java - JTable 右对齐表头

Question

基本上，我有一个 JTable，其中包含具有右对齐单元格但左对齐标题的列，这看起来非常糟糕。我想在不改变标题的“外观”的情况下右对齐这些列的标题。

谢谢

Answer 1

这是修改TableCellRenderer表的JTableHeader. 这种用法并不是绝对必要的，但它可以最大限度地减少对 UI 委托外观的影响。

典型用法：

JTable table = new JTable(…);
JTableHeader header = table.getTableHeader();
header.setDefaultRenderer(new HeaderRenderer(table));

自定义标题渲染器：

private static class HeaderRenderer implements TableCellRenderer {

    DefaultTableCellRenderer renderer;

    public HeaderRenderer(JTable table) {
        renderer = (DefaultTableCellRenderer)
            table.getTableHeader().getDefaultRenderer();
        renderer.setHorizontalAlignment(JLabel.CENTER);
    }

    @Override
    public Component getTableCellRendererComponent(
        JTable table, Object value, boolean isSelected,
        boolean hasFocus, int row, int col) {
        return renderer.getTableCellRendererComponent(
            table, value, isSelected, hasFocus, row, col);
    }
}

Answer 2

试试这个：

((DefaultTableCellRenderer)table.getTableHeader().getDefaultRenderer())
    .setHorizontalAlignment(JLabel.RIGHT);

Answer 3

DefaultTableCellRenderer renderer = (DefaultTableCellRenderer) your_jtable.getTableHeader().getDefaultRenderer();
renderer.setHorizontalAlignment(0);

中心在哪里0。

Answer 4

上面显示的 HeaderRenderer（2011/sep/21 bytrashgod）与来自 Heisenbug (2011/sep/21) 的代码相结合，只有在所有标题对齐相同的情况下才能正常工作。

如果要以不同方式对齐不同的标题，则必须使用以下代码：

int[] alignments = new int[] { JLabel.LEFT, JLabel.RIGHT, JLabel.RIGHT };
for (int i = 0 ; i < jTable.getColumnCount(); i++){
  jTable.getTableHeader().getColumnModel().getColumn(i)
    .setHeaderRenderer(new HeaderRenderer(jTable, alignments[i]));
}

和

private static class HeaderRenderer implements TableCellRenderer {
  DefaultTableCellRenderer renderer;
  int horAlignment;
  public HeaderRenderer(JTable table, int horizontalAlignment) {
    horAlignment = horizontalAlignment;
    renderer = (DefaultTableCellRenderer)table.getTableHeader()
        .getDefaultRenderer();
  }
  public Component getTableCellRendererComponent(JTable table, Object value,
      boolean isSelected, boolean hasFocus, int row, int col) {
    Component c = renderer.getTableCellRendererComponent(table, value,
      isSelected, hasFocus, row, col);
    JLabel label = (JLabel)c;
    label.setHorizontalAlignment(horAlignment);
    return label;
  }
}

即：在构造函数中而不是在构造函数
中设置对齐方式。getTableCellRendererComponentHeaderRenderer

Answer 5

关于包装默认表头要记住的一件事：不要保留对它们的引用。

如果您（或您的用户）在 Windows 7 上使用 Windows Classic 主题并且您的应用程序设置了默认系统 LAF， @trashgod 发布的答案可能会给您带来问题。

它受十年前（严重）发布的这个错误的影响。如果您的表格正在显示并且您将 Windows 首选项中的主题从 Aero 主题切换到 Windows 经典，则会出现大量 NPE。您不应该保留渲染器的引用，因为它可能在某个时间点变得无效。正如错误报告的评论中所建议的那样，包装应该以动态方式完成。我从那里获取代码并创建了以下可运行示例：

import java.awt.*;
import java.lang.ref.WeakReference;
import javax.swing.*;
import javax.swing.table.*;

public class TestFrame extends JFrame {

    private static final boolean I_WANT_THE_BUG_TO_HAPPEN = true;

    public static void main(String[] args) throws IllegalAccessException, ClassNotFoundException, InstantiationException, UnsupportedLookAndFeelException {
        SwingUtilities.invokeLater(new Runnable() {

            @Override
            public void run() {
                int res = JOptionPane.showConfirmDialog(null, "Do you want to use the XP L&F?", "laffo", JOptionPane.YES_NO_OPTION);
                if (res == JOptionPane.YES_OPTION) {
                    try {
                        UIManager.setLookAndFeel("com.sun.java.swing.plaf.windows.WindowsLookAndFeel");
                    } catch (Exception ex) {
                    }
                }
                new TestFrame().setVisible(true);
            }

        });

    }

    public class MyModel extends AbstractTableModel {

        public int getRowCount() {
            return 10;
        }

        public int getColumnCount() {
            return 10;
        }

        public Object getValueAt(int rowIndex, int columnIndex) {
            return "" + rowIndex + " X " + columnIndex;
        }

    }

    public class MyJTable extends JTable {

        /**
         *
         */
        private static final long serialVersionUID = -233098459210523146L;

        public MyJTable(TableModel model) {
            super(model);
        }

        public void doSomething() {
            System.out.println("HEHE");
        }
    }

    public class MyAlternativeJTable extends JTable {

        private WeakReference<TableCellRenderer> wrappedHeaderRendererRef = null;
        private TableCellRenderer wrapperHeaderRenderer = null;

        public MyAlternativeJTable(TableModel model) {
            super(model);
        }

        private class MyAlternativeTableColumn extends TableColumn {

            MyAlternativeTableColumn(int modelIndex) {
                super(modelIndex);
            }

            @Override
            public TableCellRenderer getHeaderRenderer() {
                TableCellRenderer defaultHeaderRenderer
                        = MyAlternativeJTable.this.getTableHeader().getDefaultRenderer();
                if (wrappedHeaderRendererRef == null
                        || wrappedHeaderRendererRef.get() != defaultHeaderRenderer) {
                    wrappedHeaderRendererRef
                            = new WeakReference<TableCellRenderer>(defaultHeaderRenderer);
                    wrapperHeaderRenderer
                            = new DecoratedHeaderRenderer(defaultHeaderRenderer);
                }
                return wrapperHeaderRenderer;
            }
        }

        @Override
        public void createDefaultColumnsFromModel() {
            TableModel m = getModel();
            if (m != null) {
                // Remove any current columns
                TableColumnModel cm = getColumnModel();
                while (cm.getColumnCount() > 0) {
                    cm.removeColumn(cm.getColumn(0));
                }

                // Create new columns from the data model info
                for (int i = 0; i < m.getColumnCount(); i++) {
                    TableColumn newColumn = new MyAlternativeTableColumn(i);
                    addColumn(newColumn);
                }
            }
        }
    }

    private JPanel jContentPane = null;
    private JScrollPane jScrollPane = null;
    private JTable table1 = null;
    private JScrollPane jScrollPane1 = null;
    private JTable table2 = null;

    /**
     * This is the default constructor
     */
    public TestFrame() {
        super();
        initialize();
        int res = JOptionPane.showConfirmDialog(null, "Do you want to call updateUI() on the tables ?", "laffo", JOptionPane.YES_NO_OPTION);
        if (res == JOptionPane.YES_OPTION) {
            table2.updateUI();
            table1.updateUI();
        }
    }

    /**
     * This method initializes this
     *
     * @return void
     */
    private void initialize() {
        this.setSize(753, 658);
        this.setDefaultCloseOperation(javax.swing.WindowConstants.DISPOSE_ON_CLOSE);
        this.setContentPane(getJContentPane());
        this.setTitle("JFrame");
    }

    /**
     * This method initializes jContentPane
     *
     * @return javax.swing.JPanel
     */
    private JPanel getJContentPane() {
        if (jContentPane == null) {
            jContentPane = new JPanel();
            jContentPane.setLayout(null);
            jContentPane.add(getJScrollPane(), null);
            jContentPane.add(getJScrollPane1(), null);
        }
        return jContentPane;
    }

    /**
     * This method initializes jScrollPane
     *
     * @return javax.swing.JScrollPane
     */
    private JScrollPane getJScrollPane() {
        if (jScrollPane == null) {
            jScrollPane = new JScrollPane();
            jScrollPane.setBounds(new java.awt.Rectangle(358, 0, 387, 618));
            jScrollPane.setViewportView(getTable1());
        }
        return jScrollPane;
    }

    /**
     * This method initializes table1
     *
     * @return javax.swing.JTable
     */
    private JTable getTable1() {
        if (table1 == null) {
            table1 = new JTable(new MyModel());
        }
        return table1;
    }

    /**
     * This method initializes jScrollPane1
     *
     * @return javax.swing.JScrollPane
     */
    private JScrollPane getJScrollPane1() {
        if (jScrollPane1 == null) {
            jScrollPane1 = new JScrollPane();
            jScrollPane1.setBounds(new java.awt.Rectangle(0, 0, 350, 618));
            jScrollPane1.setViewportView(getTable2());
        }
        return jScrollPane1;
    }

    /**
     * This method initializes table2
     *
     * @return javax.swing.JTable
     */
    private JTable getTable2() {
        if (table2 == null) {
            if (I_WANT_THE_BUG_TO_HAPPEN) {
                table2 = new MyJTable(new MyModel());
                JTableHeader header = table2.getTableHeader();
                TableCellRenderer render = new DecoratedHeaderRenderer(header.getDefaultRenderer());
                header.setDefaultRenderer(render);
            } else {
                table2 = new MyAlternativeJTable(new MyModel());
            }
        }
        return table2;
    }

    private class DecoratedHeaderRenderer implements TableCellRenderer {

        public DecoratedHeaderRenderer(TableCellRenderer render) {
            this.render = render;
        }
        private TableCellRenderer render;

        public Component getTableCellRendererComponent(JTable table, Object value, boolean isSelected, boolean hasFocus, int row, int column) {
            Component c = render.getTableCellRendererComponent(table, value, isSelected, hasFocus, row, column);
            return c;
        }

    }

}

只需运行该示例并选择Yes两次并观察它分解。然后将I_WANT_THE_BUG_TO_HAPPEN静态成员更改为false并重复。此成员设置为的情况与true此处最受好评的答案基本相同。这个例子最重要的部分是动态包装的扩展JTable（ ）。MyAlternativeJTable

目前接受的这个问题的答案被广泛使用，但不建议这样做。您可以使用丢失的应用程序重现它，包括 Netbeans 8.0.2（它本身是基于 Java 的），同时它显示一个可排序的表，例如Window > IDE Tools > Notifications，讽刺的是，您还可以在其中获得 NPE 报告。只需在 Windows 7 上将 Windows 主题从 Aero 切换到 Windows Classic（通过right-click Desktop > Personalize > Change the visuals and sounds on your computer）。

如果您使用 Glazed Lists 和 call ca.odell.glazedlists.swing.TableComparatorChooser.install，您也会受到影响。它注入了自己的自定义渲染器来对箭头进行排序。

我在试图为这个我怀疑相关的问题找到解决方案时偶然发现了这一点。

Answer 6

for (int i = 0 ; i < table.getColumnCount(); i++){

    DefaultTableCellRenderer renderer = new DefaultTableCellRenderer();
    renderer.setHorizontalAlignment(SwingConstants.RIGHT);
    table.getColumn(i).setHeaderRenderer(renderer);

}

Answer 7

DefaultTableCellRenderer renderer = (DefaultTableCellRenderer) 
MSISDNTable.getTableHeader().getDefaultRenderer();
renderer.setHorizontalAlignment(JLabel.RIGHT);

MSISDNTable你的桌子在哪里

Answer 8

DefaultTableCellRenderer defaultHeaderRenderer = (DefaultTableCellRenderer) getTableHeader().getDefaultRenderer();
defaultHeaderRenderer.setHorizontalAlignment(JLabel.CENTER);         
getTableHeader().setDefaultRenderer(defaultHeaderRenderer);

我已经在 J​​AVA8 中测试过。工作正常。

Answer 9

试试这个代码，

JTableHeader jtableHeader = jtable.getTableHeader();
DefaultTableCellRenderer rend = (DefaultTableCellRenderer) jtable.getTableHeader().getDefaultRenderer();
rend.setHorizontalAlignment(JLabel.CENTER);
jtableHeader.setDefaultRenderer(rend);

Answer 10

我基于 pvbemmelen62 的解决方案创建了一个类，可以非常容易地使用，例如：

AlignHeaderRenderer.install(myTable, new int[] { SwingConstants.RIGHT,
                        SwingConstants.RIGHT, SwingConstants.LEFT });

或者

AlignHeaderRenderer.install(myTable, 0, SwingConstants.RIGHT);
AlignHeaderRenderer.install(myTable, 1, SwingConstants.RIGHT);

这是代码：

public class AlignHeaderRenderer implements TableCellRenderer {

private final TableCellRenderer renderer;
private final int alignment;

public static void install(final JTable table, final int[] alignments) {
    for (int i = 0; i < alignments.length; ++i)
        install(table, i, alignments[i]);
}

public static void install(final JTable table, final int row,
        final int alignment) {
    table.getTableHeader().getColumnModel().getColumn(row)
            .setHeaderRenderer(new AlignHeaderRenderer(table, alignment));
}

private AlignHeaderRenderer(final JTable table, final int alignment) {
    renderer = table.getTableHeader().getDefaultRenderer();
    this.alignment = alignment;
}

@Override
public Component getTableCellRendererComponent(final JTable table,
        final Object value, final boolean isSelected,
        final boolean hasFocus, final int row, final int col) {
    final Component c = renderer.getTableCellRendererComponent(table,
            value, isSelected, hasFocus, row, col);
    ((JLabel) c).setHorizontalAlignment(alignment);
    return c;
}

}

Answer 11

秘诀是使用虚拟表中的渲染器来获得正确的 L&F，并从真实表的行渲染器中复制对齐方式。这样每一列分别对齐。这是代码：

table.getTableHeader().setDefaultRenderer(new DefaultTableCellRenderer() {
    @Override
    public Component getTableCellRendererComponent(JTable table, Object value, boolean isSelected, boolean hasFocus, int row, int col) {
        Component c2 = dummy.getTableHeader().getDefaultRenderer().getTableCellRendererComponent(table, value, isSelected, hasFocus, row, col);
        if (table.getRowCount() > 0) {
            Component c3 = table.getCellRenderer(0, col).getTableCellRendererComponent(table, value, isSelected, hasFocus, 0, col);
            if (c2 instanceof JLabel && c3 instanceof JLabel)
                ((JLabel)c2).setHorizontalAlignment(((JLabel)c3).getHorizontalAlignment());
        }
        return c2;
    }
    private final JTable dummy = new JTable();
});

上面的代码没有保留对渲染器的任何引用，因此它避免了上面提到的 NPE 错误。它不需要任何命名类，因此您可以将代码放在您需要的任何地方。

Answer 12

  ((DefaultTableCellRenderer)jTable2.getTableHeader().getDefaultRenderer())
    .setHorizontalAlignment(JLabel.CENTER);

Answer 13

((JLabel)mTabBOM.getTableHeader().getDefaultRenderer()).setHorizontalAlignment( JLabel.CENTER );