张季跃 201771010139《面向对象程序设计（java）》第十三周学习总结
实验部分：
1、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。
2、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。
测试程序：
ButtonFrame：
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;//宽300
private static final int DEFAULT_HEIGHT = 200;//高200
public ButtonFrame()
{
setSize(DEFAULT_WIDTH, DEFAULT_HEIGHT);
// 创建按钮
JButton orangeButton = new JButton("Orange");//创建一个带文本的按钮。
JButton blueButton = new JButton("blue");
JButton greyButton = new JButton("Grey");
buttonPanel = new JPanel();
// 向面板添加按钮
buttonPanel.add(orangeButton);
buttonPanel.add(blueButton);
buttonPanel.add(greyButton);
// 向框架添加面板
add(buttonPanel);
// 创建按钮操作
ColorAction orangeAction= new ColorAction(Color.ORANGE);
ColorAction blueAction = new ColorAction(Color.BLUE);
ColorAction greyAction = new ColorAction(Color.GRAY);
// 将操作与按钮相关联
orangeButton.addActionListener(orangeAction);
blueButton.addActionListener(blueAction);
greyButton.addActionListener(greyAction);
}
/**
* 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);
}
}
}
ButtonTest：
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)
{
//lambda表达式
EventQueue.invokeLater(() -> {
JFrame frame = new ButtonFrame();
frame.setTitle("ButtonTest");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
});
}
}
实验结果：
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。
测试程序：
PlafFrame：
package plaf;
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();
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)
{
// add button to panel
JButton button = new JButton(name);
buttonPanel.add(button);
// set button action
button.addActionListener(event -> {
// button action: switch to the new look-and-feel
try
{
UIManager.setLookAndFeel(className);
SwingUtilities.updateComponentTreeUI(this);
pack();
}
catch (Exception e)
{
e.printStackTrace();
}
});
}
}
PlafTest：
package plaf;
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);
});
}
}
实验结果：
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；
l 掌握GUI程序中按钮、键盘动作映射到动作对象的方法。
测试程序：
ActionFrame：
package action;
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);
// add buttons for these actions
buttonPanel.add(new JButton(yellowAction));
buttonPanel.add(new JButton(blueAction));
buttonPanel.add(new JButton(redAction));
// add panel to frame
add(buttonPanel);
// associate the Y, B, and R keys with names
InputMap imap = buttonPanel.getInputMap(JComponent.WHEN_ANCESTOR_OF_FOCUSED_COMPONENT);
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
ActionMap amap = buttonPanel.getActionMap();
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)
{
putValue(Action.NAME, name);
putValue(Action.SMALL_ICON, icon);
putValue(Action.SHORT_DESCRIPTION, "Set panel color to " + name.toLowerCase());
putValue("color", c);
}
public void actionPerformed(ActionEvent event)
{
Color c = (Color) getValue("color");
buttonPanel.setBackground(c);
}
}
}
ActionTest：
package action;
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);
});
}
}
实验结果：
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。
测试程序：
MouseCmponent：
package 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 = 30;
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();
}
}
}
}
MouseFrame：
package mouse;
import javax.swing.*;
/**
* A frame containing a panel for testing mouse operations
*/
public class MouseFrame extends JFrame
{
public MouseFrame()
{
add(new MouseComponent());
pack();
}
}
MouseTest：
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);
});
}
}
实验结果：
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。
实验程序：
package 点名器;
import java.util.*;
import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
import java.io.File;
import java.io.FileNotFoundException;
import javax.swing.event.*;
public class NameFrame extends JFrame implements ActionListener{
private JLabel jla;
private JLabel jlb;
private JButton jba;//"push" 按钮的实现
private static boolean flag = true;//开始的按钮是否点过
public NameFrame(){
this.setLayout(null);
//添加按钮
jla = new JLabel("姓名");
jlb = new JLabel("准备中");
jba = new JButton("开始");
this.add(jla);//添加组件
this.add(jlb);
jla.setFont(new Font("Courier",Font.PLAIN,26));//设置字体
jla.setHorizontalAlignment(JLabel.CENTER);//X轴对称
jla.setVerticalAlignment(JLabel.CENTER); //Y轴对称
jla.setBounds(20,100,180,30);
jlb.setOpaque(true);
jlb.setBackground(Color.cyan);//设置背景的颜色
jlb.setFont(new Font("Courier",Font.PLAIN,22));
jlb.setHorizontalAlignment(JLabel.CENTER);
jlb.setVerticalAlignment(JLabel.CENTER);
jlb.setBounds(150,100,120,30);
//设置窗口大小
this.add(jba);
jba.setBounds(150,150,80,26);
jba.addActionListener(this);
this.setTitle("点名器");//窗口标题
this.setBounds(400,400,400,300);
this.setVisible(true);
this.setDefaultCloseOperation(DISPOSE_ON_CLOSE);
}
public void actionPerformed(ActionEvent e){
int i=0;
String names[]=new String[50];
try {
Scanner in=new Scanner(new File("C:\Users\张季跃\Desktop\studentnamelist.txt"));
while(in.hasNextLine())
{
names[i]=in.nextLine();
i++;
}
} catch (FileNotFoundException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
if(jba.getText()=="开始"){//返回按钮
jlb.setBackground(Color.MAGENTA);
flag = true;
new Thread(){
public void run(){
while(NameFrame.flag){
Random r = new Random();
int i= r.nextInt(47);//返还该元素，并重新选择另一个元素
jlb.setText(names[i]);
}
}
}.start();//使该线程开始执行；Java 虚拟机调用该线程的 run 方法
jba.setText("停止");
jba.setBackground(Color.YELLOW);
}
else if(jba.getText()=="停止"){
flag = false;
jba.setText("开始");//按钮标题
jba.setBackground(Color.RED);//“开始”颜色
jlb.setBackground(Color.green);
}
}
public static void main(String arguments []){
new NameFrame();
}
}
实验结果：
实验总结：
通过这一周的学习，我初步了解了有关事件处理的基本知识，对AWT事件处理机制有了基本的认识学会了如何用程序编辑创建按钮，并初步的学会了如何在自己编写的窗口中进行简单的人机互动。但在本周的实验中，我发现我对于本周的学习以及今后知识的预习还是不到位，对于本周的编程实验我简直是毫无头绪，就算是学长发的程序我也有很多看不懂的地方，必须通过查找资料和询问同学才有所收获。