无法显示JTable

Question

我正在使用来自互联网的代码来创建Groupable TableHeader，我按照所有步骤进行了操作，但我不知道为什么我的Jtable没有出现!!

我正在使用netbeans来生成IHM，任何人都可以帮我找到Jtable没有显示的原因吗？

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
}

总结一下，整体是由netbeans（Jtable，Jtextbox，......和布局）生成的，在构造函数中，我调用一个返回Vector的方法，数据来自数据库DAO.EvolutionImportation().EvolImport(1, 2) 和column向量包含列名。

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，它会向我显示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);

由于

Answer 1

最初的问题是你已经尝试修改了你不应该拥有的代码并搞砸了订单。

您在创建滚动窗格之前将jTable1添加到滚动窗格...

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);

Answer 2

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

/**
 *
 * @author shreyansh.jogi
 */
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Component;
import java.awt.EventQueue;
import java.awt.event.ItemEvent;
import java.awt.event.ItemListener;
import java.text.DecimalFormat;
import java.util.ArrayList;
import java.util.List;
import javax.swing.AbstractCellEditor;
import javax.swing.JCheckBox;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTable;
import javax.swing.table.AbstractTableModel;
import javax.swing.table.TableCellEditor;
import javax.swing.table.TableCellRenderer;

/**
 * @author John B. Matthews; distribution per LGPL
 * 11-Jul-2011 Correct item listener in ValueEditor
 */
public class Jtable extends JPanel {

    private static DecimalFormat df = new DecimalFormat("#0.00");
    private DataModel model = new DataModel();
    private JTable table = new JTable(model);

    public Jtable() {
        this.setLayout(new BorderLayout());
        table.setDefaultRenderer(Value.class, new ValueRenderer());
        table.setDefaultEditor(Value.class, new ValueEditor());
        table.setAutoCreateRowSorter(true);
        table.setRowHeight(24);
        this.add(table.getTableHeader(), BorderLayout.NORTH);
        this.add(table, BorderLayout.CENTER);
    }

    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {

            @Override
            public void run() {
                JFrame f = new JFrame();
                f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                f.add(new Jtable());
                f.pack();
                f.setLocationRelativeTo(null);
                f.setVisible(true);
            }
        });
    }

    private static class Value implements Comparable<Value> {

        private Boolean selected;
        private Double value;

        public Value(Boolean selected, Double value) {
            this.selected = selected;
            this.value = value;
        }

        @Override
        public int compareTo(Value v) {
            return this.value.compareTo(v.value);
        }

        @Override
        public boolean equals(Object v) {
            return v instanceof Value && this.value.equals(((Value) v).value);
        }

        @Override
        public int hashCode() {
            return this.value.hashCode();
        }
    }

    private static class DataModel extends AbstractTableModel {

        private static final int MAX = 8;
        private static final String[] names = {"Number", "Value"};
        private List<Value> values = new ArrayList<Value>();

        public DataModel() {
            for (int i = 0; i < MAX; i++) {
                values.add(new Value(false, (i + 1) * 1.1));
            }
        }

        @Override
        public int getRowCount() {
            return MAX;
        }

        @Override
        public int getColumnCount() {
            return names.length;
        }

        @Override
        public Object getValueAt(int row, int col) {
            if (col == 0) {
                return row + 1;
            } else if (col == 1) {
                return values.get(row);
            } else {
                return null;
            }
        }

        @Override
        public void setValueAt(Object aValue, int row, int col) {
            if (col == 1) {
                values.get(row).selected = (Boolean) aValue;
                this.fireTableCellUpdated(row, col);

            }
        }

        @Override
        public Class<?> getColumnClass(int col) {
            if (col == 0) {
                return Integer.class;
            } else if (col == 1) {
                return Value.class;
            } else {
                return null;
            }
        }

        @Override
        public String getColumnName(int col) {
            return names[col];
        }

        @Override
        public boolean isCellEditable(int row, int col) {
            return col == 1;
        }
    }

    private static class ValueRenderer extends JCheckBox
        implements TableCellRenderer {

        private static final Color hilite = new Color(0xE8E8E8);

        public ValueRenderer() {
            this.setOpaque(true);
        }

        @Override
        public Component getTableCellRendererComponent(
            JTable table, Object value, boolean isSelected,
            boolean hasFocus, int row, int col) {
            Value v = (Value) value;
            this.setSelected(v.selected);
            this.setText(df.format(v.value));
            if (isSelected) {
                this.setBackground(hilite);
            } else {
                this.setBackground(Color.white);
            }
            return this;
        }
    }

    private class ValueEditor extends AbstractCellEditor
        implements TableCellEditor, ItemListener {

        private ValueRenderer vr = new ValueRenderer();

        public ValueEditor() {
            vr.addItemListener(this);
        }

        @Override
        public Object getCellEditorValue() {
            return vr.isSelected();
        }

        @Override
        public Component getTableCellEditorComponent(JTable table,
            Object value, boolean isSelected, int row, int col) {
            Value v = (Value) value;
            vr.setSelected(v.selected);
            vr.setText(df.format(v.value));
            return vr;
        }

        @Override
        public void itemStateChanged(ItemEvent e) {
            this.fireEditingStopped();
        }
    }
}