201771010109焦旭超《面向对象程序设计（java）》第十三周学习总结

Posted 2021-01-22 lcjcc

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;
   private static final int DEFAULT_HEIGHT = 200;

   public ButtonFrame()
   {      
      setSize(DEFAULT_WIDTH, DEFAULT_HEIGHT);

      // create buttons
      JButton yellowButton = new JButton("Yellow");
      JButton blueButton = new JButton("Blue");
      JButton redButton = new JButton("Red");

      buttonPanel = new JPanel();

      // add buttons to panel
      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);

      // associate actions with buttons
      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);
      });
   }
}

 

简化后：

一、

package button;

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

/**
 * A frame with a button panel
 */
public class ButtonFrame extends JFrame {
    // 属性的定义
    private JPanel buttonPanel;// 内容窗格对象
    private static final int DEFAULT_WIDTH = 300;// 窗口宽度
    private static final int DEFAULT_HEIGHT = 200;// 窗口高度

    public ButtonFrame() {
        setSize(DEFAULT_WIDTH, DEFAULT_HEIGHT);// 更改了GUI界面的宽度和高度

        // 生成三个按钮对象
        /*
         * JButton yellowButton = new JButton("yellow"); JButton blueButton = new
         * JButton("Blue"); JButton redButton = new JButton("Red");
         */
        buttonPanel = new JPanel();

        // 向buttonPanel内容窗格添加三个按钮组件
        /*
         * buttonPanel.add(yellowButton); buttonPanel.add(blueButton);
         * buttonPanel.add(redButton);
         */
        // 添加内容窗格
        add(buttonPanel);

        // 注册监听器类对象
        /*
         * ColorAction yellowAction = new ColorAction(Color.YELLOW); ColorAction
         * blueAction = new ColorAction(Color.BLUE); ColorAction redAction = new
         * ColorAction(Color.RED);
         */

        // 监听器类对象和组件对应
        /*
         * yellowButton.addActionListener(yellowAction);
         * blueButton.addActionListener(blueAction);
         * redButton.addActionListener(redAction);
         */
        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// ColorAction为监听器类
    {
        private Color backgroundColor;

        public ColorAction(Color c) {
            backgroundColor = c;
        }

        public void actionPerformed(ActionEvent event) {
            buttonPanel.setBackground(backgroundColor);
        }
    }
}

二、

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);

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

        // add buttons to panel
        /*
         * 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);
         */

        // associate actions with buttons
        /*
         * yellowButton.addActionListener(yellowAction);
         * blueButton.addActionListener(blueAction);
         * redButton.addActionListener(redAction);
         */
        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 e) {
                buttonPanel.setBackground(backgroundColor);
            }
        });
    }
}

/**
 * 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); } } }
 */

 

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 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 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)
   {
      // 窗格中添加按钮

      JButton button = new JButton(name);
      buttonPanel.add(button);

      // 设定按钮动作
      button.addActionListener(event -> {
         // 按钮动作: 切换到新的外观和感觉
         try
         {
            UIManager.setLookAndFeel(className);
            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；

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 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 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);

      // 为这些动作添加按钮
      buttonPanel.add(new JButton(yellowAction));
      buttonPanel.add(new JButton(blueAction));
      buttonPanel.add(new JButton(redAction));

//将Y、B和R键与名称联系起来
      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");

      // 把名字和行动联系起来
      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);
      }
   }
}

 

 

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);
      });
   }
}

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 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;

      // 绘制所有方块
      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，则删除当前正方形
         current = find(event.getPoint());
         if (current != null && event.getClickCount() >= 2) remove(current);
      }
   }

   private class MouseMotionHandler implements MouseMotionListener
   {
      public void mouseMoved(MouseEvent event)
      {
         //如果鼠标光标位于内部，则将其设置为交叉头发
//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();

            // drag the current rectangle to center it at (x, y)
            current.setFrame(x - SIDELENGTH / 2, y - SIDELENGTH / 2, SIDELENGTH, SIDELENGTH);
            repaint();
         }
      }
   }   
}

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。

学长代码添加注释：

 

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);//设置 LayoutManager。重写此方法
      //创建三个具有指定文本的 JLabel 实例
        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);//设置标签内容沿 X 轴的对齐方式
         jla.setVerticalAlignment(JLabel.CENTER);  //设置标签内容沿 Y 轴的对齐方式      
         jla.setBounds(20,100,180,30);//移动组件并调整其大小
         jlb.setOpaque(true);//如果为 true，则该组件绘制其边界内的所有像素
         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");//设置窗体标题
        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[47];
        //捕获异常
        try {
            Scanner in=new Scanner(new File("E:\\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();//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.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();
    }
}

 

 

 实验总结：

　　第一个实验两次优化，首先每个监听器执行一个单独动作，这里构造三个监听器对象，然后三个按钮共享一个监听器对象。最后一个实验不会做，用了学长的代码，然后进行注释，但还是没有理解。下去我会认真弄懂学长的示例，尽量做到自己能够模仿，然后自己写。