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//菜单项触发命令，通常采用扩展抽象类AbstractAction来定义一个实现Action接口的类

   {

      public TestAction(String name)

      {

         super(name);

      }

      public void actionPerformed(ActionEvent event)

      {

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

      }

   }

   public MenuFrame()  //构造器

   {

      setSize(DEFAULT_WIDTH, DEFAULT_HEIGHT);

      JMenu fileMenu = new JMenu("File");//为菜单建立一个菜单对象

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

      // demonstrate accelerators

      JMenuItem openItem = fileMenu.add(new TestAction("Open"));//添加菜单项open

      openItem.setAccelerator(KeyStroke.getKeyStroke("ctrl O"));//快捷键,与ctrl O联系

      fileMenu.addSeparator();//添加分隔符

      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);//真实功能

            }

         });

      // 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);//启用或禁用菜单选项利用setEnabled方法

               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有图标

      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

      var 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();//创建菜单栏

      setJMenuBar(menuBar);//将菜单栏添加到框架上

      menuBar.add(fileMenu);//将顶层菜单添加到菜单栏中

      menuBar.add(editMenu);

      menuBar.add(helpMenu);

      // demonstrate pop-ups弹出菜单

      popup = new JPopupMenu();//创建弹出菜单

      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);//边框布局的中

      // 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();//创建工具栏

      bar.add(blueAction);//将组件添加到工具栏中

      bar.add(yellowAction);

      bar.add(redAction);

      bar.addSeparator();

      bar.add(exitAction);

      add(bar, BorderLayout.NORTH);//置于边框布局的北

      // 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//菜单项触发命令

   {

      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)//重写actionPerformed方法

      {

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

         panel.setBackground(c);

      }

   }

}

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));//设置边框效果

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

      group = new ButtonGroup();

      // make one radio button for each option

      for (String option : options)//for-each循环打印

      {

         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 optionDialog;

import java.awt.*;

import java.awt.event.*;

import java.awt.geom.*;

import java.util.*;

import javax.swing.*;

/**

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

 */

public class OptionDialogFrame extends JFrame//继承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()

   {

      var 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[]");//五个按钮

      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

      var showPanel = new JPanel();

      var showButton = new JButton("Show");

      showButton.addActionListener(new ShowAction());

      showPanel.add(showButton);

      add(gridPanel, BorderLayout.CENTER);//加于中间

      add(showPanel, BorderLayout.SOUTH);//加于南面

      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));//若typePanel中选择Confirm按钮，得messageTypePanel的内容

         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)

   {

      var g2 = (Graphics2D) g;

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

      g2.setPaint(Color.YELLOW);//设置颜色

      g2.fill(rect);//进行填充

      g2.setPaint(Color.BLUE);

      g2.draw(rect);

   }

   public Dimension getPreferredSize()

   {

      return new Dimension(10, 10);

   }

}

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 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);//调用超类的构造器

      // 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));//可见

      // add OK button to southern border

       JPanel panel = new JPanel();

      panel.add(ok);

      add(panel, BorderLayout.SOUTH);

      pack();

   }

}

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();//菜单栏

      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));//退出

      fileMenu.add(exitItem);

   }

}

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(() -> {

         var frame = new DataExchangeFrame();

         frame.setTitle("DataExchangeTest");

         frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

         frame.setVisible(true);

      });

   }

}

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 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;//ok是boolean型的

   private JDialog dialog;

   public PasswordChooser()

   {

      setLayout(new BorderLayout());

      // construct a panel with user name and password fields

      var panel = new JPanel();

      panel.setLayout(new GridLayout(2, 2));//网格布局，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);

      });

      var cancelButton = new JButton("Cancel");

      cancelButton.addActionListener(event -> dialog.setVisible(false));//调用取消按钮的添加监听器，设置组件不可见

      // add buttons to southern border

      var buttonPanel = new JPanel();

      buttonPanel.add(okButton);//加OK按钮

      buttonPanel.add(cancelButton);

      add(buttonPanel, BorderLayout.SOUTH);//南边

   }

   /**

    * 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;

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

      var mbar = new JMenuBar();

      setJMenuBar(mbar);

      var fileMenu = new JMenu("File");

      mbar.add(fileMenu);

      // add Connect and Exit menu items加入Connect和Exit

      var connectItem = new JMenuItem("Connect");

      connectItem.addActionListener(new ConnectAction());

      fileMenu.add(connectItem);

      // the Exit item exits the program

      var 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 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(() -> {

         var frame = new ImageViewerFrame();

         frame.setTitle("FileChooserTest");

         frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

         frame.setVisible(true);

      });

   }

}

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)//getIcon获得文件类型的图标

   {

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

      else return null;

   }

}

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);

      // set up menu bar

      var menuBar = new JMenuBar();

      setJMenuBar(menuBar);

      var menu = new JMenu("File");

      menuBar.add(menu);

      var openItem = new JMenuItem("Open");

      menu.add(openItem);

      openItem.addActionListener(event -> {

         chooser.setCurrentDirectory(new File("."));//用setCurrentDirectory改变进程的当前目录

         // show file chooser dialog

            int result = chooser.showOpenDialog(ImageViewerFrame.this);//（不太理解）用showOpenDialog方法，显示打开文件的对话框

// if image file accepted, set it as icon of the label

            if (result == JFileChooser.APPROVE_OPTION)

            {

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

               label.setIcon(new ImageIcon(name));

               pack();

            }

         });

      var exitItem = new JMenuItem("Exit");

      menu.add(exitItem);

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

      // use a label to display the images

      label = new JLabel();

      add(label);

      // set up file chooser

      chooser = new JFileChooser();

      // accept all image files ending with .jpg, .jpeg, .gif 接受以jpg, .jpeg, .gif为扩展名的图像文件

      var 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 colorChooser;

  import java.awt.*;

  import javax.swing.*;

 /**

  * @version 1.04 2015-06-12

  * @author Cay Horstmann

  */

 public class ColorChooserTest

 {

    public static void main(String[] args)

    {

       EventQueue.invokeLater(() -> {

         JFrame frame = new ColorChooserFrame();

        frame.setTitle("ColorChooserTest");

        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        frame.setVisible(true);

       });

    }

}

package colorChooser;

import javax.swing.*;

  /**

   * A frame with a color chooser panel

   */

 public class ColorChooserFrame extends JFrame

 {

    private static final int DEFAULT_WIDTH = 300;

    private static final int DEFAULT_HEIGHT = 200;

    public ColorChooserFrame()

    {

       setSize(DEFAULT_WIDTH, DEFAULT_HEIGHT);//固定大小

       ColorChooserPanel panel = new ColorChooserPanel();

       add(panel);

    }

 }

package colorChooser;

  import java.awt.Color;

  import java.awt.Frame;

  import java.awt.event.ActionEvent;

  import java.awt.event.ActionListener;

 import javax.swing.JButton;

 import javax.swing.JColorChooser;

 import javax.swing.JDialog;

 import javax.swing.JPanel;

 /**

  * A panel with buttons to pop up three types of color choosers

  */

 public class ColorChooserPanel extends JPanel

 {

    public ColorChooserPanel()

    {

       JButton modalButton = new JButton("Modal");

       modalButton.addActionListener(new ModalListener());

       add(modalButton);

       JButton modelessButton = new JButton("Modeless");

       modelessButton.addActionListener(new ModelessListener());

       add(modelessButton);

       JButton immediateButton = new JButton("Immediate");

       immediateButton.addActionListener(new ImmediateListener());

       add(immediateButton);

    }

    /**

     * This listener pops up a modal color chooser

     */

    private class ModalListener implements ActionListener

    {

       public void actionPerformed(ActionEvent event)

       {

          Color defaultColor = getBackground();

          Color selected = JColorChooser.showDialog(ColorChooserPanel.this, "Set background",

                defaultColor);

          if (selected != null) setBackground(selected);

       }

    }

    /**

     * This listener pops up a modeless color chooser. The panel color is changed when the user

     * clicks the OK button.

     */

    private class ModelessListener implements ActionListener//实现接口

    {

       private JDialog dialog;//对话框

       private JColorChooser chooser;

       public ModelessListener()

       {

          chooser = new JColorChooser();

          dialog = JColorChooser.createDialog(ColorChooserPanel.this, "Background Color",

                false /* not modal */, chooser,

                event -> setBackground(chooser.getColor()),//getColor()设置颜色

                null /* no Cancel button listener */);

       }//不太理解

       public void actionPerformed(ActionEvent event)

       {

          chooser.setColor(getBackground());

          dialog.setVisible(true);

       }

    }

    /**

     * This listener pops up a modeless color chooser. The panel color is changed immediately when

     * the user picks a new color.

     */

    private class ImmediateListener implements ActionListener

    {

       private JDialog dialog;

       private JColorChooser chooser;

       public ImmediateListener()

       {

          chooser = new JColorChooser();

          chooser.getSelectionModel().addChangeListener(

                event -> setBackground(chooser.getColor()));

          dialog = new JDialog((Frame) null, false /* not modal */);

          dialog.add(chooser);

          dialog.pack();

       }

       public void actionPerformed(ActionEvent event)

       {

          chooser.setColor(getBackground());

          dialog.setVisible(true);

       }

    }

 }