setIconTextGap用于居中对齐的标签

Question

我需要向表标题（即JLabel）添加图标。

当文本在左侧对齐时，它工作正常。

但是，当文本居中时，不考虑以某种方式调用setIconTextGap（）。这样的效果是，图标也位于标签的中心：

这通常无法正常工作，还是我错过了一些事情？

我正在使用Java 6（无法更改该事实）。

我在下面创建了SSCCE：

import javax.swing.*;
import javax.swing.table.TableCellRenderer;
import javax.swing.table.TableColumn;
import java.awt.*;

public class Main {

    public static void main(String[] args)
    {

        IconLabel label1 = new IconLabel("test text left", new TableArrowIcon(TableArrowIcon.TableArrowDirection.NORTH), SwingConstants.LEFT);
        IconLabel label2 = new IconLabel("test text center", new TableArrowIcon(TableArrowIcon.TableArrowDirection.NORTH), SwingConstants.CENTER);

        Object[][] data = {
                {"Speed reading", 20, true },
                {"Joe", "Brown", "Pool", 10, false }
        };

        String[] columnNames = { "test", "test" };

        JPanel panel = new JPanel(new BorderLayout());

        final JTable table = new JTable(data, columnNames);
        table.setPreferredScrollableViewportSize(new Dimension(500, 70));
        table.setFillsViewportHeight(true);
        label2.setHorizontalTextPosition(JLabel.CENTER);
        TableColumn column1 = new TableColumn();
        TableColumn column2 = new TableColumn();
        column1.setHeaderRenderer(label1);
        column2.setHeaderRenderer(label2);
        table.addColumn(column1);
        table.addColumn(column2);

        JScrollPane scrollPane = new JScrollPane(table);
        panel.add(scrollPane);
        JFrame frame = new JFrame();
        frame.setDefaultCloseOperation(1);
        frame.add(panel);
        frame.pack();
        frame.setVisible(true);
    }

    public static class IconLabel extends JLabel implements TableCellRenderer {

        private final Icon icon;
        private final int alignment;

        public IconLabel(String text, Icon icon, int alignment) {
            super(text);
            this.icon = icon;
            setIcon(icon);
            setPreferredSize(new Dimension(50, 20));
            this.alignment = alignment;
        }

        @Override
        public void setBounds(int x, int y, int width, int height) {
            super.setBounds(x, y, width, height);
            int textWidth = getFontMetrics(getFont()).stringWidth(getText());
            Insets insets = getInsets();
            int iconTextGap = width - textWidth - icon.getIconWidth() - insets.left - insets.right -     3;
            setIconTextGap(iconTextGap);
        }

        @Override
        public Component getTableCellRendererComponent(JTable table, Object value, boolean     isSelected, boolean hasFocus, int row, int column) {
            setHorizontalTextPosition(alignment);
            return this;
        }
    }

    public static class TableArrowIcon implements Icon {

        public enum TableArrowDirection {
            NORTH() {
                @Override
                public void drawArrow(Graphics2D g, int controlSize, int x, int y) {
                    g.drawLine(x + 3, y + (controlSize - 10), x + 7, y + (controlSize - 14));
                    g.drawLine(x + 7, y + (controlSize - 14), x + (controlSize - 9), y + (controlSize     - 10));
                }
            };
            public abstract void drawArrow(Graphics2D g, int controlSize, int x, int y);
        }

        private final TableArrowDirection direction;



        public TableArrowIcon(TableArrowDirection direction) {
            this.direction = direction;
        }

        @Override
        public void paintIcon(Component c, Graphics g, int x, int y) {
            g.setColor(Color.darkGray);

            int controlSize = 20;
            ((Graphics2D) g).setRenderingHint( RenderingHints.KEY_ANTIALIASING,     RenderingHints.VALUE_ANTIALIAS_ON );
            direction.drawArrow((Graphics2D) g, controlSize, x, y);

        }

        @Override
        public int getIconWidth() {
            return 14;
        }

        @Override
        public int getIconHeight() {
            return 14;
        }
    }
}

预先感谢任何指针。

Answer 1

1. 使用JPanel作为渲染器，并在面板上添加两个标签。一个用于文本，另一个用于图标。
2. 您可以为面板使用BorderLayout。
3. 将文本标签添加到CENTER，将图标添加到LINE_END。
4. 然后，您需要为渲染器提供一个参数，以指示该文本是左对齐还是居中对齐。这应该在构造函数中设置。