李清华201772020113《面向对象程序设计（java）》第十三周学习总结

Posted 2021-01-22 bmwb

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。

代码：

 1 ackage button;
 2 
 3 import java.awt.*;
 4 import javax.swing.*;
 5 
 6 /**
 7  * @version 1.34 2015-06-12
 8  * @author Cay Horstmann
 9  */
10 public class ButtonTest
11 {
12    public static void main(String[] args)
13    {
14       EventQueue.invokeLater(() -> {
15          JFrame frame = new ButtonFrame();
16          frame.setTitle("ButtonTest");
17          frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
18          frame.setVisible(true);
19       });
20    }
21 }

View Code

 1 package button;
 2 
 3 import java.awt.*;
 4 import java.awt.event.*;
 5 import javax.swing.*;
 6 
 7 /**
 8  * 带按钮面板的框架
 9  */
10 public class ButtonFrame extends JFrame
11 {
12    private JPanel buttonPanel;
13    private static final int DEFAULT_WIDTH = 300;
14    private static final int DEFAULT_HEIGHT = 200;
15 
16    public ButtonFrame()
17    {      
18       setSize(DEFAULT_WIDTH, DEFAULT_HEIGHT);
19 
20       // 创建按钮
21       JButton yellowButton = new JButton("Yellow");
22       JButton blueButton = new JButton("Blue");
23       JButton redButton = new JButton("Red");
24 
25       buttonPanel = new JPanel();
26 
27       // 向面板添加按钮 
28       buttonPanel.add(yellowButton);
29       buttonPanel.add(blueButton);
30       buttonPanel.add(redButton);
31 
32       // 将面板添加到帧
33       add(buttonPanel);
34 
35       // 创建按钮动作
36       ColorAction yellowAction = new ColorAction(Color.YELLOW);
37       ColorAction blueAction = new ColorAction(Color.BLUE);
38       ColorAction redAction = new ColorAction(Color.RED);
39 
40       // 用按钮关联动作 
41       yellowButton.addActionListener(yellowAction);
42       blueButton.addActionListener(blueAction);
43       redButton.addActionListener(redAction);
44    }
45 
46    /**
47     * 设置面板背景颜色的ActualListInter.
48     */
49    private class ColorAction implements ActionListener
50    {
51       private Color backgroundColor;
52 
53       public ColorAction(Color c)
54       {
55          backgroundColor = c;
56       }
57 
58       public void actionPerformed(ActionEvent event)
59       {
60          buttonPanel.setBackground(backgroundColor);
61       }
62    }
63 }

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用lambda表达式简化后：

 代码：

 1 package lambda;
 2 
 3 import java.awt.*;
 4 import javax.swing.*;
 5 
 6 /**
 7  * @version 1.34 2015-06-12
 8  * @author Cay Horstmann
 9  */
10 public class ButtonTest
11 {
12    public static void main(String[] args)
13    {
14       EventQueue.invokeLater(() -> {
15          JFrame frame = new ButtonFrame();
16          frame.setTitle("ButtonTest");
17          frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
18          frame.setVisible(true);
19       });
20    }
21 }

View Code

 1 package lambda;
 2 
 3 import java.awt.*;
 4 import java.awt.event.*;
 5 import javax.swing.*;
 6 
 7 /**
 8  * A frame with a button panel
 9  */
10 public class ButtonFrame extends JFrame {
11     private JPanel buttonPanel;
12     private static final int DEFAULT_WIDTH = 300 * 2;
13     private static final int DEFAULT_HEIGHT = 200 * 2;
14 
15     public ButtonFrame() {
16         setSize(DEFAULT_WIDTH, DEFAULT_HEIGHT);
17         buttonPanel = new JPanel();
18         makeButton("黄色", Color.yellow);
19         makeButton("蓝色", Color.blue);
20         makeButton("红色", Color.red);
21         makeButton("绿色", Color.green);
22         add(buttonPanel);
23 
24     }
25 
26     protected void makeButton(String name, Color backgound) {
27         JButton button = new JButton(name);
28         buttonPanel.add(button);
29         button.addActionListener((e) -> {
30             buttonPanel.setBackground(backgound);
31         });
32     }
33 }

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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。

 1 package plaf;
 2 
 3 import java.awt.*;
 4 import javax.swing.*;
 5 
 6 /**
 7  * @version 1.32 2015-06-12
 8  * @author Cay Horstmann
 9  */
10 public class PlafTest
11 {
12    public static void main(String[] args)
13    {
14       EventQueue.invokeLater(() -> {
15          JFrame frame = new PlafFrame();
16          frame.setTitle("PlafTest");
17          frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
18          frame.setVisible(true);
19       });
20    }
21 }

View Code

 1 package plaf;
 2 
 3 import javax.swing.JButton;
 4 import javax.swing.JFrame;
 5 import javax.swing.JPanel;
 6 import javax.swing.SwingUtilities;
 7 import javax.swing.UIManager;
 8 
 9 /**
10  * 带有按钮面板的框架，用于改变外观和感觉 
11  */
12 public class PlafFrame extends JFrame
13 {
14    private JPanel buttonPanel;
15 
16    public PlafFrame()
17    {
18       buttonPanel = new JPanel();
19 
20       UIManager.LookAndFeelInfo[] infos = UIManager.getInstalledLookAndFeels();//获取所有的显示样式
21       for (UIManager.LookAndFeelInfo info : infos)
22          makeButton(info.getName(), info.getClassName());
23 
24       add(buttonPanel);//增加按钮点击事件
25       pack();
26    }
27 
28    /**
29     * 制作一个按钮来改变可插入的外观和感觉
30     * @param 命名按钮名称
31     * @param 类名：外观类的名称 
32     */
33    private void makeButton(String name, String className)
34    {
35       // 向面板添加按钮
36 
37       JButton button = new JButton(name);
38       buttonPanel.add(button);
39 
40       // 设置按钮动作
41 
42       button.addActionListener(event -> {
43          // 按钮动作：切换到新的外观和感觉
44          try
45          {
46             UIManager.setLookAndFeel(className);//设置外观的显示方式
47             SwingUtilities.updateComponentTreeUI(this);//给定一个组件后，更新所有的组件。
48             pack();//依据放置的组件设定窗口的大小，使之正好能容纳放置的所有组件
49          }
50          catch (Exception e)
51          {
52             e.printStackTrace();
53          }
54       });
55    }
56 }

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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。

 1 package action;
 2 
 3 import java.awt.*;
 4 import javax.swing.*;
 5 
 6 /**
 7  * @version 1.34 2015-06-12
 8  * @author Cay Horstmann
 9  */
10 public class ActionTest
11 {
12    public static void main(String[] args)
13    {
14       EventQueue.invokeLater(() -> {
15          JFrame frame = new ActionFrame();
16          frame.setTitle("ActionTest");
17          frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
18          frame.setVisible(true);
19       });
20    }
21 }

View Code

 1 package action;
 2 
 3 import java.awt.*;
 4 import java.awt.event.*;
 5 import javax.swing.*;
 6 
 7 /**
 8  * 具有显示颜色变化动作的面板的框架
 9  */
10 public class ActionFrame extends JFrame
11 {
12    private JPanel buttonPanel;
13    private static final int DEFAULT_WIDTH = 300;
14    private static final int DEFAULT_HEIGHT = 200;
15 
16    public ActionFrame()
17    {
18       setSize(DEFAULT_WIDTH, DEFAULT_HEIGHT);
19 
20       buttonPanel = new JPanel();
21 
22       // 定义行为
23       Action yellowAction = new ColorAction("Yellow", new ImageIcon("yellow-ball.gif"),
24             Color.YELLOW);
25       Action blueAction = new ColorAction("Blue", new ImageIcon("blue-ball.gif"), Color.BLUE);
26       Action redAction = new ColorAction("Red", new ImageIcon("red-ball.gif"), Color.RED);
27 
28       // 为这些操作添加按钮
29       buttonPanel.add(new JButton(yellowAction));
30       buttonPanel.add(new JButton(blueAction));
31       buttonPanel.add(new JButton(redAction));
32 
33       // 将面板添加到框架
34       add(buttonPanel);
35 
36       // 将Y、B和R键与名称关联
37       InputMap imap = buttonPanel.getInputMap(JComponent.WHEN_ANCESTOR_OF_FOCUSED_COMPONENT);
38       imap.put(KeyStroke.getKeyStroke("ctrl Y"), "panel.yellow");
39       imap.put(KeyStroke.getKeyStroke("ctrl B"), "panel.blue");
40       imap.put(KeyStroke.getKeyStroke("ctrl R"), "panel.red");
41 
42       // 把名字和动作联系起来 
43       ActionMap amap = buttonPanel.getActionMap();
44       amap.put("panel.yellow", yellowAction);
45       amap.put("panel.blue", blueAction);
46       amap.put("panel.red", redAction);
47    }
48    
49    public class ColorAction extends AbstractAction
50    {
51       /**
52        * 构造颜色动作。
53        * @param 在按钮上显示要显示的名称
54        * @param 图标按钮上显示的图标
55        * @param 背景颜色 
56        */
57       public ColorAction(String name, Icon icon, Color c)
58       {
59          putValue(Action.NAME, name);
60          putValue(Action.SMALL_ICON, icon);
61          putValue(Action.SHORT_DESCRIPTION, "Set panel color to " + name.toLowerCase());
62          putValue("color", c);
63       }
64 
65       public void actionPerformed(ActionEvent event)
66       {
67          Color c = (Color) getValue("color");
68          buttonPanel.setBackground(c);
69       }
70    }
71 }

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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。

 1 package mouse;
 2 
 3 import java.awt.*;
 4 import javax.swing.*;
 5 
 6 /**
 7  * @version 1.34 2015-06-12
 8  * @author Cay Horstmann
 9  */
10 public class MouseTest
11 {
12    public static void main(String[] args)
13    {
14       EventQueue.invokeLater(() -> {
15          JFrame frame = new MouseFrame();
16          frame.setTitle("MouseTest");
17          frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
18          frame.setVisible(true);
19       });
20    }
21 }

View Code

 1 package mouse;
 2 
 3 import javax.swing.*;
 4 
 5 /**
 6  * A frame containing a panel for testing mouse operations
 7  */
 8 public class MouseFrame extends JFrame
 9 {
10    public MouseFrame()
11    {
12       add(new MouseComponent());
13       pack();
14    }
15 }

View Code

  1 package mouse;
  2 
  3 import java.awt.*;
  4 import java.awt.event.*;
  5 import java.awt.geom.*;
  6 import java.util.*;
  7 import javax.swing.*;
  8 
  9 /**
 10  * 一个带有鼠标操作的用于添加和删除正方形的组件
 11  */
 12 public class MouseComponent extends JComponent
 13 {
 14    private static final int DEFAULT_WIDTH = 300;
 15    private static final int DEFAULT_HEIGHT = 200;
 16 
 17    private static final int SIDELENGTH = 10;
 18    private ArrayList<Rectangle2D> squares;
 19    private Rectangle2D current; //包含鼠标光标的正方形
 20 
 21    public MouseComponent()
 22    {
 23       squares = new ArrayList<>();
 24       current = null;
 25 
 26       addMouseListener(new MouseHandler());
 27       addMouseMotionListener(new MouseMotionHandler());
 28    }
 29 
 30    public Dimension getPreferredSize() { return new Dimension(DEFAULT_WIDTH, DEFAULT_HEIGHT); }   
 31    
 32    public void paintComponent(Graphics g)
 33    {
 34       Graphics2D g2 = (Graphics2D) g;
 35 
 36       // 绘制所有正方形
 37       for (Rectangle2D r : squares)
 38          g2.draw(r);
 39    }
 40 
 41    /**
 42     * 找到包含一个点的第一个方块。 
 43     * @param P—A点
 44     * @return 包含P的第一个正方形
 45     */
 46    public Rectangle2D find(Point2D p)
 47    {
 48       for (Rectangle2D r : squares)
 49       {
 50          if (r.contains(p)) return r;
 51       }
 52       return null;
 53    }
 54 
 55    /**
 56     * 向集合中添加正方形
 57     * @param p在正方形的中心
 58     */
 59    public void add(Point2D p)
 60    {
 61       double x = p.getX();
 62       double y = p.getY();
 63 
 64       current = new Rectangle2D.Double(x - SIDELENGTH / 2, y - SIDELENGTH / 2, SIDELENGTH,
 65             SIDELENGTH);
 66       squares.add(current);
 67       repaint();
 68    }
 69 
 70    /**
 71     * 从集合中移除正方形.
 72     * @param 从正方形中移除s
 73     */
 74    public void remove(Rectangle2D s)
 75    {
 76       if (s == null) return;
 77       if (s == current) current = null;
 78       squares.remove(s);
 79       repaint();
 80    }
 81 
 82    private class MouseHandler extends MouseAdapter
 83    {
 84       public void mousePressed(MouseEvent event)
 85       {
 86          // 如果光标不在正方形中，则添加一个新的正方形
 87          current = find(event.getPoint());
 88          if (current == null) add(event.getPoint());
 89       }
 90 
 91       public void mouseClicked(MouseEvent event)
 92       {
 93          // 如果双击，删除当前方块 
 94          current = find(event.getPoint());
 95          if (current != null && event.getClickCount() >= 2) remove(current);
 96       }
 97    }
 98 
 99    private class MouseMotionHandler implements MouseMotionListener
100    {
101       public void mouseMoved(MouseEvent event)
102       {
103          // set the mouse cursor to cross hairs if it is inside
104          // 一个长方形
105 
106          if (find(event.getPoint()) == null) setCursor(Cursor.getDefaultCursor());
107          else setCursor(Cursor.getPredefinedCursor(Cursor.CROSSHAIR_CURSOR));
108       }
109 
110       public void mouseDragged(MouseEvent event)
111       {
112          if (current != null)
113          {
114             int x = event.getX();
115             int y = event.getY();
116 
117             // 拖动当前矩形将其置于（x，y）中心
118             current.setFrame(x - SIDELENGTH / 2, y - SIDELENGTH / 2, SIDELENGTH, SIDELENGTH);
119             repaint();
120          }
121       }
122    }   
123 }

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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

图2 点名器点名界面

 1 package dmq2;
 2 
 3 import java.util.*;
 4 import java.awt.*;
 5 import javax.swing.*;
 6 import java.awt.event.*;
 7 import java.io.File;
 8 import java.io.FileNotFoundException;
 9 
10 import javax.swing.event.*;
11 
12 public class NameFrame extends JFrame implements ActionListener {
13     //private JLabel jla;
14     private JLabel jlb;
15     private JButton jba;
16     private static boolean flag = true;
17 
18     public NameFrame() {
19         this.setLayout(null);
20 
21         jlb = new JLabel("随机点名器");
22         jba = new JButton("开始");
23         this.add(jlb);
24         jlb.setOpaque(true);
25         jlb.setBackground(Color.cyan);
26         jlb.setFont(new Font("Courier", Font.PLAIN, 22));
27         jlb.setHorizontalAlignment(JLabel.CENTER);
28         jlb.setVerticalAlignment(JLabel.CENTER);
29         jlb.setBounds(120, 100, 150, 30);
30 
31         this.add(jba);
32         jba.setBounds(150, 150, 80, 26);
33 
34         jba.addActionListener(this);
35 
36         this.setTitle("点名器");
37         this.setBounds(400, 400, 400, 300);
38         this.setVisible(true);
39         this.setDefaultCloseOperation(DISPOSE_ON_CLOSE);
40     }
41 
42     public void actionPerformed(ActionEvent e) {
43         int i = 0;
44         String names[] = new String[50];
45         try {
46             Scanner in = new Scanner(new File("studentnamelist.txt"));
47             while (in.hasNextLine()) {
48                 names[i] = in.nextLine();
49                 i++;
50             }
51         } catch (FileNotFoundException e1) {
52             // TODO Auto-generated catch block
53             e1.printStackTrace();
54         }
55         if (jba.getText() == "开始") {
56             jlb.setBackground(Color.RED);
57             flag = true;
58             new Thread() {
59                 public void run() {
60                     while (NameFrame.flag) {
61                         Random r = new Random();//
62                         int i = r.nextInt(47);
63                         jlb.setText(names[i]);
64                     }
65                 }
66             }.start();
67             jba.setText("停止");
68             jba.setBackground(Color.YELLOW);
69         } else if (jba.getText() == "停止") {
70             flag = false;
71             jba.setText("开始");
72             jba.setBackground(Color.RED);
73             jlb.setBackground(Color.gray);
74         }
75     }
76 
77     public static void main(String arguments[]) {
78         new NameFrame();
79     }
80 }

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