javax.swing.JTable有一个bug， 如果我们在编辑空值单元格时对表进行排序， 并且其列类没有带有“new Object [] {new String（）}”参数的构造函数，例如。 Long.class， JTable将抛出异常。
我认为因为javax.swing.JTable尝试删除单元格编辑器两次; 所以我打算将JTable.columnMoved方法覆盖为：
@Override
public void columnMoved(TableColumnModelEvent e) {
if (isEditing() && !getCellEditor().stopCellEditing()) {
if(getCellEditor() != null) { // In javax.swing.JTable, no this check point
getCellEditor().cancelCellEditing();
}
}
repaint();
}
我觉得这还不够好，因为它对代码阅读器不友好，他们可能很了解JTable，并且不喜欢我这样的子类。 有更好的解决方案吗？ 非常感谢。
运行以下代码时，双击一个单元格（不输入任何内容），然后单击标题，将显示异常。
public class NewJFrame extends javax.swing.JFrame {
public NewJFrame() {
initComponents();
}
@SuppressWarnings("unchecked")
// <editor-fold defaultstate="collapsed" desc="Generated Code">
private void initComponents() {
jScrollPane1 = new javax.swing.JScrollPane();
jTable1 = new javax.swing.JTable();
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
jTable1.setModel(new javax.swing.table.DefaultTableModel(
new Object [][] {
{null, null},
{null, null},
{null, null},
{null, null}
},
new String [] {
"Title 1", "Title 2"
}
) {
Class[] types = new Class [] {
java.lang.Long.class, java.lang.Long.class
};
public Class getColumnClass(int columnIndex) {
return types [columnIndex];
}
});
jScrollPane1.setViewportView(jTable1);
javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
getContentPane().setLayout(layout);
layout.setHorizontalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addContainerGap()
.addComponent(jScrollPane1, javax.swing.GroupLayout.PREFERRED_SIZE, 375, javax.swing.GroupLayout.PREFERRED_SIZE)
.addContainerGap(15, Short.MAX_VALUE))
);
layout.setVerticalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addContainerGap()
.addComponent(jScrollPane1, javax.swing.GroupLayout.PREFERRED_SIZE, 275, javax.swing.GroupLayout.PREFERRED_SIZE)
.addContainerGap(14, Short.MAX_VALUE))
);
pack();
}// </editor-fold>
/**
* @param args the command line arguments
*/
public static void main(String args[]) {
/* Set the Nimbus look and feel */
//<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) ">
/* If Nimbus (introduced in Java SE 6) is not available, stay with the default look and feel.
* For details see http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html
*/
try {
for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
if ("Nimbus".equals(info.getName())) {
javax.swing.UIManager.setLookAndFeel(info.getClassName());
break;
}
}
} catch (ClassNotFoundException ex) {
java.util.logging.Logger.getLogger(NewJFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (InstantiationException ex) {
java.util.logging.Logger.getLogger(NewJFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (IllegalAccessException ex) {
java.util.logging.Logger.getLogger(NewJFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (javax.swing.UnsupportedLookAndFeelException ex) {
java.util.logging.Logger.getLogger(NewJFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
}
//</editor-fold>
/* Create and display the form */
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
new NewJFrame().setVisible(true);
}
});
}
// Variables declaration - do not modify
private javax.swing.JScrollPane jScrollPane1;
private javax.swing.JTable jTable1;
// End of variables declaration
}
答案 0 :(得分：4)
我可以使用您提供的代码重现该问题。我责怪JTable#stopCellEditing实施
public boolean stopCellEditing() {
String s = (String)super.getCellEditorValue();
// Here we are dealing with the case where a user
// has deleted the string value in a cell, possibly
// after a failed validation. Return null, so that
// they have the option to replace the value with
// null or use escape to restore the original.
// For Strings, return "" for backward compatibility.
if ("".equals(s)) {
if (constructor.getDeclaringClass() == String.class) {
value = s;
}
super.stopCellEditing();
}
try {
value = constructor.newInstance(new Object[]{s});
}
catch (Exception e) {
((JComponent)getComponent()).setBorder(new LineBorder(Color.red));
return false;
}
return super.stopCellEditing();
}
您输入第一个if，其中super.stopCellEditing被调用。忽略此调用的返回值。然后，newInstance调用抛出异常，该异常被捕获，但无论返回值是false，都会返回super.stopCellEditing。这对我来说听起来不对。我会使用您提供的代码将Oracle的错误记录下来
答案 1 :(得分：3)
我看不出任何问题，任何错误，TableCellEditor在排序和列重新排序时被正确取消，
import java.awt.*;
import javax.swing.*;
import javax.swing.table.DefaultTableModel;
public class TableWithTimer {
private static final long serialVersionUID = 1L;
private JFrame frame = new JFrame();
private JScrollPane scroll = new JScrollPane();
private JTable myTable;
private String[] head = {"One", "Two", "Three", "Four", "Five", "Six"};
private Object[][] data = {{null, null, null, null, null, null},
{null, null, null, null, null, null},
{null, null, null, null, null, null},
{null, null, null, null, null, null},
{null, null, null, null, null, null},
{null, null, null, null, null, null},
{null, null, null, null, null, null}};
private DefaultTableModel model;
public TableWithTimer() {
model = new DefaultTableModel(data, head) {
private static final long serialVersionUID = 1L;
@Override
public Class<?> getColumnClass(int colNum) {
switch (colNum) {
case 0:
return Integer.class;
case 1:
return Double.class;
case 2:
return Long.class;
case 3:
return Boolean.class;
default:
return String.class;
}
}
};
myTable = new JTable(model);
myTable.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
myTable.setGridColor(Color.gray);
myTable.setFillsViewportHeight(true);
myTable.setAutoResizeMode(JTable.AUTO_RESIZE_OFF);
myTable.setAutoCreateRowSorter(true);
scroll.setViewportView(myTable);
frame.add(scroll, BorderLayout.CENTER);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLocation(100, 100);
frame.pack();
frame.setVisible(true);
}
public static void main(String args[]) {
SwingUtilities.invokeLater(new Runnable() {
@Override
public void run() {
TableWithTimer tableWithTimer = new TableWithTimer();
}
});
}
}
答案 2 :(得分：1)
问题 - 由@Robin正确分析 - 有几个方面：
虽然第二个“只是”违反合同，但第一个会产生严重后果：
有足够的理由通过GenericEditor中的不同逻辑修复JXTable（该修复也可用于自定义GenericEditor，不与swingx耦合：只需c＆amp; p核心GenericEditor并用以下内容替换其stopCellEditing）：
@Override
public boolean stopCellEditing() {
String s = (String) super.getCellEditorValue();
// JW: changed logic to hack around (core!) Issue #1535-swingx
// don't special case empty, but string contructor:
// if so, by-pass reflection altogether
if (constructor.getDeclaringClass() == String.class) {
value = s;
} else { // try instantiating a new Object with the string
try {
value = constructor.newInstance(new Object[] { s });
} catch (Exception e) {
((JComponent) getComponent()).setBorder(new LineBorder(
Color.red));
return false;
}
}
return super.stopCellEditing();
}