我有这个类扩展了jComboBox，并且我想将这些属性应用于摆动jComboBox，我该怎么做？例如，我创建了一个带有gui swing的jFrame，并创建了一个jComboBox到jPanel中，我需要这个jComboBox来像扩展的jComboBox类一样。
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.ItemEvent;
import java.awt.event.ItemListener;
import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import java.util.ArrayList;
import javax.swing.DefaultComboBoxModel;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JPanel;
/**
* This class extends JComboBox providing it with filtering capability.
*
* So the idea is this
*
* 1. Focus the combo
* 2. Type a character sequence
* 3. With each key press the box will update itself filtering out the items that do
* not match the users character sequence.
*
* Note 1:
* The user can press the left and right arrow keys to move forward and backward
* in the filter character sequence.
*
* Note 2:
* The user can press the "Back Space", "Delete", or "Escape" keys to restore the
* original values and reset the filtering sequence.
*
* Enjoy!
*
*/
public class FilterCombo extends JComboBox {
public FilterCombo(String[] itemList) {
FilterComboBoxModel model = new FilterComboBoxModel(itemList);
setModel(model);
model.addAllElements(itemList);
// Remove standard key listeners that come with the JComboBox
KeyListener[] lis = getKeyListeners();
for (int i = 0; i < lis.length; i++) {
removeKeyListener(lis[i]);
}
// Add custom KeyListener class
addKeyListener(model.getKeyListener());
// Add custom ActionListener class
addActionListener(model.getActionListener());
// Add your own custom action listener here if needed
addActionListener( new ActionListener() {
public void actionPerformed(ActionEvent e) {
System.out.println("Action Listener in FilterCombo class -- Add your code here");
}
});
// Add your own custom item listener here if needed
addItemListener( new ItemListener() {
public void itemStateChanged(ItemEvent e) {
System.out.println("Item Listener in FilterCombo class -- Add your code here");
}
});
}
public class FilterComboBoxModel extends DefaultComboBoxModel {
private String[] masterItemList;
private String masterSelectedItem;
private StringBuilder filter = new StringBuilder(8);
private int fidx = 0;
private CustomKeyListener keylis = null;
private CustomActionListener actionlis = null;
private ActionListener[] actionLisList;
private ItemListener[] itemLisList;
public FilterComboBoxModel(String[] itemList) {
initComboBoxModel(itemList);
}
private void initComboBoxModel( String[] itemList ) {
setMasterItemList(itemList);
}
public CustomKeyListener getKeyListener() {
if (keylis == null) {
keylis = new CustomKeyListener();
}
return keylis;
}
public CustomActionListener getActionListener() {
if (actionlis == null) {
actionlis = new CustomActionListener();
}
return actionlis;
}
public void setMasterItemList(String[] items) {
masterItemList = items;
masterSelectedItem = items[0];
restoreItems();
}
public void addAllElements(Object[] items) {
for (int i = 0; i < items.length; i++) {
addItem(items[i]);
}
}
public Object[] getAllElements() {
Object[] list = new Object[getItemCount()];
for (int i = 0; i < list.length; i++) {
list[i] = this.getElementAt(i);
}
return list;
}
public void filterItems(String pat) {
ArrayList<String> newList = new ArrayList<String>();
String[] list = masterItemList;
int patlen = pat.length();
for (int i = 0; i < list.length; i++) {
String item = list[i];
if (item.length() < patlen) {
continue;
}
String tok = item.substring(0, patlen);
if (tok.equalsIgnoreCase(pat)) {
newList.add(item);
}
}
// Add the new list to the combobox - notice we disable listeners
suspendAllListeners();
removeAllElements();
if (newList.isEmpty()) {
addItem("<Empty>");
} else {
addAllElements(newList.toArray());
}
if (fidx == 0)
setSelectedItem(masterSelectedItem);
restoreAllListeners();
}
private void suspendAllListeners() {
actionLisList = getActionListeners();
for (ActionListener a : actionLisList) {
removeActionListener(a);
}
itemLisList = getItemListeners();
for (ItemListener i : itemLisList) {
removeItemListener(i);
}
}
private void restoreAllListeners() {
for (ActionListener a : actionLisList) {
addActionListener(a);
}
for (ItemListener i : itemLisList) {
addItemListener(i);
}
}
public void restoreItems() {
suspendAllListeners();
removeAllElements();
addAllElements(masterItemList);
resetFilter();
setSelectedItem(masterSelectedItem);
restoreAllListeners();
}
private void resetFilter() {
filter.setLength(0);
fidx = 0;
}
public class CustomKeyListener extends KeyAdapter {
@Override
public void keyPressed(KeyEvent e) {
int keyCode = e.getKeyCode();
if (keyCode >= KeyEvent.VK_A && keyCode <= KeyEvent.VK_Z) {
char letter = (char) keyCode;
filter.insert(fidx, letter);
fidx++;
filter.setLength(fidx);
filterItems(filter.toString());
} else if (keyCode == KeyEvent.VK_LEFT) {
fidx = (fidx == 0 ? fidx : fidx - 1);
filterItems(filter.substring(0, fidx));
} else if (keyCode == KeyEvent.VK_RIGHT) {
fidx = (fidx == filter.length() ? fidx : fidx + 1);
filterItems(filter.substring(0, fidx));
} else if (keyCode == KeyEvent.VK_BACK_SPACE
|| keyCode == KeyEvent.VK_DELETE
|| keyCode == KeyEvent.VK_ESCAPE) {
restoreItems();
}
// System.out.println("fidx = " + fidx + " -- Filter: " + filter);
setToolTipText("Current filter: " + filter.substring(0, fidx));
}
}
public class CustomActionListener implements ActionListener {
public void actionPerformed(ActionEvent e) {
masterSelectedItem = (String) getSelectedItem();
restoreItems();
}
}
}
}
如果您要测试此类，请将此代码添加到同一类。
public static void main(String[] args) {
FilterCombo fc = new FilterCombo(new String[]{
"aaaaaaaaaaaaaaaaaa",
"bbbbbbbbbbbbbbbbbb",
"cccccccccccccccccc",
"ababababababababab",
"bababababababababa",
"cacaacacacacacacac",
"apple",
"banana",
"citrus"
});
// Create the frame
JFrame frame = new JFrame("FilterCombo Test");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLocationRelativeTo(null);
JPanel panel = new JPanel();
panel.add(fc);
frame.add(panel);
frame.pack();
frame.setVisible(true);
}
谢谢。