2 Responses to “AutoComplete JComboBox”

1. 
   1
   Oso Says:
   August 17th, 2010 at 6:48 pm

   Your code works great… I’ve made a couple changes so that you can change the ComboBoxModel at runtime with and still have the functionallity:

   package net.perroazul.nalib.desktop;

   import java.awt.event.FocusEvent;
   import java.awt.event.FocusListener;
   import java.awt.event.KeyEvent;
   import java.awt.event.KeyListener;
   import java.beans.PropertyChangeEvent;
   import java.beans.PropertyChangeListener;
   import javax.swing.ComboBoxModel;
   import javax.swing.JComboBox;
   import javax.swing.text.AttributeSet;
   import javax.swing.text.BadLocationException;
   import javax.swing.text.JTextComponent;
   import javax.swing.text.PlainDocument;

   /*
   * Tomado de http://tech.chitgoks.com/2009/11/06/autocomplete-jcombobox/
   */
   public class JComboBoxAutoCompletador extends PlainDocument implements FocusListener, KeyListener, PropertyChangeListener {

   //
   private JComboBox comboBox;
   private ComboBoxModel model;
   private JTextComponent editor;
   private boolean hidePopupOnFocusLoss;
   //

   //
   public JComboBoxAutoCompletador() {
   // Bug 5100422 on Java 1.5: Editable JComboBox won’t hide popup when tabbing out
   hidePopupOnFocusLoss = System.getProperty(“java.version”).startsWith(“1.5″);
   }

   public JComboBoxAutoCompletador(JComboBox jcb) {
   this();
   registraComboBox(jcb);
   }
   //

   //
   public void registraComboBox(JComboBox jcb) {
   desregistraComboBox();
   this.comboBox = jcb;
   comboBox.setEditable(true);
   model = comboBox.getModel();
   editor = (JTextComponent) comboBox.getEditor().getEditorComponent();
   editor.setDocument(this);
   // Highlight whole text when focus gets lost
   editor.addFocusListener(this);
   // Highlight whole text when user hits enter
   editor.addKeyListener(this);
   comboBox.addPropertyChangeListener(this);
   // Handle initially selected object
   Object selected = comboBox.getSelectedItem();
   if(selected != null)
   editor.setText(selected.toString());
   else
   editor.setText(“”);
   }

   public void desregistraComboBox() {
   if(comboBox != null) {
   comboBox.getEditor().getEditorComponent().removeFocusListener(this);
   comboBox.getEditor().getEditorComponent().removeKeyListener(this);
   comboBox.removePropertyChangeListener(this);
   comboBox.setSelectedItem(null);
   comboBox = null;
   }
   }
   //

   //
   @Override
   public void insertString(int offs, String str, AttributeSet a) throws BadLocationException {
   // construct the resulting string
   String currentText = getText(0, getLength());
   String beforeOffset = currentText.substring(0, offs);
   String afterOffset = currentText.substring(offs, currentText.length());
   String futureText = beforeOffset + str + afterOffset;
   // lookup and select a matching item
   Object item = lookupItem(futureText);
   if (item != null)
   comboBox.setSelectedItem(item);
   else {
   // keep old item selected if there is no match
   item = comboBox.getSelectedItem();
   // imitate no insert (later on offs will be incremented by str.length(): selection won’t move forward)
   offs = offs – str.length();
   // provide feedback to the user that his input has been received but can not be accepted
   comboBox.getToolkit().beep(); // when available use: UIManager.getLookAndFeel().provideErrorFeedback(comboBox);
   }

   // remove all text and insert the completed string
   super.remove(0, getLength());
   super.insertString(0, item.toString(), a);

   // if the user selects an item via mouse the the whole string will be inserted.
   // highlight the entire text if this happens.
   if (item.toString().equals(str) && offs == 0)
   highlightCompletedText(0);
   else {
   highlightCompletedText(offs + str.length());
   // show popup when the user types
   if(comboBox.isShowing() && comboBox.isFocusOwner())
   comboBox.setPopupVisible(true);
   }
   }

   private void highlightCompletedText(int start) {
   editor.setCaretPosition(getLength());
   editor.moveCaretPosition(start);
   }

   private Object lookupItem(String pattern) {
   Object selectedItem = model.getSelectedItem();
   // only search for a different item if the currently selected does not match
   if (selectedItem != null && startsWithIgnoreCase(selectedItem.toString(), pattern))
   return selectedItem;
   else {
   // iterate over all items
   for (int i = 0, n = model.getSize(); i < n; i++) {
   Object currentItem = model.getElementAt(i);
   // current item starts with the pattern?
   if(startsWithIgnoreCase(currentItem.toString(), pattern))
   return currentItem;
   }
   }
   // no item starts with the pattern => return null
   return null;
   }

   private boolean startsWithIgnoreCase(String str1, String str2) {
   return str1.toUpperCase().startsWith(str2.toUpperCase());
   }
   //

   //
   @Override
   public void focusGained(FocusEvent e) { }

   @Override
   public void focusLost(FocusEvent e) {
   highlightCompletedText(0);
   // Workaround for Bug 5100422 – Hide Popup on focus loss
   if(hidePopupOnFocusLoss)
   comboBox.setPopupVisible(false);
   }
   //

   //
   @Override
   public void keyTyped(KeyEvent e) { }

   @Override
   public void keyReleased(KeyEvent e) { }

   @Override
   public void keyPressed(KeyEvent e) {
   if (e.getKeyCode() == KeyEvent.VK_ENTER)
   highlightCompletedText(0);
   else if (e.getKeyCode() == KeyEvent.VK_ESCAPE) {
   comboBox.setSelectedIndex(0);
   editor.setText(comboBox.getSelectedItem().toString());
   highlightCompletedText(0);
   }
   }
   //

   //
   @Override
   public void propertyChange(PropertyChangeEvent evt) {
   if(evt.getPropertyName().equals(“model”))
   registraComboBox(comboBox);
   }
   //

   }

2. 
   2
   tech Says:
   August 17th, 2010 at 6:52 pm

   @oso: thanks for sharing. this can come in handy

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