ComboBox Menu Example
// Example from http://www.crionics.com/products/opensource/faq/swing_ex/SwingExamples.html
import java.awt.Color;
import java.awt.Component;
import java.awt.Dimension;
import java.awt.FlowLayout;
import java.awt.Graphics;
import java.awt.Insets;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import javax.swing.Icon;
import javax.swing.JButton;
import javax.swing.JComboBox;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JMenuItem;
import javax.swing.JPanel;
import javax.swing.SwingConstants;
import javax.swing.UIManager;
import javax.swing.border.EtchedBorder;
import javax.swing.border.TitledBorder;
import javax.swing.plaf.basic.BasicArrowButton;
/**
* @version 1.0 05/10/99
*/
public class ComboBoxMenuExample extends JFrame {
public ComboBoxMenuExample() {
super("ComboBoxMenu Example");
String[] itemStr = { "name", "Red", "Blue", "number", "255,0,0",
"0,0,255",
// separator
"system", "control", "controlHighlight", "controlShadow",
"text" };
JMenuItem[] menuItems = new JMenuItem[7];
menuItems[0] = new JMenuItem(itemStr[1]);
menuItems[1] = new JMenuItem(itemStr[2]);
menuItems[2] = new JMenuItem(itemStr[4]);
menuItems[3] = new JMenuItem(itemStr[5]);
menuItems[4] = new JMenuItem(itemStr[8]);
menuItems[5] = new JMenuItem(itemStr[9]);
menuItems[6] = new JMenuItem(itemStr[10]);
JMenu[] menus = new JMenu[4];
menus[0] = new JMenu(itemStr[0]);
menus[1] = new JMenu(itemStr[3]);
menus[2] = new JMenu(itemStr[6]);
menus[3] = new JMenu(itemStr[7]);
menus[0].add(menuItems[0]);
menus[0].add(menuItems[1]);
menus[1].add(menuItems[2]);
menus[1].add(menuItems[3]);
menus[3].add(menuItems[4]);
menus[3].add(menuItems[5]);
menus[2].add(menus[3]);
menus[2].add(menuItems[6]);
JMenu menu = ComboMenuBar.createMenu(menuItems[0].getText());
menu.add(menus[0]);
menu.add(menus[1]);
menu.addSeparator();
menu.add(menus[2]);
ComboMenuBar comboMenu = new ComboMenuBar(menu);
JComboBox combo = new JComboBox();
combo.addItem(itemStr[1]);
combo.addItem(itemStr[2]);
combo.addItem(itemStr[4]);
combo.addItem(itemStr[5]);
combo.addItem(itemStr[8]);
combo.addItem(itemStr[9]);
combo.addItem(itemStr[10]);
getContentPane().setLayout(new FlowLayout());
getContentPane().add(new ComboPanel("Fake ComboBox", comboMenu));
getContentPane().add(new ComboPanel("ComboBox", combo));
}
class ComboPanel extends JPanel {
ComboPanel(String title, JComponent c) {
setLayout(new FlowLayout());
setBorder(new TitledBorder(title));
add(c);
}
}
public static void main(String args[]) {
try {
UIManager.setLookAndFeel("com.sun.java.swing.plaf.windows.WindowsLookAndFeel");
} catch (Exception evt) {}
ComboBoxMenuExample frame = new ComboBoxMenuExample();
frame.addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent e) {
System.exit(0);
}
});
frame.setSize(370, 100);
frame.setVisible(true);
}
}
class ComboMenuBar extends JMenuBar {
JMenu menu;
Dimension preferredSize;
public ComboMenuBar(JMenu menu) {
this.menu = menu;
Color color = UIManager.getColor("Menu.selectionBackground");
UIManager.put("Menu.selectionBackground", UIManager
.getColor("Menu.background"));
menu.updateUI();
UIManager.put("Menu.selectionBackground", color);
MenuItemListener listener = new MenuItemListener();
setListener(menu, listener);
add(menu);
}
class MenuItemListener implements ActionListener {
public void actionPerformed(ActionEvent e) {
JMenuItem item = (JMenuItem) e.getSource();
menu.setText(item.getText());
menu.requestFocus();
}
}
private void setListener(JMenuItem item, ActionListener listener) {
if (item instanceof JMenu) {
JMenu menu = (JMenu) item;
int n = menu.getItemCount();
for (int i = 0; i < n; i++) {
setListener(menu.getItem(i), listener);
}
} else if (item != null) { // null means separator
item.addActionListener(listener);
}
}
public String getSelectedItem() {
return menu.getText();
}
public void setPreferredSize(Dimension size) {
preferredSize = size;
}
public Dimension getPreferredSize() {
if (preferredSize == null) {
Dimension sd = super.getPreferredSize();
Dimension menuD = getItemSize(menu);
Insets margin = menu.getMargin();
Dimension retD = new Dimension(menuD.width, margin.top
+ margin.bottom + menuD.height);
menu.setPreferredSize(retD);
preferredSize = retD;
}
return preferredSize;
}
private Dimension getItemSize(JMenu menu) {
Dimension d = new Dimension(0, 0);
int n = menu.getItemCount();
for (int i = 0; i < n; i++) {
Dimension itemD;
JMenuItem item = menu.getItem(i);
if (item instanceof JMenu) {
itemD = getItemSize((JMenu) item);
} else if (item != null) {
itemD = item.getPreferredSize();
} else {
itemD = new Dimension(0, 0); // separator
}
d.width = Math.max(d.width, itemD.width);
d.height = Math.max(d.height, itemD.height);
}
return d;
}
public static class ComboMenu extends JMenu {
ArrowIcon iconRenderer;
public ComboMenu(String label) {
super(label);
iconRenderer = new ArrowIcon(SwingConstants.SOUTH, true);
setBorder(new EtchedBorder());
setIcon(new BlankIcon(null, 11));
setHorizontalTextPosition(JButton.LEFT);
setFocusPainted(true);
}
public void paintComponent(Graphics g) {
super.paintComponent(g);
Dimension d = this.getPreferredSize();
int x = Math.max(0, d.width - iconRenderer.getIconWidth() - 3);
int y = Math.max(0,
(d.height - iconRenderer.getIconHeight()) / 2 - 2);
iconRenderer.paintIcon(this, g, x, y);
}
}
public static JMenu createMenu(String label) {
return new ComboMenu(label);
}
}
class ArrowIcon implements Icon, SwingConstants {
private static final int DEFAULT_SIZE = 11;
//private static final int DEFAULT_SIZE = 5;
private int size;
private int iconSize;
private int direction;
private boolean isEnabled;
private BasicArrowButton iconRenderer;
public ArrowIcon(int direction, boolean isPressedView) {
this(DEFAULT_SIZE, direction, isPressedView);
}
public ArrowIcon(int iconSize, int direction, boolean isEnabled) {
this.size = iconSize / 2;
this.iconSize = iconSize;
this.direction = direction;
this.isEnabled = isEnabled;
iconRenderer = new BasicArrowButton(direction);
}
public void paintIcon(Component c, Graphics g, int x, int y) {
iconRenderer.paintTriangle(g, x, y, size, direction, isEnabled);
}
public int getIconWidth() {
//int retCode;
switch (direction) {
case NORTH:
case SOUTH:
return iconSize;
case EAST:
case WEST:
return size;
}
return iconSize;
}
public int getIconHeight() {
switch (direction) {
case NORTH:
case SOUTH:
return size;
case EAST:
case WEST:
return iconSize;
}
return size;
}
}
class BlankIcon implements Icon {
private Color fillColor;
private int size;
public BlankIcon() {
this(null, 11);
}
public BlankIcon(Color color, int size) {
//UIManager.getColor("control")
//UIManager.getColor("controlShadow")
fillColor = color;
this.size = size;
}
public void paintIcon(Component c, Graphics g, int x, int y) {
if (fillColor != null) {
g.setColor(fillColor);
g.drawRect(x, y, size - 1, size - 1);
}
}
public int getIconWidth() {
return size;
}
public int getIconHeight() {
return size;
}
}
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