JTable单元格中的小部件 [英] Widgets in JTable cells

问题描述

JTable 列中的小部件与正常列无法区分，对吧？似乎存在行为差异，请参阅 Swing文档示例并将鼠标移动到 Vegetarian 列中的复选框...他们根本没有反应。我知道那些只是小部件代理，所以突出显示必须手动完成，所以我该如何解决这个问题呢？我在代理小部件事件处理程序中尝试 widget.requestFocusInWindow（）;
in mouseMoved（）但没有成功。还有其他解决方法吗？

Widgets in JTable columns are expected to be not distinguishable from normal ones, right? There seems to be behavioral difference, take Swing documentation example and move mouse over checkboxes in the Vegetarian column... They don't react at all. I understand that those are just widget surrogates, so highlighting has to be done manually, so how would I fix this? I tried widget.requestFocusInWindow(); in mouseMoved() for the surrogate widget event handler without success. Any other workaround?

推荐答案

您可以创建自己的单元格渲染器来应用翻转效果。然后，添加一个跟踪鼠标移动的鼠标监听器并重新绘制相关单元格。您需要将效果应用于光标下的当前单元格并清除上一个单元格。

You can create your own cell renderer that applies a rollover effect. Then, add a mouse listener that tracks the mouse movement and repaints the relevant cells. You need to apply the effect to the current cell under the cursor and clear the previous cell.

下面是一个简短的例子，它在复选框渲染器上演示了这种方法。该示例扩展了默认 BooleanRenderer 。唯一的变化是 getModel（）。setRollover（...） in getTableCellRendererComponent（）。

Below is a short example that demonstrates this approach on a checkbox renderer. The example extends default BooleanRenderer. The only change is getModel().setRollover(...) in getTableCellRendererComponent().

import java.awt.Component;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import javax.swing.JCheckBox;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.SwingUtilities;
import javax.swing.UIManager;
import javax.swing.border.Border;
import javax.swing.border.EmptyBorder;
import javax.swing.plaf.UIResource;
import javax.swing.table.DefaultTableModel;
import javax.swing.table.TableCellRenderer;

public class TableRolloverDemo {
    private static void createAndShowGUI() {
        JFrame frame = new JFrame("TableRolloverDemo");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        final JTable table = new JTable();

        final DefaultTableModel model = new DefaultTableModel(new Object[][] {
                { false }, { false }, { true }, { true } },
                new Object[] { "Column" }) {
            public Class<?> getColumnClass(int columnIndex) {
                return Boolean.class;
            }
        };

        RolloverMouseAdapter rolloverAdapter = new RolloverMouseAdapter(table);
        RolloverBooleanRenderer renderer = new RolloverBooleanRenderer(rolloverAdapter);

        table.addMouseListener(rolloverAdapter);
        table.addMouseMotionListener(rolloverAdapter);

        table.setDefaultRenderer(Boolean.class, renderer);
        table.setModel(model);

        frame.add(new JScrollPane(table));
        frame.pack();
        frame.setLocationByPlatform(true);
        frame.setVisible(true);
    }

    static class RolloverMouseAdapter extends MouseAdapter {
        private int row = -1;
        private int column = -1;
        private JTable table;

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

        public boolean isRolloverCell(int row, int column) {
            return this.row == row && this.column == column;
        }

        @Override
        public void mouseMoved(MouseEvent e) {
            int lastRow = row;
            int lastColumn = column;

            row = table.rowAtPoint(e.getPoint());
            column = table.columnAtPoint(e.getPoint());

            if (row == lastRow && column == lastColumn)
                return;

            if (row >= 0 && column >= 0) {
                table.repaint(table.getCellRect(row, column, false));
            }
            if (lastRow >= 0 && lastColumn >= 0) {
                table.repaint(table.getCellRect(lastRow, lastColumn, false));
            }
        }

        @Override
        public void mouseExited(MouseEvent e) {
            if (row >= 0 && column >= 0) {
                table.repaint(table.getCellRect(row, column, false));
            }
            row = column = -1;
        }

    }

    static class RolloverBooleanRenderer extends JCheckBox implements
            TableCellRenderer, UIResource {
        private static final Border noFocusBorder = new EmptyBorder(1, 1, 1, 1);
        private RolloverMouseAdapter adapter;

        public RolloverBooleanRenderer(RolloverMouseAdapter adapter) {
            super();
            this.adapter = adapter;
            setHorizontalAlignment(JLabel.CENTER);
            setBorderPainted(true);
        }

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

            getModel().setRollover(adapter.isRolloverCell(row, column));

            if (isSelected) {
                setForeground(table.getSelectionForeground());
                super.setBackground(table.getSelectionBackground());
            } else {
                setForeground(table.getForeground());
                setBackground(table.getBackground());
            }
            setSelected((value != null && ((Boolean) value).booleanValue()));

            if (hasFocus) {
                setBorder(UIManager.getBorder("Table.focusCellHighlightBorder"));
            } else {
                setBorder(noFocusBorder);
            }

            return this;
        }
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                createAndShowGUI();
            }
        });
    }
}

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