java - 无法显示 JTable

Question

我正在使用互联网上的代码来创建 Groupable TableHeader，我遵循了所有步骤，但我不知道为什么我的 Jtable 没有显示!!

我正在使用 netbeans 生成 IHM，任何人都可以帮我找出 Jtable 不显示的原因吗？

注意:IHM 的 OnLoad，Jtable 应该出现

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

import Control.ColumnGroup;
import Control.GroupableTableHeader;
import java.util.Calendar;
import java.util.Vector;
import javax.swing.JTable;
import javax.swing.table.DefaultTableModel;
import javax.swing.table.JTableHeader;
import javax.swing.table.TableColumnModel;

/**
 *
 * @author  Archavine
 */
public class EvolImportations extends javax.swing.JInternalFrame {

    DefaultTableModel dm = null;
    int thisyear = 0;
    Vector column = new Vector();

    /** Creates new form EvolImportations */
    public EvolImportations() {
        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.
     */
    // <editor-fold defaultstate="collapsed" desc="Generated Code">
    private void initComponents() {

        jScrollPane1 = new javax.swing.JScrollPane();
        jTable1 = new javax.swing.JTable();
        jLabel1 = new javax.swing.JLabel();
        jComboBox1 = new javax.swing.JComboBox();
        jTextField1 = new javax.swing.JTextField();
        jButton1 = new javax.swing.JButton();
        jTextField2 = new javax.swing.JTextField();
        jLabel2 = new javax.swing.JLabel();

        setClosable(true);
        setIconifiable(true);
        setTitle("Evolution des importations par principaux produits");


        column.addElement("");
        column.addElement("");
        column.addElement(thisyear);
        column.addElement(thisyear - 1);
        column.addElement("Valeur");
        column.addElement("%");


        Calendar now = Calendar.getInstance();   // This gets the current date and time.
        thisyear = now.get(Calendar.YEAR);                 // This returns the year as an int.

        dm = new DefaultTableModel();
        dm.setDataVector(new DAO.EvolutionImportation().EvolImport(1, 2), column);

System.err.println("Nombre de lignes : "+dm.getRowCount());

        jScrollPane1.setViewportView(jTable1);


        jTable1 = new JTable(dm) {

            protected JTableHeader createDefaultTableHeader() {
                return new GroupableTableHeader(columnModel);
            }
        };

        System.err.println("Nombre de lignes Jtable : "+jTable1.getRowCount());

        TableColumnModel cm = jTable1.getColumnModel();
        ColumnGroup g_name = new ColumnGroup("Periode");
        g_name.add(cm.getColumn(1));
        g_name.add(cm.getColumn(2));
        ColumnGroup g_lang = new ColumnGroup("Evolution");
        g_lang.add(cm.getColumn(3));
        g_lang.add(cm.getColumn(4));

        GroupableTableHeader header = (GroupableTableHeader) jTable1.getTableHeader();
        header.addColumnGroup(g_name);
        header.addColumnGroup(g_lang);

        jTable1.setRowHeight(30);


        jLabel1.setFont(new java.awt.Font("Tahoma", 0, 12));
        jLabel1.setText("MOIS");

        jComboBox1.setFont(new java.awt.Font("Tahoma", 0, 12));
        jComboBox1.setModel(new javax.swing.DefaultComboBoxModel(new String[]{"Egale à", "Entre"}));
        jComboBox1.addActionListener(new java.awt.event.ActionListener() {

            public void actionPerformed(java.awt.event.ActionEvent evt) {
                jComboBox1ActionPerformed(evt);
            }
        });

        jTextField1.setFont(new java.awt.Font("Tahoma", 0, 12));

        jButton1.setFont(new java.awt.Font("Tahoma", 0, 12));
        jButton1.setText("Valider");
        jButton1.addActionListener(new java.awt.event.ActionListener() {

            public void actionPerformed(java.awt.event.ActionEvent evt) {
                jButton1ActionPerformed(evt);
            }
        });

        jTextField2.setFont(new java.awt.Font("Tahoma", 0, 12));

        jLabel2.setFont(new java.awt.Font("Tahoma", 0, 12));
        jLabel2.setText("&");

        javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
        getContentPane().setLayout(layout);
        layout.setHorizontalGroup(
                layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING).addGroup(layout.createSequentialGroup().addContainerGap().addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING).addComponent(jScrollPane1, javax.swing.GroupLayout.Alignment.TRAILING, javax.swing.GroupLayout.DEFAULT_SIZE, 707, Short.MAX_VALUE).addGroup(layout.createSequentialGroup().addComponent(jLabel1).addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED).addComponent(jComboBox1, javax.swing.GroupLayout.PREFERRED_SIZE, 75, javax.swing.GroupLayout.PREFERRED_SIZE).addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED).addComponent(jTextField1, javax.swing.GroupLayout.PREFERRED_SIZE, 43, javax.swing.GroupLayout.PREFERRED_SIZE).addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED).addComponent(jLabel2).addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED).addComponent(jTextField2, javax.swing.GroupLayout.PREFERRED_SIZE, 43, javax.swing.GroupLayout.PREFERRED_SIZE).addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED).addComponent(jButton1))).addContainerGap()));
        layout.setVerticalGroup(
                layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING).addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup().addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE).addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE).addComponent(jLabel1, javax.swing.GroupLayout.PREFERRED_SIZE, 25, javax.swing.GroupLayout.PREFERRED_SIZE).addComponent(jComboBox1, javax.swing.GroupLayout.PREFERRED_SIZE, 25, javax.swing.GroupLayout.PREFERRED_SIZE).addComponent(jTextField1, javax.swing.GroupLayout.PREFERRED_SIZE, 25, javax.swing.GroupLayout.PREFERRED_SIZE).addComponent(jButton1, javax.swing.GroupLayout.PREFERRED_SIZE, 25, javax.swing.GroupLayout.PREFERRED_SIZE).addComponent(jTextField2, javax.swing.GroupLayout.PREFERRED_SIZE, 25, javax.swing.GroupLayout.PREFERRED_SIZE).addComponent(jLabel2, javax.swing.GroupLayout.PREFERRED_SIZE, 25, javax.swing.GroupLayout.PREFERRED_SIZE)).addGap(18, 18, 18).addComponent(jScrollPane1, javax.swing.GroupLayout.PREFERRED_SIZE, 483, javax.swing.GroupLayout.PREFERRED_SIZE).addContainerGap()));

        pack();
    }// </editor-fold>
    private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {
        String mois1 = jTextField1.getText();
        String mois2 = jTextField2.getText();
        if (jComboBox1.getSelectedItem().equals("Egale à")) {
            dm.setDataVector(new DAO.EvolutionImportation().EvolImport(Integer.parseInt(mois1), Integer.parseInt(mois1)), column);
            System.err.println("egale");
        } else if (jComboBox1.getSelectedItem().equals("Entre")) {
            dm.setDataVector(new DAO.EvolutionImportation().EvolImport(Integer.parseInt(mois1), Integer.parseInt(mois2)), column);
            System.err.println("Entre");
        }
    }

    private void jComboBox1ActionPerformed(java.awt.event.ActionEvent evt) {
    // TODO add your handling code here:
    }
    // Variables declaration - do not modify
    private javax.swing.JButton jButton1;
    private javax.swing.JComboBox jComboBox1;
    private javax.swing.JLabel jLabel1;
    private javax.swing.JLabel jLabel2;
    private javax.swing.JScrollPane jScrollPane1;
    private javax.swing.JTable jTable1;
    private javax.swing.JTextField jTextField1;
    private javax.swing.JTextField jTextField2;
    // End of variables declaration
}

总而言之，整个是由netbeans(Jtable，Jtextbox，...以及布局)生成的，在构造函数中，我调用一个方法，该方法返回带有来自数据库的数据的Vector DAO.EvolutionImportation( ).EvolImport(1, 2)和column vector 包含列名称。

这是主要代码:

dm = new DefaultTableModel();
            dm.setDataVector(new DAO.EvolutionImportation().EvolImport(1, 2), column);

    System.err.println("Nombre de lignes : "+dm.getRowCount());

            jScrollPane1.setViewportView(jTable1);


            jTable1 = new JTable(dm) {

                protected JTableHeader createDefaultTableHeader() {
                    return new GroupableTableHeader(columnModel);
                }
            };

            System.err.println("Nombre de lignes Jtable : "+jTable1.getRowCount());

            TableColumnModel cm = jTable1.getColumnModel();
            ColumnGroup g_name = new ColumnGroup("Periode");
            g_name.add(cm.getColumn(1));
            g_name.add(cm.getColumn(2));
            ColumnGroup g_lang = new ColumnGroup("Evolution");
            g_lang.add(cm.getColumn(3));
            g_lang.add(cm.getColumn(4));

            GroupableTableHeader header = (GroupableTableHeader) jTable1.getTableHeader();
            header.addColumnGroup(g_name);
            header.addColumnGroup(g_lang);

            jTable1.setRowHeight(30);

当我运行我的示例时，它显示了 JinternalFrame 和 jtable 边框，但没有数据!!

解决方案是:

Vector column = new Vector();

        column.addElement("");
        column.addElement("2013");
        column.addElement("2012");
        column.addElement("Valeur");
        column.addElement("%");

        DefaultTableModel dm = null;
        int thisyear = 0;

        String mois1 = jTextField1.getText();
        String mois2 = jTextField2.getText();
        Vector v = new DAO.EvolutionImportation().EvolImport(Integer.parseInt(mois1), Integer.parseInt(mois2));

        dm = new DefaultTableModel();
        dm.setDataVector(v, column);
        jTable1.setModel(dm);

        jTable1 = new JTable(dm) {

            protected JTableHeader createDefaultTableHeader() {
                return new GroupableTableHeader(columnModel);
            }
        };

        TableColumnModel cm = jTable1.getColumnModel();
        ColumnGroup g_name = new ColumnGroup("Periode");
        g_name.add(cm.getColumn(1));
        g_name.add(cm.getColumn(2));
        ColumnGroup g_lang = new ColumnGroup("Evolution");
        g_lang.add(cm.getColumn(3));
        g_lang.add(cm.getColumn(4));

        GroupableTableHeader header = (GroupableTableHeader) jTable1.getTableHeader();
        header.addColumnGroup(g_name);
        header.addColumnGroup(g_lang);

        jTable1.setRowHeight(30);
        jScrollPane1.setViewportView(jTable1);

谢谢

Answer 1

最初的问题是您尝试修改不应该修改的代码并打乱了顺序。

您在创建jTable1 之前将其添加到滚动 Pane 中...

jScrollPane1.setViewportView(jTable1);

jTable1 = new JTable(dm) {
    protected JTableHeader createDefaultTableHeader() {
        return new GroupableTableHeader(columnModel);
    }
};

尝试切换语句...

jTable1 = new JTable(dm) {
    protected JTableHeader createDefaultTableHeader() {
        return new GroupableTableHeader(columnModel);
    }
};

jScrollPane1.setViewportView(jTable1);