package menu;

import java.awt.*;

import javax.swing.*;

/**

 * @version 1.25 2018-04-10

 * @author Cay Horstmann

 */

public class MenuTest

{

   public static void main(String[] args)

   {

      EventQueue.invokeLater(() -> {

         MenuFrame frame = new MenuFrame();

         frame.setTitle("MenuTest");

         frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

         frame.setVisible(true);

      });

   }

}

package menu;

import java.awt.event.*;

import javax.swing.*;

/**

 * A frame with a sample menu bar.

 */

public class MenuFrame extends JFrame

{

   private static final int DEFAULT_WIDTH = 300;

   private static final int DEFAULT_HEIGHT = 200;

   private Action saveAction;

   private Action saveAsAction;

   private JCheckBoxMenuItem readonlyItem;

   private JPopupMenu popup;

   /**

    * A sample action that prints the action name to System.out.

    */

   class TestAction extends AbstractAction

   {

      public TestAction(String name)

      {

         super(name);

      }

      public void actionPerformed(ActionEvent event)

      {

         System.out.println(getValue(Action.NAME) + " selected.");

      }

   }

   public MenuFrame()

   {

      setSize(DEFAULT_WIDTH, DEFAULT_HEIGHT);

      JMenu fileMenu = new JMenu("File");

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

      // demonstrate accelerators

      JMenuItem openItem = fileMenu.add(new TestAction("Open"));

      openItem.setAccelerator(KeyStroke.getKeyStroke("ctrl O"));

      fileMenu.addSeparator();

      saveAction = new TestAction("Save");

      JMenuItem saveItem = fileMenu.add(saveAction);

      saveItem.setAccelerator(KeyStroke.getKeyStroke("ctrl S"));

      saveAsAction = new TestAction("Save As");

      fileMenu.add(saveAsAction);

      fileMenu.addSeparator();

      fileMenu.add(new AbstractAction("Exit")

         {

            public void actionPerformed(ActionEvent event)

            {

               System.exit(0);

            }

         });

      // demonstrate checkbox and radio button menus

      readonlyItem = new JCheckBoxMenuItem("Read-only");

      readonlyItem.addActionListener(new ActionListener()

         {

            public void actionPerformed(ActionEvent event)

            {

               boolean saveOk = !readonlyItem.isSelected();

               saveAction.setEnabled(saveOk);

               saveAsAction.setEnabled(saveOk);

            }

         });

      ButtonGroup group = new ButtonGroup();

      JRadioButtonMenuItem insertItem = new JRadioButtonMenuItem("Insert");

      insertItem.setSelected(true);

      JRadioButtonMenuItem overtypeItem = new JRadioButtonMenuItem("Overtype");

      group.add(insertItem);

      group.add(overtypeItem);

      // demonstrate icons

      TestAction cutAction = new TestAction("Cut");

      cutAction.putValue(Action.SMALL_ICON, new ImageIcon("cut.gif"));

      TestAction copyAction = new TestAction("Copy");

      copyAction.putValue(Action.SMALL_ICON, new ImageIcon("copy.gif"));

      TestAction pasteAction = new TestAction("Paste");

      pasteAction.putValue(Action.SMALL_ICON, new ImageIcon("paste.gif"));

      JMenu editMenu = new JMenu("Edit");

      editMenu.add(cutAction);

      editMenu.add(copyAction);

      editMenu.add(pasteAction);

      // demonstrate nested menus

      JMenu optionMenu = new JMenu("Options");

      optionMenu.add(readonlyItem);

      optionMenu.addSeparator();

      optionMenu.add(insertItem);

      optionMenu.add(overtypeItem);

      editMenu.addSeparator();

      editMenu.add(optionMenu);

      // demonstrate mnemonics

      JMenu helpMenu = new JMenu("Help");

      helpMenu.setMnemonic('H');

      JMenuItem indexItem = new JMenuItem("Index");

      indexItem.setMnemonic('I');

      helpMenu.add(indexItem);

      // you can also add the mnemonic key to an action

      TestAction aboutAction = new TestAction("About");

      aboutAction.putValue(Action.MNEMONIC_KEY, new Integer('A'));

      helpMenu.add(aboutAction);

      // add all top-level menus to menu bar

      JMenuBar menuBar = new JMenuBar();

      setJMenuBar(menuBar);

      menuBar.add(fileMenu);

      menuBar.add(editMenu);

      menuBar.add(helpMenu);

      // demonstrate pop-ups

      popup = new JPopupMenu();

      popup.add(cutAction);

      popup.add(copyAction);

      popup.add(pasteAction);

      JPanel panel = new JPanel();

      panel.setComponentPopupMenu(popup);

      add(panel);

   }

}

package toolBar;

import java.awt.*;

import javax.swing.*;

/**

 * @version 1.15 2018-04-10

 * @author Cay Horstmann

 */

public class ToolBarTest

{

   public static void main(String[] args)

   {

      EventQueue.invokeLater(() -> {

         ToolBarFrame frame = new ToolBarFrame();

         frame.setTitle("ToolBarTest");

         frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

         frame.setVisible(true);

      });

   }

}

package toolBar;

import java.awt.*;

import java.awt.event.*;

import javax.swing.*;

/**

 * A frame with a toolbar and menu for color changes.

 */

public class ToolBarFrame extends JFrame

{

   private static final int DEFAULT_WIDTH = 300;

   private static final int DEFAULT_HEIGHT = 200;

   private JPanel panel;

   public ToolBarFrame()

   {

      setSize(DEFAULT_WIDTH, DEFAULT_HEIGHT);

      // add a panel for color change

      panel = new JPanel();

      add(panel, BorderLayout.CENTER);

      // set up actions

      ColorAction blueAction = new ColorAction("Blue", new ImageIcon("blue-ball.gif"), Color.BLUE);

      ColorAction yellowAction = new ColorAction("Yellow", new ImageIcon("yellow-ball.gif"),

            Color.YELLOW);

      ColorAction redAction = new ColorAction("Red", new ImageIcon("red-ball.gif"), Color.RED);

      AbstractAction exitAction = new AbstractAction("Exit", new ImageIcon("exit.gif"))

         {

            public void actionPerformed(ActionEvent event)

            {

               System.exit(0);

            }

         };

      exitAction.putValue(Action.SHORT_DESCRIPTION, "Exit");

      // populate toolbar

      JToolBar bar = new JToolBar();

      bar.add(blueAction);

      bar.add(yellowAction);

      bar.add(redAction);

      bar.addSeparator();

      bar.add(exitAction);

      add(bar, BorderLayout.NORTH);

      // populate menu

      JMenu menu = new JMenu("Color");

      menu.add(yellowAction);

      menu.add(blueAction);

      menu.add(redAction);

      menu.add(exitAction);

      JMenuBar menuBar = new JMenuBar();

      menuBar.add(menu);

      setJMenuBar(menuBar);

   }

   /**

    * The color action sets the background of the frame to a given color.

    */

   class ColorAction extends AbstractAction

   {

      public ColorAction(String name, Icon icon, Color c)

      {

         putValue(Action.NAME, name);

         putValue(Action.SMALL_ICON, icon);

         putValue(Action.SHORT_DESCRIPTION, name + " background");

         putValue("Color", c);

      }

      public void actionPerformed(ActionEvent event)

      {

         Color c = (Color) getValue("Color");

         panel.setBackground(c);

      }

   }

}

package optionDialog;

import java.awt.*;

import java.awt.event.*;

import java.awt.geom.*;

import java.awt.geom.Rectangle2D.Double;

import java.util.*;

import javax.swing.*;

/**

 * A frame that contains settings for selecting various option dialogs.

 */

public class OptionDialogFrame extends JFrame

{

   private ButtonPanel typePanel;

   private ButtonPanel messagePanel;

   private ButtonPanel messageTypePanel;

   private ButtonPanel optionTypePanel;

   private ButtonPanel optionsPanel;

   private ButtonPanel inputPanel;

   private String messageString = "Message";

   private Icon messageIcon = new ImageIcon("blue-ball.gif");

   private Object messageObject = new Date();

   private Component messageComponent = new SampleComponent();

   public OptionDialogFrame()

   {

      JPanel gridPanel = new JPanel();

      gridPanel.setLayout(new GridLayout(2, 3));

      typePanel = new ButtonPanel("Type", "Message", "Confirm", "Option", "Input");

      messageTypePanel = new ButtonPanel("Message Type", "ERROR_MESSAGE", "INFORMATION_MESSAGE",

            "WARNING_MESSAGE", "QUESTION_MESSAGE", "PLAIN_MESSAGE");

      messagePanel = new ButtonPanel("Message", "String", "Icon", "Component", "Other",

            "Object[]");

      optionTypePanel = new ButtonPanel("Confirm", "DEFAULT_OPTION", "YES_NO_OPTION",

            "YES_NO_CANCEL_OPTION", "OK_CANCEL_OPTION");

      optionsPanel = new ButtonPanel("Option", "String[]", "Icon[]", "Object[]");

      inputPanel = new ButtonPanel("Input", "Text field", "Combo box");

      gridPanel.add(typePanel);

      gridPanel.add(messageTypePanel);

      gridPanel.add(messagePanel);

      gridPanel.add(optionTypePanel);

      gridPanel.add(optionsPanel);

      gridPanel.add(inputPanel);

      // add a panel with a Show button

      JPanel showPanel = new JPanel();

      JButton showButton = new JButton("Show");

      showButton.addActionListener(new ShowAction());

      showPanel.add(showButton);

      add(gridPanel, BorderLayout.CENTER);

      add(showPanel, BorderLayout.SOUTH);

      pack();

   }

   /**

    * Gets the currently selected message.

    * @return a string, icon, component, or object array, depending on the Message panel selection

    */

   public Object getMessage()

   {

      String s = messagePanel.getSelection();

      if (s.equals("String")) return messageString;

      else if (s.equals("Icon")) return messageIcon;

      else if (s.equals("Component")) return messageComponent;

      else if (s.equals("Object[]")) return new Object[] { messageString, messageIcon,

            messageComponent, messageObject };

      else if (s.equals("Other")) return messageObject;

      else return null;

   }

   /**

    * Gets the currently selected options.

    * @return an array of strings, icons, or objects, depending on the Option panel selection

    */

   public Object[] getOptions()

   {

      String s = optionsPanel.getSelection();

      if (s.equals("String[]")) return new String[] { "Yellow", "Blue", "Red" };

      else if (s.equals("Icon[]")) return new Icon[] { new ImageIcon("yellow-ball.gif"),

            new ImageIcon("blue-ball.gif"), new ImageIcon("red-ball.gif") };

      else if (s.equals("Object[]")) return new Object[] { messageString, messageIcon,

            messageComponent, messageObject };

      else return null;

   }

   /**

    * Gets the selected message or option type

    * @param panel the Message Type or Confirm panel

    * @return the selected XXX_MESSAGE or XXX_OPTION constant from the JOptionPane class

    */

   public int getType(ButtonPanel panel)

   {

      String s = panel.getSelection();

      try

      {

         return JOptionPane.class.getField(s).getInt(null);

      }

      catch (Exception e)

      {

         return -1;

      }

   }

   /**

    * The action listener for the Show button shows a Confirm, Input, Message, or Option dialog

    * depending on the Type panel selection.

    */

   private class ShowAction implements ActionListener

   {

      public void actionPerformed(ActionEvent event)

      {

         if (typePanel.getSelection().equals("Confirm")) JOptionPane.showConfirmDialog(

               OptionDialogFrame.this, getMessage(), "Title", getType(optionTypePanel),

               getType(messageTypePanel));

         else if (typePanel.getSelection().equals("Input"))

         {

            if (inputPanel.getSelection().equals("Text field")) JOptionPane.showInputDialog(

                  OptionDialogFrame.this, getMessage(), "Title", getType(messageTypePanel));

            else JOptionPane.showInputDialog(OptionDialogFrame.this, getMessage(), "Title",

                  getType(messageTypePanel), null, new String[] { "Yellow", "Blue", "Red" },

                  "Blue");

         }

         else if (typePanel.getSelection().equals("Message")) JOptionPane.showMessageDialog(

               OptionDialogFrame.this, getMessage(), "Title", getType(messageTypePanel));

         else if (typePanel.getSelection().equals("Option")) JOptionPane.showOptionDialog(

               OptionDialogFrame.this, getMessage(), "Title", getType(optionTypePanel),

               getType(messageTypePanel), null, getOptions(), getOptions()[0]);

      }

   }

}

/**

 * A component with a painted surface

 */

class SampleComponent extends JComponent

{

   public void paintComponent(Graphics g)

   {

      Graphics2D g2 = (Graphics2D) g;

      Double rect = new Rectangle2D.Double(0, 0, getWidth() - 1, getHeight() - 1);

      g2.setPaint(Color.YELLOW);

      g2.fill(rect);

      g2.setPaint(Color.BLUE);

      g2.draw(rect);

   }

   public Dimension getPreferredSize()

   {

      return new Dimension(10, 10);

   }

}

package optionDialog;

import java.awt.*;

import javax.swing.*;

/**

 * @version 1.35 2018-04-10

 * @author Cay Horstmann

 */

public class OptionDialogTest

{

   public static void main(String[] args)

   {

      EventQueue.invokeLater(() -> {

         OptionDialogFrame frame = new OptionDialogFrame();

         frame.setTitle("OptionDialogTest");

         frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

         frame.setVisible(true);

      });

   }

}

package optionDialog;

import javax.swing.*;

/**

 * A panel with radio buttons inside a titled border.

 */

public class ButtonPanel extends JPanel

{

   private ButtonGroup group;

   /**

    * Constructs a button panel.

    * @param title the title shown in the border

    * @param options an array of radio button labels

    */

   public ButtonPanel(String title, String... options)

   {

      setBorder(BorderFactory.createTitledBorder(BorderFactory.createEtchedBorder(), title));

      setLayout(new BoxLayout(this, BoxLayout.Y_AXIS));

      group = new ButtonGroup();

      // make one radio button for each option

      for (String option : options)

      {

         JRadioButton button = new JRadioButton(option);

         button.setActionCommand(option);

         add(button);

         group.add(button);

         button.setSelected(option == options[0]);

      }

   }

   /**

    * Gets the currently selected option.

    * @return the label of the currently selected radio button.

    */

   public String getSelection()

   {

      return group.getSelection().getActionCommand();

   }

}

package dialog;

import java.awt.*;

import javax.swing.*;

/**

 * @version 1.35 2018-04-10

 * @author Cay Horstmann

 */

public class DialogTest

{

   public static void main(String[] args)

   {

      EventQueue.invokeLater(() -> {

         DialogFrame frame = new DialogFrame();

         frame.setTitle("DialogTest");

         frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

         frame.setVisible(true);

      });

   }

}

package dialog;

import javax.swing.JFrame;

import javax.swing.JMenu;

import javax.swing.JMenuBar;

import javax.swing.JMenuItem;

/**

 * A frame with a menu whose File->About action shows a dialog.

 */

public class DialogFrame extends JFrame

{

   private static final int DEFAULT_WIDTH = 300;

   private static final int DEFAULT_HEIGHT = 200;

   private AboutDialog dialog;

   public DialogFrame()

   {

      setSize(DEFAULT_WIDTH, DEFAULT_HEIGHT);

      // construct a File menu

      JMenuBar menuBar = new JMenuBar();

      setJMenuBar(menuBar);

      JMenu fileMenu = new JMenu("File");

      menuBar.add(fileMenu);

      // add About and Exit menu items

      // the About item shows the About dialog

      JMenuItem aboutItem = new JMenuItem("About");

      aboutItem.addActionListener(event -> {

         if (dialog == null) // first time

            dialog = new AboutDialog(DialogFrame.this);

         dialog.setVisible(true); // pop up dialog

      });

      fileMenu.add(aboutItem);

      // the Exit item exits the program

      JMenuItem exitItem = new JMenuItem("Exit");

      exitItem.addActionListener(event -> System.exit(0));

      fileMenu.add(exitItem);

   }

}

package dialog;

import java.awt.BorderLayout;

import javax.swing.JButton;

import javax.swing.JDialog;

import javax.swing.JFrame;

import javax.swing.JLabel;

import javax.swing.JPanel;

/**

 * A sample modal dialog that displays a message and waits for the user to click

 * the OK button.

 */

public class AboutDialog extends JDialog

{

   public AboutDialog(JFrame owner)

   {

      super(owner, "About DialogTest", true);

      // add HTML label to center

      add(

         new JLabel(

            "<html><h1><i>Core Java</i></h1><hr>By Cay Horstmann</html>"),

         BorderLayout.CENTER);

      // OK button closes the dialog

      JButton ok = new JButton("OK");

      ok.addActionListener(event -> setVisible(false));

      // add OK button to southern border

      JPanel panel = new JPanel();

      panel.add(ok);

      add(panel, BorderLayout.SOUTH);

      pack();

   }

}

package dataExchange;

import java.awt.*;

import java.awt.event.*;

import javax.swing.*;

/**

 * A frame with a menu whose File->Connect action shows a password dialog.

 */

public class DataExchangeFrame extends JFrame

{

   public static final int TEXT_ROWS = 20;

   public static final int TEXT_COLUMNS = 40;

   private PasswordChooser dialog = null;

   private JTextArea textArea;

   public DataExchangeFrame()

   {

      // construct a File menu

      JMenuBar mbar = new JMenuBar();

      setJMenuBar(mbar);

      JMenu fileMenu = new JMenu("File");

      mbar.add(fileMenu);

      // add Connect and Exit menu items

      JMenuItem connectItem = new JMenuItem("Connect");

      connectItem.addActionListener(new ConnectAction());

      fileMenu.add(connectItem);

      // the Exit item exits the program

      JMenuItem exitItem = new JMenuItem("Exit");

      exitItem.addActionListener(event -> System.exit(0));

      fileMenu.add(exitItem);

      textArea = new JTextArea(TEXT_ROWS, TEXT_COLUMNS);

      add(new JScrollPane(textArea), BorderLayout.CENTER);

      pack();

   }

   /**

    * The Connect action pops up the password dialog.

    */

   private class ConnectAction implements ActionListener

   {

      public void actionPerformed(ActionEvent event)

      {

         // if first time, construct dialog

         if (dialog == null) dialog = new PasswordChooser();

         // set default values

         dialog.setUser(new User("yourname", null));

         // pop up dialog

         if (dialog.showDialog(DataExchangeFrame.this, "Connect"))

         {

            // if accepted, retrieve user input

            User u = dialog.getUser();

            textArea.append("user name = " + u.getName() + ", password = "

               + (new String(u.getPassword())) + "\n");

         }

      }

   }

}

package dataExchange;

import java.awt.*;

import javax.swing.*;

/**

 * @version 1.35 2018-04-10

 * @author Cay Horstmann

 */

public class DataExchangeTest

{

   public static void main(String[] args)

   {

      EventQueue.invokeLater(() -> {

         DataExchangeFrame frame = new DataExchangeFrame();

         frame.setTitle("DataExchangeTest");

         frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

         frame.setVisible(true);

      });

   }

}

package dataExchange;

import java.awt.BorderLayout;

import java.awt.Component;

import java.awt.Frame;

import java.awt.GridLayout;

import javax.swing.JButton;

import javax.swing.JDialog;

import javax.swing.JLabel;

import javax.swing.JPanel;

import javax.swing.JPasswordField;

import javax.swing.JTextField;

import javax.swing.SwingUtilities;

/**

 * A password chooser that is shown inside a dialog.

 */

public class PasswordChooser extends JPanel

{

   private JTextField username;

   private JPasswordField password;

   private JButton okButton;

   private boolean ok;

   private JDialog dialog;

   public PasswordChooser()

   {

      setLayout(new BorderLayout());

      // construct a panel with user name and password fields

      JPanel panel = new JPanel();

      panel.setLayout(new GridLayout(2, 2));

      panel.add(new JLabel("User name:"));

      panel.add(username = new JTextField(""));

      panel.add(new JLabel("Password:"));

      panel.add(password = new JPasswordField(""));

      add(panel, BorderLayout.CENTER);

      // create Ok and Cancel buttons that terminate the dialog

      okButton = new JButton("Ok");

      okButton.addActionListener(event -> {

         ok = true;

         dialog.setVisible(false);

      });

      JButton cancelButton = new JButton("Cancel");

      cancelButton.addActionListener(event -> dialog.setVisible(false));

      // add buttons to southern border

      JPanel buttonPanel = new JPanel();

      buttonPanel.add(okButton);

      buttonPanel.add(cancelButton);

      add(buttonPanel, BorderLayout.SOUTH);

   }

   /**

    * Sets the dialog defaults.

    * @param u the default user information

    */

   public void setUser(User u)

   {

      username.setText(u.getName());

   }

   /**

    * Gets the dialog entries.

    * @return a User object whose state represents the dialog entries

    */

   public User getUser()

   {

      return new User(username.getText(), password.getPassword());

   }

   /**

    * Show the chooser panel in a dialog.

    * @param parent a component in the owner frame or null

    * @param title the dialog window title

    */

   public boolean showDialog(Component parent, String title)

   {

      ok = false;

      // locate the owner frame

      Frame owner = null;

      if (parent instanceof Frame)

         owner = (Frame) parent;

      else

         owner = (Frame) SwingUtilities.getAncestorOfClass(Frame.class, parent);

      // if first time, or if owner has changed, make new dialog

      if (dialog == null || dialog.getOwner() != owner)

      {

         dialog = new JDialog(owner, true);

         dialog.add(this);

         dialog.getRootPane().setDefaultButton(okButton);

         dialog.pack();

      }

      // set title and show dialog

      dialog.setTitle(title);

      dialog.setVisible(true);

      return ok;

   }

}

package dataExchange;

/**

 * A user has a name and password. For security reasons, the password is stored as a char[], not a

 * String.

 */

public class User

{

   private String name;

   private char[] password;

   public User(String aName, char[] aPassword)

   {

      name = aName;

      password = aPassword;

   }

   public String getName()

   {

      return name;

   }

   public char[] getPassword()

   {

      return password;

   }

   public void setName(String aName)

   {

      name = aName;

   }

   public void setPassword(char[] aPassword)

   {

      password = aPassword;

   }

}

package fileChooser;

import java.awt.*;

import java.io.*;

import javax.swing.*;

/**

 * A file chooser accessory that previews images.

 */

public class ImagePreviewer extends JLabel

{

   /**

    * Constructs an ImagePreviewer.

    * @param chooser the file chooser whose property changes trigger an image

    *        change in this previewer

    */

   public ImagePreviewer(JFileChooser chooser)

   {

      setPreferredSize(new Dimension(100, 100));

      setBorder(BorderFactory.createEtchedBorder());

      chooser.addPropertyChangeListener(event -> {

         if (event.getPropertyName() == JFileChooser.SELECTED_FILE_CHANGED_PROPERTY)

         {

            // 用户选择一个新文件

            File f = (File) event.getNewValue();

            if (f == null)

            {

               setIcon(null);

               return;

            }

            // 将影像读取成图示

            ImageIcon icon = new ImageIcon(f.getPath());

            // 如果图标太大，无法安装，请缩放

            if (icon.getIconWidth() > getWidth())

               icon = new ImageIcon(icon.getImage().getScaledInstance(

                     getWidth(), -1, Image.SCALE_DEFAULT));

            setIcon(icon);

         }

      });

   }

}

package fileChooser;

import java.io.*;

import javax.swing.*;

import javax.swing.filechooser.*;

import javax.swing.filechooser.FileFilter;

/**

 * A frame that has a menu for loading an image and a display area for the

 * loaded image.

 */

public class ImageViewerFrame extends JFrame

{

   private static final int DEFAULT_WIDTH = 300;

   private static final int DEFAULT_HEIGHT = 400;

   private JLabel label;

   private JFileChooser chooser;

   public ImageViewerFrame()

   {

      setSize(DEFAULT_WIDTH, DEFAULT_HEIGHT);

      // 设置菜单栏

      JMenuBar menuBar = new JMenuBar();

      setJMenuBar(menuBar);

      JMenu menu = new JMenu("File");

      menuBar.add(menu);

      JMenuItem openItem = new JMenuItem("Open");

      menu.add(openItem);

      openItem.addActionListener(event -> {

         chooser.setCurrentDirectory(new File("."));

         // 显示文件选择器对话框

            int result = chooser.showOpenDialog(ImageViewerFrame.this);

            // 如果图像文件被接受，将其设置为标签的图标

            if (result == JFileChooser.APPROVE_OPTION)

            {

               String name = chooser.getSelectedFile().getPath();

               label.setIcon(new ImageIcon(name));

               pack();

            }

         });

      JMenuItem exitItem = new JMenuItem("Exit");

      menu.add(exitItem);

      exitItem.addActionListener(event -> System.exit(0));

      // 使用标签显示影像

      label = new JLabel();

      add(label);

      //设置文件选择器

      chooser = new JFileChooser();

      // 接受所有以之结尾的影像档案。JPG。杰伯图形交换格式

      FileNameExtensionFilter filter = new FileNameExtensionFilter(

            "Image files", "jpg", "jpeg", "gif");

      chooser.setFileFilter(filter);

      chooser.setAccessory(new ImagePreviewer(chooser));

      chooser.setFileView(new FileIconView(filter, new ImageIcon("palette.gif")));

   }

}

package fileChooser;

import java.io.*;

import javax.swing.*;

import javax.swing.filechooser.*;

import javax.swing.filechooser.FileFilter;

/**

 * A file view that displays an icon for all files that match a file filter.

 */

public class FileIconView extends FileView

{

   private FileFilter filter;

   private Icon icon;

   /**

    * Constructs a FileIconView.

    * @param aFilter a file filter--all files that this filter accepts will be shown

    * with the icon.

    * @param anIcon--the icon shown with all accepted files.

    */

   public FileIconView(FileFilter aFilter, Icon anIcon)

   {

      filter = aFilter;

      icon = anIcon;

   }

   public Icon getIcon(File f)

   {

      if (!f.isDirectory() && filter.accept(f)) return icon;

      else return null;

   }

}

package fileChooser;

import java.awt.*;

import javax.swing.*;

/**

 * @version 1.26 2018-04-10

 * @author Cay Horstmann

 */

public class FileChooserTest

{

   public static void main(String[] args)

   {

      EventQueue.invokeLater(() -> {

         ImageViewerFrame frame = new ImageViewerFrame();

         frame.setTitle("FileChooserTest");

         frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

         frame.setVisible(true);

      });

   }

}