苏浪浪 201771010120 面向对象程序设计（Java）第13周

/实验十三  图形界面事件处理技术

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.*;

/**
 * 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);
      }
   }
}

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);//关闭按钮生效
         frame.setVisible(true);//界面的可见
      });
   }
}

 改进后

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);
   makeButton("green",Color.GREEN);

   }
   public void makeButton(String name , Color backgroundColor)
   {
   JButton button=new JButton(name);
   buttonPanel.add(button);
   ColorAction action=new ColorAction(backgroundColor);
   button.addActionListener(action);
   }
   
   /**
    * 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);
      }
   }
   }

 再度改进：（匿名内部类）

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);
   makeButton("green",Color.GREEN);

   }
   public void makeButton(String name , Color backgroundColor)
   {
   JButton button=new JButton(name);
   buttonPanel.add(button);
   //ColorAction action=new ColorAction(backgroundColor);
   //button.addActionListener(action);
   button.addActionListener(new ActionListener()
   {
   public void actionPerformed(ActionEvent event)
   {
   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。

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();
      //为了配置菜单或为了初始应用程序设置而提供关于已安装的 LookAndFeel 的少量信息
      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);

      //设置按钮操作

      button.addActionListener(event -> {
         // 按钮动作:切换到新的外观
         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);
      });
   }
}

 

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.*;

/**
 * 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();

      // 定义的行为
      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));

      //  向框架添加面板
      add(buttonPanel);

      //将Y、B和R键与名称关联起来
      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");

      // 将名称与动作关联起来
      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);
      }
   }
}

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);
      });
   }
}

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.*;

/**
 * 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; //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;

      // 画出所有方块
      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)
      {
         //如果光标不在正方形内，则添加一个新的正方形
         current = find(event.getPoint());
         if (current == null) add(event.getPoint());
      }

      public void mouseClicked(MouseEvent event)
      {
         //如果双击，则删除当前方块
         current = find(event.getPoint());
         if (current != null && event.getClickCount() >= 2) remove(current);
      }
   }

   private class MouseMotionHandler implements MouseMotionListener
   {
      public void mouseMoved(MouseEvent event)
      {
         // 如果鼠标在内部，则将鼠标光标设置为十字线
         // 一个矩形

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

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();
   }
}

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

 百度程序：

package personal;
 
import java.awt.Color;
import java.awt.Font;
import java.awt.Rectangle;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.image.BufferedImage;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.Random;
import java.util.Scanner;
 
import javax.imageio.ImageIO;
import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextArea;
 
 
public class StartJFrame extends JFrame{
    private static final long serialVersionUID = 1L;
    JFrame jframe= new JFrame("窗体生成");
    JPanel jpanel=null;
    JPanel imagePanel = null;
    BufferedImage image= null;
    JLabel label3 = new JLabel(); 
    ImageIcon background = new ImageIcon();
    JTextArea jtext = new JTextArea();
    JButton jbutton1=new JButton("开始"); 
    JButton jbutton2=new JButton("暂停");
    JButton jbutton3=new JButton("确定");
    String strPath = "";
    public static boolean flag = true;//判断开始按钮是否被点过
    private static Thread t;
    private int count = 0;
    
    public StartJFrame(){  
    
        //添加文字
        jpanel = (JPanel)this.getContentPane();//每次添加必须要加的语句
        Font font = new Font("",Font.BOLD,30);
        //添加按钮
        jpanel=(JPanel)this.getContentPane();  
        jpanel.setLayout(null);
        //（左，上，宽，高）
        jbutton3.setBounds(new Rectangle(330,180,60,20));
        jbutton3.addActionListener(new TextValue(this));
        jpanel.add(jbutton3);
        
        //添加文本框（左，上，宽，高）
        jtext.setBounds(40, 180, 260, 20);
        jpanel.add(jtext);
        
    }
    /**
     * 重写构造器
     */
    public StartJFrame(String str){  
        //将路径传入开始按钮
        strPath = str;
        
    
        //添加提示文字
        jpanel = (JPanel)this.getContentPane();//每次添加必须要加的语句
        JLabel label2 = new JLabel("点名开始啦！！！");
        Font font = new Font("",Font.BOLD,30);
        label2.setFont(font);
        label2.setForeground(Color.black);
        label2.setBounds(100,20,450,100);
        jpanel.add(label2);
        
        //显示名字信息
        label3.setBounds(150,120,450,100);
        //设置字体颜色
        label3.setForeground(Color.yellow);
        
        //添加按钮
        jpanel=(JPanel)this.getContentPane();  
        jpanel.setLayout(null);   
        jbutton1.setBounds(new Rectangle(100,300,75,25));  
        jpanel.add(jbutton1);  
        jbutton1.addActionListener(new Action(this));
        jbutton2.setBounds(new Rectangle(250,300,75,25));  
        jpanel.add(jbutton2);  
        jbutton2.addActionListener(new Stop(this));
        
    }
    
    /**
     * 从控制台输入路径
     */
    public static String InputPath(){
        String str ="";
        System.out.println("F:\xll.txt");
        Scanner sc= new Scanner(System.in);
        str = sc.nextLine();
        return str;
    }
    /**
     * 读取文档数据
     * @param filePath
     * @return
     */
    public static String ReadFile(String filePath){
        String str = "";
        try {
        String encoding="GBK";
        File file = new File(filePath);
        if(file.isFile()&&file.exists()){
                InputStreamReader reader = 
                    new InputStreamReader(new FileInputStream(file),encoding);
                BufferedReader bufferedReader = new BufferedReader(reader);
                String lineTxt = "";
                    while((lineTxt = bufferedReader.readLine()) != null){
                        str+=lineTxt+";
";
                    }
                 reader.close();
            }else{
                System.out.println("找不到指定的文件");
            } 
        }catch (Exception e) {
            System.out.println("读取文件内容出错");
            e.printStackTrace();
        }
        return str;
    }
    /**
     * 将字符串转换为String数组
     */
    public static String[] ChangeType(String str){
        ArrayList<String> list=new ArrayList<String>();
        String[] string = str.split(";");
        return string;
    }
    /**
     * main方法
     * @param args
     */
    public static void main(String args[]){
        StartJFrame jframe=new StartJFrame();
        jframe.setTitle("点名器");
        jframe.setSize(550,400);  
        jframe.setVisible(true);  
        jframe.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        jframe.setResizable(false);
        jframe.setLocationRelativeTo(null);
        System.out.println();
    }
    /**
     * 点击确定按钮后的方法
     */
    public void chooseValue(ActionEvent e){
        String str = "";
        str = jtext.getText();
        if(str != "" || str != null){
        StartJFrame jframe = new StartJFrame(str);
        jframe.setTitle("点名器");
        jframe.setSize(550,500);  
        jframe.setVisible(true);  
        jframe.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        jframe.setResizable(false);
        jframe.setLocationRelativeTo(null);
        System.out.println(str);
        }
    }
    /**
     * 点击开始按钮后的方法
     */
    public void actionRun(ActionEvent e){
        if(flag){
        //线程开始
        t = new Thread(new Runnable(){
            public void run(){//
                while(count<=10000){
                    //文件路径
                    String strTest = strPath;
                    //开始读取数据
                    String strRead = ReadFile(strTest);
                    //将读取到的数据变为数组
                    String[] strc = ChangeType(strRead);
                    //获取随机的姓名
                    Random random = new Random();
                    int a = 0;
                    a = random.nextInt(strc.length-1);
                    String str = strc[a];
                    System.out.println("输出名字为："+str);
                    label3.setFont(new java.awt.Font(str,1,60));
                    //设置名字标签的文字
                    label3.setText(str);
                    try{
                        t.sleep(20);//使线程休眠50毫秒
                    }catch(Exception e){
                    e.printStackTrace();
                    }
                    count+=1;//显示次数
                }
            }
        });
        t.start();
        //设置字体颜色
        jpanel.add(label3);
        flag = false;
        }
        flag = false;
    }
    /**
     * 点击暂停按钮后的方法
     */
    @SuppressWarnings("deprecation")
    public void stopRun(ActionEvent e){
        if(!flag){
        t.stop();
        flag = true;
        }
        flag = true;
    }
}  
 
/**
 *确定按键监控类
 */
class TextValue implements ActionListener {  
    private StartJFrame startJFrame;  
    TextValue(StartJFrame startJFrame) {  
        this.startJFrame = startJFrame;  
   }
    public void actionPerformed(ActionEvent e) {  
        startJFrame.chooseValue(e); 
        startJFrame.setVisible(false);
    }
}
 
/**
 *开始按键监控类
 */
class Action implements ActionListener {  
    private StartJFrame jFrameIng;  
    Action(StartJFrame jFrameIng) {  
        this.jFrameIng = jFrameIng;  
   }  
    public void actionPerformed(ActionEvent e) {
        jFrameIng.actionRun(e);
        
    }
} 
/**
 *暂停按键监控类
 */
class Stop implements ActionListener {  
    private StartJFrame jFrameIng;  
    Stop(StartJFrame jFrameIng) {  
        this.jFrameIng = jFrameIng;  
   }  
    public void actionPerformed(ActionEvent e) {
        jFrameIng.stopRun(e);
    }  
}

未完成代码：

package c;

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

import java.io.*;
import java.util.*;
import java.util.List;
import java.util.Timer;
import java.util.jar.Attributes.Name;

/**
 * A frame with a button panel
 */
public class ButtonFrame extends JFrame {

    private JPanel buttonPanel;
    private static final int DEFAULT_WIDTH = 500;
    private static final int DEFAULT_HEIGHT = 400;
    public  ButtonFrame() {
        try {
            String line = null;
            List<String> list = new ArrayList<String>();
            BufferedReader in = new BufferedReader(new FileReader("F:\xll.txt"));
            while ((line = in.readLine()) != null) {
                String temp = line.trim();
                if (temp != null && !"".equals(temp))
                    list.add(temp);
                }
            String[] arr = (String[]) list.toArray(new String[list.size()]);
            setSize(DEFAULT_WIDTH, DEFAULT_HEIGHT);

            buttonPanel = new JPanel();
            buttonPanel.setLayout(null);
            JLabel jLabel = new JLabel("   ");
            JButton jButton = new JButton("开始");
            jLabel.setBounds(130, 60, 200, 60);
            jButton.setBounds(110, 110, 60, 30);
            jButton.addActionListener(new ActionListener() {
                public void actionPerformed(ActionEvent e) {
                    Timer timer = new Timer();
                    TimerTask timerTask = new TimerTask() {
                        public void run() {
                            String[] name = arr;
                            jLabel.setText(name[(int) Math.round(Math.random() * 32)]);
                        }
                    };
                    timer.schedule(timerTask, 10, 10);
                }
            });
            buttonPanel.add(jLabel);
            buttonPanel.add(jButton);
            add(buttonPanel);

            } catch (FileNotFoundException e1) {
            // TODO 自动生成的 catch 块
            e1.printStackTrace();
        }catch (IOException e1) {
                // TODO 自动生成的 catch 块
                e1.printStackTrace();
            }
     
            

    }
}

package c;

import java.awt.*;
import javax.swing.*;

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);
        });
    }
}

实验总结：

 掌握了事件处理的基本原理、 AWT事件模型的工作机制； 掌握了事件处理的基本编程模型；了解了GUI界面组件观感设置方法；学习了WindowAdapter类、AbstractAction类的用法 以及GUI程序中鼠标事件处理技术。

 能够触发动作事件的动作，主要包括：

(1) 点击按钮

(2) 双击一个列表中的选项；

(3) 选择菜单项；

(4) 在文本框中输入回车。

通过实验结对编程练习我初步的了解到了一些