201871010117-石欣钰《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	<任课教师博客主页链接>https://www.cnblogs.com/nwnu-daizh/
这个作业的要求在哪里	<作业链接地址>https://www.cnblogs.com/nwnu-daizh/p/11995615.htmll
作业学习目标	（1）掌握GUI布局管理器用法； （2）掌握Java Swing文本输入组件用途及常用API； （3）掌握Java Swing选择输入组件用途及常用API。

第一部分：总结菜单、对话框两类组件用途及常用API

菜单：

1.JMenuBar 菜单栏

菜单栏是窗口中用于容纳菜单JMenu的容器。 JFrame对象可以调用setJMenuBar()方法将一个菜单栏实例menubar添加到容器中，作为整个菜单树的根基。菜单栏被添加到窗口的上方，不受布局管理器控制。

注意：只能向窗口中添加一个菜单栏。

public JMenuBar(){

//默认构造方法,创建新的菜单栏

}

public JMenu add(JMenu c){

//将菜单追加到菜单栏末尾

}

2.JMenu 菜单

菜单是若干个菜单项(JMenuItem)或子菜单的容器，它能被添加到JMenuBar或其他JMenu中。

public JMenu(){

//默认构造方法,创建没有文本的新菜单

}

public JMenu(String s){

//构造方法,用提供的字符串作为文本构造一个新菜单

}

public Component add(Component c){

//将某个组件追加到此菜单的末尾

}

public JMenuItem add(JMenuItem c){

//将某个菜单项追加到此菜单的末尾

}

public void addSeparator(){

//将新分隔符追加到菜单的末尾

}

3.JMenuItem 菜单项
   菜单项是组成菜单或快捷键的最小单位，用于完成特定功能。

public JMenuItem(){

//默认构造方法,创建不带文本或图标的菜单项

}

public JMenuItem(String text){

//构造方法

}

public void setAccelerator(KeyStroke keystroke){

//为菜单项设置快捷键

}

4.选择菜单项
   Java除了提供JMenuItem，还提供了两种可选择的菜单项：复选菜单项(JCheckBoxMenuItem)和单选菜单项(JRadioButtonMenuItem)。
5.JPopupMenu 快捷菜单项

菜单除了可以放置在窗口，也可以依附于一个组件，当用户右击鼠标时弹出

public JPopupMenu(){

//默认构造方法

}

public JPopupMenu(String s)

//构造方法,具有指定标题

}

public JMenuItem add(JMenuItem jm){

//将指定菜单项添加到此菜单的末尾

}

public void addSeparator(){

//将新分隔符追加到菜单的末尾

}

对话框：

1、对话框模式
       对话框分为无模式和有模式两种。

如果一个对话框是有模式的，那么当这个对话框处于激活状态时，只让程序响应对话框内部的事件，而且将堵塞其它线程的执行，用户不能再激活对话框所在程序中的其它窗口，直到该对话框消失不可见。

无模式对话框处于激活状态时，能再激活其它窗口，也不堵塞其它线程执行。

3、文件对话框(FileDialog)
       文件对话框是一个从文件中选择文件的界面，文件对话框事实上并不能打开或保存文件，它只能得到要打开或保存的文件的名字或所在的目录，要想真正实现打开或保存文件，还必须使用输入、输出流。

javax.swing包中的JFileChooser类可以创建文件对话框，使用该类的构造方法JFileChooser()创建初始不可见的有模式的文件对话框。showSaveDialog(Component a), showOpenDialog(Component a)都可使得对话框可见，但外观有所不同。showSaveDialog(Component a)方法提供保存文件的界面，showOpenDialog(Component a)方法提供打开文件的界面。参数a指定对话框可见时的位置。
       当用户单击文件对话框上的“确定”、“取消”按键或关闭图标，文件对话框将消失，方法返回：JFileChooser.APPROVE_OPTION和JFileChooser.CANCEL_OPTION之一。当返回值是JFileChooser.APPROVE_OPTION时，可以使用JFileChooser类的getSelectedFile()得到文件对话框所选择的文件。

FileDialog是Dialog的子类，主要方法有：
　　1、FileDialog(Frame f,String s,int mode)：构造方法，f为所依赖的窗口对象，s是对话框的名字，mode取值为FileDialog.LOAD或FileDialog.SAVE。
　　2、public String getDirwctory()：获取当前对话框中所显示的文件目录。
　　3、public String getFile()：获取对话框中显示的文件的字符串表示，如不存在则为null。

4、消息对话框
       消息对话框是有模式对话框，进行一个重要的操作动作之前，弹出一个消息对话框。可以用javax.swing包中的JOptionPane类的静态方法。

public static void showMessageDialog(Component parentComponent,String message, String title, int messageType);

 

Component parentComponent：//消息对话框依赖的组件

 

String message：// 要显示的消息

 

String title：//对话框的标题

 

int messageType)：//对话框的外观，取值如下：

 

JOptionPane.INFORMATION_MESSAGE

 

JOptionPane.WARNING_MESSAGE

 

JOptionPane.ERROR_MESSAGE

 

JOptionPane.QUESTION_MESSAGE

 

JOptionPane.PLAIN_MESSAGE

5、输入对话框
       输入对话框含有供用户输入文本的文本框、一个“确定”和“取消”按钮，是有模式对话框。当输入对话框可见时，要求用户输入一个字符串。javax.swing包中的JOptionPane类静态方法：

public static String showInputDialog(Component parentComponent, Object message, String title, int messageType);

 

Component parentComponent//指定输入对话框所依赖的组件。

 

Object message//指定对话框上的提示信息。

 

String title//对话框上的标题。

 

int messageType//确定对话框的外观，取值如下：

 

ERROR_MESSAGE

 

INFORMATION_MESSAGE

 

WARNING_MESSAGE

 

QUESTION_MESSAGE

 

PLAIN_MESSAGE

6、确认对话框
       确认对话框是有模式对话框，可以用javax.swing包中的JOptionPane类的静态方法创建：
　　

public static int showConfirmDialog(Component parentComponent, Object message, String title, int optionType);

 

Component parentComponent //对话框所依赖的组件。

 

Object messag //对话框上显示的消息

 

String titl //对话框的标题

 

int optionType //对话框的外观，取值如下：

 

JOptionPane.YES_NO_OPTION

 

JOptionPane.YES_NO_CANCEL_OPTION

 

JOptionPane.OK_CANCEL_OPTION

当对话框消失后，showConfirmDialog方法会返回下列整数之一：

JOptionPane.YES_OPTION

JOptionPane.NO_OPTION

JOptionPane.CANCEL_OPTION

JOptionPane.OK_OPTION

JOptionPane.CLOSED_OPTION

7、颜色对话框
      使用java.swing包中的JColorChooser类表静态方法创建：

public static Color showDialog(Component component,String title,Color initialColor);

 

Component component//对话框所依赖的组件。

 

String title//对话框的标题。

 

Color initialColor)//对话框消失后返回的默认颜色

第二部分：实验部分

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

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。

代码如下：

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);

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

// demonstrate accelerators

var 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);
}
});

var group = new ButtonGroup();

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

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

// demonstrate icons

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

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

// demonstrate nested menus

var optionMenu = new JMenu("Options");

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

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

// demonstrate mnemonics

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

var 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

var 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);

var 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(() -> {
var frame = new MenuFrame();
frame.setTitle("MenuTest");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
});
}
}

运行结果如下：

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。

程序代码如下：

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(() -> {
var 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

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

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

// populate toolbar

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

// populate menu

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

运行结果如下：

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。

程序代码如下：

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(() -> {
var 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
{
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[]");
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);
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)
{
var g2 = (Graphics2D) g;
var 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 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)
{
var 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：

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。

程序代码如下：

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(() -> {
var 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

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

// add About and Exit menu items

// the About item shows the About dialog

var 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

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

package dialog;

import java.awt.BorderLayout;

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

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

// add HTML label to center

add(
new JLabel(
"<html><h1><i>Core Java</i></h1><hr>By Cay Horstmann</html>"),
BorderLayout.CENTER);

// OK button closes the dialog

var ok = new JButton("OK");
ok.addActionListener(event -> setVisible(false));

// add OK button to southern border

var panel = new JPanel();
panel.add(ok);
add(panel, BorderLayout.SOUTH);

pack();
}
}

运行结果如下：

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。

程序代码如下：

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;

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

var connectItem = new JMenuItem("Connect");
connectItem.addActionListener(new ConnectAction());
fileMenu.add(connectItem);

// the Exit item exits the program

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

textArea = new JTextArea(TEXT_ROWS, TEXT_COLUMNS);
add(new JScrollPane(textArea), BorderLayout.CENTER);
pack();
}

/**
* The Connect action pops up the password dialog.
*/
private class ConnectAction implements ActionListener
{
public void actionPerformed(ActionEvent event)
{
// if first time, construct dialog

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

// set default values
dialog.setUser(new User("yourname", null));

// pop up dialog
if (dialog.showDialog(DataExchangeFrame.this, "Connect"))
{
// if accepted, retrieve user input
User u = dialog.getUser();
textArea.append("user name = " + u.getName() + ", password = "
+ (new String(u.getPassword())) + "\n");
}
}
}
}

package 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

var 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);
});

var cancelButton = new JButton("Cancel");
cancelButton.addActionListener(event -> dialog.setVisible(false));

// add buttons to southern border

var 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;
}
}

运行结果如下：

测试程序6

l 在elipse IDE中调试运行教材556页程序12-21、12-22、12-23，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。

程序代码如下：

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("."));

// 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();
}
});

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
var filter = new FileNameExtensionFilter(
"Image files", "jpg", "jpeg", "gif");
chooser.setFileFilter(filter);

chooser.setAccessory(new ImagePreviewer(chooser));

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

package 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
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);
}
});
}
}

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(() -> {
var frame = new ImageViewerFrame();
frame.setTitle("FileChooserTest");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
});
}
}

运行结果如下：

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。

程序代码如下：

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 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()

   {

       //在面板设置三个按钮

      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

    */

   //设置了Modal按钮的监听事件

   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.

    */

   //设置了Modeless按钮的监听事件

   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.

    */

 //设置了Immediate按钮的监听事件

   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();//创建一个颜色选择器

      add(panel);

   }

}

运行结果如图：

3、实验总结:

这周为了界面的美观，学习了各种布局。还继续学习了有关Swing用户界面组件的相关知识，对菜单、对话框等的运用有了一定的了解以及一些常用的API。布局有五种，分别是

（1）FlowLayout: 流布局(Applet和Panel的默认布局管理器）
（2）BorderLayout:边框布局( Window、Frame和Dialog的默认布局管理器）
（3）GridLayout: 网格布局
（4）GridBagLayout: 网格组布局
（5）CardLayout :卡片布局