使用 setModel() 更新 JComboBox 时出现 java.lang.IllegalStateException？

Question

我试图用 setModel() 更新 JComboBox。但是，它会抛出 java.lang.IllegalStateException。具体来说，我使用 JTextField 指向 JComboBox 的可编辑组件，并在每次 JTextField 收到新输入时更新 JComboBox。

谁能告诉我原因吗？

package ui;

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;

import javax.swing.DefaultComboBoxModel;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.JToolBar;
import javax.swing.event.DocumentEvent;
import javax.swing.event.DocumentListener;

public class TestFrame extends JFrame implements DocumentListener {

    private static final long serialVersionUID = 1L;

    // tool bar
    private JToolBar topToolBar;
    private JTextField wordSearchField;
    private JComboBox<String> wordSearchTips;

    // window size
    private static final int width = 700;
    private static final int height = 500;

    public TestFrame() {
    }

    public static void main(String[] argv) {
        new TestFrame().CreateUI();
    }

    public void CreateUI() {
        setPreferredSize(new Dimension(width, height));
        setResizable(false);
        setLayout(new BorderLayout());

        // bottom
        JPanel bottom = new JPanel();
        bottom.setPreferredSize(new Dimension(width, 480));
        bottom.setLayout(new BorderLayout());

        // top
        topToolBar = new JToolBar();
        topToolBar.setBackground(Color.WHITE);
        topToolBar.setPreferredSize(new Dimension(width, 30));

        wordSearchTips = new JComboBox<String>();
        wordSearchTips.setEditable(true);
        wordSearchTips.setSelectedIndex(-1);
        wordSearchField = (JTextField) wordSearchTips.getEditor()
                .getEditorComponent();
        wordSearchField.getDocument().addDocumentListener(this);

        topToolBar.add(wordSearchTips);

        add(topToolBar, BorderLayout.NORTH);
        add(bottom, BorderLayout.SOUTH);

        pack();
        setVisible(true);

    }

    @Override
    public void changedUpdate(DocumentEvent e) {

    }

    @Override
    public void insertUpdate(DocumentEvent e) {

        String keyword = wordSearchField.getText().trim();
        DefaultComboBoxModel<String> m = new DefaultComboBoxModel<String>();
        ;
        for (int i = 0; i < 10; i++) {
            m.addElement(i + "");
        }
        wordSearchTips.setModel(m);
        wordSearchTips.setSelectedIndex(-1);
        ((JTextField) wordSearchTips.getEditor().getEditorComponent())
                .setText(keyword);
        wordSearchTips.showPopup();
    }

    @Override
    public void removeUpdate(DocumentEvent e) {
    }
}

以下是异常(exception)情况:

Exception in thread "AWT-EventQueue-0" java.lang.IllegalStateException: Attempt to mutate in notification
    at javax.swing.text.AbstractDocument.writeLock(Unknown Source)
    at javax.swing.text.AbstractDocument.replace(Unknown Source)
    at javax.swing.text.JTextComponent.setText(Unknown Source)
    at javax.swing.plaf.metal.MetalComboBoxEditor$1.setText(Unknown Source)
    at javax.swing.plaf.basic.BasicComboBoxEditor.setItem(Unknown Source)
    at javax.swing.JComboBox.configureEditor(Unknown Source)
    at javax.swing.plaf.basic.BasicComboBoxUI$Handler.propertyChange(Unknown Source)
    at javax.swing.plaf.basic.BasicComboBoxUI$PropertyChangeHandler.propertyChange(Unknown Source)
    at javax.swing.plaf.metal.MetalComboBoxUI$MetalPropertyChangeListener.propertyChange(Unknown Source)
    at java.beans.PropertyChangeSupport.fire(Unknown Source)
    at java.beans.PropertyChangeSupport.firePropertyChange(Unknown Source)
    at java.beans.PropertyChangeSupport.firePropertyChange(Unknown Source)
    at java.awt.Component.firePropertyChange(Unknown Source)
    at javax.swing.JComboBox.setModel(Unknown Source)
    at ui.TestFrame.insertUpdate(TestFrame.java:94)
    at javax.swing.text.AbstractDocument.fireInsertUpdate(Unknown Source)
    at javax.swing.text.AbstractDocument.handleInsertString(Unknown Source)
    at javax.swing.text.AbstractDocument.insertString(Unknown Source)
    at javax.swing.text.PlainDocument.insertString(Unknown Source)
    at javax.swing.text.AbstractDocument.replace(Unknown Source)
    at javax.swing.text.JTextComponent.replaceSelection(Unknown Source)
    at javax.swing.text.DefaultEditorKit$DefaultKeyTypedAction.actionPerformed(Unknown Source)
    at javax.swing.SwingUtilities.notifyAction(Unknown Source)
    at javax.swing.JComponent.processKeyBinding(Unknown Source)
    at javax.swing.JComponent.processKeyBindings(Unknown Source)
    at javax.swing.JComponent.processKeyEvent(Unknown Source)
    at java.awt.Component.processEvent(Unknown Source)
    at java.awt.Container.processEvent(Unknown Source)
    at java.awt.Component.dispatchEventImpl(Unknown Source)
    at java.awt.Container.dispatchEventImpl(Unknown Source)
    at java.awt.Component.dispatchEvent(Unknown Source)
    at java.awt.KeyboardFocusManager.redispatchEvent(Unknown Source)
    at java.awt.DefaultKeyboardFocusManager.dispatchKeyEvent(Unknown Source)
    at java.awt.DefaultKeyboardFocusManager.preDispatchKeyEvent(Unknown Source)
    at java.awt.DefaultKeyboardFocusManager.typeAheadAssertions(Unknown Source)
    at java.awt.DefaultKeyboardFocusManager.dispatchEvent(Unknown Source)
    at java.awt.Component.dispatchEventImpl(Unknown Source)
    at java.awt.Container.dispatchEventImpl(Unknown Source)
    at java.awt.Window.dispatchEventImpl(Unknown Source)
    at java.awt.Component.dispatchEvent(Unknown Source)
    at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
    at java.awt.EventQueue.access$200(Unknown Source)
    at java.awt.EventQueue$3.run(Unknown Source)
    at java.awt.EventQueue$3.run(Unknown Source)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
    at java.awt.EventQueue$4.run(Unknown Source)
    at java.awt.EventQueue$4.run(Unknown Source)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
    at java.awt.EventQueue.dispatchEvent(Unknown Source)
    at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
    at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
    at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
    at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
    at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
    at java.awt.EventDispatchThread.run(Unknown Source)

Answer 1

将 insertUpdate(DocumentEvent e) 中的代码包装在 SwingUtilities.invokeLater()

中