没有显示表头

Question

我的错误是没有显示两个表的表头。现在我用new JTable(data, columnNames)设置标题。

下面是一个例子，显示了我的问题:

import java.awt.BorderLayout;
import java.awt.Dimension;
import javax.swing.Box;
import javax.swing.BoxLayout;
import javax.swing.JFrame;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTabbedPane;
import javax.swing.JTable;
import javax.swing.ScrollPaneConstants;
import net.miginfocom.swing.MigLayout;
public class Test extends JFrame {
    private static final long serialVersionUID = -4682396888922360841L;
    private JMenuBar menuBar;
    private JMenu mAbout;
    private JMenu mMain;
    private JTabbedPane tabbedPane;
    public SettingsTab settings = new SettingsTab();
    private void addMenuBar() {
        menuBar = new JMenuBar();
        mMain = new JMenu("Main");
        mAbout = new JMenu("About");
        menuBar.add(mMain);
        menuBar.add(mAbout);
        setJMenuBar(menuBar);
    }
    public void createTabBar() {
        tabbedPane = new JTabbedPane(JTabbedPane.TOP);
        tabbedPane.addTab("Settings", settings.createLayout());
        add(tabbedPane);
        tabbedPane.setTabLayoutPolicy(JTabbedPane.SCROLL_TAB_LAYOUT);
    }
    private void makeLayout() {
        setTitle("Test");
        setLayout(new BorderLayout());
        setPreferredSize(new Dimension(1000, 500));
        addMenuBar();
        createTabBar();
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        pack();
        setVisible(true);
    }
    public void start() {
        javax.swing.SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                makeLayout();
            }
        });
    }
    public static void main(String[] args) {
        Test gui = new Test();
        gui.start();
    }
    public class SettingsTab extends JPanel {
        public JScrollPane createLayout() {
            JPanel panel = new JPanel(new MigLayout(""));
            JScrollPane sp = new JScrollPane(panel);
            sp.setVerticalScrollBarPolicy(ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS);
            panel.add(table1(), "growx, wrap");
            panel.add(Box.createRigidArea(new Dimension(0, 10)));
            panel.add(table2());
            //          panel.add(Box.createRigidArea(new Dimension(0,10)));
            return sp;
        }
        public JPanel table1() {
            JPanel panel1 = new JPanel();
            String[] columnNames = {"First Name", "Last Name"};
            Object[][] data = {{"Kathy", "Smith"}, {"John", "Doe"},
                {"Sue", "Black"}, {"Jane", "White"}, {"Joe", "Brown"},
                {"John", "Doe"}, {"Sue", "Black"}, {"Jane", "White"},
                {"Joe", "Brown"}};
            final JTable table = new JTable(data, columnNames);
            tableProperties(table);
            panel1.add(table);
            panel1.setLayout(new BoxLayout(panel1, BoxLayout.Y_AXIS));
            return panel1;
        }
        public JPanel table2() {
            JPanel panel1 = new JPanel();
            String[] columnNames = {"First Name", "Last Name"};
            Object[][] data = {{"Kathy", "Smith"}, {"John", "Doe"},
                {"Sue", "Black"}, {"Jane", "White"}, {"Joe", "Brown"},
                {"John", "Doe"}, {"Sue", "Black"}, {"Jane", "White"},
                {"Joe", "Brown"}};
            final JTable table = new JTable(data, columnNames);
            table.setPreferredScrollableViewportSize(new Dimension(500, 70));
            table.setFillsViewportHeight(true);
            tableProperties(table);
            panel1.add(table);
            panel1.setLayout(new BoxLayout(panel1, BoxLayout.Y_AXIS));
            return panel1;
        }
        public void tableProperties(JTable table) {
            table.setAutoResizeMode(JTable.AUTO_RESIZE_ALL_COLUMNS);
            table.repaint();
            table.revalidate();
        }
    }
}

有什么建议我做错了吗?

Answer 1

• JTableHeader要求JScrollPane作为集装箱

• 你必须从JTable中获得JTableHeader，并把它单独放置，例如panel.add(table1.getTableHeader(), "constant, constant, constant");，在那里使用BorderLayout作为更好，更简单的LayoutManager, JPanel比BoxLayout，例如panel.add(table1.getTableHeader(), BorderLayout.NORTH);，然后把JTable放在中心区域

• 更好的应该是-不要在JScrollPane中使用JPanel，将JTable直接放到JScrollPane中，然后JTableHeader是可见的，否则你必须为JPanel实现Scrollable用于自然滚动

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• 使用MigLayout为整个容器(指定为)，使用此自定义LayoutManager不需要混合不同的LayoutManagers

• 使用DefaultTableModel来存储JTable s视图的值

• 参见Oracle tutorial Initial Thread

• setPreferredScrollableViewportSize被JScrollPane使用

• 您的PreferredSize设置创建**** Swing GUI

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• void tableProperties包含两个无用的代码行table.repaint();和table.revalidate();，并且顺序错误