一、实验目的与要求
(1) 掌握事件处理的基本原理，理解其用途；
(2) 掌握AWT事件模型的工作机制；
(3) 掌握事件处理的基本编程模型；
(4) 了解GUI界面组件观感设置方法；
(5) 掌握WindowAdapter类、AbstractAction类的用法；
(6) 掌握GUI程序中鼠标事件处理技术。
二、实验内容和步骤
实验1： 导入第11章示例程序，测试程序并进行代码注释。
测试程序1：
l 在elipse IDE中调试运行教材443页-444页程序11-1，结合程序运行结果理解程序；
l 在事件处理相关代码处添加注释；
l 用lambda表达式简化程序；
l 掌握JButton组件的基本API；
l 掌握Java中事件处理的基本编程模型。
package button;
import java.awt.*;
import javax.swing.*;
/**
* @version 1.34 2015-06-12
* @author Cay Horstmann
*/
public class ButtonTest {
public static void main(String[] args) {
EventQueue.invokeLater(() -> {
JFrame frame = new ButtonFrame();
frame.setTitle("ButtonTest");// 将窗体的标题设置为指定的字符串。
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);// 设置用户在窗体上发起 "close" 时默认执行的操作。
frame.setVisible(true);// 设置窗口可见
});
}
}package button;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
/**
* A frame with a button panel
*/
public class ButtonFrame extends JFrame {
private JPanel buttonPanel;
private static final int DEFAULT_WIDTH = 300;
private static final int DEFAULT_HEIGHT = 200;
public ButtonFrame() {
setSize(DEFAULT_WIDTH, DEFAULT_HEIGHT);// 调整组件的大小.
// 创建按钮
JButton yellowButton = new JButton("Yellow");
JButton blueButton = new JButton("Blue");
JButton redButton = new JButton("Red");
buttonPanel = new JPanel();
// 将按钮添加到面板中
buttonPanel.add(yellowButton);
buttonPanel.add(blueButton);
buttonPanel.add(redButton);
add(buttonPanel);
// 为每种颜色创建一个对象
ColorAction yellowAction = new ColorAction(Color.YELLOW);
ColorAction blueAction = new ColorAction(Color.BLUE);
ColorAction redAction = new ColorAction(Color.RED);
// 将这些对象设置为按钮监听器
yellowButton.addActionListener(yellowAction);
blueButton.addActionListener(blueAction);
redButton.addActionListener(redAction);
}
/**
* An action listener that sets the panel's background color.
*/
private class ColorAction implements ActionListener {
private Color backgroundColor;
public ColorAction(Color c) {
backgroundColor = c;
}
public void actionPerformed(ActionEvent event) {
buttonPanel.setBackground(backgroundColor);
}
}
}
匿名类简化：
package button;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
/**
* A frame with a button panel
*/
public class ButtonFrame extends JFrame {
private JPanel buttonPanel;
private static final int DEFAULT_WIDTH = 300;
private static final int DEFAULT_HEIGHT = 200;
public ButtonFrame() {
setSize(DEFAULT_WIDTH, DEFAULT_HEIGHT);
buttonPanel = new JPanel();
add(buttonPanel);
makeButton("Yellow", Color.yellow);
makeButton("blue", Color.blue);
makeButton("red", Color.red);
}
public void makeButton(String name, Color backgroundColor) {
JButton button = new JButton(name);
buttonPanel.add(button);
button.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent event) {
buttonPanel.setBackground(backgroundColor);
}
});
}
}lambda表达式简化：
package button;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
/**
* A frame with a button panel
*/
public class ButtonFrame extends JFrame {
private JPanel buttonPanel;
private static final int DEFAULT_WIDTH = 300;
private static final int DEFAULT_HEIGHT = 200;
public ButtonFrame() {
setSize(DEFAULT_WIDTH, DEFAULT_HEIGHT);
buttonPanel = new JPanel();
add(buttonPanel);
makeButton("黄色", Color.yellow);
makeButton("蓝色", Color.blue);
makeButton("红色", Color.red);
}
public void makeButton(String name, Color backgroundColor) {
JButton button = new JButton(name);
buttonPanel.add(button);
button.addActionListener((e) -> {
buttonPanel.setBackground(backgroundColor);
});
}
}测试程序2：
l 在elipse IDE中调试运行教材449页程序11-2，结合程序运行结果理解程序；
l 在组件观感设置代码处添加注释；
l 了解GUI程序中观感的设置方法。
代码：
package Second;
import java.awt.*;
import javax.swing.*;
/**
* @version 1.32 2015-06-12
* @author Cay Horstmann
*/
public class PlafTest
{
public static void main(String[] args)
{
EventQueue.invokeLater(() -> {
JFrame frame = new PlafFrame();
frame.setTitle("PlafTest");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
});
}
}package Second;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
import javax.swing.UIManager;
/**
* A frame with a button panel for changing look-and-feel
*/
public class PlafFrame extends JFrame
{
private JPanel buttonPanel;
public PlafFrame()
{
buttonPanel = new JPanel();
//获取所有安装的观感实现
UIManager.LookAndFeelInfo[] infos = UIManager.getInstalledLookAndFeels();
for (UIManager.LookAndFeelInfo info : infos)
makeButton(info.getName(), info.getClassName());
add(buttonPanel);
pack();
}
/**
* Makes a button to change the pluggable look-and-feel.
* @param name the button name
* @param className the name of the look-and-feel class
*/
private void makeButton(String name, String className)
{
// 向面板添加按钮；
JButton button = new JButton(name);
buttonPanel.add(button);
// 设置按钮动作；
button.addActionListener(event -> {
// 按钮动作：切换到新的外观和感觉
try
{
UIManager.setLookAndFeel(className);
//调用静态方法，刷新全部的组件集。这里需要向方法提供一个组件，并由此找到其他的所有组件
//外部对象的this引用必须将外部类名作为前缀
SwingUtilities.updateComponentTreeUI(this);
pack();
}
catch (Exception e)
{
e.printStackTrace();
}
});
}
}
测试程序3：
l 在elipse IDE中调试运行教材457页-458页程序11-3，结合程序运行结果理解程序；
l 掌握AbstractAction类及其动作对象；
掌握GUI程序中按钮、键盘动作映射到动作对象的方法。
代码：
package three;
import java.awt.*;
import javax.swing.*;
/**
* @version 1.34 2015-06-12
* @author Cay Horstmann
*/
public class ActionTest
{
public static void main(String[] args)
{
EventQueue.invokeLater(() -> {
JFrame frame = new ActionFrame();
frame.setTitle("ActionTest");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
});
}
}package three;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
/**
* A frame with a panel that demonstrates color change actions.
*/
public class ActionFrame extends JFrame
{
private JPanel buttonPanel;
private static final int DEFAULT_WIDTH = 300;
private static final int DEFAULT_HEIGHT = 200;
public ActionFrame()
{
setSize(DEFAULT_WIDTH, DEFAULT_HEIGHT);
buttonPanel = new JPanel();
// define actions
Action yellowAction = new ColorAction("Yellow", new ImageIcon("yellow-ball.gif"),
Color.YELLOW);
Action blueAction = new ColorAction("Blue", new ImageIcon("blue-ball.gif"), Color.BLUE);
Action redAction = new ColorAction("Red", new ImageIcon("red-ball.gif"), Color.RED);
//用Action对象构造按钮，把动作和按钮关联起来
buttonPanel.add(new JButton(yellowAction));
buttonPanel.add(new JButton(blueAction));
buttonPanel.add(new JButton(redAction));
// add panel to frame
add(buttonPanel);
//得到顶层组件的WHEN_ANCESTOR_OF_FOCUSED_COMPONENT输入映射
// associate the Y, B, and R keys with names
InputMap imap = buttonPanel.getInputMap(JComponent.WHEN_ANCESTOR_OF_FOCUSED_COMPONENT);
//将(按键，动作键)添加到输入映射中
imap.put(KeyStroke.getKeyStroke("ctrl Y"), "panel.yellow");
imap.put(KeyStroke.getKeyStroke("ctrl B"), "panel.blue");
imap.put(KeyStroke.getKeyStroke("ctrl R"), "panel.red");
// associate the names with actions、
//得到顶层组件的动作映射
ActionMap amap = buttonPanel.getActionMap();
//将(动作键，动作对象)添加到映射中
amap.put("panel.yellow", yellowAction);
amap.put("panel.blue", blueAction);
amap.put("panel.red", redAction);
}
public class ColorAction extends AbstractAction
{
/**
* Constructs a color action.
* @param name the name to show on the button
* @param icon the icon to display on the button
* @param c the background color
*/
public ColorAction(String name, Icon icon, Color c)
{
//存储命令的名称、图标、简要说明和需要的颜色
putValue(Action.NAME, name);
putValue(Action.SMALL_ICON, icon);
putValue(Action.SHORT_DESCRIPTION, "Set panel color to " + name.toLowerCase());//显示在工具提示里
putValue("color", c);
}
public void actionPerformed(ActionEvent event)
{
Color c = (Color) getValue("color");
buttonPanel.setBackground(c);
}
}
}
测试程序4：
l 在elipse IDE中调试运行教材462页程序11-4、11-5，结合程序运行结果理解程序；
l 掌握GUI程序中鼠标事件处理技术。
package mouse;
import java.awt.*;
import javax.swing.*;
/**
* @version 1.34 2015-06-12
* @author Cay Horstmann
*/
public class MouseTest
{
public static void main(String[] args)
{
EventQueue.invokeLater(() -> {
JFrame frame = new MouseFrame();
frame.setTitle("MouseTest");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
});
}
}
MouseTestpackage mouse;
import javax.swing.*;
/**
* A frame containing a panel for testing mouse operations
*/
public class MouseFrame extends JFrame
{
public MouseFrame()
{
add(new MouseComponent());
pack();
}
}
MouseFramepackage mouse;
import java.awt.*;
import java.awt.event.*;
import java.awt.geom.*;
import java.util.*;
import javax.swing.*;
/**
* A component with mouse operations for adding and removing squares.
*/
public class MouseComponent extends JComponent
{
private static final int DEFAULT_WIDTH = 300;
private static final int DEFAULT_HEIGHT = 200;
private static final int SIDELENGTH = 10;
private ArrayList<Rectangle2D> squares;
private Rectangle2D current; // the square containing the mouse cursor
public MouseComponent()
{
squares = new ArrayList<>();
current = null;
addMouseListener(new MouseHandler());
addMouseMotionListener(new MouseMotionHandler());
}
public Dimension getPreferredSize() { return new Dimension(DEFAULT_WIDTH, DEFAULT_HEIGHT); }
public void paintComponent(Graphics g)
{
Graphics2D g2 = (Graphics2D) g;
// draw all squares
for (Rectangle2D r : squares)
g2.draw(r);
}
/**
* Finds the first square containing a point.
* @param p a point
* @return the first square that contains p
*/
public Rectangle2D find(Point2D p)
{
for (Rectangle2D r : squares)
{
if (r.contains(p)) return r;
}
return null;
}
/**
* Adds a square to the collection.
* @param p the center of the square
*/
public void add(Point2D p)
{
double x = p.getX();
double y = p.getY();
current = new Rectangle2D.Double(x - SIDELENGTH / 2, y - SIDELENGTH / 2, SIDELENGTH,
SIDELENGTH);
squares.add(current);
repaint();
}
/**
* Removes a square from the collection.
* @param s the square to remove
*/
public void remove(Rectangle2D s)
{
if (s == null) return;
if (s == current) current = null;
squares.remove(s);
repaint();
}
private class MouseHandler extends MouseAdapter
{
public void mousePressed(MouseEvent event)
{
// add a new square if the cursor isn't inside a square
current = find(event.getPoint());
if (current == null) add(event.getPoint());
}
public void mouseClicked(MouseEvent event)
{
// remove the current square if double clicked
current = find(event.getPoint());
if (current != null && event.getClickCount() >= 2) remove(current);
}
}
private class MouseMotionHandler implements MouseMotionListener
{
public void mouseMoved(MouseEvent event)
{
// set the mouse cursor to cross hairs if it is inside
// a rectangle
if (find(event.getPoint()) == null) setCursor(Cursor.getDefaultCursor());
else setCursor(Cursor.getPredefinedCursor(Cursor.CROSSHAIR_CURSOR));
}
public void mouseDragged(MouseEvent event)
{
if (current != null)
{
int x = event.getX();
int y = event.getY();
// drag the current rectangle to center it at (x, y)
current.setFrame(x - SIDELENGTH / 2, y - SIDELENGTH / 2, SIDELENGTH, SIDELENGTH);
repaint();
}
}
}
}
MouseComponent 
实验2：结对编程练习
利用班级名单文件、文本框和按钮组件，设计一个有如下界面（图1）的点名器，要求用户点击开始按钮后在文本输入框随机显示2017级网络与信息安全班同学姓名，如图2所示，点击停止按钮后，文本输入框不再变换同学姓名，此同学则是被点到的同学姓名。
图1 点名器启动界面
package 点名器;
import java.awt.EventQueue;
import javax.swing.JFrame;
public class test {
public static void main(String[] args) {
EventQueue.invokeLater(() -> {
ButtonFrame frame = new ButtonFrame();
frame.setTitle("点名器");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
frame.setResizable(false);
});
}
}package 点名器;
import java.awt.Color;
import java.awt.event.*;
import java.io.*;
import java.util.*;
import java.util.Timer;
import javax.swing.*;
public class ButtonFrame extends JFrame {
JButton pausecontBtn;
private ArrayList arrayList;
{
arrayList = new ArrayList<>();
File file = new File("studentnamelist.txt");
FileInputStream fis;
try {
fis = new FileInputStream(file);
InputStreamReader in = new InputStreamReader(fis);
BufferedReader bf = new BufferedReader(in);
String readLine;
while ((readLine = bf.readLine()) != null) {
arrayList.add(readLine);
}
} catch (FileNotFoundException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
} catch (IOException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
}
private JPanel buttonPanel;
private static final int DEFAULT_WIDTH = 500;
private static final int DEFAULT_HEIGHT = 300;
protected static final String ture = null;
public ButtonFrame() {
setSize(DEFAULT_WIDTH, DEFAULT_HEIGHT);
buttonPanel = new JPanel();
buttonPanel.setLayout(null);
JLabel jLabel = new JLabel("随机点名器");
JButton jButton = new JButton("开始");
jLabel.setBounds(200, 40, 65, 40);
jButton.setBounds(200, 90, 65, 40);
jButton.addActionListener(new ActionListener() {
Timer timer;
public void actionPerformed(ActionEvent e) {
if (jButton.getText().equals("开始")) {
timer = new Timer();
TimerTask timerTask = new TimerTask() {
public void run() {
jButton.setText("停止");
jButton.setBackground(Color.yellow);
jLabel.setText((String) arrayList.get((int) (Math.random() * 42)));
}
};
timer.schedule(timerTask, 0, 5);
}
if (jButton.getText().equals("停止")) {
timer.cancel();
jButton.setText("开始");
jButton.setBackground(Color.red);
}
}
});
buttonPanel.add(jLabel);
buttonPanel.add(jButton);
add(buttonPanel);
}
}
三、实验总结：
通过这次实验我了解了事件处理的基本原理，知道了它的用途，了解了AWT事件模型的工作机制，事件处理的基本编程模型，还了解了GUI界面组件观感设置方法，掌握了WindowAdapter类、AbstractAction类的用法以及GUI程序中鼠标事件处理技术。并且在这次实验中通过结对编程知道了如何去互相学习，收获很大。
来源：oschina
链接：https://my.oschina.net/u/4371026/blog/4152007