java - 停止 JTable 仅在获得焦点并按下按键时才可编辑

Question

我写了一个自定义的 DefaultCellEditor，这样当我在示例 JTable 的 length 列中输入时，我只能输入数字

为此，我向用作编辑器组件的 JTextField 添加了一个 KeyListener。虽然如果您双击单元格以编辑值，效果很好，但如果您单击单元格一次然后开始键入，则效果不佳。

如果用户单击单元格一次然后开始键入，我如何防止用户能够编辑单元格，同时仍然允许用户双击单元格开始编辑它？

import java.awt.Color;
import java.awt.Component;
import java.awt.EventQueue;
import java.awt.GridLayout;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import java.lang.reflect.Constructor;

import javax.swing.DefaultCellEditor;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.JTextField;
import javax.swing.border.LineBorder;

@SuppressWarnings("serial")
public class JTableTest extends JFrame {
    private JTableTest() {
        super("JTable Test");
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setLayout(new GridLayout(1, 1));
        createPanel();
        pack();
        setVisible(true);
    }

    JPanel panel = new JPanel(new GridLayout(1, 1));
    JScrollPane scroll;

    private void createPanel() {
        Object[] headers = {"Length", "Title"};
        Object[][] sampleData = {{"673", "Bat Outta Hell"},
                {"358", "Spanish Train"},
                {"673", "Bat Outta Hell"}};
        JTable table = new JTable(sampleData, headers);
        table.setDefaultEditor(Object.class, new NumEditor());
        scroll = new JScrollPane(table);
        panel.add(scroll);
        getContentPane().add(panel);
    }

    private class NumEditor extends DefaultCellEditor {
        Class<?>[] argTypes = new Class<?>[]{String.class};
        Constructor<?> constructor;
        Object value;

        public NumEditor() {
            super(new JTextField());
            getComponent().setName("Table.editor");
        }

        public boolean stopCellEditing() {
            String s = (String)super.getCellEditorValue();
            try {
                if ("".equals(s)) {
                    if (constructor.getDeclaringClass() == String.class) {
                        value = s;
                    }
                    return super.stopCellEditing();
                }
                value = constructor.newInstance(new Object[]{s});
            }
            catch (Exception e) {
                ((JComponent)getComponent()).setBorder(new LineBorder(Color.red));
                return false;
            }
            return super.stopCellEditing();
        }

        public Component getTableCellEditorComponent(JTable table, Object value, boolean isSelected, int row, int column) {
            this.value = null;
            ((JComponent)getComponent()).setBorder(new LineBorder(Color.black));
            try {
                Class<?> type = table.getColumnClass(column);

                if (type == Object.class) {
                    type = String.class;
                }

                KeyListener kL = new KeyListener() {
                    public void keyPressed(KeyEvent e) {

                    }
                    public void keyReleased(KeyEvent e) {

                    }
                    public void keyTyped(KeyEvent e) {
                        char c = e.getKeyChar();
                        if(Character.isDigit(c)){

                        } else {
                            e.consume();
                        }
                    }
                };

                if(column == 0)
                    ((JComponent)getComponent()).addKeyListener(kL);
                else
                    ((JComponent)getComponent()).removeKeyListener(kL);

                constructor = type.getConstructor(argTypes);
            }
            catch (Exception e) {
                return null;
            }
            return super.getTableCellEditorComponent(table, value, isSelected, row, column);
        }

        public Object getCellEditorValue() {
            return value;
        }
    }

    public static void main(String[] args) {
        EventQueue.invokeLater(() -> new JTableTest());
    }
}

Answer 1

Stop JTable being editable only when focussed and key pressed

好吧，当您使用字符串数据编辑单元格时，这是默认行为。

当您尝试输入数字数据时，为什么会有所不同？

I wrote a custom DefaultCellEditor so that when I type in the length column of the example JTable I can not enter anything but numbers in it.

无需编写自定义编辑器。只需使用 JFormattedTextField 作为编辑器而不是 JTextField:

类似的东西。

MaskFormatter format = new MaskFormatter("######");
JFormattedTextField ftf = new JFormattedTextField( format );
DefaultCellEditor dce = new DefaultCellEditor( ftf );
table.getColumnModel().getColumn(2).setCellEditor(dce);