201871020225-牟星源《面向对象程序设计（java）》第十五周学习总结

201871020225-牟星源《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

一、菜单

（1）1创建一个菜单栏：JMenuBar menuBar=new JMenuBar();

2将菜单栏放置在frame的顶部：frame.setMenuBar(menuBar);

3为每个菜单建立一个菜单对象：JMenu editMenu=new jMenu("Edit");

4将顶层菜单添加到菜单栏中：menuBar.add(editMenu);

5往菜单对象中添加菜单项、分隔符和子菜单：-JMenultem pasteltem=new JMenultem("Paste");  -editMenu.add(pasteltem)

6用户点击菜单项的动作监听器为实现ActionListener接口(actionPerformed方法)的类对象或关联一个动作事件：-ActionListenerlistener=pasteltem.addActionListener(listener)，或将一个动作直接与菜单项关联

（2）菜单中的图标

JMenuItem类扩展自AbstructButton类,故菜单项与按钮很相似。

有3种方法为菜单项指定一个图标:

1.构造器方法：-JMenultem cutltem=newJMenultem("Cut",newImagelcon("cut.gif")  //默认图形在名称的左侧

2.seticon方法：-cutltem.seticon(new Imageicon("cut.gif");

3.把一个图标添加到一个动作上,再用该动作构造菜单项;cutAction.putValue(Action.SMALL_ICON,new Imageicon("cut.gif"));  JMenultem cutltem =new JMenultem(cutAction);

使用动作构造菜单项时,Action.NAME将会成为菜单项的文本,而Action.SMALL_ICON成为图标。

（3）弹出菜单

弹出菜单(pop-up menu)即单击鼠标右键可弹出的快捷菜单。

建立弹出菜单的方法与一般菜单相似：

1）创建一个弹出式菜单：JPopupMenu popup=new JPopupMenu()

2）在菜单中添加菜单项：JMenultem item=new JMenultem("Cut")

item.addActionListener(listener);

popup.add(item);

（4）弹出式触发器

弹出式触发器(pop-up tigger)：用户点击鼠标某个键时,弹出菜单。

在Windows或者Linux中,弹出式触发器是右键。

要想在用户点击某一个组件的时候弹出菜单,就要使用弹出式触发器：component.setComponentPopupMenu(pop up);

（5）快捷键

可以为菜单项设置快捷键。在当前菜单打开的情况下,可以按下某菜单项的快捷键,相当于鼠标单击了该菜单项。

JMenultem Cutltem=new JMenultem("lndex");

Cutltem.setMnemonic("p")

快捷键就会自动显示在菜单项中,快捷键下面有一条下划线。

（6）加速器

加速器可以在不打开菜单的情况下选中菜单项的快捷键

例如,很多程序把CTRL+O和CTRL+S关联到菜单中的Open和Save项。

使用方法可以将加速器关联到一个菜单项。该方法使用类型的对象作为参数。

当用户按下加速器组合键时,就自动选择了相应的菜单项,同时激活一个动作事件。

注意:加速器实际上并不打开菜单,而是直接激活菜单关联的动作事件。

（7）启用和禁用菜单项

在程序运行过程中,经常需要屏蔽某些暂时不适用的命令,待到条件允许时再使之重新可用。

屏蔽/启用菜单项的方法：aMenultem.setEnabled(boolean)

当参数值为ale时,屏蔽该菜单项，当参数值为tue时,启用该菜单项。

如果需要动态启用/屏蔽某菜单项,则需要为“menu selected”事件注册监听器。javax.swing.event包定义了MenuListener接口,它有三个方法：

void menuSelected(MenuEvent event)

voidmenuDeselected(MenuEventevent)

void menuCanceled(MenuEvent event)

二、工具栏

工具栏是在程序中提供快速访问常用命令的按钮栏。

工具栏的特别之处在于可以移动,脱离工具栏或拖拽到框架其他地方。

（1）工具栏的创建

创建工具栏时,直接将组件添加到工具栏中,再将工具栏放入框架

JToolBar bar=new JToolBar();

-bar. add(blue Button);

-frame.add(bar,BorderLayout.NORTH);

也可以使用添加Action对象的方法来填充工具栏：-bar.add(blueAction)

可以设置工具提示：-setToolTipText(String);

如果使用Action对象,则可使用PutValue方法

注意;按钮是工具栏中最賞见的组件类型。但其它组件也可以放置在工具栏中,例如复选框等。

（2）工具栏相关的常用方法

Java.swing.JToolBar

JToolBar()

JToolBar(String titleString)

JToolBar(intorientation)

JButton add(Action a) //在工具栏添加与动作a关联的按钮

void addSeparator() //在工具栏末尾添加一个分隔符

Java.swing. JToolBar

void setToolTipText(String text) //设置当鼠标停留在组件上时显示的工具提示的文本

三、对话框的种类

对话框分为模式对话框和无模式对话框。

（1）模式对话框

在用户结束对它的操作之前,不允许用户与应用程序其他窗口的交互

模式对话框的作用:在程序继续运行之前,必须获得用户提供的信息。

（2）无模式对话框

无模式对话框运行用户同时在对话框和应用程序的其它窗口中输入信息

例如:工具栏：工具栏可以停靠在任何地方,并且用户可以在需要时与应用程序窗口和工具栏进行交互。

（3）一些常用的对话框：

1选项对话框

Swing提供了一组简单的对话框,用于收集用户提供的简单信息。有四个用于显示这些简单对话框的静态方法

showMessageDialog:显示一条消息,并等待用户点击OK

showConfirmDialog:显示一条消息,并等待用户点击确认(与按钮类似）

showOptionDialog:显示一条消息,并等待用户作出某一种选择

showInputDialog:显示一条消息,并等待用户输入一行信息

创建对话框

创建一个对话框的步骤：

1.创建一个派生自JDialog类的子类。

2.在子类的构造器中,需要进行以下工作

(1)调用超类的构造器,用于指定对话框的拥有者(owner frame),(也可以设置为null,但这样对话框有可能被隐藏在其它窗口后面),对话框的标题以及是否模式对话框

(2)添加对话框的用户界面组件

(3)添加相应的事件处理器

(4)设置对话框的大小

使用对话框的一个重要目的是获取用户的输入信息

2文本对话框

文件对话框甩于帮助用戶打开或煮保存文件。下面是建立文件对话框并且获取用戶选择信息的步骤:

1.建立一个对象。与类构造器不同,这种对象不需要指定父组件,因而允许在多个框架中重用一个文件选择器

JFileChooser chooser=new JFileChooser0);

2.调用方法设置当前目录

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

3.如果要指定一个默认的文件名,可以使用setSelected方法

chooser.setSelectedFile(newFile(filename))

4.如果要允许用户能同时选中多个文件,可以使用setMultiSelectionEnabled方法

chooser.setMultiSelectionEnabled(true);

5.如果希望在对话框中只显示某一类型的文件(如所有.gif文件),则需要文件过滤器。

6.默认情况下只能选中文件,如果希望允许用户选择目录,则需要使用setFileSelectionMode方法。

7.调用showOpenDialog或者showSaveDialog方法显示对话框。必须为这些调用指定父组件：

int result=chooser.showOpenDialog(parent)

int result=chooser. showSaveDialog(parent);

8.使用getSelectedFile或者getSelectedFiles获得选中的一个或多个文件。这些方法返回一个File对象或者组File对象。如果需要文件对象名字时,可以调用getPath方法

String filename=chooser.getSelectedfile().getPath();

第二部分：实验部分

导入第12章示例程序，测试程序并进行组内讨论。

实验1：测试程序1

l 在elipse IDE中调试运行教材512页程序12-8，结合运行结果理解程序；

l 掌握菜单的创建、菜单事件监听器、复选框和单选按钮菜单项、弹出菜单以及快捷键和加速器的用法。

l 记录示例代码阅读理解中存在的问题与疑惑。

具体代码如下：

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);
   }
}

运行结果如下：

实验1：测试程序2

l 在elipse IDE中调试运行教材517页程序12-9，结合运行结果理解程序；

l 掌握工具栏和工具提示的用法；

l 记录示例代码阅读理解中存在的问题与疑惑。

具体代码如下：

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);
      }
   }
}

运行结果如下：

实验1：测试程序3

l 在elipse IDE中调试运行教材544页程序12-15、12-16，结合运行结果理解程序；

l 掌握选项对话框的用法。

l 记录示例代码阅读理解中存在的问题与疑惑。

具体代码如下：

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 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 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();
   }
}

运行结果如下：

实验1：测试程序4

l 在elipse IDE中调试运行教材552页程序12-17、12-18，结合运行结果理解程序；

l 掌握对话框的创建方法；

l 记录示例代码阅读理解中存在的问题与疑惑。

具体代码如下：

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);
   }
}

运行结果如下：

实验1：测试程序5

l 在elipse IDE中调试运行教材556页程序12-19、12-20，结合运行结果理解程序；

l 掌握对话框的数据交换用法;

l 记录示例代码阅读理解中存在的问题与疑惑。

具体代码如下：

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");
         }
      }
   }
}

运行结果如下：

实验1：测试程序6

l 在elipse IDE中调试运行教材556页程序12-21、12-2212-23，结合程序运行结果理解程序；

l 掌握文件对话框的用法;

l 记录示例代码阅读理解中存在的问题与疑惑。

具体代码如下：

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.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));//setPreferredSize在布局管理器会获取空间的PreferredSize
      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
            var 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);//设置此文件或文件类型的图标
         }
      });
   }
}

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")));
   }
}

运行结果如下：

实验1：测试程序7

l 在elipse IDE中调试运行教材570页程序12-24，结合运行结果理解程序；

l 了解颜色选择器的用法。

l 记录示例代码阅读理解中存在的问题与疑惑。

具体代码如下：

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);
       }
    }
 }

运行结果如下：

第三部分：实验总结：

本周重点学了菜单和对话框，包括在菜单栏上添加菜单项，嵌套菜单，以及弹出菜单的使用，还有对话框的很多类型，有选择对话框，确认对话框，消息对话框，还有确认对话框。本周的实验都是验证性实验，通过看书，注释，网上查找，还有听网课就感觉懂了，但是理解的还不是很透彻，我会课余时间多进行练习以提高编程水平。