java - 从同一列的组件菜单中删除 JTable 列时出错

Question

我有一个 JTable，其中为表头设置了组件菜单。它包含用于删除列的条目。当删除触发组件菜单的同一列时，出现问题，并且似乎将此操作视为被拖动的列，这会导致 ArrayIndexOutOfBoundsException 与 -1 .

如何安全地从组件菜单中删除当前列而不引发此错误？

这是一个如何触发这种行为的最小示例。只需运行它并删除您所在的同一列(请注意，当您删除最后一列时，它似乎可以工作，但这与我无关):

import java.awt.BorderLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JFrame;
import javax.swing.JMenuItem;
import javax.swing.JPopupMenu;
import javax.swing.JTable;
import javax.swing.table.DefaultTableModel;
import javax.swing.table.TableColumn;

public class BasicExample extends JFrame {

    private JTable t;
    private DefaultTableModel dtm;

    public BasicExample() {
        init();
    }

    private void init() {
        dtm = new DefaultTableModel(new String[][]{{"a", "b"}, {"c", "d"}}, new String[]{"A", "B"});
        t = new JTable(dtm);
        t.getTableHeader().setComponentPopupMenu(new PopupMenu(t));
        this.setLayout(new BorderLayout());
        add(t.getTableHeader(), BorderLayout.NORTH);
        add(t, BorderLayout.CENTER);
        pack();
        setVisible(true);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    }

    public class PopupMenu extends JPopupMenu {

        private JTable table;

        public PopupMenu(JTable table) {
            this.table = table;
            init();
        }

        private void init() {
            for (int i = 0; i < table.getModel().getColumnCount(); i++) {
                String columnName = table.getModel().getColumnName(i);

                JMenuItem item = new JMenuItem(columnName);
                item.addActionListener(new ActionListener() {
                    @Override
                    public void actionPerformed(ActionEvent e) {
                        TableColumn tc = table.getColumn(columnName);
                        table.getColumnModel().removeColumn(tc);
                    }
                });
                this.add(item);
            }
        }
    }

    public static void main(String[] args) {
        BasicExample be = new BasicExample();
    }
}

在堆栈跟踪中，我看到它似乎将该列视为已拖动，因为它在 BasicTableHeaderUI.java 中输入条件 if (draggedColumn != null) { ，而我正在执行的操作并不是真正的阻力。完整的堆栈跟踪如下:

Exception in thread "AWT-EventQueue-0" java.lang.ArrayIndexOutOfBoundsException: -1
    at java.util.Vector.elementData(Vector.java:734)
    at java.util.Vector.elementAt(Vector.java:477)
    at javax.swing.table.DefaultTableColumnModel.getColumn(DefaultTableColumnModel.java:294)
    at javax.swing.plaf.basic.BasicTableHeaderUI.getHeaderRenderer(BasicTableHeaderUI.java:693)
    at javax.swing.plaf.basic.BasicTableHeaderUI.paintCell(BasicTableHeaderUI.java:709)
    at javax.swing.plaf.basic.BasicTableHeaderUI.paint(BasicTableHeaderUI.java:685)
    at javax.swing.plaf.ComponentUI.update(ComponentUI.java:161)
    at javax.swing.JComponent.paintComponent(JComponent.java:780)
    at javax.swing.JComponent.paint(JComponent.java:1056)
    at javax.swing.JComponent.paintToOffscreen(JComponent.java:5210)
    at javax.swing.RepaintManager$PaintManager.paintDoubleBuffered(RepaintManager.java:1579)
    at javax.swing.RepaintManager$PaintManager.paint(RepaintManager.java:1502)
    at javax.swing.RepaintManager.paint(RepaintManager.java:1272)
    at javax.swing.JComponent._paintImmediately(JComponent.java:5158)
    at javax.swing.JComponent.paintImmediately(JComponent.java:4969)
    at javax.swing.RepaintManager$4.run(RepaintManager.java:831)
    at javax.swing.RepaintManager$4.run(RepaintManager.java:814)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:76)
    at javax.swing.RepaintManager.paintDirtyRegions(RepaintManager.java:814)
    at javax.swing.RepaintManager.paintDirtyRegions(RepaintManager.java:789)
    at javax.swing.RepaintManager.prePaintDirtyRegions(RepaintManager.java:738)
    at javax.swing.RepaintManager.access$1200(RepaintManager.java:64)
    at javax.swing.RepaintManager$ProcessingRunnable.run(RepaintManager.java:1732)
    at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:311)
    at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:756)
    at java.awt.EventQueue.access$500(EventQueue.java:97)
    at java.awt.EventQueue$3.run(EventQueue.java:709)
    at java.awt.EventQueue$3.run(EventQueue.java:703)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:76)
    at java.awt.EventQueue.dispatchEvent(EventQueue.java:726)
    at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:201)
    at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116)
    at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93)
    at java.awt.EventDispatchThread.run(EventDispatchThread.java:82)

如果相关的话，这会在 Java 8 中发生。更改 JRE/JDK 不是一个选项。

Answer 1

我们的环境中意外地遇到了相同的错误，但确实是零星的，所以我无法重现它。但你的例子是完美的，我能够重现我的错误。请参阅下面的代码。

我在调查过程中修改了我的答案。旧的注释不会反射(reflect)最新的代码。

您的问题是已报告的错误: https://bugs.java.com/bugdatabase/view_bug.do?bug_id=8068824

这是一个基于错误解决方法的解决方案:

import java.awt.BorderLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.JFrame;
import javax.swing.JMenuItem;
import javax.swing.JPopupMenu;
import javax.swing.JTable;
import javax.swing.table.DefaultTableModel;
import javax.swing.table.TableColumn;

public class BasicExample extends JFrame {
  private JTable t;
  private DefaultTableModel dtm;

  public BasicExample() {
    init();
  }

  private void init() {
    dtm = new DefaultTableModel(new String[][] { { "a", "b" }, { "c", "d" } },
        new String[] { "A", "B" });
    t = new JTable(dtm);

    t.getTableHeader().setComponentPopupMenu(new PopupMenu(t));
    this.setLayout(new BorderLayout());
    add(t.getTableHeader(), BorderLayout.NORTH);
    add(t, BorderLayout.CENTER);
    pack();
    setVisible(true);
    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
  }

  public class PopupMenu extends JPopupMenu {

    private JTable table;

    public PopupMenu(JTable table) {
      this.table = table;
      init();
    }

    private void init() {
      for (int i = 0; i < table.getModel().getColumnCount(); i++) {
        String columnName = table.getModel().getColumnName(i);

        JMenuItem item = new JMenuItem(columnName);
        item.addActionListener(new ActionListener() {
          @Override
          public void actionPerformed(ActionEvent e) {
            TableColumn tc = table.getColumn(columnName);

            t.getTableHeader().setDraggedColumn(null);

            table.getColumnModel().removeColumn(tc);
          }
        });
        this.add(item);
      }
    }
  }

  public static void main(String[] args) {
    BasicExample be = new BasicExample();
  }
}

只需在删除之前将draggedColumn设置为null即可。

我一直在挖掘，因为它没有解释为什么在我们的环境中该错误很少发生并且仅在 QA 中发生。 :)

这是代码在我们的环境中的外观(再次感谢非常好的小示例)。

import java.awt.BorderLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;

import javax.swing.JFrame;
import javax.swing.JMenuItem;
import javax.swing.JPopupMenu;
import javax.swing.JTable;
import javax.swing.table.DefaultTableModel;
import javax.swing.table.TableColumn;

public class BasicExample extends JFrame {
  private JTable t;
  private DefaultTableModel dtm;

  public BasicExample() {
    init();
  }

  private void init() {
    dtm = new DefaultTableModel(new String[][] { { "a", "b" }, { "c", "d" } },
        new String[] { "A", "B" });
    t = new JTable(dtm);

    PopupMenu lPopupMenu = new PopupMenu(t);

    //    t.getTableHeader().setComponentPopupMenu(new PopupMenu(t));
    t.getTableHeader().addMouseListener(new MouseAdapter() {
      @Override
      public void mousePressed(MouseEvent pE) {
        lPopupMenu.show(pE.getComponent(), pE.getX(), pE.getY());
      }
    });

    this.setLayout(new BorderLayout());
    add(t.getTableHeader(), BorderLayout.NORTH);
    add(t, BorderLayout.CENTER);
    pack();
    setVisible(true);
    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
  }

  public class PopupMenu extends JPopupMenu {

    private JTable table;

    public PopupMenu(JTable table) {
      this.table = table;
      init();
    }

    private void init() {
      for (int i = 0; i < table.getModel().getColumnCount(); i++) {
        String columnName = table.getModel().getColumnName(i);

        JMenuItem item = new JMenuItem(columnName);
        item.addActionListener(new ActionListener() {
          @Override
          public void actionPerformed(ActionEvent e) {
            TableColumn tc = table.getColumn(columnName);

            //            t.getTableHeader().setDraggedColumn(null);

            table.getColumnModel().removeColumn(tc);
          }
        });
        this.add(item);
      }
    }
  }

  public static void main(String[] args) {
    BasicExample be = new BasicExample();
  }
}

与您的代码的区别在于我们不使用setComponentPopupMenu()，而是手动显示PopupMenu。并且您的用例不会在我们的代码中产生异常。
为什么？
好问题，但我没有答案。
不知何故，您的代码 JPopupMenu 消耗了鼠标事件。并使用我们的代码 JPopupMenu 将鼠标事件传播到底层组件。如果你用 UI 代替表头就可以看到它。
这就是我用我们的代码重现异常的方式:在标题上按鼠标右键，但不要释放它，并继续将鼠标移到远离标题的弹出窗口上。当指针远离标题时释放右键(这样标题就不会处理 MOUSE_RELEASED 事件)。获取异常。