java - 突出显示 JTable 的列标题

Question

我目前正在构建一个小型 JTable，并且希望在选择单元格时突出显示列标题(和行标题 - 行标题部分实际上正在工作)，以便更轻松地找到与此单元格相关的名称。这是一张图片:

我已经尝试用以下方法切换标题的渲染器:

table.getTableHeader().setDefaultRenderer(new ColumnHeaderRenderer());

但只有当我单击标题时才会调用它，并且总是说 isSelected 为 false。

这是我用于行名称的代码，包括渲染器内的突出显示 - 代码不是我编写的，我只是对其进行了一些修改:

/*
 *  Use a JTable as a renderer for row numbers of a given main table.
 *  This table must be added to the row header of the scrollpane that
 *  contains the main table.
 */
public class RowNameTable extends JTable
        implements ChangeListener, PropertyChangeListener {

    private JTable main;

    public RowNameTable(JTable table) {
        main = table;
        main.addPropertyChangeListener(this);

        setFocusable(false);
        setAutoCreateColumnsFromModel(false);
        setModel(main.getModel());
        setSelectionModel(main.getSelectionModel());

        TableColumn column = new TableColumn();
        column.setHeaderValue(" ");
        addColumn(column);
        column.setCellRenderer(new RowNameRenderer(main));

        getColumnModel().getColumn(0).setPreferredWidth(table.getColumnModel().getColumn(0).getPreferredWidth());
        setPreferredScrollableViewportSize(getPreferredSize());
    }

    @Override
    public void addNotify() {
        super.addNotify();

        Component c = getParent();

        //  Keep scrolling of the row table in sync with the main table.

        if (c instanceof JViewport) {
            JViewport viewport = (JViewport) c;
            viewport.addChangeListener(this);
        }
    }

    /*
     *  Delegate method to main table
     */
    @Override
    public int getRowCount() {
        return main.getRowCount();
    }

    @Override
    public int getRowHeight(int row) {
        return main.getRowHeight(row);
    }

    /*
     *  This table does not use any data from the main TableModel,
     *  so just return a value based on the row parameter.
     */
    @Override
    public Object getValueAt(int row, int column) {
        return Integer.toString(row + 1);
    }

    /*
     *  Don't edit data in the main TableModel by mistake
     */
    @Override
    public boolean isCellEditable(int row, int column) {
        return false;
    }
//
//  Implement the ChangeListener
//

    public void stateChanged(ChangeEvent e) {
        //  Keep the scrolling of the row table in sync with main table

        JViewport viewport = (JViewport) e.getSource();
        JScrollPane scrollPane = (JScrollPane) viewport.getParent();
        scrollPane.getVerticalScrollBar().setValue(viewport.getViewPosition().y);
    }
//
//  Implement the PropertyChangeListener
//

    public void propertyChange(PropertyChangeEvent e) {
        //  Keep the row table in sync with the main table

        if ("selectionModel".equals(e.getPropertyName())) {
            setSelectionModel(main.getSelectionModel());
        }

        if ("model".equals(e.getPropertyName())) {
            setModel(main.getModel());
        }
    }

    /*
     *  Borrow the renderer from JDK1.4.2 table header
     */
    private static class RowNameRenderer extends DefaultTableCellRenderer {

        private JTable main;

        public RowNameRenderer(JTable main) {
            this.main = main;
            setHorizontalAlignment(JLabel.CENTER);
        }

        @Override
        public Component getTableCellRendererComponent(JTable table, Object value, boolean isSelected, boolean hasFocus, int row, int column) {
            if (table != null) {
                JTableHeader header = table.getTableHeader();

                if (header != null) {
                    setForeground(header.getForeground());
                    setBackground(header.getBackground());
                    setFont(header.getFont());
                }
            }

            if (isSelected) {
                setFont(getFont().deriveFont(Font.BOLD));
            }

            setText((value == null) ? "" : main.getColumnName(row));
            setBorder(UIManager.getBorder("TableHeader.cellBorder"));

            return this;
        }
    }
}

这里我们有创建表的相关部分:

    costTableModel = new CostTableModel(costCalc);
    table = new JTable(costTableModel);
    table.setPreferredScrollableViewportSize(table.getPreferredSize());
    table.setAutoResizeMode(JTable.AUTO_RESIZE_OFF);
    table.setCellSelectionEnabled(true);

    scrollPane = new JScrollPane(table);

    RowNameTable nameTable = new RowNameTable(table);
    scrollPane.setRowHeaderView(nameTable);

还有 costTableModel 类，只是为了完整性:

public class CostTableModel extends AbstractTableModel {
    private CostCalculator costCalc;

    public CostTableModel(CostCalculator costCalc) {
        this.costCalc = costCalc;
    }

    @Override
    public int getRowCount() {
        return costCalc.getPersonsList().size();
    }

    @Override
    public int getColumnCount() {
        return costCalc.getPersonsList().size();
    }

    @Override
    public String getColumnName(int col) {
        return costCalc.getPersonsList().get(col).getName();
    }

    @Override
    public Object getValueAt(int rowIndex, int columnIndex) {
        Person debtor = costCalc.getPersonsList().get(rowIndex);
        Person debtee = costCalc.getPersonsList().get(columnIndex);

        return costCalc.getAmountOwed(debtor, debtee);
    }

    @Override
    public Class getColumnClass(int c) {
        return getValueAt(0, c).getClass();

    }
}

提前感谢您的帮助!

Answer 1

一个细微的变化:当我阅读问题时，主要问题是标题未在列选择更改上更新。让自定义 header 监听行选择更改对于这种情况没有多大帮助。

事实上，JTableHeader 已经在监听 Co​​lumnModel，并且模型的更改通知包括选择更改。只是故意实现了 columnSelectionChange 方法而不执行任何操作:

// --Redrawing the header is slow in cell selection mode.
// --Since header selection is ugly and it is always clear from the
// --view which columns are selected, don't redraw the header.

自定义 header 可以简单地实现重绘(这里懒惰的我在表的工厂方法中这样做只是为了省去与表的连接，您可以轻松地将其设为独立的类:-)。

final JTable table = new JTable(new AncientSwingTeam()) {

    @Override
    protected JTableHeader createDefaultTableHeader() {
        // subclassing to take advantage of super's auto-wiring
        // as ColumnModelListener
        JTableHeader header = new JTableHeader(getColumnModel()) {

            @Override
            public void columnSelectionChanged(ListSelectionEvent e) {
                repaint();
            }

        };
        return header;
    }

};
table.setCellSelectionEnabled(true);
table.getTableHeader().setDefaultRenderer(new ColumnHeaderRenderer());

还使用表 api 对 Mad 的渲染器进行了一些调整:

/**
 * Slightly adjusted compared to @Mad
 * - use table's selectionBackground
 * - use table's isColumnSelected to decide on highlight
 */
public static class ColumnHeaderRenderer extends DefaultTableCellHeaderRenderer {

    @Override
    public Component getTableCellRendererComponent(JTable table, Object value, boolean selected,  
        boolean focused, int row, int column) {
        super.getTableCellRendererComponent(table, value, selected, focused, row, column); 
        if (table.isColumnSelected(column)) {
            setBackground(table.getSelectionBackground());
        }
        return this;
    }
}

关于观察:

always says isSelected is false

原因是 BasicTableHeaderUI 中的一个小怪癖:

ui.selected != columnModel.selected

uiSelected 是键绑定(bind)可以访问的列 - 如果 laf 支持它并且标题是 focusOwner。对我来说确实没有意义，但完全定义 ui 和 columnModel 选择的语义陷入了对新 babe fx 的兴奋中，这一点被遗忘了;-)