JTable的JComboBox单元格编辑器在打开列表时已经设置了值,即使在组合框外单击也是如此

Question

JTable的JComboBox细胞编辑器中打开列表时,即使点击了组合框外已设置的值.此外,一旦选择了某个值,下次打开选择时,该值将成为默认值:

这是代码:

public class Main {
    public static void main(String[] args) {
        new QuestionFrame();
    }
}

QuestionFrame:

import javax.swing.*;
import javax.swing.table.AbstractTableModel;
import java.awt.*;

class QuestionFrame extends JFrame {
    QuestionFrame(){
        class Model {
            int num;
            private Model(int n) { num = n; }
        }
        final Model[] model = {new Model(9), new Model(8), new Model(7)};

        JPanel panel = new JPanel(new BorderLayout());
        JTable table = new JTable(new AbstractTableModel(){
            @Override public int getRowCount() { return model.length; }
            @Override public int getColumnCount() { return 1; }
            @Override public Object getValueAt(int rowIndex, int columnIndex) {
                return model[rowIndex].num;
            }
            @Override public String getColumnName(int column){ return "NUM"; }
            @Override public Class<?> getColumnClass(int columnIndex) { return Integer.class; }
            @Override public boolean isCellEditable(int rowIndex, int columnIndex) { return true; }
            @Override public void setValueAt(Object aValue, int rowIndex, int columnIndex) {
                model[rowIndex].num = (int) aValue;
            }
        });
        DefaultCellEditor cellEditor = new DefaultCellEditor(new JComboBox<>(new Integer[]{1,2,3}));
        cellEditor.setClickCountToStart(1);
        table.getColumnModel().getColumn(0).setCellEditor(cellEditor);
        panel.add(new JScrollPane(table), BorderLayout.CENTER);

        setBounds(new Rectangle(500,250,200,200));
        add(panel);
        setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
        setVisible(true);
    }
}

这有点意义,因为setCellEditor(cellEditor)重用相同的JComboBox对象实例,但我找不到另一种方法来做它.

那怎么解决呢？

Answer 1

您的问题是因为当前单元格值不是组合框编辑器的可能选择之一,因此组合默认为第一个选择.如果更改编辑器以包含当前值,例如,

DefaultCellEditor cellEditor = new DefaultCellEditor(
        new JComboBox<>(new Integer[] { 1, 2,3, 4, 5, 6, 7, 8, 9 }));

然后它工作正常,如预期的那样.

如果你想对编辑器进行更细粒度的控制,那么你将需要自己滚动而不使用默认编辑器.