在 JTable 列标题的左侧显示附加图标 (Nimbus)

Question

当我的 JTable 的列标题的值是表的 rowFilter 的基础时，我希望它们的左侧有一个附加图标。排序图标显示在右侧，因此将两个图标“粘合”成一个不算数（尽管我也无法使 Nimbus 正常工作......）。我已经尝试了一些关于渲染器的想法，但我做不到......“方法”的描述以及它们的问题都包含在发布的代码中。

编辑：忘记了一个简单的 setIcon - 在这种情况下，问题在于排序图标。使排序图标可见会隐藏其他图标。

编辑：这个Nimbus TableHeader was not highlighted as 'pressed' 给出了如何解决下面第三次尝试的问题（使用模型背景图像的那个）。但我不知道如何知道 MouseOver、Focused 等的值......我怎样才能将这些值作为布尔值？ （我的意思是鼠标悬停状态的真/假，聚焦状态的真/假等，因此我可以准备模型图像的查找表并为列标题的当前状态获取正确的图像）...

编辑：要查看这三种情况的输出，您必须使用所需的渲染器类修改table.getTableHeader().setDefaultRenderer(new FilterIconHeaderRenderer3(table)); 行。

I've tried to show the problems with the three attempts on this image

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Component;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Rectangle;
import java.awt.image.BufferedImage;
import javax.swing.ImageIcon;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
import javax.swing.table.DefaultTableModel;
import javax.swing.table.TableCellRenderer;
import javax.swing.table.TableRowSorter;

public class TableHeaderTest extends JFrame {

    JTable table = new JTable(new DefaultTableModel(new Object[]{"Column1", "Column2", "Column3"}, 3));

    TableHeaderTest() {

        TableRowSorter sorter = new TableRowSorter(table.getModel());
        table.setRowSorter(sorter);
        table.getTableHeader().setDefaultRenderer(new FilterIconHeaderRenderer3(table));

        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        JScrollPane scrollPane = new JScrollPane();
        scrollPane.setViewportView(table);
        add(scrollPane, BorderLayout.CENTER);
        pack();
        setVisible(true);
    }

    public static void main(String[] args) {
        try {
            UIManager.setLookAndFeel("com.sun.java.swing.plaf.nimbus.NimbusLookAndFeel");
        } catch (UnsupportedLookAndFeelException | ClassNotFoundException | IllegalAccessException | InstantiationException ex) {
            System.out.println("[L&F][Exception] " + ex.getMessage());
        }
        EventQueue.invokeLater(() -> {

            new TableHeaderTest();

        });
    }

}

/**
 * Trying to copy the look of a TableHeader and override its paintComponent
 * method for drawing the additional icon. However the look can't be entirely
 * copied and for example the sorting icon and background behave differently.
 * Also the indent of column name dissapeared.
 */
class FilterIconHeaderRenderer1 implements TableCellRenderer {

    TableCellRenderer delegate;
    ImageIcon filterIcon = new ImageIcon(getClass().getResource("/res/marker-dot-green.png"));

    public FilterIconHeaderRenderer1(JTable table) {
        this.delegate = table.getTableHeader().getDefaultRenderer();
    }

    @Override
    public Component getTableCellRendererComponent(JTable table, Object value, boolean isSelected, boolean hasFocus, int row, int column) {
        Component c = delegate.getTableCellRendererComponent(table, value, isSelected, hasFocus, row, column);
        if (c instanceof JLabel) {
            JLabelCopy label = new JLabelCopy((JLabel) c);
            return label;
        }
        return c;
    }

    class JLabelCopy extends JLabel {

        boolean withIcon = true;

        JLabelCopy(JLabel label) {
            this.ui = label.getUI();
            this.setText(label.getText());
            this.setPreferredSize(label.getPreferredSize());
            this.setVerticalTextPosition(label.getVerticalTextPosition());
            this.setHorizontalTextPosition(label.getHorizontalTextPosition());
            this.setVerticalAlignment(label.getVerticalAlignment());
            this.setHorizontalAlignment(label.getHorizontalAlignment());
            this.setIcon(label.getIcon());
            this.setIconTextGap(label.getIconTextGap());
            this.setAlignmentX(label.getAlignmentX());
            this.setAlignmentY(label.getAlignmentY());
            this.setLayout(label.getLayout());
        }

        @Override
        public void paintComponent(Graphics g) {
            super.paintComponent(g);
            if (withIcon) {
                g.drawImage(filterIcon.getImage(), 4, 4, null);
            }
        }

    }

}

/**
 * Also trying to copy the look of a TableHeader but without overriding its
 * paintComponent method. Instead I make the header a panel consiting of two
 * jLabels - the original column header and a jlabel of copied look with added
 * icon. Problem with this method is theseparator of the visible separator of
 * the two labels and the color difference of when a column is sorted (the
 * copied-look-label doesn't change it's background to match a sorted header).
 *
 */
class FilterIconHeaderRenderer2 implements TableCellRenderer {

    TableCellRenderer delegate;
    ImageIcon filterIcon = new ImageIcon(getClass().getResource("/res/marker-dot-green.png"));

    public FilterIconHeaderRenderer2(JTable table) {
        this.delegate = table.getTableHeader().getDefaultRenderer();
    }

    @Override
    public Component getTableCellRendererComponent(JTable table, Object value, boolean isSelected, boolean hasFocus, int row, int column) {
        JPanel newHeader = new JPanel(new BorderLayout());
        Component c = delegate.getTableCellRendererComponent(table, value, isSelected, hasFocus, row, column);
        if (c instanceof JLabel) {
            JLabel label = (JLabel) c;
            JLabelCopy filterIconLabel = new JLabelCopy(label);
            filterIconLabel.setText("");
            filterIconLabel.setIcon(filterIcon);
            filterIconLabel.setPreferredSize(new Dimension(filterIcon.getIconWidth() + 4, filterIconLabel.getPreferredSize().height));
            newHeader.add(filterIconLabel, BorderLayout.WEST);
            newHeader.add(label, BorderLayout.CENTER);
            return newHeader;
        }
        return c;
    }

    class JLabelCopy extends JLabel {

        boolean withIcon = true;

        JLabelCopy(JLabel label) {
            this.ui = label.getUI();
            this.setPreferredSize(label.getPreferredSize());
            this.setVerticalTextPosition(label.getVerticalTextPosition());
            this.setHorizontalTextPosition(label.getHorizontalTextPosition());
            this.setVerticalAlignment(label.getVerticalAlignment());
            this.setHorizontalAlignment(label.getHorizontalAlignment());
            this.setIcon(label.getIcon());
            this.setIconTextGap(label.getIconTextGap());
            this.setAlignmentX(label.getAlignmentX());
            this.setAlignmentY(label.getAlignmentY());
            this.setLayout(label.getLayout());
        }

    }
}

/**
 * Having an array of header mockups for each state for selected and hasFocus
 * (lacks sorted state) of the column header. Using these as background of panel
 * loaded with two labels - original header and label with just the new icon.
 * Both have setOpaque(false). Problem with this is the problem with choosing
 * the right background image for the panel as the isSelected and hasFocus
 * parameters of getRendererComponent don't work as you think they should.
 */
class FilterIconHeaderRenderer3 implements TableCellRenderer {

    private BufferedImage[][] headerImages = new BufferedImage[2][2];
    TableCellRenderer delegate;
    ImageIcon filterIcon = new ImageIcon(getClass().getResource("/res/marker-dot-green.png"));

    public FilterIconHeaderRenderer3(JTable table) {
        this.delegate = table.getTableHeader().getDefaultRenderer();

        for (int i = 0; i < 2; i++) {
            for (int j = 0; j < 2; j++) {
                JLabel comp = (JLabel) delegate.getTableCellRendererComponent(table, "     ", i == 1, j == 1, 0, 0);
                headerImages[i][j] = createUMPFake(comp);
            }
        }
    }

    @Override
    public Component getTableCellRendererComponent(JTable table, Object value, boolean isSelected, boolean hasFocus, int row, int column) {

        Component c = delegate.getTableCellRendererComponent(table, value, isSelected, hasFocus, row, column);
        if (c instanceof JLabel) {
            JPanel newHeader = new JPanel(new BorderLayout()) {
                @Override
                public void paintComponent(Graphics g) {
                    super.paintComponent(g);
                    g.drawImage(headerImages[isSelected ? 1 : 0][hasFocus ? 1 : 0], 0, 0, null);
                }
            };
            JLabel label = (JLabel) c;
            label.setOpaque(false);
            JLabel filterIconLabel = new JLabel();
            filterIconLabel.setText("");
            filterIconLabel.setOpaque(false);
            filterIconLabel.setIcon(filterIcon);
            filterIconLabel.setPreferredSize(new Dimension(filterIcon.getIconWidth() + 4, filterIconLabel.getPreferredSize().height));
            newHeader.add(filterIconLabel, BorderLayout.WEST);
            newHeader.add(label, BorderLayout.CENTER);
            return newHeader;
        }
        return c;
    }

    /*
     * Following methods were taken from:
     * https://stackoverflow.com/questions/4028898/create-an-image-from-a-non-visible-awt-component
     */
    private BufferedImage createUMPFake(Component comp) {

        JFrame invisibleFrame = new JFrame();
        invisibleFrame.setSize(comp.getPreferredSize());
        JPanel colorPanel = new JPanel();
        colorPanel.setOpaque(false);
        colorPanel.setLayout(new BorderLayout());
        colorPanel.setBackground(new Color(0, 0, 255, 0));
        colorPanel.setSize(invisibleFrame.getSize());
        colorPanel.add(comp, BorderLayout.CENTER);

        invisibleFrame.add(colorPanel);

        colorPanel.setVisible(true);

        return createImage((JComponent) colorPanel, new Rectangle(invisibleFrame.getBounds()));

    }

    /**
     * Create a BufferedImage for Swing components. All or part of the component
     * can be captured to an image.
     *
     * @param component component to create image from
     * @param region The region of the component to be captured to an image
     * @return image the image for the given region
     */
    private static BufferedImage createImage(Component component, Rectangle region) {
        //  Make sure the component has a size and has been layed out.
        //  (necessary check for components not added to a realized frame)

        if (!component.isDisplayable()) {
            Dimension d = component.getSize();

            if (d.width == 0 || d.height == 0) {
                d = component.getPreferredSize();
                component.setSize(d);
            }

            layoutComponent(component);
        }

        BufferedImage image = new BufferedImage(region.width, region.height, BufferedImage.TYPE_INT_ARGB);
        Graphics2D g2d = image.createGraphics();

        //  Paint a background for non-opaque components,
        //  otherwise the background will be black
        if (!component.isOpaque()) {
            g2d.setColor(component.getBackground());
            g2d.fillRect(region.x, region.y, region.width, region.height);
        }

        g2d.translate(-region.x, -region.y);
        component.paint(g2d);
        g2d.dispose();
        return image;
    }

    private static void layoutComponent(Component component) {
        synchronized (component.getTreeLock()) {
            component.doLayout();

            if (component instanceof Container) {
                for (Component child : ((Container) component).getComponents()) {
                    layoutComponent(child);
                }
            }
        }
    }

}

Answer 1

或者更简单，你可以使用 HTML 标签在HeaderRenderer上显示图标：

import java.awt.*;
import java.awt.event.*;
import java.net.URL;
import java.util.Objects;
import javax.swing.*;
import javax.swing.table.*;

public class TableHeaderIconTest {
  //private final URL url = getClass().getResource("a.png");
  public JComponent makeUI() {
    String[] columnNames = {"Column1", "Column2", "Column3"};
    JTable table = new JTable(new DefaultTableModel(columnNames, 3));
    TableColumnModel m = table.getColumnModel();
    for (int i = 0; i < m.getColumnCount(); i++) {
      TableColumn column = m.getColumn(i);
      column.setHeaderRenderer(new FilterIconHeaderRenderer4());
      //column.setHeaderValue(
      //  String.format("<html><table><td><img src='%s'/><td>%s", url, columnNames[i]));
    }
    table.setAutoCreateRowSorter(true);

    JPanel p = new JPanel(new BorderLayout());
    p.add(new JScrollPane(table));
    return p;
  }
  public static void main(String[] args) {
    EventQueue.invokeLater(new Runnable() {
      @Override public void run() {
        createAndShowGUI();
      }
    });
  }
  public static void createAndShowGUI() {
    try {
      for (UIManager.LookAndFeelInfo laf : UIManager.getInstalledLookAndFeels()) {
        if ("Nimbus".equals(laf.getName())) {
          UIManager.setLookAndFeel(laf.getClassName());
        }
      }
    } catch (Exception e) {
      e.printStackTrace();
    }
    JFrame f = new JFrame();
    f.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
    f.getContentPane().add(new TableHeaderIconTest().makeUI());
    f.setSize(320, 240);
    f.setLocationRelativeTo(null);
    f.setVisible(true);
  }
}

class FilterIconHeaderRenderer4 implements TableCellRenderer {
  private final URL url = getClass().getResource("Ok2mc.png");
  @Override public Component getTableCellRendererComponent(
      JTable table, Object value, boolean isSelected, boolean hasFocus, int row, int column) {
    TableCellRenderer r = table.getTableHeader().getDefaultRenderer();
    String str = Objects.toString(value, "");
    String html = String.format("<html><table><td><img src='%s'/><td>%s", url, str);
    return r.getTableCellRendererComponent(table, html, isSelected, hasFocus, row, column);
  }
}