201871010101-陈来弟《面向对象程序设计(java)》第十五周学习总结

                                                                                                                                                                               实验十三  Swing图形界面组件(二)

实验时间 2019-12-6

 

第一部分:理论知识

A、菜单:

       有两种类型的菜单:下拉式菜单和弹出式菜单。菜单与JComboBox和JCheckBox不同,它们在界面中是一直可见的。菜单与JComboBox的相同之处是每次只可选择一个项目。

在下拉式菜单或弹出式菜单中选择一个选项就产生一个ActionEvent事件。该事件被发送给那个选项的监视器,事件的意义由监视器解释。
菜单条、菜单和菜单项
下拉式菜单通过出现在菜单条上的名字可视化表示,菜单条(JMenuBar)通常出现在JFrame的顶部,一个菜单条显示多个下拉式菜单的名字。可以用两种方式来激活下拉式菜单。一种是按下鼠标的按钮,并保持按下状态,移动鼠标,直至释放鼠标完成选择,高亮度显示的菜单项即为所选择的。另一种方式是当光标位于菜单条中的菜单名上时,点击鼠标,在这种情况下,菜单会展开,且高亮度显示菜单项。

一个菜单条可以放多个菜单(JMenu),每个菜单又可以有许多菜单项(JMenuItem)。例如,Eclipse环境的菜单条有File、Edit、Source、Refactor等菜单,每个菜单又有许多菜单项。例如,File菜单有New、Open File、Close 、Close All等菜单项。

向窗口增设菜单的方法是:先创建一个菜单条对象,然后再创建若干菜单对象,把这些菜单对象放在菜单条里,再按要求为每个菜单对象添加菜单项。
菜单中的菜单项也可以是一个完整的菜单。由于菜单项又可以是另一个完整菜单,因此可以构造一个层次状菜单结构。

1.菜单条
类JMenuBar的实例就是菜单条。例如,以下代码创建菜单条对象menubar:
    JMenuBar menubar = new JMenuBar();
在窗口中增设菜单条,必须使用JFrame类中的setJMenuBar()方法。例如,代码:
    setJMenuBar(menubar);

类JMenuBar的常用方法有:
add(JMenu m):将菜单m加入到菜单条中。
countJMenus():获得菜单条中菜单条数。
getJMenu(int p):取得菜单条中的菜单。
remove(JMenu m):删除菜单条中的菜单m。

2. 菜单
由类JMenu创建的对象就是菜单。类JMenu的常用方法如下:
JMenu():建立一个空标题的菜单。
JMenu(String s):建立一个标题为s的菜单。
add(JMenuItem item):向菜单增加由参数item指定的菜单选项。
add(JMenu menu):向菜单增加由参数menu指定的菜单。实现在菜单嵌入子菜单。
addSeparator():在菜单选项之间画一条分隔线。
getItem(int n):得到指定索引处的菜单项。
getItemCount():得到菜单项数目。
insert(JMenuItem item,int n):在菜单的位置n插入菜单项item.
remove(int n):删除菜单位置n的菜单项
removeAll():删除菜单的所有菜单项。

3.菜单项
类JMenuItem 的实例就是菜单项。类JMenuItem的常用方法如下:
JMenuItem():构造无标题的菜单项。
JMenuItem(String s):构造有标题的菜单项。
setEnabled(boolean b):设置当前单项是否可被选择。
isEnabled():返回当前菜单项是否可被用户选择。
getLabel():得到菜单项的名称。
setLabel():设置菜单选项的名称。
addActionListener(ActionListener e):为菜单项设置监视器。监视器接受点击某个菜单的动作事件。

4. 处理菜单事件
菜单的事件源是用鼠标点击某个菜单项。处理该事件的接口是ActionListener,要实现的接口方法是actionPerformed(ActionEvent e),获得事件源的方法getSource(). 

【例 11-15】小应用程序示意窗口有菜单条的实现方法。设有一个按钮,当按钮处于打开窗口状态时,单击按钮将打开一个窗口,窗口设有一个菜单条,有两个菜单,每个菜单又各有三个菜单项。当一个菜单项被选中时,菜单项监视方法在文本框中显示相应菜单项被选中字样(查看源文件)。

5. 嵌入子菜单
创建了一个菜单,并创建多个菜单项,其中某个菜单项又是一个(含其他菜单项的)菜单,这就构成菜单嵌套。例如,将上述程序中的有关代码改成如下:
    Menu menu1,menu2,item4;
    MenuItem item3,item5,item6,item41,item42;
另插入以下代码创建item41和item42菜单项,并把它们加入到item4菜单中:
    item41= new MenuItem(“东方红”);
    item42 = new MenuItem(“牡丹”);
    item4.add(item41);
    item4.add(item42);
则点击item4菜单时,又会打开两个菜单项供选择。

6. 向菜单增加退出项
增设一个新的菜单项,对该菜单项加入监视,对应的监视方法中使用System.exit()方法,就能实现单击该菜单项时退出Java运行环境。例如,以下示意代码:

item7 = new MenuItem(“退出”);
item7.addActionListener(this);

public void actionPerformed(ActionEvent e){
    if(e.getSource()==item7){
        System.exit(0);
    }
}

7.设置菜单项的快捷键
用MenuShortcut类为菜单项设置快捷键。构造方法是MenuShortcut(int key)。其中key可以取值KeyEvent.VK_A至KenEvent.VK_Z,也可以取 ‘a’到 ‘z’键码值。菜单项使用setShortcut(MenuShortcut k)方法来设置快捷键。例如,以下代码设置字母e为快捷键。
class Herwindow extends Frame implements ActionListener{
    MenuBar menbar;
    Menu menu;
    MenuItem item;
    MenuShortcut shortcut = new MenuShortcut(KeyEvent.VK_E);
    …
    item.setShortcut(shortcut);
    …
}

B、对话框

Dialog 是一个带标题和边界的顶层窗口,边界一般用于从用户处获得某种形式的输入。 Dialog 的大小包括边界所指定的任何区域。边界区的维度可以使用 getInsets 方法获得,但是,由于这些维度是依赖于平台的,因此只有通过调用 pack 或 show 将 dialog 设置为可显示的,才能获得有效的 insets 值。由于 dialog 的总大小包括了边界区,因此边界有效地模糊了 dialog 的部分区域,约束了可用于在矩形中呈现或显示子部件的区域,矩形左上角的位置为(insets.left, insets.top),宽度为 width - (insets.left + insets.right),长度为 height - (insets.top + insets.bottom)

 

        Dialog 的默认布局为 BorderLayout

 

        Dialog 可以使用 setUndecorated 关闭本机装饰(例如 Frame & Titlebar)。只有在 dialog 不是 displayable时才能完成此操作。

 

        Dialog 在构造时必须有一个框架,或者将另一个 dialog 定义为它的所有者。当可见的 dialog 的所有者窗口被最小化时,dialog 会自动隐藏为对用户不可见。当所有者窗口被还原时,dialog 重新又变为用户可见的。

 

        dialog 可以是无模式的(默认情况下)或有模式的。一个有模式的 dialog 将阻断输入到应用程序中其他所有顶层窗口的内容(将此 dialog 作为其所有者创建的窗口除外)。

 

        Dialog 能够产生以下WindowEventsWindowOpenedWindowClosingWindowClosedWindowActivatedWindowDeactivatedWindowGained

效果图如下:

201871010101-陈来弟《面向对象程序设计(java)》第十五周学习总结_第1张图片

 

 

 

第二部分:实验

1、实验目的与要求

(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。

2、实验内容和步骤

实验1: 导入第12章示例程序,测试程序并进行组内讨论。

测试程序1

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;

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。

记录示例代码阅读理解中存在的问题与疑惑。

 

12-8 代码:

package menu;

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

/**
 * @version 1.25 2018-04-10
 * @author Cay Horstmann
 */
public class MenuTest
{
   public static void main(String[] args)
   {
      EventQueue.invokeLater(() -> {
         MenuFrame frame = new MenuFrame();
         frame.setTitle("MenuTest");
         frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
         frame.setVisible(true);
      });
   }
}

 

package menu;

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

/**
 * A frame with a sample menu bar.
 */
public class MenuFrame extends JFrame
{
   private static final int DEFAULT_WIDTH = 300;
   private static final int DEFAULT_HEIGHT = 200;
   private Action saveAction;
   private Action saveAsAction;
   private JCheckBoxMenuItem readonlyItem;
   private JPopupMenu popup;

   /**
    * A sample action that prints the action name to System.out.
    */
   class TestAction extends AbstractAction
   {
      public TestAction(String name)
      {
         super(name);
      }

      public void actionPerformed(ActionEvent event)
      {
         System.out.println(getValue(Action.NAME) + " selected.");
      }
   }

   public MenuFrame()
   {
      setSize(DEFAULT_WIDTH, DEFAULT_HEIGHT);

      JMenu fileMenu = new JMenu("File");
      fileMenu.add(new TestAction("New"));

      // demonstrate accelerators

      JMenuItem openItem = fileMenu.add(new TestAction("Open"));
      openItem.setAccelerator(KeyStroke.getKeyStroke("ctrl O"));

      fileMenu.addSeparator();

      saveAction = new TestAction("Save");
      JMenuItem saveItem = fileMenu.add(saveAction);
      saveItem.setAccelerator(KeyStroke.getKeyStroke("ctrl S"));

      saveAsAction = new TestAction("Save As");
      fileMenu.add(saveAsAction);
      fileMenu.addSeparator();

      fileMenu.add(new AbstractAction("Exit")
         {
            public void actionPerformed(ActionEvent event)
            {
               System.exit(0);
            }
         });

      // demonstrate checkbox and radio button menus

      readonlyItem = new JCheckBoxMenuItem("Read-only");
      readonlyItem.addActionListener(new ActionListener()
         {
            public void actionPerformed(ActionEvent event)
            {
               boolean saveOk = !readonlyItem.isSelected();
               saveAction.setEnabled(saveOk);
               saveAsAction.setEnabled(saveOk);
            }
         });

      ButtonGroup group = new ButtonGroup();

      JRadioButtonMenuItem insertItem = new JRadioButtonMenuItem("Insert");
      insertItem.setSelected(true);
      JRadioButtonMenuItem overtypeItem = new JRadioButtonMenuItem("Overtype");

      group.add(insertItem);
      group.add(overtypeItem);

      // demonstrate icons

      TestAction cutAction = new TestAction("Cut");
      cutAction.putValue(Action.SMALL_ICON, new ImageIcon("cut.gif"));
      TestAction copyAction = new TestAction("Copy");
      copyAction.putValue(Action.SMALL_ICON, new ImageIcon("copy.gif"));
      TestAction pasteAction = new TestAction("Paste");
      pasteAction.putValue(Action.SMALL_ICON, new ImageIcon("paste.gif"));

      JMenu editMenu = new JMenu("Edit");
      editMenu.add(cutAction);
      editMenu.add(copyAction);
      editMenu.add(pasteAction);

      // demonstrate nested menus

      JMenu optionMenu = new JMenu("Options");

      optionMenu.add(readonlyItem);
      optionMenu.addSeparator();
      optionMenu.add(insertItem);
      optionMenu.add(overtypeItem);

      editMenu.addSeparator();
      editMenu.add(optionMenu);

      // demonstrate mnemonics

      JMenu helpMenu = new JMenu("Help");
      helpMenu.setMnemonic('H');

      JMenuItem indexItem = new JMenuItem("Index");
      indexItem.setMnemonic('I');
      helpMenu.add(indexItem);

      // you can also add the mnemonic key to an action
      TestAction aboutAction = new TestAction("About");
      aboutAction.putValue(Action.MNEMONIC_KEY, new Integer('A'));
      helpMenu.add(aboutAction);
      
      // add all top-level menus to menu bar

      JMenuBar menuBar = new JMenuBar();
      setJMenuBar(menuBar);

      menuBar.add(fileMenu);
      menuBar.add(editMenu);
      menuBar.add(helpMenu);

      // demonstrate pop-ups

      popup = new JPopupMenu();
      popup.add(cutAction);
      popup.add(copyAction);
      popup.add(pasteAction);

      JPanel panel = new JPanel();
      panel.setComponentPopupMenu(popup);
      add(panel);
   }
}

运行结果:

201871010101-陈来弟《面向对象程序设计(java)》第十五周学习总结_第2张图片

 

 

 

测试程序2

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;

掌握工具栏和工具提示的用法;

记录示例代码阅读理解中存在的问题与疑惑。

12-9 代码:

package toolBar;

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

/**
 * @version 1.15 2018-04-10
 * @author Cay Horstmann
 */
public class ToolBarTest
{
   public static void main(String[] args)
   {
      EventQueue.invokeLater(() -> {
         ToolBarFrame frame = new ToolBarFrame();
         frame.setTitle("ToolBarTest");
         frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
         frame.setVisible(true);
      });
   }
}

 

package toolBar;

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

/**
 * A frame with a toolbar and menu for color changes.
 */
public class ToolBarFrame extends JFrame
{
   private static final int DEFAULT_WIDTH = 300;
   private static final int DEFAULT_HEIGHT = 200;
   private JPanel panel;

   public ToolBarFrame()
   {
      setSize(DEFAULT_WIDTH, DEFAULT_HEIGHT);

      // add a panel for color change

      panel = new JPanel();
      add(panel, BorderLayout.CENTER);

      // set up actions

      ColorAction blueAction = new ColorAction("Blue", new ImageIcon("blue-ball.gif"), Color.BLUE);
      ColorAction yellowAction = new ColorAction("Yellow", new ImageIcon("yellow-ball.gif"),
            Color.YELLOW);
      ColorAction redAction = new ColorAction("Red", new ImageIcon("red-ball.gif"), Color.RED);

      AbstractAction exitAction = new AbstractAction("Exit", new ImageIcon("exit.gif"))
         {
            public void actionPerformed(ActionEvent event)
            {
               System.exit(0);
            }
         };
      exitAction.putValue(Action.SHORT_DESCRIPTION, "Exit");

      // populate toolbar

      JToolBar bar = new JToolBar();
      bar.add(blueAction);
      bar.add(yellowAction);
      bar.add(redAction);
      bar.addSeparator();
      bar.add(exitAction);
      add(bar, BorderLayout.NORTH);

      // populate menu

      JMenu menu = new JMenu("Color");
      menu.add(yellowAction);
      menu.add(blueAction);
      menu.add(redAction);
      menu.add(exitAction);
      JMenuBar menuBar = new JMenuBar();
      menuBar.add(menu);
      setJMenuBar(menuBar);
   }

   /**
    * The color action sets the background of the frame to a given color.
    */
   class ColorAction extends AbstractAction
   {
      public ColorAction(String name, Icon icon, Color c)
      {
         putValue(Action.NAME, name);
         putValue(Action.SMALL_ICON, icon);
         putValue(Action.SHORT_DESCRIPTION, name + " background");
         putValue("Color", c);
      }

      public void actionPerformed(ActionEvent event)
      {
         Color c = (Color) getValue("Color");
         panel.setBackground(c);
      }
   }
}

其运行结果:

 

201871010101-陈来弟《面向对象程序设计(java)》第十五周学习总结_第3张图片

 

 

测试程序3

elipse IDE中调试运行教材544页程序12-1512-16,结合运行结果理解程序;

掌握选项对话框的用法。

记录示例代码阅读理解中存在的问题与疑惑。

 代码如下:

 

package optionDialog;

import java.awt.*;
import java.awt.event.*;
import java.awt.geom.*;
import java.awt.geom.Rectangle2D.Double;
import java.util.*;
import javax.swing.*;

/**
 * A frame that contains settings for selecting various option dialogs.
 */
public class OptionDialogFrame extends JFrame
{
   private ButtonPanel typePanel;
   private ButtonPanel messagePanel;
   private ButtonPanel messageTypePanel;
   private ButtonPanel optionTypePanel;
   private ButtonPanel optionsPanel;
   private ButtonPanel inputPanel;
   private String messageString = "Message";
   private Icon messageIcon = new ImageIcon("blue-ball.gif");
   private Object messageObject = new Date();
   private Component messageComponent = new SampleComponent();

   public OptionDialogFrame()
   {
      JPanel gridPanel = new JPanel();
      gridPanel.setLayout(new GridLayout(2, 3));

      typePanel = new ButtonPanel("Type", "Message", "Confirm", "Option", "Input");
      messageTypePanel = new ButtonPanel("Message Type", "ERROR_MESSAGE", "INFORMATION_MESSAGE",
            "WARNING_MESSAGE", "QUESTION_MESSAGE", "PLAIN_MESSAGE");
      messagePanel = new ButtonPanel("Message", "String", "Icon", "Component", "Other", 
            "Object[]");
      optionTypePanel = new ButtonPanel("Confirm", "DEFAULT_OPTION", "YES_NO_OPTION",
            "YES_NO_CANCEL_OPTION", "OK_CANCEL_OPTION");
      optionsPanel = new ButtonPanel("Option", "String[]", "Icon[]", "Object[]");
      inputPanel = new ButtonPanel("Input", "Text field", "Combo box");

      gridPanel.add(typePanel);
      gridPanel.add(messageTypePanel);
      gridPanel.add(messagePanel);
      gridPanel.add(optionTypePanel);
      gridPanel.add(optionsPanel);
      gridPanel.add(inputPanel);

      // add a panel with a Show button

      JPanel showPanel = new JPanel();
      JButton showButton = new JButton("Show");
      showButton.addActionListener(new ShowAction());
      showPanel.add(showButton);

      add(gridPanel, BorderLayout.CENTER);
      add(showPanel, BorderLayout.SOUTH);
      pack();
   }

   /**
    * Gets the currently selected message.
    * @return a string, icon, component, or object array, depending on the Message panel selection
    */
   public Object getMessage()
   {
      String s = messagePanel.getSelection();
      if (s.equals("String")) return messageString;
      else if (s.equals("Icon")) return messageIcon;
      else if (s.equals("Component")) return messageComponent;
      else if (s.equals("Object[]")) return new Object[] { messageString, messageIcon,
            messageComponent, messageObject };
      else if (s.equals("Other")) return messageObject;
      else return null;
   }

   /**
    * Gets the currently selected options.
    * @return an array of strings, icons, or objects, depending on the Option panel selection
    */
   public Object[] getOptions()
   {
      String s = optionsPanel.getSelection();
      if (s.equals("String[]")) return new String[] { "Yellow", "Blue", "Red" };
      else if (s.equals("Icon[]")) return new Icon[] { new ImageIcon("yellow-ball.gif"),
            new ImageIcon("blue-ball.gif"), new ImageIcon("red-ball.gif") };
      else if (s.equals("Object[]")) return new Object[] { messageString, messageIcon,
            messageComponent, messageObject };
      else return null;
   }

   /**
    * Gets the selected message or option type
    * @param panel the Message Type or Confirm panel
    * @return the selected XXX_MESSAGE or XXX_OPTION constant from the JOptionPane class
    */
   public int getType(ButtonPanel panel)
   {
      String s = panel.getSelection();
      try
      {
         return JOptionPane.class.getField(s).getInt(null);
      }
      catch (Exception e)
      {
         return -1;
      }
   }

   /**
    * The action listener for the Show button shows a Confirm, Input, Message, or Option dialog
    * depending on the Type panel selection.
    */
   private class ShowAction implements ActionListener
   {
      public void actionPerformed(ActionEvent event)
      {
         if (typePanel.getSelection().equals("Confirm")) JOptionPane.showConfirmDialog(
               OptionDialogFrame.this, getMessage(), "Title", getType(optionTypePanel),
               getType(messageTypePanel));
         else if (typePanel.getSelection().equals("Input"))
         {
            if (inputPanel.getSelection().equals("Text field")) JOptionPane.showInputDialog(
                  OptionDialogFrame.this, getMessage(), "Title", getType(messageTypePanel));
            else JOptionPane.showInputDialog(OptionDialogFrame.this, getMessage(), "Title",
                  getType(messageTypePanel), null, new String[] { "Yellow", "Blue", "Red" },
                  "Blue");
         }
         else if (typePanel.getSelection().equals("Message")) JOptionPane.showMessageDialog(
               OptionDialogFrame.this, getMessage(), "Title", getType(messageTypePanel));
         else if (typePanel.getSelection().equals("Option")) JOptionPane.showOptionDialog(
               OptionDialogFrame.this, getMessage(), "Title", getType(optionTypePanel),
               getType(messageTypePanel), null, getOptions(), getOptions()[0]);
      }
   }
}

/**
 * A component with a painted surface
 */

class SampleComponent extends JComponent
{
   public void paintComponent(Graphics g)
   {
      Graphics2D g2 = (Graphics2D) g;
      Double rect = new Rectangle2D.Double(0, 0, getWidth() - 1, getHeight() - 1);
      g2.setPaint(Color.YELLOW);
      g2.fill(rect);
      g2.setPaint(Color.BLUE);
      g2.draw(rect);
   }

   public Dimension getPreferredSize()
   {
      return new Dimension(10, 10);
   }
}

 

package optionDialog;

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

/**
 * @version 1.35 2018-04-10
 * @author Cay Horstmann
 */
public class OptionDialogTest
{
   public static void main(String[] args)
   {
      EventQueue.invokeLater(() -> {
         OptionDialogFrame frame = new OptionDialogFrame();
         frame.setTitle("OptionDialogTest");
         frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
         frame.setVisible(true);
      });
   }
}

 

package optionDialog;

import javax.swing.*;

/**
 * A panel with radio buttons inside a titled border.
 */
public class ButtonPanel extends JPanel
{
   private ButtonGroup group;

   /**
    * Constructs a button panel.
    * @param title the title shown in the border
    * @param options an array of radio button labels
    */
   public ButtonPanel(String title, String... options)
   {
      setBorder(BorderFactory.createTitledBorder(BorderFactory.createEtchedBorder(), title));
      setLayout(new BoxLayout(this, BoxLayout.Y_AXIS));
      group = new ButtonGroup();

      // make one radio button for each option
      for (String option : options)
      {
         JRadioButton button = new JRadioButton(option);
         button.setActionCommand(option);
         add(button);
         group.add(button);
         button.setSelected(option == options[0]);
      }
   }

   /**
    * Gets the currently selected option.
    * @return the label of the currently selected radio button.
    */
   public String getSelection()
   {
      return group.getSelection().getActionCommand();
   }
}

 程序的运行结果:

201871010101-陈来弟《面向对象程序设计(java)》第十五周学习总结_第4张图片

 

 

 

测试程序4

elipse IDE中调试运行教材552页程序12-1712-18,结合运行结果理解程序;

掌握对话框的创建方法;

记录示例代码阅读理解中存在的问题与疑惑。

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 javax.swing.JFrame;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JMenuItem;

/**
 * A frame with a menu whose File->About action shows a dialog.
 */
public class DialogFrame extends JFrame
{
   private static final int DEFAULT_WIDTH = 300;
   private static final int DEFAULT_HEIGHT = 200;
   private AboutDialog dialog;

   public DialogFrame()
   {
      setSize(DEFAULT_WIDTH, DEFAULT_HEIGHT);

      // construct a File menu

      JMenuBar menuBar = new JMenuBar();
      setJMenuBar(menuBar);
      JMenu fileMenu = new JMenu("File");
      menuBar.add(fileMenu);

      // add About and Exit menu items

      // the About item shows the About dialog

      JMenuItem aboutItem = new JMenuItem("About");
      aboutItem.addActionListener(event -> {
         if (dialog == null) // first time
            dialog = new AboutDialog(DialogFrame.this);
         dialog.setVisible(true); // pop up dialog
      });
      fileMenu.add(aboutItem);

      // the Exit item exits the program

      JMenuItem exitItem = new JMenuItem("Exit");
      exitItem.addActionListener(event -> System.exit(0));
      fileMenu.add(exitItem);
   }
}

 

package dialog;

import java.awt.BorderLayout;

import javax.swing.JButton;
import javax.swing.JDialog;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;

/**
 * A sample modal dialog that displays a message and waits for the user to click
 * the OK button.
 */
public class AboutDialog extends JDialog
{
   public AboutDialog(JFrame owner)
   {
      super(owner, "About DialogTest", true);

      // add HTML label to center

      add(
         new JLabel(
            "

Core Java


By Cay Horstmann"), 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(); } }

 

运行结果:

201871010101-陈来弟《面向对象程序设计(java)》第十五周学习总结_第5张图片

 

 

 

测试程序5

elipse IDE中调试运行教材556页程序12-1912-20,结合运行结果理解程序;

掌握对话框的数据交换用法;

记录示例代码阅读理解中存在的问题与疑惑。

 代码如下:

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;
   }
}

程序的运行结果:

201871010101-陈来弟《面向对象程序设计(java)》第十五周学习总结_第6张图片

 

 

 

测试程序6

elipse IDE中调试运行教材564页程序12-21、12-22、12-23,结合程序运行结果理解程序;

掌握文件对话框的用法;

记录示例代码阅读理解中存在的问题与疑惑。

 代码如下:

 

package fileChooser;

import java.awt.*;
import java.io.*;

import javax.swing.*;

/**
 * A file chooser accessory that previews images.
 */
public class ImagePreviewer extends JLabel
{
   /**
    * Constructs an ImagePreviewer.
    * @param chooser the file chooser whose property changes trigger an image
    *        change in this previewer
    */
   public ImagePreviewer(JFileChooser chooser)
   {
      setPreferredSize(new Dimension(100, 100));
      setBorder(BorderFactory.createEtchedBorder());

      chooser.addPropertyChangeListener(event -> {
         if (event.getPropertyName() == JFileChooser.SELECTED_FILE_CHANGED_PROPERTY)
         {
            // 用户选择一个新文件
            File f = (File) event.getNewValue();
            if (f == null)
            {
               setIcon(null);
               return;
            }

            // 将影像读取成图示
            ImageIcon icon = new ImageIcon(f.getPath());

            // 如果图标太大,无法安装,请缩放
            if (icon.getIconWidth() > getWidth())
               icon = new ImageIcon(icon.getImage().getScaledInstance(
                     getWidth(), -1, Image.SCALE_DEFAULT));

            setIcon(icon);
         }
      });
   }
}

 

package fileChooser;

import java.io.*;

import javax.swing.*;
import javax.swing.filechooser.*;
import javax.swing.filechooser.FileFilter;

/**
 * A frame that has a menu for loading an image and a display area for the
 * loaded image.
 */
public class ImageViewerFrame extends JFrame
{
   private static final int DEFAULT_WIDTH = 300;
   private static final int DEFAULT_HEIGHT = 400;
   private JLabel label;
   private JFileChooser chooser;

   public ImageViewerFrame()
   {
      setSize(DEFAULT_WIDTH, DEFAULT_HEIGHT);

      // 设置菜单栏
      JMenuBar menuBar = new JMenuBar();
      setJMenuBar(menuBar);

      JMenu menu = new JMenu("File");
      menuBar.add(menu);

      JMenuItem openItem = new JMenuItem("Open");
      menu.add(openItem);
      openItem.addActionListener(event -> {
         chooser.setCurrentDirectory(new File("."));

         // 显示文件选择器对话框
            int result = chooser.showOpenDialog(ImageViewerFrame.this);

            // 如果图像文件被接受,将其设置为标签的图标
            if (result == JFileChooser.APPROVE_OPTION)
            {
               String name = chooser.getSelectedFile().getPath();
               label.setIcon(new ImageIcon(name));
               pack();
            }
         });

      JMenuItem exitItem = new JMenuItem("Exit");
      menu.add(exitItem);
      exitItem.addActionListener(event -> System.exit(0));

      // 使用标签显示影像
      label = new JLabel();
      add(label);

      //设置文件选择器
      chooser = new JFileChooser();

      // 接受所有以之结尾的影像档案。JPG。杰伯图形交换格式
      FileNameExtensionFilter filter = new FileNameExtensionFilter(
            "Image files", "jpg", "jpeg", "gif");
      chooser.setFileFilter(filter);

      chooser.setAccessory(new ImagePreviewer(chooser));

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

 

package fileChooser;

import java.io.*;
import javax.swing.*;
import javax.swing.filechooser.*;
import javax.swing.filechooser.FileFilter;

/**
 * A file view that displays an icon for all files that match a file filter.
 */
public class FileIconView extends FileView
{
   private FileFilter filter;
   private Icon icon;

   /**
    * Constructs a FileIconView.
    * @param aFilter a file filter--all files that this filter accepts will be shown 
    * with the icon.
    * @param anIcon--the icon shown with all accepted files.
    */
   public FileIconView(FileFilter aFilter, Icon anIcon)
   {
      filter = aFilter;
      icon = anIcon;
   }

   public Icon getIcon(File f)
   {
      if (!f.isDirectory() && filter.accept(f)) return icon;
      else return null;
   }
}

 

package fileChooser;

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

/**
 * @version 1.26 2018-04-10
 * @author Cay Horstmann
 */
public class FileChooserTest
{
   public static void main(String[] args)
   {
      EventQueue.invokeLater(() -> {
         ImageViewerFrame frame = new ImageViewerFrame();
         frame.setTitle("FileChooserTest");
         frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
         frame.setVisible(true);
      });
   }
}

 

程序的运行结果如下:

 

 201871010101-陈来弟《面向对象程序设计(java)》第十五周学习总结_第7张图片201871010101-陈来弟《面向对象程序设计(java)》第十五周学习总结_第8张图片

 

 

 

 

测试程序7

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;

了解颜色选择器的用法。

记录示例代码阅读理解中存在的问题与疑惑。

 代码如下:

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);
  
      // 添加颜色选择器面板到框架
  
      ColorChooserPanel panel = new ColorChooserPanel();
      add(panel);
   }
}

 

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);
      }
   }
}

 

 其运行结果:

201871010101-陈来弟《面向对象程序设计(java)》第十五周学习总结_第9张图片

 

 

 201871010101-陈来弟《面向对象程序设计(java)》第十五周学习总结_第10张图片201871010101-陈来弟《面向对象程序设计(java)》第十五周学习总结_第11张图片

 

 

 

 

 第三部分:实验总结

        老师在上一周的的基础上,又讲了与菜单、对话框相关的内容。在实验课上,对一部分代码进行了运行,测试代码是我发现菜单的类型有两种类型的菜单:下拉式菜单和弹出式菜单。其次就是对话框了,对话框有文件对话框,消息对话框,输入对话框,确认对话框以及颜色对话框。在实验过程中,请教了老师实验时一再出现的问题,通过老师的讲解,我对一些问题有了解决办法,在课堂上我做了笔记,以防下次再出现这样的状况。

     

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