一、实现效果

二、代码

Java代码  

importjava.awt.*;

importjava.awt.event.*;

importjava.util.*;

importjavax.swing.*;

importjavax.swing.event.*;

publicclassTest {

publicstaticvoidmain(String[] args)throwsException {

UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());

JFrame frame =newJFrame();

frame.setTitle("Auto Completion Test");

frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

frame.setBounds(200,200,500,400);

ArrayList items =newArrayList();

Locale[] locales = Locale.getAvailableLocales();

for(inti =0; i

String item = locales[i].getDisplayName();

System.out.println(item);

items.add(item);

}

JTextField txtInput =newJTextField();

setupAutoComplete(txtInput, items);

txtInput.setColumns(30);

frame.getContentPane().setLayout(newFlowLayout());

frame.getContentPane().add(txtInput, BorderLayout.NORTH);

frame.setVisible(true);

}

privatestaticbooleanisAdjusting(JComboBox cbInput) {

if(cbInput.getClientProperty("is_adjusting")instanceofBoolean) {

return(Boolean) cbInput.getClientProperty("is_adjusting");

}

returnfalse;

}

privatestaticvoidsetAdjusting(JComboBox cbInput,booleanadjusting) {

cbInput.putClientProperty("is_adjusting", adjusting);

}

publicstaticvoidsetupAutoComplete(finalJTextField txtInput,finalArrayList items) {

finalDefaultComboBoxModel model =newDefaultComboBoxModel();

finalJComboBox cbInput =newJComboBox(model) {

publicDimension getPreferredSize() {

returnnewDimension(super.getPreferredSize().width,0);

}

};

setAdjusting(cbInput,false);

for(String item : items) {

model.addElement(item);

}

cbInput.setSelectedItem(null);

cbInput.addActionListener(newActionListener() {

@Override

publicvoidactionPerformed(ActionEvent e) {

if(!isAdjusting(cbInput)) {

if(cbInput.getSelectedItem() !=null) {

txtInput.setText(cbInput.getSelectedItem().toString());

}

}

}

});

txtInput.addKeyListener(newKeyAdapter() {

@Override

publicvoidkeyPressed(KeyEvent e) {

setAdjusting(cbInput,true);

if(e.getKeyCode() == KeyEvent.VK_SPACE) {

if(cbInput.isPopupVisible()) {

e.setKeyCode(KeyEvent.VK_ENTER);

}

}

if(e.getKeyCode() == KeyEvent.VK_ENTER || e.getKeyCode() == KeyEvent.VK_UP || e.getKeyCode() == KeyEvent.VK_DOWN) {

e.setSource(cbInput);

cbInput.dispatchEvent(e);

if(e.getKeyCode() == KeyEvent.VK_ENTER) {

txtInput.setText(cbInput.getSelectedItem().toString());

cbInput.setPopupVisible(false);

}

}

if(e.getKeyCode() == KeyEvent.VK_ESCAPE) {

cbInput.setPopupVisible(false);

}

setAdjusting(cbInput,false);

}

});

txtInput.getDocument().addDocumentListener(newDocumentListener() {

publicvoidinsertUpdate(DocumentEvent e) {

updateList();

}

publicvoidremoveUpdate(DocumentEvent e) {

updateList();

}

publicvoidchangedUpdate(DocumentEvent e) {

updateList();

}

privatevoidupdateList() {

setAdjusting(cbInput,true);

model.removeAllElements();

String input = txtInput.getText();

if(!input.isEmpty()) {

for(String item : items) {

if(item.toLowerCase().startsWith(input.toLowerCase())) {

model.addElement(item);

}

}

}

cbInput.setPopupVisible(model.getSize() >0);

setAdjusting(cbInput,false);

}

});

txtInput.setLayout(newBorderLayout());

txtInput.add(cbInput, BorderLayout.SOUTH);

}

}

import java.awt.*;

import java.awt.event.*;

import java.util.*;

import javax.swing.*;

import javax.swing.event.*;

public class Test {

public static void main(String[] args) throws Exception {

UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());

JFrame frame = new JFrame();

frame.setTitle("Auto Completion Test");

frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

frame.setBounds(200, 200, 500, 400);

ArrayList items = new ArrayList();

Locale[] locales = Locale.getAvailableLocales();

for (int i = 0; i < locales.length; i++) {

String item = locales[i].getDisplayName();

System.out.println(item);

items.add(item);

}

JTextField txtInput = new JTextField();

setupAutoComplete(txtInput, items);

txtInput.setColumns(30);

frame.getContentPane().setLayout(new FlowLayout());

frame.getContentPane().add(txtInput, BorderLayout.NORTH);

frame.setVisible(true);

}

private static boolean isAdjusting(JComboBox cbInput) {

if (cbInput.getClientProperty("is_adjusting") instanceof Boolean) {

return (Boolean) cbInput.getClientProperty("is_adjusting");

}

return false;

}

private static void setAdjusting(JComboBox cbInput, boolean adjusting) {

cbInput.putClientProperty("is_adjusting", adjusting);

}

public static void setupAutoComplete(final JTextField txtInput, final ArrayList items) {

final DefaultComboBoxModel model = new DefaultComboBoxModel();

final JComboBox cbInput = new JComboBox(model) {

public Dimension getPreferredSize() {

return new Dimension(super.getPreferredSize().width, 0);

}

};

setAdjusting(cbInput, false);

for (String item : items) {

model.addElement(item);

}

cbInput.setSelectedItem(null);

cbInput.addActionListener(new ActionListener() {

@Override

public void actionPerformed(ActionEvent e) {

if (!isAdjusting(cbInput)) {

if (cbInput.getSelectedItem() != null) {

txtInput.setText(cbInput.getSelectedItem().toString());

}

}

}

});

txtInput.addKeyListener(new KeyAdapter() {

@Override

public void keyPressed(KeyEvent e) {

setAdjusting(cbInput, true);

if (e.getKeyCode() == KeyEvent.VK_SPACE) {

if (cbInput.isPopupVisible()) {

e.setKeyCode(KeyEvent.VK_ENTER);

}

}

if (e.getKeyCode() == KeyEvent.VK_ENTER || e.getKeyCode() == KeyEvent.VK_UP || e.getKeyCode() == KeyEvent.VK_DOWN) {

e.setSource(cbInput);

cbInput.dispatchEvent(e);

if (e.getKeyCode() == KeyEvent.VK_ENTER) {

txtInput.setText(cbInput.getSelectedItem().toString());

cbInput.setPopupVisible(false);

}

}

if (e.getKeyCode() == KeyEvent.VK_ESCAPE) {

cbInput.setPopupVisible(false);

}

setAdjusting(cbInput, false);

}

});

txtInput.getDocument().addDocumentListener(new DocumentListener() {

public void insertUpdate(DocumentEvent e) {

updateList();

}

public void removeUpdate(DocumentEvent e) {

updateList();

}

public void changedUpdate(DocumentEvent e) {

updateList();

}

private void updateList() {

setAdjusting(cbInput, true);

model.removeAllElements();

String input = txtInput.getText();

if (!input.isEmpty()) {

for (String item : items) {

if (item.toLowerCase().startsWith(input.toLowerCase())) {

model.addElement(item);

}

}

}

cbInput.setPopupVisible(model.getSize() > 0);

setAdjusting(cbInput, false);

}

});

txtInput.setLayout(new BorderLayout());

txtInput.add(cbInput, BorderLayout.SOUTH);

}

}