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在this thread中，我找到了一種在JTextField（和JComboBox，但沒有問題）中實現AutoComplete功能的方法。JTextField AutoCompletion Error
當試圖在JTextField中實現此功能時，會引發一些例外情況。以下代碼將演示此問題。它非常簡單，非常類似於我用JComboBox，這很好。
有人可以幫我找到解決辦法。
下面的代碼：
（請注意，我使用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);
}
}
這是錯誤消息我得到：
（這是一個有點長：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)