带有JCombobox编辑器的JTable:处理鼠标点击

Question

我有一个带有JCombobox编辑器的JTable，用于某一列。

import javax.swing.JFrame;
import javax.swing.JTable;
import javax.swing.DefaultCellEditor;
import javax.swing.JComboBox;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.table.AbstractTableModel;
import javax.swing.table.TableColumn;
public class TablePanel extends JPanel {
    public TablePanel() {
        JTable table = new JTable(new MyTableModel());
        setComboboxColumn(table.getColumnModel().getColumn(1));
        add(new JScrollPane(table));
    }
    public void setComboboxColumn(TableColumn cbColumn) {
        JComboBox<String> comboBox = new JComboBox<>();
        comboBox.addItem("Item 1");
        comboBox.addItem("Item 2");
        comboBox.addItem("Item 3");
        cbColumn.setCellEditor(new DefaultCellEditor(comboBox));
    }
    private static class MyTableModel extends AbstractTableModel {
        private String[] columnNames = {"Normal cell", "Combobox cell"};
        private Object[][] data = {
                {"Cell 1", "Item 2"},
                {"Cell 2", "Item 1"},
                {"Cell 3", "Item 1"},
                {"Cell 4", "Item 3"},
        };
        @Override
        public int getColumnCount() {
            return columnNames.length;
        }
        @Override
        public int getRowCount() {
            return data.length;
        }
        @Override
        public String getColumnName(int col) {
            return columnNames[col];
        }
        @Override
        public Object getValueAt(int row, int col) {
            return data[row][col];
        }
        @Override
        public Class getColumnClass(int c) {
            return getValueAt(0, c).getClass();
        }
        @Override
        public boolean isCellEditable(int row, int col) {
            return true;
        }
        @Override
        public void setValueAt(Object aValue, int rowIndex, int columnIndex) {
            data[rowIndex][columnIndex] = aValue;
        }
    }
    public static void main(String[] args) {
        javax.swing.SwingUtilities.invokeLater(new Runnable() {
            @Override
            public void run() {
                JFrame frame = new JFrame("TablePanel");
                frame.getContentPane().add(new TablePanel());
                frame.pack();
                frame.setVisible(true);
            }
        });
    }
}

现在发生了什么：

• 当我第一次点击该列的单元格时，会立即显示组合框弹出窗口
• 如果我单击同一列的其他单元格，则会显示组合框，但弹出窗口仍处于关闭状态
• 如果我单击其他单元格，然后再次返回该列的某个单元格，则组合框弹出窗口会立即再次显示

我想要什么：

• 首先单击该列的单元格：组合框显示，但弹出列表仍然关闭
• 再次点击同一单元格：弹出列表显示

我知道我可以使用cellEditor.setClickCountToStart(2)，但在这种情况下，第二次单击必须在第一次单击后的短时间内执行，我希望避免这种限制。

Answer 1

来自BasicComboPopup.Handler#mousePressed(...):

public void mousePressed(MouseEvent e) {
  if (e.getSource() == list) {
    return;
  }
  if (!SwingUtilities.isLeftMouseButton(e) || !comboBox.isEnabled())
    return;
  //...
  togglePopup();
}

您可以使用AncestorListener:

• 当第一次单击该列的单元格combobox.isEnabled()==false时，不显示弹出窗口，稍后AncestorListener#ancestorAdded()调用combobox.setEnabled(true)
• 再次点击同一单元格：combobox.isEnabled()==true，弹出窗口显示
• 如果单击其他单元格：AncestorListener#ancestorRemoved()调用combobox.setEnabled(false)

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.table.*;
import javax.swing.event.*;
public class ComboBoxCellEditorTogglePopupTest {
  private JComboBox<String> makeComboBox() {
    JComboBox<String> combobox = new JComboBox<>();
    combobox.addItem("Item 1");
    combobox.addItem("Item 2");
    combobox.addItem("Item 3");
    return combobox;
  }
  public JComponent makeUI() {
    String[] columnNames = {"Default", "setEnabled", "String"};
    Object[][] data = {
      {"Item 1", "Item 1", "aaa"}, {"Item 2", "Item 3", "bbb"}
    };
    JTable table = new JTable(new DefaultTableModel(data, columnNames));
    table.setRowHeight(20);
    table.getColumnModel().getColumn(0).setCellEditor(
        new DefaultCellEditor(makeComboBox()));
    final JComboBox<String> combobox = makeComboBox();
    combobox.setEnabled(false);
    combobox.addAncestorListener(new AncestorListener() {
      @Override public void ancestorAdded(AncestorEvent e) {
        System.out.println("ancestorAdded");
        EventQueue.invokeLater(new Runnable() {
          @Override public void run() {
            combobox.setEnabled(true);
          }
        });
      }
      @Override public void ancestorRemoved(AncestorEvent e) {
        System.out.println("ancestorRemoved");
        combobox.setEnabled(false);
      }
      @Override public void ancestorMoved(AncestorEvent e) {}
    });
    table.getColumnModel().getColumn(1).setCellEditor(
        new DefaultCellEditor(combobox));
    JPanel p = new JPanel(new BorderLayout());
    p.add(new JScrollPane(table));
    return p;
  }
  public static void main(String[] args) {
    EventQueue.invokeLater(new Runnable() {
      @Override public void run() {
        createAndShowGUI();
      }
    });
  }
  public static void createAndShowGUI() {
    JFrame f = new JFrame();
    f.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
    f.getContentPane().add(new ComboBoxCellEditorTogglePopupTest().makeUI());
    f.setSize(320, 240);
    f.setLocationRelativeTo(null);
    f.setVisible(true);
  }
}