JTable 中 JEditorPane 中的超链接

Question

我发誓...我希望这是我必须问的最后一个问题，但我快要疯了。

我有一个使用自定义 TableCellRenderer 的 JTable，它使用 JEditorPane 在 JTable 的各个单元格中显示 html。如何处理对 JEditorPane 中显示的链接的单击？

我了解 HyperlinkListener，但没有鼠标事件通过 JTable 到达 EditorPane 来处理任何 HyperlinkEvent。

如何处理 JTable 中 JEditorPane 中的超链接？

Answer 1

EditorPane没有收到任何事件，因为从TableCellRenderer返回的组件只允许显示，而不是截取事件，使其与图像几乎相同，不允许任何行为。因此，即使在监听者注册时，返回的组件也不会“意识到”任何事件。解决方法是在JTable上注册MouseListener，并从那里拦截所有相关事件。

这里是我过去创建的一些类，它们允许JButton翻转在JTable中工作，但你应该能够重复使用大部分这些类来解决你的问题。我为每个需要它的单元都有一个单独的JButton。这样，此ActiveJComponentTableMouseListener可以在鼠标事件发生的单元格中运行，并将事件调度到相应的组件。 ActiveJComponentTableCellRenderer的工作是通过Map跟踪组件。

知道它什么时候已经触发了事件，这很聪明，所以你不会得到积压的冗余事件。为超文本实现这一点不应该那么不同，你可能仍然想要翻转。这是课程

public class ActiveJComponentTableMouseListener extends MouseAdapter implements MouseMotionListener {

private JTable table;
private JComponent oldComponent = null;
private TableCell oldTableCell = new TableCell();

public ActiveJComponentTableMouseListener(JTable table) {
    this.table = table;
}

@Override
public void mouseMoved(MouseEvent e) {
    TableCell cell = new TableCell(getRow(e), getColumn(e));

    if (alreadyVisited(cell)) {
        return;
    }
    save(cell);

    if (oldComponent != null) {
        dispatchEvent(createMouseEvent(e, MouseEvent.MOUSE_EXITED), oldComponent);
        oldComponent = null;
    }

    JComponent component = getComponent(cell);
    if (component == null) {
        return;
    }
    dispatchEvent(createMouseEvent(e, MouseEvent.MOUSE_ENTERED), component);
    saveComponent(component);
    save(cell);
}

@Override
public void mouseExited(MouseEvent e) {
    TableCell cell = new TableCell(getRow(e), getColumn(e));

    if (alreadyVisited(cell)) {
        return;
    }
    if (oldComponent != null) {
        dispatchEvent(createMouseEvent(e, MouseEvent.MOUSE_EXITED), oldComponent);
        oldComponent = null;
    }
}

@Override
public void mouseEntered(MouseEvent e) {
    forwardEventToComponent(e);
}

private void forwardEventToComponent(MouseEvent e) {
    TableCell cell = new TableCell(getRow(e), getColumn(e));
    save(cell);
    JComponent component = getComponent(cell);
    if (component == null) {
        return;
    }
    dispatchEvent(e, component);
    saveComponent(component);
}

private void dispatchEvent(MouseEvent componentEvent, JComponent component) {
    MouseEvent convertedEvent = (MouseEvent) SwingUtilities.convertMouseEvent(table, componentEvent, component);
    component.dispatchEvent(convertedEvent);
    // This is necessary so that when a button is pressed and released
    // it gets rendered properly.  Otherwise, the button may still appear
    // pressed down when it has been released.
    table.repaint();
}

private JComponent getComponent(TableCell cell) {
    if (rowOrColumnInvalid(cell)) {
        return null;
    }
    TableCellRenderer renderer = table.getCellRenderer(cell.row, cell.column);

    if (!(renderer instanceof ActiveJComponentTableCellRenderer)) {
        return null;
    }
    ActiveJComponentTableCellRenderer activeComponentRenderer = (ActiveJComponentTableCellRenderer) renderer;

    return activeComponentRenderer.getComponent(cell);
}

private int getColumn(MouseEvent e) {
    TableColumnModel columnModel = table.getColumnModel();
    int column = columnModel.getColumnIndexAtX(e.getX());
    return column;
}

private int getRow(MouseEvent e) {
    int row = e.getY() / table.getRowHeight();
    return row;
}

private boolean rowInvalid(int row) {
    return row >= table.getRowCount() || row < 0;
}

private boolean rowOrColumnInvalid(TableCell cell) {
    return rowInvalid(cell.row) || columnInvalid(cell.column);
}

private boolean alreadyVisited(TableCell cell) {
    return oldTableCell.equals(cell);
}

private boolean columnInvalid(int column) {
    return column >= table.getColumnCount() || column < 0;
}

private MouseEvent createMouseEvent(MouseEvent e, int eventID) {
    return new MouseEvent((Component) e.getSource(), eventID, e.getWhen(), e.getModifiers(), e.getX(), e.getY(), e.getClickCount(), e.isPopupTrigger(), e.getButton());
}
private void save(TableCell cell) {
    oldTableCell = cell;
}

private void saveComponent(JComponent component) {
    oldComponent = component;
}}


public class TableCell {

public int row;
public int column;

public TableCell() {
}

public TableCell(int row, int column) {
    this.row = row;
    this.column = column;
}

@Override
public boolean equals(Object obj) {
    if (obj == null) {
        return false;
    }
    if (getClass() != obj.getClass()) {
        return false;
    }
    final TableCell other = (TableCell) obj;
    if (this.row != other.row) {
        return false;
    }
    if (this.column != other.column) {
        return false;
    }
    return true;
}

@Override
public int hashCode() {
    int hash = 7;
    hash = 67 * hash + this.row;
    hash = 67 * hash + this.column;
    return hash;
}}

public class ActiveJComponentTableCellRenderer<T extends JComponent> extends AbstractCellEditor implements TableCellEditor, TableCellRenderer {

private Map<TableCell, T> components;
private JComponentFactory<T> factory;

public ActiveJComponentTableCellRenderer() {
    this.components = new HashMap<TableCell, T>();        
}

public ActiveJComponentTableCellRenderer(JComponentFactory<T> factory) {
    this();
    this.factory = factory;
}

public T getComponent(TableCell key) {
    T component = components.get(key);
    if (component == null && factory != null) {
        // lazy-load component
        component = factory.build();
        initialiseComponent(component);
        components.put(key, component);
    }
    return component;
}

/**
 * Override this method to provide custom component initialisation code
 * @param component passed in component from getComponent(cell)
 */
protected void initialiseComponent(T component) {
}

@Override
public Component getTableCellRendererComponent(JTable table, Object value, boolean isSelected, boolean hasFocus, int row, int column) {
    return getComponent(new TableCell(row, column));
}

@Override
public Object getCellEditorValue() {
    return null;
}

@Override
public Component getTableCellEditorComponent(JTable table, Object value, boolean isSelected, int row, int column) {
    return getComponent(new TableCell(row, column));
}

public void setComponentFactory(JComponentFactory factory) {
    this.factory = factory;
}}

public interface JComponentFactory<T extends JComponent> {
T build();
}

要使用它，您需要将侦听器注册为表上的鼠标和动作侦听器，并在适当的单元格上注册渲染器。如果要拦截actionPerformed类型事件，请覆盖ActiveJComponentTableCellRenderer.initialiseComponent（），如下所示：

protected void initialiseComponent(T component) {
    component.addActionListener(new ActionListener() {
        @Override
        public void actionPerformed(ActionEvent e) {
            stopCellEditing();
        }
    });
}

Answer 2

如果在JTable上注册 MouseListener ，则可以轻松地在鼠标单击点处获取文本。这可以通过使用 event.getX（）和 event.getY（）<从 MouseEvent 生成 Point 对象来完成。 /代码>。然后将 Point 传递给 JTable 的 rowAtPoint（pt）和 columnAtPoint（pt）。从那里，您可以通过 JTable.getValueAt（row，column）获取文本。现在您拥有了单元格的值，因此您可以确定它是否是链接，并根据结果执行您想要的操作。

Answer 3

为了解决同样的问题，我没有尝试让 JEditorPane 生成事件，而是处理 JTable 生成的 MouseEvent，让侦听器弄清楚我们何时单击了链接。

这是代码。它保留 JEditorPanes 的映射，因此请确保没有内存泄漏，并且如果表中的数据可能发生更改，请适当地清除此映射。它对我实际使用的代码进行了稍微修改 - 在我实际使用的版本中，它仅在实际链接位于 html 中时才生成 JEditorPane，并且当不存在此类链接时不会打扰 JEditorPanes...

public class MessageWithPossibleHtmlLinksRenderer extends DefaultTableCellRenderer {

private final Map<Integer, JEditorPane> editorPanes = new HashMap<>();

public MessageWithPossibleHtmlLinksRenderer(JTable table) {
    // register mouseAdapter to table for link-handling
    table.addMouseMotionListener(this.mouseAdapter);
    table.addMouseListener(this.mouseAdapter);
}

private JEditorPane getOrCreateEditorPane(int row, int col) {
    final int key = combine(row, col);
    JEditorPane jep = editorPanes.get(key);
    if (jep == null) {
        jep = new JEditorPane();
        jep.putClientProperty(JEditorPane.HONOR_DISPLAY_PROPERTIES, Boolean.TRUE);
        jep.setContentType("text/html");
        jep.setEditable(false);
        jep.setOpaque(true);
        editorPanes.put(key, jep);
    }
    return jep;
}

private static int combine(int row, int col) {
    return row * 10 + col; // works for up to 10 columns
}

@Override
public Component getTableCellRendererComponent(JTable table, Object value, boolean isSelected, boolean hasFocus, int row, int column) {
    // modify here if you want JEditorPane only when links exist
    if (value instanceof String && ((String) value).startsWith("<html>")) { 
        final JEditorPane jep = getOrCreateEditorPane(row, column);
        jep.setText((String) value);
        // code to adjust row height
        return jep;
    } else {
        return super.getTableCellRendererComponent(table, value, isSelected, hasFocus, row, column);
    }
}

private AttributeSet anchorAt(MouseEvent e) {
    // figure out the JEditorPane we clicked on, or moved over, if any
    final JTable table = (JTable) e.getSource();
    final Point p = e.getPoint();
    final int row = table.rowAtPoint(p);
    final int col = table.columnAtPoint(p);
    final int key = combine(row, col);
    final JEditorPane pane = this.editorPanes.get(key);
    if (pane == null) {
        return null;
    }
    // figure out the exact link, if any 
    final Rectangle r = table.getCellRect(row, col, false);
    final Point relativePoint = new Point((int) (p.getX() - r.x), (int) (p.getY() - r.y));
    pane.setSize(r.getSize()); // size the component to the size of the cell
    final int pos = pane.viewToModel(relativePoint);
    if (pos >= 0) {
        final Document doc = pane.getDocument();
        if (doc instanceof HTMLDocument) {
            final Element el = ((HTMLDocument) doc).getCharacterElement(pos);
            return (AttributeSet) el.getAttributes().getAttribute(HTML.Tag.A);
        }
    }
    return null;
}

private final MouseAdapter mouseAdapter = new MouseAdapter() {
    @Override
    public void mouseMoved(MouseEvent e) {
        final AttributeSet anchor = anchorAt(e);
        final Cursor cursor = anchor == null
                ? Cursor.getDefaultCursor()
                : Cursor.getPredefinedCursor(Cursor.HAND_CURSOR);
        final JTable table = (JTable) e.getSource();
        if (table.getCursor() != cursor) {
            table.setCursor(cursor);
        }
    }

    @Override
    public void mouseClicked(MouseEvent e) {
        if (! SwingUtilities.isLeftMouseButton(e)) {
            return;
        }
        final AttributeSet anchor = anchorAt(e);
        if (anchor != null) {
            try {
                String href = (String) anchor.getAttribute(HTML.Attribute.HREF);
                Desktop.getDesktop().browse(new URL(href).toURI());
            } catch (Exception ex) {
                // ignore
            }
        }
    }
};
}