JTable：将一个添加到JPanel，它不显示自己

Question

It's Monday morning where I am, which means it's time for me to fail at Java Swing! But in all seriousness, I cannot figure out why my dynamically created JTable refuses to show itself once added to a JPanel on a JFrame, and would greatly appreciate any help in isolating this troublesome problem. As you can see from the code, I've called a dozen different methods, but can't seem to get the right one to get it to display...perhaps I am missing one?

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */
package energizingemerald;


import javax.swing.*;
import java.awt.Dimension;
/**
 *
 * @author Ryan
 */
public class SectionManagerFrame extends javax.swing.JFrame {

    /**
     * Creates new form SectionManagerFrame
     */
    public SectionManagerFrame() {
        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() {

        jButton_Cancel = new javax.swing.JButton();
        jButton_OK = new javax.swing.JButton();
        jLabel_Title = new javax.swing.JLabel();
        jLabel_Description = new javax.swing.JLabel();
        jTextField_Title = new javax.swing.JTextField();
        jScrollPane2 = new javax.swing.JScrollPane();
        jTextArea_Description = new javax.swing.JTextArea();
        jButton_Remove = new javax.swing.JButton();
        jButton_Add = new javax.swing.JButton();
        jButton_Edit = new javax.swing.JButton();
        jPanel_Grid = new javax.swing.JPanel();

        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
        addWindowListener(new java.awt.event.WindowAdapter() {
            public void windowOpened(java.awt.event.WindowEvent evt) {
                formWindowOpened(evt);
            }
        });

        jButton_Cancel.setText("Cancel");
        jButton_Cancel.addMouseListener(new java.awt.event.MouseAdapter() {
            public void mouseClicked(java.awt.event.MouseEvent evt) {
                jButton_CancelMouseClicked(evt);
            }
        });

        jButton_OK.setText("OK");
        jButton_OK.addMouseListener(new java.awt.event.MouseAdapter() {
            public void mouseClicked(java.awt.event.MouseEvent evt) {
                jButton_OKMouseClicked(evt);
            }
        });

        jLabel_Title.setText("Review Title:");

        jLabel_Description.setText("Review Description:");

        jTextArea_Description.setColumns(20);
        jTextArea_Description.setRows(5);
        jScrollPane2.setViewportView(jTextArea_Description);

        jButton_Remove.setText("Remove");

        jButton_Add.setText("Add");

        jButton_Edit.setText("Edit");

        javax.swing.GroupLayout jPanel_GridLayout = new javax.swing.GroupLayout(jPanel_Grid);
        jPanel_Grid.setLayout(jPanel_GridLayout);
        jPanel_GridLayout.setHorizontalGroup(
            jPanel_GridLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGap(0, 0, Short.MAX_VALUE)
        );
        jPanel_GridLayout.setVerticalGroup(
            jPanel_GridLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGap(0, 268, Short.MAX_VALUE)
        );

        javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
        getContentPane().setLayout(layout);
        layout.setHorizontalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                    .addGroup(layout.createSequentialGroup()
                        .addGap(122, 122, 122)
                        .addComponent(jButton_Cancel)
                        .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                        .addComponent(jButton_OK)
                        .addGap(0, 0, Short.MAX_VALUE))
                    .addGroup(layout.createSequentialGroup()
                        .addContainerGap()
                        .addComponent(jPanel_Grid, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
                        .addGap(18, 18, 18)
                        .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false)
                            .addComponent(jButton_Remove, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
                            .addComponent(jButton_Add, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
                            .addComponent(jButton_Edit, javax.swing.GroupLayout.PREFERRED_SIZE, 71, javax.swing.GroupLayout.PREFERRED_SIZE)))
                    .addGroup(layout.createSequentialGroup()
                        .addContainerGap()
                        .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                            .addComponent(jLabel_Description)
                            .addComponent(jLabel_Title))
                        .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                        .addComponent(jTextField_Title))
                    .addGroup(layout.createSequentialGroup()
                        .addContainerGap()
                        .addComponent(jScrollPane2, javax.swing.GroupLayout.DEFAULT_SIZE, 587, Short.MAX_VALUE)))
                .addContainerGap())
        );
        layout.setVerticalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addContainerGap()
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                    .addComponent(jLabel_Title)
                    .addComponent(jTextField_Title, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                .addComponent(jLabel_Description)
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                .addComponent(jScrollPane2, javax.swing.GroupLayout.DEFAULT_SIZE, 196, Short.MAX_VALUE)
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                    .addGroup(layout.createSequentialGroup()
                        .addComponent(jButton_Add)
                        .addGap(3, 3, 3)
                        .addComponent(jButton_Edit)
                        .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                        .addComponent(jButton_Remove))
                    .addComponent(jPanel_Grid, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
                .addGap(18, 18, 18)
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                    .addComponent(jButton_Cancel)
                    .addComponent(jButton_OK))
                .addContainerGap())
        );

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

    private void jButton_CancelMouseClicked(java.awt.event.MouseEvent evt) {                                            
        // TODO add your handling code here:
        this.setVisible(false);
        this.dispose();
    }                                           

    private void jButton_OKMouseClicked(java.awt.event.MouseEvent evt) {                                        
        // TODO add your handling code here:
    }                                       

    private void formWindowOpened(java.awt.event.WindowEvent evt) {                                  
        // TODO add your handling code here:
        //ManagerDataModel newManagerDataModel = new ManagerDataModel();
        /*
        newManagerDataModel.AddColumn("Section Name");
        newManagerDataModel.AddColumn("Section Type");
        newManagerDataModel.AddColumn("# of Particles");
        newManagerDataModel.AddRow(new String[]{"Test","Test","Test"});
        */
        jTable_Sections = new JTable(5, 5);
        //jTable_Sections.setPreferredScrollableViewportSize(new Dimension(500, 500));
        jTable_Sections.setMinimumSize(new Dimension(200, 200));
        jTable_Sections.setFillsViewportHeight(true);
        jScrollPane_Sections = new JScrollPane(jTable_Sections);
        jScrollPane_Sections.setMinimumSize(new Dimension(200, 200));
        jPanel_Grid.add(jTable_Sections);
        jPanel_Grid.add(jScrollPane_Sections);
        jPanel_Grid.validate();
        jPanel_Grid.repaint();
        this.validate();
        this.pack();
        this.repaint();


    }                                 
    private JTable jTable_Sections;
    private JScrollPane jScrollPane_Sections;
    /**
     * @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(SectionManagerFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (InstantiationException ex) {
            java.util.logging.Logger.getLogger(SectionManagerFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (IllegalAccessException ex) {
            java.util.logging.Logger.getLogger(SectionManagerFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (javax.swing.UnsupportedLookAndFeelException ex) {
            java.util.logging.Logger.getLogger(SectionManagerFrame.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 SectionManagerFrame().setVisible(true);
            }
        });
    }
    // Variables declaration - do not modify                     
    private javax.swing.JButton jButton_Add;
    private javax.swing.JButton jButton_Cancel;
    private javax.swing.JButton jButton_Edit;
    private javax.swing.JButton jButton_OK;
    private javax.swing.JButton jButton_Remove;
    private javax.swing.JLabel jLabel_Description;
    private javax.swing.JLabel jLabel_Title;
    private javax.swing.JPanel jPanel_Grid;
    private javax.swing.JScrollPane jScrollPane2;
    private javax.swing.JTextArea jTextArea_Description;
    private javax.swing.JTextField jTextField_Title;
    // End of variables declaration                   
}

Answer 1

not GroupLayout fan, but is quite to simple fix that

• don't to use private void formWindowOpened(java.awt.event.WindowEvent evt) { for add JComponents to already visible container, because caused with resize and flashing with Swing GUI

• for GroupLayout must be Min, Max and PreferredSize overrode in both directions, otherwise is ignored (by default, see generated code)

• JPanel has FlowLayout implemented in API, and then JTable wrapped in JScollPane is lost in GroupLayout (sure there must be solution) probably issue with setMin, Max and PreferredSize

required code (don't solve something with my next point)

private void formWindowOpened(java.awt.event.WindowEvent evt) {
    jTable_Sections = new JTable(5, 5);
    jTable_Sections.setFillsViewportHeight(true);
    jScrollPane_Sections = new JScrollPane(jTable_Sections);
    jPanel_Grid.setLayout(new BorderLayout());
    jPanel_Grid.add(jScrollPane_Sections);
    this.validate();
    this.repaint();
    this.pack();
}

• this code could be about 50-70 code lines in the case that all code will be made by your hands