201874040116-李鑫《面向对象程序设计（java）》第十五周学习总结

项目	内容
这个作业属于哪个课程	https://www.cnblogs.com/nwnu-daizh/
这个作业的要求在哪里	https://www.cnblogs.com/nwnu-daizh/p/11995615.html
作业学习目标	(1) 掌握菜单组件用途及常用API； (2) 掌握对话框组件用途及常用API； (3) 学习设计简单应用程序的GUI。

 

 

 

 

 

 

 

第一部分：总结菜单、对话框两类组件用途及常用API

　　菜单是GUI编程中经常用到的一种组件。位于窗口顶部的菜单栏（menu bar）中能包含实现各种操作的子菜单，利于用户进行各种操作，对于一些功能十分丰富的程序，可以使其更加方便使用。

　　对话框用于在某些情况下显示信息或者获取信息，合理的利于对话框可以构造具有良好的交互性的程序。

 　　

2、实验内容和步骤

　　

测试程序1

 

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 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);
      });
   }
}

 

测试程序2

 

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 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);
      });
   }
}

测试程序3

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 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);
      });
   }
}

　

测试程序4

　　

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 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.*;
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);
      });
   }
}

测试程序5

　　

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;
   }
}

测试程序6

　　

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);
      });
   }
}

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 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)
         {
            // the user has selected a new file
            File f = (File) event.getNewValue();
            if (f == null)
            {
               setIcon(null);
               return;
            }

            // read the image into an icon
            ImageIcon icon = new ImageIcon(f.getPath());

            // if the icon is too large to fit, scale it
            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);

      // set up menu bar
      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("."));

         // show file chooser dialog
            int result = chooser.showOpenDialog(ImageViewerFrame.this);

            // 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();
            }
         });

      JMenuItem 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
      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")));
   }
}

测试程序7

 

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 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
   {
      private JDialog dialog;
      private JColorChooser chooser;

      public ModelessListener()
      {
         chooser = new JColorChooser();
         dialog = JColorChooser.createDialog(ColorChooserPanel.this, "Background Color",
               false /* not modal */, chooser, 
               event -> setBackground(chooser.getColor()), 
               null /* no Cancel button listener */);
      }

      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);
      }
   }

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);

      // add color chooser panel to frame

      ColorChooserPanel panel = new ColorChooserPanel();
      add(panel);
   }
}

 

实验总结：

　　这次实验让我熟悉了菜单，对话框，文件选择器的基本使用，但离自如的使用这些组件还需要更多的学习与练习。