Using JComboBox as a Search

Possible Duplicate JComboBox autocomplete.However if you want to use a pure swing based solution follow this article. it's quite comprehensive

http://www.orbital-computer.de/JComboBox/

If you want the quick and easy solution, simply add this class to your project;

import java.awt.event.*;import java.beans.PropertyChangeEvent;import java.beans.PropertyChangeListener;import javax.swing.*;import javax.swing.text.*;/* This work is hereby released into the Public Domain. * To view a copy of the public domain dedication, visit * http://creativecommons.org/licenses/publicdomain/ */public class AutoCompletion extends PlainDocument {JComboBox comboBox;ComboBoxModel model;JTextComponent editor;// flag to indicate if setSelectedItem has been called// subsequent calls to remove/insertString should be ignoredboolean selecting=false;boolean hidePopupOnFocusLoss;boolean hitBackspace=false;boolean hitBackspaceOnSelection;KeyListener editorKeyListener;FocusListener editorFocusListener;public AutoCompletion(final JComboBox comboBox) {    this.comboBox = comboBox;    model = comboBox.getModel();    comboBox.addActionListener(new ActionListener() {        public void actionPerformed(ActionEvent e) {            if (!selecting) highlightCompletedText(0);        }    });    comboBox.addPropertyChangeListener(new PropertyChangeListener() {        public void propertyChange(PropertyChangeEvent e) {            if (e.getPropertyName().equals("editor")) configureEditor((ComboBoxEditor) e.getNewValue());            if (e.getPropertyName().equals("model")) model = (ComboBoxModel) e.getNewValue();        }    });    editorKeyListener = new KeyAdapter() {        public void keyPressed(KeyEvent e) {            if (comboBox.isDisplayable()) comboBox.setPopupVisible(true);            hitBackspace=false;            switch (e.getKeyCode()) {                // determine if the pressed key is backspace (needed by the remove method)                case KeyEvent.VK_BACK_SPACE : hitBackspace=true;                hitBackspaceOnSelection=editor.getSelectionStart()!=editor.getSelectionEnd();                break;                // ignore delete key                case KeyEvent.VK_DELETE : e.consume();                comboBox.getToolkit().beep();                break;            }        }    };    // Bug 5100422 on Java 1.5: Editable JComboBox won't hide popup when tabbing out    hidePopupOnFocusLoss=System.getProperty("java.version").startsWith("1.5");    // Highlight whole text when gaining focus    editorFocusListener = new FocusAdapter() {        public void focusGained(FocusEvent e) {            highlightCompletedText(0);        }        public void focusLost(FocusEvent e) {            // Workaround for Bug 5100422 - Hide Popup on focus loss            if (hidePopupOnFocusLoss) comboBox.setPopupVisible(false);        }    };    configureEditor(comboBox.getEditor());    // Handle initially selected object    Object selected = comboBox.getSelectedItem();    if (selected!=null) setText(selected.toString());    highlightCompletedText(0);}public static void enable(JComboBox comboBox) {    // has to be editable    comboBox.setEditable(true);    // change the editor's document    new AutoCompletion(comboBox);}void configureEditor(ComboBoxEditor newEditor) {    if (editor != null) {        editor.removeKeyListener(editorKeyListener);        editor.removeFocusListener(editorFocusListener);    }    if (newEditor != null) {        editor = (JTextComponent) newEditor.getEditorComponent();        editor.addKeyListener(editorKeyListener);        editor.addFocusListener(editorFocusListener);        editor.setDocument(this);    }}public void remove(int offs, int len) throws BadLocationException {    // return immediately when selecting an item    if (selecting) return;    if (hitBackspace) {        // user hit backspace => move the selection backwards        // old item keeps being selected        if (offs>0) {            if (hitBackspaceOnSelection) offs--;        } else {            // User hit backspace with the cursor positioned on the start => beep            comboBox.getToolkit().beep(); // when available use: UIManager.getLookAndFeel().provideErrorFeedback(comboBox);        }        highlightCompletedText(offs);    } else {        super.remove(offs, len);    }}public void insertString(int offs, String str, AttributeSet a) throws BadLocationException {    // return immediately when selecting an item    if (selecting) return;    // insert the string into the document    super.insertString(offs, str, a);    // lookup and select a matching item    Object item = lookupItem(getText(0, getLength()));    if (item != null) {        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);    }    setText(item.toString());    // select the completed part    highlightCompletedText(offs+str.length());}private void setText(String text) {    try {        // remove all text and insert the completed string        super.remove(0, getLength());        super.insertString(0, text, null);    } catch (BadLocationException e) {        throw new RuntimeException(e.toString());    }}private void highlightCompletedText(int start) {    editor.setCaretPosition(getLength());    editor.moveCaretPosition(start);}private void setSelectedItem(Object item) {    selecting = true;    model.setSelectedItem(item);    selecting = false;}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 (currentItem != null && startsWithIgnoreCase(currentItem.toString(), pattern)) {                return currentItem;            }        }    }    // no item starts with the pattern => return null    return null;}// checks if str1 starts with str2 - ignores caseprivate boolean startsWithIgnoreCase(String str1, String str2) {    return str1.toUpperCase().startsWith(str2.toUpperCase());}private static void createAndShowGUI() {    // the combo box (add/modify items if you like to)    final JComboBox comboBox = new JComboBox(new Object[] {"Ester", "Jordi", "Jordina", "Jorge", "Sergi"});    enable(comboBox);    // create and show a window containing the combo box    final JFrame frame = new JFrame();    frame.setDefaultCloseOperation(3);    frame.getContentPane().add(comboBox);    frame.pack(); frame.setVisible(true);}public static void main(String[] args) {    javax.swing.SwingUtilities.invokeLater(new Runnable() {        public void run() {            createAndShowGUI();        }    });}}

And then, to add the AutoCompletion feature to a JComboBox simply call;

AutoCompletion.enable(yourComboBox);