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《Java 2 图形设计卷Ⅱ- SWING》第10章 菜单和工具条
阅读量：6638 次
发布时间：2019-06-25

本文共 38989 字，大约阅读时间需要 129 分钟。

第10章 菜单和工具条

　　菜单和工具条是现代用户界面的重要组成部分。Swing提供了对这两者的完全支持。Swing提供菜单组件（即菜单条中的菜单和弹出式菜单中的菜单）和菜单项组件（包括复选框和单选按钮菜单项）。

　　Swing还提供一个工具条组件，根据工具条的方向，工具条组件包含一行按钮或一列按钮。工具条通常提供对普通特性的简单访问。通常，除键盘捷径键提供对相同功能的访问外，菜单栏和工具条不提供对相同功能集的访问。工具条还可以是悬浮的，这样，可以把工具条在窗口中任意拖动或拖到一个单独的窗口中。
　　Swing菜单和菜单项是按钮，因为JMenuItem扩展AbstractButton，JMenu扩展JMenuItem，如图10-1所示。因此，Swing菜单和菜单项继承了如下功能，即包含文本和（或)图标、显示光标进入时的图标和助记符等。
　　图10-1示出了JMenuItem和JMenu的父组件，它们最后都归于java.awt.Container，以强调菜单和菜单项都是容器。可以把任何类型的组件（从包含一个动画GIF的标签到JTree的一个实例）添加到一个菜单或菜单项中。
　　菜单和菜单项还实现MenuElement接口，以便参与菜单事件的处理。MenuElement接口在10.7节“菜单元素”中介绍。
　　工具条和弹出式菜单都扩展JComponent类，即任意组件都可以添加到一个工具条或弹出式菜单中。
　　本章将介绍下面的组件：
　　·JMenuItem
　　·JCheckBoxMenuItem
　　·JRadioButtonMenuItem
　　·JMenu
　　·JPopupMenu
　　·JMenuBar
　　·JToolBar

10.1 菜单、菜单栏和工具条

 

例10-1 JRootPane中的菜单栏和工具条

import javax.swing.*;

import java.awt.*;
import java.awt.event.*;

public class Test extends JApplet {

Icon
dukeStanding = new ImageIcon("duke_standing.gif"),
dukeWaving = new ImageIcon("duke_waving.gif"),
dukeStandingSmall =
new ImageIcon("duke_standing_small.gif"),
dukeWavingSmall = new ImageIcon("duke_waving_small.gif");

public void init() {

Container contentPane = getContentPane();
Action[] actions = {
new NewAction(),
new OpenAction(),
new CutAction(),
new CopyAction(),
new PasteAction(),
new ExitAction()
};
JToolBar toolbar = new JToolBar();
JMenuBar menubar = new JMenuBar();
JMenu fileMenu = new JMenu("File");

JRadioButton

menubarDuke = new JRadioButton(dukeStandingSmall),
menuDuke = new JRadioButton(dukeStandingSmall),
toolbarDuke = new JRadioButton(dukeStanding);
menuDuke.setRolloverIcon(dukeWavingSmall);
menubarDuke.setRolloverIcon(dukeWavingSmall);
toolbarDuke.setRolloverIcon(dukeWaving);

menubar.add(menubarDuke);

toolbar.add(toolbarDuke);
fileMenu.add(menuDuke);

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

fileMenu.add(actions[i]);

if(i != actions.length-1)

toolbar.add(actions[i]);

if(i == 2 || i == actions.length-2){

toolbar.addSeparator();
fileMenu.addSeparator();
}
}
menubar.add(fileMenu);

contentPane.add(toolbar, BorderLayout.NORTH);

getRootPane().setJMenuBar(menubar);
System.out.println(contentPane.getClass().getName());
LayoutManager lm = contentPane.getLayout();
System.out.println(lm.getClass());

}

class NewAction extends AbstractAction {
public NewAction() {
super("New ...", new ImageIcon("new.gif"));
}
public void actionPerformed(ActionEvent event) {
showStatus("new");
}
}
class OpenAction extends AbstractAction {
public OpenAction() {
super("Open ...", new ImageIcon("open.gif"));
}
public void actionPerformed(ActionEvent event) {
showStatus("open");
}
}
class CutAction extends AbstractAction {
public CutAction() {
super("Cut", new ImageIcon("cut.gif"));
}
public void actionPerformed(ActionEvent event) {
showStatus("cut");
}
}
class CopyAction extends AbstractAction {
public CopyAction() {
super("Copy", new ImageIcon("copy.gif"));
}
public void actionPerformed(ActionEvent event) {
showStatus("copy");
}
}
class PasteAction extends AbstractAction {
public PasteAction() {
super("Paste", new ImageIcon("paste.gif"));
}
public void actionPerformed(ActionEvent event) {
showStatus("paste");
}
}
class ExitAction extends AbstractAction {
public ExitAction() {
super("Exit");
putValue(Action.SMALL_ICON, dukeWavingSmall);
}
public void actionPerformed(ActionEvent event) {
System.exit(0);
}
}
}

10.2 菜单和弹出式菜单

 

例10-2 一个简单的菜单举例

import javax.swing.*;

import java.awt.*;
import java.awt.event.*;

public class Test extends JApplet {

public void init() {
JMenuBar mb = new JMenuBar();
JMenu fileMenu = new JMenu("File");
JMenu pullRightMenu = new JMenu("pull right");

fileMenu.add("New ...");

fileMenu.add("Open ...");
fileMenu.add("Save");
fileMenu.add("Save As ..");
fileMenu.addSeparator();
fileMenu.add(pullRightMenu);
fileMenu.add("Exit");

pullRightMenu.add(new JCheckBoxMenuItem("Bush"));

pullRightMenu.add(new JCheckBoxMenuItem("Tonic"));
pullRightMenu.add(new JCheckBoxMenuItem("Radio Head"));
pullRightMenu.add(new JCheckBoxMenuItem("Marcy Playground"));
pullRightMenu.add(new JCheckBoxMenuItem("Silver Chair"));

mb.add(fileMenu);

setJMenuBar(mb);
}
}

10.3 JMenuItem

 

例10-3 安装一些菜单项

import javax.swing.*;

import java.awt.*;
import java.awt.event.*;

public class Test extends JApplet {

public void init() {
Container contentPane = getContentPane();
Icon newIcon = new ImageIcon("new.gif",
"Create a new document");
Icon openIcon = new ImageIcon("open.gif",
"Open an existing document");

JMenuBar mb = new JMenuBar();

JMenu fileMenu = new JMenu("File");

JMenuItem newItem = new JMenuItem(newIcon);

JMenuItem openItem = new JMenuItem("Open ...", openIcon);
JMenuItem saveItem = new JMenuItem("Save");
JMenuItem saveAsItem = new JMenuItem("Save As ...");
JMenuItem exitItem = new JMenuItem("Exit", 'x');

fileMenu.add(newItem);

fileMenu.add(openItem);
fileMenu.add(saveItem);
fileMenu.add(saveAsItem);
fileMenu.addSeparator();
fileMenu.add(exitItem);

MenuItemListener listener = new MenuItemListener(this);

newItem.addActionListener(listener);

openItem.addActionListener(listener);
saveItem.addActionListener(listener);
saveAsItem.addActionListener(listener);

exitItem.addActionListener(new ActionListener() {

public void actionPerformed(ActionEvent e) {
System.exit(0);
}
});

mb.add(fileMenu);

setJMenuBar(mb);
}
}
class MenuItemListener implements ActionListener {
private JApplet applet;

public MenuItemListener(JApplet applet) {

this.applet = applet;
}
public void actionPerformed(ActionEvent e) {
JMenuItem item = (JMenuItem)e.getSource();
ImageIcon icon = (ImageIcon)item.getIcon();

if(icon != null)

System.out.println(icon.getDescription());
else
System.out.println(item.getText());
}
}

10.3.1菜单项快捷键助记符键

 

例10-4 带助记符键和快捷键的菜单项

import javax.swing.*;

import java.awt.*;
import java.awt.event.*;

public class Test extends JFrame {

public Test() {
Container contentPane = getContentPane();

JMenuBar mb = new JMenuBar();

JMenu fileMenu = new JMenu("File");
JMenuItem exitItem = new JMenuItem("Exit");

fileMenu.add("New ...");

fileMenu.add("Open ...");
fileMenu.add("Save");
fileMenu.add("Save As ..");
fileMenu.addSeparator();
fileMenu.add(exitItem);

exitItem.addActionListener(new ActionListener() {

public void actionPerformed(ActionEvent e) {
System.exit(0);
}
});

KeyStroke ks = KeyStroke.getKeyStroke(KeyEvent.VK_X,

Event.ALT_MASK);
exitItem.setAccelerator(ks);

fileMenu.setMnemonic('F');

exitItem.setMnemonic(KeyEvent.VK_X);

mb.add(fileMenu);

setJMenuBar(mb);
}
public static void main(String args[]) {
GJApp.launch(new Test(),
"Accelerators and Mnemonics",300,300,450,300);
}
}
class GJApp extends WindowAdapter {
static private JPanel statusArea = new JPanel();
static private JLabel status = new JLabel(" ");

public static void launch(final JFrame f, String title,

final int x, final int y,
final int w, int h) {
f.setTitle(title);
f.setBounds(x,y,w,h);
f.setVisible(true);

statusArea.setBorder(BorderFactory.createEtchedBorder());

statusArea.setLayout(new FlowLayout(FlowLayout.LEFT,0,0));
statusArea.add(status);
status.setHorizontalAlignment(JLabel.LEFT);

f.setDefaultCloseOperation(

WindowConstants.DISPOSE_ON_CLOSE);

f.addWindowListener(new WindowAdapter() {

public void windowClosed(WindowEvent e) {
System.exit(0);
}
});
}
static public JPanel getStatusArea() {
return statusArea;
}
static public void updateStatus(String s) {
status.setText(s);
}
}

10.3.2 JMenuItem属性

 

10.3.3 JMenuItem事件

 

例10-5 监听菜单项动作和菜单项变化事件

import javax.swing.*;

import javax.swing.event.*;
import java.awt.*;
import java.awt.event.*;

public class Test extends JApplet {

public void init() {
JMenuBar mb = new JMenuBar();
JMenu fileMenu = new JMenu("File");
JMenuItem newItem = new JMenuItem("New ..."),
openItem = new JMenuItem("Open ..."),
saveItem = new JMenuItem("Save"),
saveAsItem = new JMenuItem("Save As ..."),
exitItem = new JMenuItem("Exit");
Listener listener = new Listener(this);

fileMenu.add(newItem);

fileMenu.add(openItem);
fileMenu.add(saveItem);
fileMenu.add(saveAsItem);
fileMenu.addSeparator();
fileMenu.add(exitItem);

newItem.setActionCommand("Create a New Document");

openItem.setActionCommand("Open an Existing Document");
saveItem.setActionCommand("Save Document");
saveAsItem.setActionCommand("Save Document As ...");
exitItem.setActionCommand("Exit the applet");

newItem.addChangeListener(listener);

openItem.addChangeListener(listener);
saveItem.addChangeListener(listener);
saveAsItem.addChangeListener(listener);
exitItem.addChangeListener(listener);

mb.add(fileMenu);

setJMenuBar(mb);

exitItem.addActionListener(new ActionListener() {

public void actionPerformed(ActionEvent e) {
System.exit(0);
}
});
}
}
class Listener implements ChangeListener {
private JApplet applet;

public Listener(JApplet applet) {

this.applet = applet;
}
public void stateChanged(ChangeEvent e) {
JMenuItem b = (JMenuItem)e.getSource();

if(b.isArmed())

applet.showStatus(b.getActionCommand());
}
}

10.3.4 JMenuItem类总结

 

10.3.5 AWT兼容

 

10.4 JCheckBoxMenuItem

 

例10-6 实例化复选框菜单项

import javax.swing.*;

import java.awt.*;
import java.awt.event.*;

public class Test extends JApplet {

public void init() {
Container contentPane = getContentPane();

JMenuBar mb = new JMenuBar();

JMenu checkBoxMenu = new JMenu("Endangered Species");

ImageIcon crabIcon = new ImageIcon("crab.gif");

ImageIcon eagleIcon = new ImageIcon("eagle.gif");

JMenuItem

crabItem = new JCheckBoxMenuItem(crabIcon),
eagleItem = new JCheckBoxMenuItem("eagle",
eagleIcon, true),
ladybugItem = new JCheckBoxMenuItem("ladybug");

checkBoxMenu.add(crabItem);

checkBoxMenu.add(eagleItem);
checkBoxMenu.add(ladybugItem);

ladybugItem.setMnemonic('l');

mb.add(checkBoxMenu);

setJMenuBar(mb);
}
}

10.4.1 JCheckBoxMenuItem属性

 

10.4.2 JCheckBoxMenuItem事件

 

例10-7 访问JCheckBoxMenuItem状态

import javax.swing.*;

import javax.swing.event.*;
import java.awt.*;
import java.awt.event.*;

public class Test extends JApplet {

private ImageIcon crabIcon = new ImageIcon("crab.gif");
private ImageIcon eagleIcon = new ImageIcon("eagle.gif");

private JCheckBoxMenuItem

crabItem = new JCheckBoxMenuItem(crabIcon),
eagleItem = new JCheckBoxMenuItem("eagle", eagleIcon),
ladybugItem = new JCheckBoxMenuItem("ladybug");

public void init() {

Container contentPane = getContentPane();

JMenuBar mb = new JMenuBar();

JMenu checkBoxMenu = new JMenu("Endangered Species");
Listener listener = new Listener();

checkBoxMenu.add(crabItem);

checkBoxMenu.add(eagleItem);
checkBoxMenu.add(ladybugItem);

crabItem.addActionListener(listener);

eagleItem.addActionListener(listener);
ladybugItem.addActionListener(listener);

mb.add(checkBoxMenu);

setJMenuBar(mb);
}
class Listener implements ActionListener {
public void actionPerformed(ActionEvent e) {
showStatus("crab: " + crabItem.getState() + ", " +
"eagle: " + eagleItem.getState() + ", " +
"ladybug: " + ladybugItem.getState());
}
}
}

10.4.3 JCheckBoxMenuItem类总结

 

10.4.4 AWT兼容

 

10.5 JRadioButtonMenuItem

 

例10-8 实例化单选按钮菜单项

import javax.swing.*;

import javax.swing.event.*;
import java.awt.*;
import java.awt.event.*;

public class Test extends JApplet {

public void init() {
Container contentPane = getContentPane();

JMenuBar mb = new JMenuBar();

JMenu radioMenu = new JMenu("Favorite Animal");

ImageIcon crabIcon = new ImageIcon("crab.gif");

ImageIcon eagleIcon = new ImageIcon("eagle.gif");

final JMenuItem

crabItem = new JRadioButtonMenuItem(crabIcon),
eagleItem = new JRadioButtonMenuItem("eagle",
eagleIcon),
ladybugItem = new JRadioButtonMenuItem("ladybug");

radioMenu.add(crabItem);

radioMenu.add(eagleItem);
radioMenu.add(ladybugItem);

mb.add(radioMenu);

setJMenuBar(mb);
}
}

10.5.1 JRadioButtonMenuItem属性

 

10.5.2 JRadioButtonMenuItem事件

 

例10-9 为JRadioButton的实例监视事件

import javax.swing.*;

import javax.swing.event.*;
import java.awt.*;
import java.awt.event.*;

public class Test extends JApplet {

private ImageIcon crabIcon = new ImageIcon("crab.gif",
"Crab");
private ImageIcon eagleIcon = new ImageIcon("eagle.gif",
"Eagle");
private JMenuItem
crabItem = new JRadioButtonMenuItem(crabIcon),
eagleItem = new JRadioButtonMenuItem("eagle",
eagleIcon),
ladybugItem = new JRadioButtonMenuItem("ladybug");

public void init() {

Container contentPane = getContentPane();

JMenuBar mb = new JMenuBar();

JMenu radioMenu = new JMenu("Favorite Animal");

AnItemListener itemListener = new AnItemListener();

AnActionListener actionListener = new AnActionListener();
AChangeListener changeListener = new AChangeListener();

radioMenu.add(crabItem);

radioMenu.add(eagleItem);
radioMenu.add(ladybugItem);

ButtonGroup group = new ButtonGroup();

group.add(crabItem);
group.add(eagleItem);
group.add(ladybugItem);

mb.add(radioMenu);

setJMenuBar(mb);

crabItem.addItemListener(itemListener);

eagleItem.addItemListener(itemListener);
ladybugItem.addItemListener(itemListener);

crabItem.addActionListener(actionListener);

eagleItem.addActionListener(actionListener);
ladybugItem.addActionListener(actionListener);

crabItem.addChangeListener(changeListener);

eagleItem.addChangeListener(changeListener);
ladybugItem.addChangeListener(changeListener);
}
private String getItemDescription(JMenuItem item) {
String s;
ImageIcon icon = (ImageIcon)item.getIcon();

if(icon != null) return icon.getDescription();

else return item.getText();
}

// Inner class event handlers follow ...

class AnActionListener implements ActionListener {

public void actionPerformed(ActionEvent e) {
JMenuItem item = (JMenuItem) e.getSource();
String s = getItemDescription(item);
showStatus(s + " activated");

System.out.println("action event fired");

}
};
class AChangeListener implements ChangeListener {
public void stateChanged(ChangeEvent e) {
Object[] selectedObjs =
ladybugItem.getSelectedObjects();

if(selectedObjs == null)

System.out.println("selected objs is null");
else
System.out.println(selectedObjs[0] + "selected");

JMenuItem item = (JMenuItem)e.getSource();

if(item.isArmed()) {

String s = getItemDescription(item);
showStatus(s + " armed");
}
System.out.println("change event fired");
}
};
class AnItemListener implements ItemListener {
public void itemStateChanged(ItemEvent e) {
JMenuItem item = (JMenuItem) e.getSource();
String s = getItemDescription(item);

if(e.getStateChange() == ItemEvent.SELECTED)

s += " selected";
else
s += " deselected";

showStatus(s);

System.out.println("item event fired");
}
};
}

10.5.3 JRadioButtonMenuItem类总结

 

10.5.4 AWT兼容

 

10.6 JMenu

 

例10-10 JMenu的一个简单例子

10.6.1动态修改菜单

 

例10-11 一个自修改菜单

import javax.swing.*;

import java.awt.*;
import java.awt.event.*;
import java.util.Vector;

public class Test extends JApplet {

private SelfModifyingMenu selfModifyingMenu;

public void init() {

JMenuBar menuBar = new JMenuBar();
createMenus(menuBar);
setJMenuBar(menuBar);
}
public void createMenus(JMenuBar mbar) {
mbar.add(createFileMenu());
mbar.add(selfModifyingMenu = new SelfModifyingMenu());
}
private JMenu createFileMenu() {
JMenu fileMenu = new JMenu("File");
JMenuItem quitItem = new JMenuItem("Quit");

fileMenu.add(quitItem);

quitItem.addActionListener(new ActionListener() {

public void actionPerformed(ActionEvent event) {
System.exit(0);
}
});
return fileMenu;
}
}
class SelfModifyingMenu extends JMenu {
private Vector newItems = new Vector();
private Listener menuItemListener = new Listener();
private JMenuItem toggleItem, enablerItem,
addItem, removeItem;

public SelfModifyingMenu() {

super("Self Modifying Menu");

add(enablerItem = new JMenuItem("Disable Item Below"));

add(toggleItem = new JMenuItem("Enable/Disable Me"));
addSeparator();

add(addItem = new JMenuItem("Add a JMenuItem ..."));

add(removeItem = new JMenuItem(
"Remove last JMenuItem ..."));
addItem.setFont(new Font("Helvetica", Font.BOLD, 18));
addSeparator();

enablerItem.addActionListener(menuItemListener);

toggleItem.addActionListener(menuItemListener);
addItem.addActionListener(menuItemListener);
removeItem.addActionListener(menuItemListener);
}
public void addItem() {
JMenuItem newItem =
new JMenuItem("Extra Item #" + newItems.size());
add(newItem);
newItems.addElement(newItem);
}
public void removeLastItem() {
if(newItems.size() == 0)
System.out.println("Nothing to remove!");
else {
JMenuItem removeMe =
(JMenuItem)newItems.lastElement();

remove(removeMe);

newItems.removeElement(removeMe);
}
}
public void toggleItem() {
if(toggleItem.isEnabled()) toggleItem.setEnabled(false);
else toggleItem.setEnabled(true);
}
class Listener implements ActionListener {
public void actionPerformed(ActionEvent event) {
JMenuItem item = (JMenuItem)event.getSource();

if(item == enablerItem) {

toggleItem();

if(toggleItem.isEnabled())

enablerItem.setText("Disable Item Below");
else
enablerItem.setText("Enable Item Below");
}
else if(item == addItem) addItem();
else if(item == removeItem) removeLastItem();
}
}
}

10.6.2右拉式菜单

 

例10-12 右拉式菜单

import javax.swing.*;

import java.awt.*;
import java.awt.event.*;

public class Test extends JApplet {

public void init() {

JMenuBar menuBar = new JMenuBar();
createMenus(menuBar);
setJMenuBar(menuBar);
}
public void createMenus(JMenuBar mbar) {
mbar.add(createFileMenu());
mbar.add(createCascadingMenu());
}
private JMenu createFileMenu() {
JMenu fileMenu = new JMenu("File");
JMenuItem quitItem = new JMenuItem("Quit");

fileMenu.add(quitItem);

quitItem.addActionListener(new ActionListener() {

public void actionPerformed(ActionEvent event) {
System.exit(0);
}
});
return fileMenu;
}
private JMenu createCascadingMenu() {
JMenu cascading = new JMenu("Cascading", true);
JMenu submenu = new JMenu("pull right menu 1", true);
JMenu subsubmenu = new JMenu("pull right menu 2", true);

submenu.add("submenu item 1");

submenu.add("submenu item 2");
submenu.add("submenu item 3");
submenu.add("submenu item 4");
submenu.add("submenu item 5");

subsubmenu.add("subsubmenu item 1");

subsubmenu.add("subsubmenu item 2");
subsubmenu.add("subsubmenu item 3");
subsubmenu.add("subsubmenu item 4");
subsubmenu.add("subsubmenu item 5");

submenu.add(subsubmenu);

cascading.add(submenu);

return cascading;

}
}

10.6.3 JMenu属性

 

10.6.4 JMenu事件

 

例10-13 监听菜单事件

import javax.swing.*;

import javax.swing.event.*;
import java.awt.*;
import java.awt.event.*;

public class Test extends JApplet {

public void init() {
JMenuBar mb = new JMenuBar();
JMenu fileMenu = new JMenu("File");

fileMenu.add("New ...");

fileMenu.add("Open ...");
fileMenu.add("Save");
fileMenu.add("Save As ..");
fileMenu.addSeparator();
fileMenu.add("Exit");

mb.add(fileMenu);

setJMenuBar(mb);

fileMenu.addMenuListener(new MenuListener() {

public void menuCanceled(MenuEvent e) {
System.out.println("menu canceled");
}
public void menuSelected(MenuEvent e) {
System.out.println("menu selected");
}
public void menuDeselected(MenuEvent e) {
System.out.println("menu deselected");
}
});
}
}

 

10.6.5 JMenu类总结

 

例10-14 显示一个菜单条中菜单的信息

import javax.swing.*;

import java.awt.*;
import java.awt.event.*;

public class Test extends JApplet {

public void init() {
Container contentPane = getContentPane();

final JMenuBar mb = new JMenuBar();

final MenuBarPrinter printer = new MenuBarPrinter();

JMenu fileMenu = new JMenu("File");

JMenu editMenu = new JMenu("Edit");
JMenuItem exitItem = new JMenuItem("Exit");

fileMenu.setMnemonic('F');

editMenu.setMnemonic('F');

fileMenu.add("New ...");

fileMenu.add("Open ...");
fileMenu.add("Save");
fileMenu.add("Save As ..");
fileMenu.addSeparator();
fileMenu.add(exitItem);

editMenu.add("Cut");

editMenu.add("Copy");
editMenu.add("Paste");

mb.add(fileMenu);

mb.add(editMenu);
setJMenuBar(mb);

JButton button = new JButton("show menu information");

contentPane.setLayout(new FlowLayout());
contentPane.add(button);

button.addActionListener(new ActionListener() {

public void actionPerformed(ActionEvent e) {
printer.print(mb);
}
});

exitItem.addActionListener(new ActionListener() {

public void actionPerformed(ActionEvent e) {
System.exit(0);
}
});
}
}
class MenuBarPrinter {
static public void print(JMenuBar menubar) {
int numMenus = menubar.getMenuCount();
JMenu nextMenu;
JMenuItem nextItem;

System.out.println();

System.out.println("MenuBar has " +
menubar.getMenuCount() +
" menus");
System.out.println();

for(int i=0; i < numMenus; ++i) {

nextMenu = menubar.getMenu(i);
System.out.println(nextMenu.getText() + " menu ...");
System.out.println(nextMenu);

int numItems = nextMenu.getItemCount();

for(int j=0; j < numItems; ++j) {

nextItem = nextMenu.getItem(j);
System.out.println(nextItem);
}
System.out.println();
}
}
}

10.6.6 AWT兼容

 

10.7 菜单元素

 

例10-15 实现定制菜单元素

import javax.swing.*;

import java.awt.*;
import java.awt.event.*;
import java.util.*;

public class Test extends JApplet {

public void init() {
Container contentPane = getContentPane();
JMenuBar menuBar = new JMenuBar();
JMenu fileMenu = new JMenu("File");

fileMenu.add(new UnderlineElement("item one"));

fileMenu.add(new UnderlineElement("item two"));
fileMenu.add(new UnderlineElement("item three"));

menuBar.add(fileMenu);

setJMenuBar(menuBar);
}
}
class UnderlineElement extends JButton implements MenuElement {
private boolean drawUnderline = false;

public UnderlineElement(String s) {

super(s);
setBorder(BorderFactory.createEmptyBorder(2,2,2,2));
}
public Component getComponent() {
return this;
}
public MenuElement[] getSubElements() {
return new MenuElement[0];
}
public void menuSelectionChanged(boolean b) {
drawUnderline = b;
repaint();
}
public void paintComponent(Graphics g) {
super.paintComponent(g);

Insets insets = getInsets();

if(drawUnderline) {

FontMetrics fm = g.getFontMetrics();
g.drawLine(insets.left, insets.top + fm.getHeight(),
fm.stringWidth(getText()),
insets.top + fm.getHeight());
}
}
public void processKeyEvent(KeyEvent me,
MenuElement[] element,
MenuSelectionManager msm) {
}
public void processMouseEvent(MouseEvent me) {
super.processMouseEvent(me);
MenuSelectionManager.defaultManager().processMouseEvent(
me);
}
public void processMouseEvent(MouseEvent me,
MenuElement[] element,
MenuSelectionManager msm) {
if(me.getID() == MouseEvent.MOUSE_CLICKED ||
me.getID() == MouseEvent.MOUSE_RELEASED) {

msm.setSelectedPath(null);

doClick();
}
else
msm.setSelectedPath(getPath());
}
public MenuElement[] getPath() {
MenuSelectionManager defaultManager =
MenuSelectionManager.defaultManager();
MenuElement oldPath[] = defaultManager.getSelectedPath();
MenuElement newPath[];
int len = oldPath.length;

if(len > 0) {

MenuElement lastElement = oldPath[len-1];
Component parent = getParent();

if (lastElement == parent) {

newPath = new MenuElement[len+1];

System.arraycopy(oldPath, 0, newPath, 0, len);

newPath[len] = this;
}
else {
int j;

for (j = len-1; j >= 0; j--) {

if (oldPath[j].getComponent() == parent)
break;
}
newPath = new MenuElement[j+2];
System.arraycopy(oldPath, 0, newPath, 0, j+1);
newPath[j+1] = this;
}
}
else
return new MenuElement[0];

return newPath;

}
}

10.8 JPopupMenu

 

例10-16 使用弹出式菜单

import javax.swing.*;

import javax.swing.event.*;
import java.awt.*;
import java.awt.event.*;

public class Test extends JApplet {

public void init() {
Container contentPane = getContentPane();
final JLabel label = new JLabel("Click here for popup");
final JPopupMenu popup = new JPopupMenu();
final JSlider slider = new JSlider();

popup.add(new JMenuItem("Copy", new ImageIcon(this.getClass().getResource("copy.gif"))));

popup.add(new CutAction(new ImageIcon(this.getClass().getResource("cut.gif"))));
popup.addSeparator();
popup.add(slider);

label.addMouseListener(new MouseAdapter() {

public void mousePressed (MouseEvent e) {
popup.show(label, e.getX(), e.getY());
}
});
slider.addChangeListener(new ChangeListener() {
public void stateChanged(ChangeEvent e) {
if( ! slider.getValueIsAdjusting())
popup.setVisible(false);
}
});

label.setHorizontalAlignment(JLabel.CENTER);

contentPane.add(label, BorderLayout.CENTER);
}
class CutAction extends AbstractAction {
java.net.URL iconurl;
public CutAction(Icon icon) {
//super("Cut", new ImageIcon("cut.gif"));
super("Cut",icon);
}
public void actionPerformed(ActionEvent e) {
System.out.println("cut");
}
}
}

10.8.1弹出式菜单触发器

 

例10-17 显示一个弹出式菜单以响应弹出式菜单触发器

import javax.swing.*;

import java.awt.*;
import java.awt.event.*;

public class Test extends JApplet {

private JPopupMenu popup = new JPopupMenu();

public void init() {

Container contentPane = getContentPane();

popup.add(new JMenuItem("item one"));

popup.add(new JMenuItem("item two"));
popup.add(new JMenuItem("item three"));
popup.add(new JMenuItem("item four"));

contentPane.addMouseListener(new MouseAdapter() {

public void mousePressed (MouseEvent e) {
showPopup(e);
}
public void mouseClicked (MouseEvent e) {
showPopup(e);
}
public void mouseReleased(MouseEvent e) {
showPopup(e);
}
});
}
void showPopup(MouseEvent e) {
if(e.isPopupTrigger())
popup.show(this, e.getX(), e.getY());
}
}

10.8.2轻量/中量/重量弹出式菜单

 

10.8.3弹出式菜单调用者

 

例10-18 相对于其调用者显示弹出式菜单

import javax.swing.*;

import java.awt.*;
import java.awt.event.*;

public class Test extends JApplet {

JComboBox combobox = new JComboBox();
JPopupMenu popup = new JPopupMenu();
ColoredCanvas popupRelativeToMe;
ColoredCanvas blueCanvas, redCanvas, yellowCanvas;

public void init() {

Container contentPane = getContentPane();
blueCanvas = new ColoredCanvas(Color.blue);
redCanvas = new ColoredCanvas(Color.red);
yellowCanvas = new ColoredCanvas(Color.yellow);
popupRelativeToMe = blueCanvas;

popup.add(new JMenuItem("item one"));

popup.add(new JMenuItem("item two"));
popup.add(new JMenuItem("item three"));
popup.add(new JMenuItem("item four"));

contentPane.setLayout(new FlowLayout());

contentPane.add(new JLabel("Popup Over:"));
contentPane.add(combobox);
contentPane.add(blueCanvas);
contentPane.add(redCanvas);
contentPane.add(yellowCanvas);

combobox.addItem("Blue Canvas");

combobox.addItem("Yellow Canvas");
combobox.addItem("Red Canvas");

combobox.addItemListener(new ItemListener() {

public void itemStateChanged(ItemEvent event) {
if(event.getStateChange() == ItemEvent.SELECTED) {
JComboBox c = (JComboBox)event.getSource();
String label = (String)c.getSelectedItem();

if(label.equals("Blue Canvas"))

popupRelativeToMe = blueCanvas;
else if(label.equals("Red Canvas"))
popupRelativeToMe = redCanvas;
else if(label.equals("Yellow Canvas"))
popupRelativeToMe = yellowCanvas;

popup.show(popupRelativeToMe, 5, 5);

}
}
});
}
}
class ColoredCanvas extends JPanel {
private Color color;

public ColoredCanvas(Color color) {

this.color = color;
}
public void paintComponent(Graphics g) {
super.paintComponent(g);

Dimension size = getSize();

g.setColor (color);
g.fill3DRect(0,0,size.width-1,size.height-1,true);
}
public Dimension getPreferredSize() {
return new Dimension(100,100);
}
}

10.8.4 JPopupMenu属性

 

10.8.5 JPopupMenu事件

 

例10-19 弹出式菜单事件的清单

import javax.swing.*;

import javax.swing.event.*;
import java.awt.*;
import java.awt.event.*;
import java.beans.*;

public class Test extends JApplet {

public void init() {
final Container contentPane = getContentPane();
final JPopupMenu popup = new JPopupMenu();
popup.add(new JMenuItem("item one"));
popup.add(new JMenuItem("item two"));
popup.add(new JMenuItem("item three"));
popup.add(new JMenuItem("item four"));

popup.addPopupMenuListener(new PopupMenuListener() {

public void popupMenuCanceled(PopupMenuEvent e) {
showStatus("menu canceled");
}
public void popupMenuWillBecomeVisible(
PopupMenuEvent e) {
showStatus("menu will become visible");
}
public void popupMenuWillBecomeInvisible(
PopupMenuEvent e) {
showStatus("menu will become invisible");
}
});
addMouseListener(new MouseAdapter() {
public void mousePressed (MouseEvent e) {
popup.show(contentPane, e.getX(), e.getY());
}
});
}
}

10.8.6 JPopupMenu类总结

 

例10-20 为弹出式菜单设置位置、边框和调用者

import javax.swing.*;

import java.awt.*;
import java.awt.event.*;

public class Test extends JApplet {

private JPopupMenu popup = new JPopupMenu();

public void init() {

Container contentPane = getContentPane();
JLabel label = new JLabel("Click To Show Popup");

popup.add(new JMenuItem("item one"));

popup.add(new JMenuItem("item two"));
popup.add(new JMenuItem("item three"));
popup.add(new JMenuItem("item four"));

label.setHorizontalAlignment(JLabel.CENTER);

contentPane.add(label, BorderLayout.CENTER);

label.addMouseListener(new MouseAdapter() {

public void mousePressed(MouseEvent e) {
//if(e.isPopupTrigger()) {
popup.setVisible(true);
//}
}
});
}
}

10.8.7 AWT兼容

 

10.9 JMenuBar

 

例10-21 一个简单的菜单栏

import javax.swing.*;

import java.awt.*;
import java.awt.event.*;
import java.util.*;

public class Test extends JFrame {

public Test() {
final JMenuBar mb = new JMenuBar();
final JMenu fileMenu = new JMenu("File");
JMenuItem exitItem = new JMenuItem("Exit");

fileMenu.add("New ...");

fileMenu.add("Open ...");
fileMenu.add("Save");
fileMenu.add("Save As ..");
fileMenu.addSeparator();
fileMenu.add(exitItem);

mb.add(new JLabel(

new ImageIcon("smiley_face_small.gif")));

mb.add(fileMenu);

// Either one of the following two lines will

// attach the menu bar to the application
//setJMenuBar(mb);
getRootPane().setJMenuBar(mb);

exitItem.addActionListener(new ActionListener() {

public void actionPerformed(ActionEvent e) {
dispose();
System.exit(0);
}
});
System.out.println("component count: " +
mb.getComponentCount());
System.out.println("first component: " +
(mb.getComponentAtIndex(0)).getClass().getName());

System.out.println("menu count: " + (mb.getMenuCount()));

JMenu menu = mb.getMenu(0);

if(menu == null) System.out.println("null menu");
else System.out.println("got menu");
}
public static void main(String args[]) {
GJApp.launch(new Test(),
"A Menu Bar",300,300,300,250);
}
}
class GJApp extends WindowAdapter {
static private JPanel statusArea = new JPanel();
static private JLabel status = new JLabel(" ");
static private ResourceBundle resources;

public static void launch(final JFrame f, String title,

final int x, final int y,
final int w, int h) {
launch(f,title,x,y,w,h,null);
}
public static void launch(final JFrame f, String title,
final int x, final int y,
final int w, int h,
String propertiesFilename) {
f.setTitle(title);
f.setBounds(x,y,w,h);
f.setVisible(true);

statusArea.setBorder(BorderFactory.createEtchedBorder());

statusArea.setLayout(new FlowLayout(FlowLayout.LEFT,0,0));
statusArea.add(status);
status.setHorizontalAlignment(JLabel.LEFT);

f.setDefaultCloseOperation(

WindowConstants.DISPOSE_ON_CLOSE);

if(propertiesFilename != null) {

resources = ResourceBundle.getBundle(
propertiesFilename, Locale.getDefault());
}

f.addWindowListener(new WindowAdapter() {

public void windowClosed(WindowEvent e) {
System.exit(0);
}
});
}
static public JPanel getStatusArea() {
return statusArea;
}
static public void showStatus(String s) {
status.setText(s);
}
static Object getResource(String key) {
if(resources != null) {
return resources.getString(key);
}
return null;
}
}

10.9.1菜单栏菜单和组件

 

例10-22 菜单栏中的菜单和组件

import javax.swing.*;

import java.awt.*;
import java.awt.event.*;

public class Test extends JApplet {

public void init() {
Container contentPane = getContentPane();

final JMenuBar mb = new JMenuBar();

JMenu fileMenu = new JMenu("File");
JMenu editMenu = new JMenu("Edit");
JMenuItem exitItem = new JMenuItem("Exit");
JButton compButton = new JButton(
"show menubar components ...");
JButton menuButton = new JButton(
"show menubar menus ...");

fileMenu.add("New ...");

fileMenu.add("Open ...");
fileMenu.add("Save");
fileMenu.add("Save As ..");
fileMenu.addSeparator();
fileMenu.add(exitItem);

editMenu.add("Undo");

editMenu.addSeparator();
editMenu.add("Cut");
editMenu.add("Copy");
editMenu.add("Paste");

mb.setMargin(new Insets(30,20,10,5));

mb.add(new JLabel(new ImageIcon("smiley.gif")));
mb.add(fileMenu);
mb.add(editMenu);

setJMenuBar(mb);

contentPane.setLayout(new FlowLayout());
contentPane.add(compButton);
contentPane.add(menuButton);

exitItem.addActionListener(new ActionListener() {

public void actionPerformed(ActionEvent e) {
System.exit(0);
}
});
menuButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
Component c;
int cnt = mb.getMenuCount();

for(int i=0; i < cnt; ++i) {

c = mb.getMenu(i);
System.out.println(c);
System.out.println();
}
}
});
compButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
Component c;
int cnt = mb.getComponentCount();

for(int i=0; i < cnt; ++i) {

c = mb.getComponentAtIndex(i);
System.out.println(c);
System.out.println();
}
}
});
}
}

10.9.2 JMenuBar属性

 

10.9.3 JMenuBar事件

 

10.9.4JMenuBar类总结

 

10.9.5 AWT兼容

 

10.10 JToolBar

 

例10-23 把组件添加到一个菜单栏中

import java.awt.*;

import java.awt.event.*;
import javax.swing.*;

public class Test extends JApplet {

public Test() {
Container contentPane = getContentPane();
JToolBar tb = new JToolBar();
JComboBox fontCombo = new JComboBox(),
fontSizeCombo = new JComboBox();

JButton newButton = new JButton(new ImageIcon("new.gif")),

openButton = new JButton(new ImageIcon("open.gif")),
cutButton = new JButton(new ImageIcon("cut.gif")),
copyButton = new JButton(new ImageIcon("copy.gif")),
pasteButton = new JButton(new ImageIcon("paste.gif"));

fontCombo.addItem("Helvetica");

fontCombo.addItem("Palatino");
fontCombo.addItem("Courier");
fontCombo.addItem("Times");
fontCombo.addItem("Times-Roman");

fontSizeCombo.addItem("10");

fontSizeCombo.addItem("12");
fontSizeCombo.addItem("14");
fontSizeCombo.addItem("16");
fontSizeCombo.addItem("18");

tb.add(newButton);

tb.add(openButton);

tb.addSeparator();

tb.add(cutButton);

tb.add(copyButton);
tb.add(pasteButton);

tb.addSeparator();

tb.add(fontCombo);

tb.add(fontSizeCombo);

contentPane.setLayout(new BorderLayout());

contentPane.add(tb, BorderLayout.NORTH);
}
}

例10-24 把组件添加到一个工具条中(方法2)

import java.awt.*;

import java.awt.event.*;
import javax.swing.*;

public class Test extends JApplet {

public Test() {
Container contentPane = getContentPane();
JToolBar tb = new JToolBar();
JComboBox fontCombo = new JComboBox(),
fontSizeCombo = new JComboBox();

JButton newButton = new JButton(new ImageIcon("new.gif")),

openButton = new JButton(new ImageIcon("open.gif")),
cutButton = new JButton(new ImageIcon("cut.gif")),
copyButton = new JButton(new ImageIcon("copy.gif")),
pasteButton = new JButton(new ImageIcon("paste.gif"));

fontCombo.addItem("Helvetica");

fontCombo.addItem("Palatino");
fontCombo.addItem("Courier");
fontCombo.addItem("Times");
fontCombo.addItem("Times-Roman");

fontSizeCombo.addItem("10");

fontSizeCombo.addItem("12");
fontSizeCombo.addItem("14");
fontSizeCombo.addItem("16");
fontSizeCombo.addItem("18");

tb.add(newButton);

tb.add(openButton);

tb.addSeparator();

tb.add(cutButton);

tb.add(copyButton);
tb.add(pasteButton);

tb.addSeparator();

tb.add(fontCombo);

tb.add(fontSizeCombo);

newButton.setAlignmentY(0.5f);

openButton.setAlignmentY(0.5f);
cutButton.setAlignmentY(0.5f);
copyButton.setAlignmentY(0.5f);
pasteButton.setAlignmentY(0.5f);

newButton.setAlignmentX(0.5f);

openButton.setAlignmentX(0.5f);
cutButton.setAlignmentX(0.5f);
copyButton.setAlignmentX(0.5f);
pasteButton.setAlignmentX(0.5f);

fontCombo.setMaximumSize(fontCombo.getPreferredSize());

fontSizeCombo.setMaximumSize(
fontSizeCombo.getPreferredSize());

contentPane.setLayout(new BorderLayout());

contentPane.add(tb, BorderLayout.NORTH);
}
}

 

10.10.1滚过式工具条

 

例10-25 JTooBar.isRollover属性

import javax.swing.*;

import java.awt.*;
import java.awt.event.*;

public class Test extends JApplet {

public void init() {
Container contentPane = getContentPane();
JToolBar toolbar = new JToolBar();

toolbar.add(new NewAction());

toolbar.add(new OpenAction());
toolbar.addSeparator();
toolbar.add(new CutAction());
toolbar.add(new CopyAction());
toolbar.add(new PasteAction());

toolbar.putClientProperty("JToolBar.isRollover",

Boolean.TRUE);

contentPane.add(toolbar, BorderLayout.NORTH);

}
class NewAction extends AbstractAction {
public NewAction() {
putValue(Action.SMALL_ICON,
new ImageIcon("new.gif"));
}
public void actionPerformed(ActionEvent event) {
showStatus("new");
}
}
class OpenAction extends AbstractAction {
public OpenAction() {
putValue(Action.SMALL_ICON,
new ImageIcon("open.gif"));
}
public void actionPerformed(ActionEvent event) {
showStatus("open");
}
}
class CutAction extends AbstractAction {
public CutAction() {
putValue(Action.SMALL_ICON, new ImageIcon("cut.gif"));
}
public void actionPerformed(ActionEvent event) {
showStatus("cut");
}
}
class CopyAction extends AbstractAction {
public CopyAction() {
putValue(Action.SMALL_ICON,
new ImageIcon("copy.gif"));
}
public void actionPerformed(ActionEvent event) {
showStatus("copy");
}
}
class PasteAction extends AbstractAction {
public PasteAction() {
putValue(Action.SMALL_ICON,
new ImageIcon("paste.gif"));
}
public void actionPerformed(ActionEvent event) {
showStatus("paste");
}
}
}

10.10.2在工具条中使用动作

 

例10-26 把动作添加到一个工具条中

import javax.swing.*;

import java.awt.*;
import java.awt.event.*;

public class Test extends JApplet {

public void init() {
Container contentPane = getContentPane();
JToolBar toolbar = new JToolBar();

toolbar.add(new NewAction());

toolbar.add(new OpenAction());
toolbar.addSeparator();
toolbar.add(new CutAction());
toolbar.add(new CopyAction());
toolbar.add(new PasteAction());

contentPane.add(toolbar, BorderLayout.NORTH);

}
class NewAction extends AbstractAction {
public NewAction() {
super("new", new ImageIcon("new.gif"));
}
public void actionPerformed(ActionEvent event) {
showStatus("new");
}
}
class OpenAction extends AbstractAction {
public OpenAction() {
putValue(Action.SMALL_ICON,
new ImageIcon("open.gif"));
}
public void actionPerformed(ActionEvent event) {
showStatus("open");
}
}
class CutAction extends AbstractAction {
public CutAction() {
super("cut", new ImageIcon("cut.gif"));
putValue(Action.SMALL_ICON, new ImageIcon("cut.gif"));
}
public void actionPerformed(ActionEvent event) {
showStatus("cut");
}
}
class CopyAction extends AbstractAction {
public CopyAction() {
putValue(Action.SMALL_ICON,
new ImageIcon("copy.gif"));
}
public void actionPerformed(ActionEvent event) {
showStatus("copy");
}
}
class PasteAction extends AbstractAction {
public PasteAction() {
putValue(Action.SMALL_ICON,
new ImageIcon("paste.gif"));
}
public void actionPerformed(ActionEvent event) {
showStatus("paste");
}
}
}

10.10.3浮动工具条

 

例10-27 固定位置的工具提示

import java.awt.*;

import java.awt.event.*;
import javax.swing.*;

public class Test extends JApplet {

public Test() {
Container contentPane = getContentPane();
JToolBar toolbar = new JToolBar();

String[] tooltipTexts = { "new", "open", "cut", "copy",

"paste"
};
ImageIcon[] icons = {
new ImageIcon("new.gif"),
new ImageIcon("open.gif"),
new ImageIcon("cut.gif"),
new ImageIcon("copy.gif"),
new ImageIcon("paste.gif")
};

JButton[] buttons = {

new ButtonWithFixedTooltip(icons[0],tooltipTexts[0]),
new ButtonWithFixedTooltip(icons[1],tooltipTexts[1]),
new ButtonWithFixedTooltip(icons[2],tooltipTexts[2]),
new ButtonWithFixedTooltip(icons[3],tooltipTexts[3]),
new ButtonWithFixedTooltip(icons[4],tooltipTexts[4])
};

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

toolbar.add(buttons[i]);

if(tooltipTexts[i].equals("open"))

toolbar.addSeparator();
}
contentPane.add(toolbar, BorderLayout.NORTH);
}
}
class ButtonWithFixedTooltip extends JButton {
public ButtonWithFixedTooltip(Icon icon, String tooltipText) {
super(icon);
setToolTipText(tooltipText);
}
public Point getToolTipLocation(MouseEvent e){
Dimension size = getSize();
return new Point(0, size.height);
}
}

10.10.4位置固定的工具提示

 略

10.10.5 JToolBar属性

  略

10.10.6 JMenuBar事件

  略

10.10.7 JMenuBar类总结

  略

10.10.8 AWT兼容

  略

 

 

 

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