JTextField 自动完成错误答案

【问题标题】：JTextField AutoCompletion ErrorJTextField 自动完成错误
【发布时间】：2012-08-09 08:51:43
【问题描述】：

在this thread 中，我找到了一种在JTextField（和JComboBox，但没有问题）中实现AutoComplete 功能的方法。

当尝试在 JTextField 中实现此功能时，它会引发一些异常。以下代码将演示该问题。它非常简单，与我使用JComboBox 的方式非常相似，效果很好。

谁能帮我找到解决办法。

代码如下：
（请注意我使用的是swingx）

import javax.swing.JList;
import org.jdesktop.swingx.JXFrame;
import org.jdesktop.swingx.JXTextField;
import org.jdesktop.swingx.autocomplete.AutoCompleteDecorator;

public class ErrorDemo {

    public static void main(String[] args) {
        JXFrame frame = new JXFrame("Error Demo");
        JXTextField field = new JXTextField();
        String[] users = {"aaa", "bbb", "ccc"};
        AutoCompleteDecorator.decorate(new JList(users), field);

        frame.getContentPane().add(field);
        frame.pack();
        frame.setLocationByPlatform(true);
        frame.setDefaultCloseOperation(JXFrame.EXIT_ON_CLOSE);
        frame.setVisible(true);
    }
}

这是我收到的错误消息：
（有点长：D）

Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
    at org.jdesktop.swingx.autocomplete.ListAdaptor.valueChanged(ListAdaptor.java:76)
    at javax.swing.JList.fireSelectionValueChanged(JList.java:1765)
    at javax.swing.JList$ListSelectionHandler.valueChanged(JList.java:1779)
    at javax.swing.DefaultListSelectionModel.fireValueChanged(DefaultListSelectionModel.java:167)
    at javax.swing.DefaultListSelectionModel.fireValueChanged(DefaultListSelectionModel.java:147)
    at javax.swing.DefaultListSelectionModel.fireValueChanged(DefaultListSelectionModel.java:194)
    at javax.swing.DefaultListSelectionModel.changeSelection(DefaultListSelectionModel.java:388)
    at javax.swing.DefaultListSelectionModel.changeSelection(DefaultListSelectionModel.java:398)
    at javax.swing.DefaultListSelectionModel.setSelectionInterval(DefaultListSelectionModel.java:442)
    at javax.swing.JList.setSelectedIndex(JList.java:2179)
    at javax.swing.JList.setSelectedValue(JList.java:2295)
    at org.jdesktop.swingx.autocomplete.ListAdaptor.setSelectedItem(ListAdaptor.java:98)
    at org.jdesktop.swingx.autocomplete.AutoCompleteDocument.setSelectedItem(AutoCompleteDocument.java:317)
    at org.jdesktop.swingx.autocomplete.AutoCompleteDocument.insertString(AutoCompleteDocument.java:265)
    at javax.swing.text.JTextComponent.replaceSelection(JTextComponent.java:1358)
    at javax.swing.text.DefaultEditorKit$DefaultKeyTypedAction.actionPerformed(DefaultEditorKit.java:859)
    at javax.swing.SwingUtilities.notifyAction(SwingUtilities.java:1636)
    at javax.swing.JComponent.processKeyBinding(JComponent.java:2849)
    at javax.swing.JComponent.processKeyBindings(JComponent.java:2884)
    at javax.swing.JComponent.processKeyEvent(JComponent.java:2812)
    at java.awt.Component.processEvent(Component.java:5815)
    at java.awt.Container.processEvent(Container.java:2058)
    at java.awt.Component.dispatchEventImpl(Component.java:4410)
    at java.awt.Container.dispatchEventImpl(Container.java:2116)
    at java.awt.Component.dispatchEvent(Component.java:4240)
    at java.awt.KeyboardFocusManager.redispatchEvent(KeyboardFocusManager.java:1848)
    at java.awt.DefaultKeyboardFocusManager.dispatchKeyEvent(DefaultKeyboardFocusManager.java:697)
    at java.awt.DefaultKeyboardFocusManager.preDispatchKeyEvent(DefaultKeyboardFocusManager.java:962)
    at java.awt.DefaultKeyboardFocusManager.typeAheadAssertions(DefaultKeyboardFocusManager.java:834)
    at java.awt.DefaultKeyboardFocusManager.dispatchEvent(DefaultKeyboardFocusManager.java:661)
    at java.awt.Component.dispatchEventImpl(Component.java:4282)
    at java.awt.Container.dispatchEventImpl(Container.java:2116)
    at java.awt.Window.dispatchEventImpl(Window.java:2429)
    at java.awt.Component.dispatchEvent(Component.java:4240)
    at java.awt.EventQueue.dispatchEvent(EventQueue.java:599)
    at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:273)
    at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:183)
    at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:173)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:168)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:160)
    at java.awt.EventDispatchThread.run(EventDispatchThread.java:121)

【问题讨论】：

标签： java autocomplete nullpointerexception jtextfield swingx

【解决方案1】：

您的代码中没有JList。我认为它应该是这样的......

        org.jdesktop.swingx.autocomplete.AutoCompleteDecorator.decorate(field, Arrays.asList(users), false);

如果您想将JList 绑定到TextField（以便文本字段将更新JList 的选择），您需要decorate(JList list, JTextComponent textComponent, ObjectToStringConverter stringConverter)...

【讨论】：