, null, null, null},
            {null, null, null, null},
            {null, null, null, null},
            {null, null, null, null},
            {null, null, null, null},
            {null, null, null, null},
            {null, null, null, null},
            {null, null, null, null},
            {null, null, null, null},
            {null, null, null, null},
            {null, null, null, null},
            {null, null, null, null},
            {null, null, null, null},
            {null, null, null, null},
            {null, null, null, null},
            {null, null, null, null},
            {null, null, null, null},
            {null, null, null, null},
            {null, null, null, null},
            {null, null, null, null},
            {null, null, null, null}
        },
        new String [] {
            "Title 1", "Title 2", "Title 3", "Title 4"
        }
    ));
    jScrollPane2.setViewportView(jTable1);

    jButton1.setText("Save Values");

    javax.swing.GroupLayout tablePanelLayout = new javax.swing.GroupLayout(tablePanel);
    tablePanel.setLayout(tablePanelLayout);
    tablePanelLayout.setHorizontalGroup(
        tablePanelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(tablePanelLayout.createSequentialGroup()
            .addComponent(jScrollPane2, javax.swing.GroupLayout.PREFERRED_SIZE, 303, javax.swing.GroupLayout.PREFERRED_SIZE)
            .addGap(0, 0, Short.MAX_VALUE))
        .addGroup(tablePanelLayout.createSequentialGroup()
            .addGap(101, 101, 101)
            .addComponent(jButton1)
            .addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
    );
    tablePanelLayout.setVerticalGroup(
        tablePanelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(tablePanelLayout.createSequentialGroup()
            .addComponent(jScrollPane2, javax.swing.GroupLayout.PREFERRED_SIZE, 201, javax.swing.GroupLayout.PREFERRED_SIZE)
            .addGap(27, 27, 27)
            .addComponent(jButton1)
            .addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
    );

    outerPanel.add(tablePanel, java.awt.BorderLayout.SOUTH);

    getContentPane().add(outerPanel, java.awt.BorderLayout.CENTER);

    pack();
}// </editor-fold>                        

/**
 * @param args the command line arguments
 */
public static void main(String args[]) {
    /* Set the Nimbus look and feel */
    //<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) ">
    /* If Nimbus (introduced in Java SE 6) is not available, stay with the default look and feel.
     * For details see http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html 
     */
    try {
        for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
            if ("Nimbus".equals(info.getName())) {
                javax.swing.UIManager.setLookAndFeel(info.getClassName());
                break;
            }
        }
    } catch (ClassNotFoundException ex) {
        java.util.logging.Logger.getLogger(NewJFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
    } catch (InstantiationException ex) {
        java.util.logging.Logger.getLogger(NewJFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
    } catch (IllegalAccessException ex) {
        java.util.logging.Logger.getLogger(NewJFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
    } catch (javax.swing.UnsupportedLookAndFeelException ex) {
        java.util.logging.Logger.getLogger(NewJFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
    }
    //</editor-fold>

    /* Create and display the form */
    java.awt.EventQueue.invokeLater(new Runnable() {
        public void run() {
            new NewJFrame().setVisible(true);
        }
    });
}

// Variables declaration - do not modify                     
private javax.swing.JButton jButton1;
private javax.swing.JLabel jLabel1;
private javax.swing.JList jList1;
private javax.swing.JScrollPane jScrollPane1;
private javax.swing.JScrollPane jScrollPane2;
private javax.swing.JTable jTable1;
private javax.swing.JPanel listPanel;
private javax.swing.JPanel outerPanel;
private javax.swing.JPanel tablePanel;
// End of variables declaration                   
}

输出