201771010106东文财《面向对象程序设计（java）》实验13-白红宇

201771010106东文财《面向对象程序设计（java）》实验13

阅读量：5334 次

发布时间：2019-06-15

本文共 12916 字，大约阅读时间需要 43 分钟。

实验十三图形界面事件处理技术

实验时间 2018-11-22

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。

package button;import java.awt.*;import java.awt.event.*;import javax.swing.*;/** * //带按钮面板的框架

*/

public class ButtonFrame extends JFrame{   private JPanel buttonPanel;   private static final int DEFAULT_WIDTH = 300;   private static final int DEFAULT_HEIGHT = 200;

//像素大小

public ButtonFrame() {
      setSize(DEFAULT_WIDTH, DEFAULT_HEIGHT); //创建按钮

JButton yellowButton = new JButton("Yellow");  JButton blueButton = new JButton("Blue"); JButton redButton = new JButton("Red"); buttonPanel = new JPanel(); //

向面板添加按钮

buttonPanel.add(yellowButton);  buttonPanel.add(blueButton);  buttonPanel.add(redButton); // add panel to frame  add(buttonPanel); // create button actions ColorAction yellowAction = new ColorAction(Color.YELLOW);  ColorAction blueAction = new ColorAction(Color.BLUE); ColorAction redAction = new ColorAction(Color.RED); //

用按钮关联动作

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);  }  }  }

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");         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。

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(); // 获得一个用于描述已安装的观感实现的对象数组      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);      //设置按钮动作

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();         }      });   }}

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。

package action;import java.awt.*;import java.awt.event.*;import javax.swing.*;/** *

具有显示颜色变化动作的面板的框架。

*/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();

// 定义动作

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);

// 为这些操作添加按钮

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   {      /**       *构造颜色动作。

* @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);      }   }}

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。

package mouse;import java.awt.*;import java.awt.event.*;import java.awt.geom.*;import java.util.*;import javax.swing.*;/** * 一个带有鼠标操作的用于添加和删除正方形的组件。

*/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
     
       squares;   private Rectangle2D current;

// 包含鼠标光标的正方形

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();

// 拖动当前矩形将其置于（x，y）中心

current.setFrame(x - SIDELENGTH / 2, y - SIDELENGTH / 2, SIDELENGTH, SIDELENGTH);            repaint();         }      }   }   }

package mouse;import javax.swing.*;/** *

包含用于测试鼠标操作的面板的框架

*/public class MouseFrame extends JFrame{   public MouseFrame()   {      add(new MouseComponent());      pack();   }}

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。

package hh;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;//boolean变量    public NameFrame(){        this.setLayout(null);/        jla = new JLabel("姓名");        jlb = new JLabel("  ");        jba = new JButton("开始");        this.add(jla);//添加组件        this.add(jlb);        jla.setFont(new Font("Courier",Font.PLAIN,25));//设置字体        jla.setHorizontalAlignment(JLabel.CENTER);         jla.setVerticalAlignment(JLabel.CENTER);                jla.setBounds(20,100,180,30);//移动组件并调整其大小         jlb.setOpaque(true);         jlb.setBackground(Color.cyan);//设置组件的背景色         jlb.setFont(new Font("Courier",Font.PLAIN,25));         jlb.setHorizontalAlignment(JLabel.CENTER);         jlb.setVerticalAlignment(JLabel.CENTER);                 jlb.setBounds(150,100,150,30);                   this.add(jba);         jba.setBounds(150,150,80,26);               jba.addActionListener(this);//添加监听器按钮         this.setTitle("点名器");        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[47];        //捕获异常        try {            Scanner in=new Scanner(new File("D:\\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"){
   //返回按钮文本            jlb.setBackground(Color.PINK);            flag = true;            new Thread(){                   public void run(){                    while(NameFrame.flag){                    Random r = new Random();                     int i= r.nextInt(47);                    jlb.setText(names[i]);                    }                }            }.start();            jba.setText("停止");            jba.setBackground(Color.GREEN);        }            else if(jba.getText()=="停止"){            flag = false;            jba.setText("开始");//设置按钮的文本            jba.setBackground(Color.WHITE);            jlb.setBackground(Color.WHITE);        }     }    public static void main(String arguments []){         new NameFrame();    }}