理论知识部分
1.监听器：监听器类必须实现与事件源相对应的接口，即必须提供接口中方法的实现。
监听器接口方法实现
class Mylistener implements ActionListener { public void actionPerformed (ActionEvent event) { …… } }
2.用匿名类、lambda表达式简化程序：
例ButtonTest.java中，各按钮需要同样的处理：
a.使用字符串构造按钮对象；
b.把按钮添加到面板上；
c.用对应的颜色构造一个动作监听器；
d.注册动作监听器。
3.适配器类:
当程序用户试图关闭一个框架窗口时，Jframe 对象就是WindowEvent的事件源。
捕获窗口事件的监听器：
WindowListener listener=…..; frame.addWindowListener(listener);
注册事件监听器:
可将一个Terminator对象注册为事件监听器：
WindowListener listener=new Terminator();
frame.addWindowListener(listener);
4.动作事件:
Swing包提供了非常实用的机制来封装命令，并将它们连接到多个事件源，这就是Action接口。
动作对象是一个封装下列内容的对象：
–命令的说明：一个文本字符串和一个可选图标;
–执行命令所需要的参数。
5.鼠标事件:
鼠标事件 – MouseEvent
鼠标监听器接口
– MouseListener
– MouseMotionListener
鼠标监听器适配器
– MouseAdapter
– MouseMotionAdapter
实验部分：
实验1：
测试程序1：
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();//构建一个ButtonFrame类对象
frame.setTitle("ButtonTest");//设置Title属性，确定框架标题栏中的文字
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);//设置默认关闭操作，退出并关闭
frame.setVisible(true);//设置Visible属性，组件可见
});
}
}
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);
// 创建按钮
JButton yellowButton = new JButton("Yellow");
JButton blueButton = new JButton("Blue");
JButton redButton = new JButton("Red");
buttonPanel = new JPanel();
// 添加按钮到面板
buttonPanel.add(yellowButton);//调用add方法将按钮添加到面板
buttonPanel.add(blueButton);
buttonPanel.add(redButton);
// 添加面板到框架
add(buttonPanel);
// 创建按钮事件
ColorAction yellowAction = new ColorAction(Color.YELLOW);
ColorAction blueAction = new ColorAction(Color.BLUE);
ColorAction redAction = new ColorAction(Color.RED);
// 将时间与按钮关联
yellowButton.addActionListener(yellowAction);
blueButton.addActionListener(blueAction);
redButton.addActionListener(redAction);
}
/**
* An action listener that sets the panel's background color.
*/
private class ColorAction implements ActionListener//实现了ActionListener的接口类
{
private Color backgroundColor;
public ColorAction(Color c)
{
backgroundColor = c;
}
public void actionPerformed(ActionEvent event)//actionListener方法接收一个ActionEvent对象参数
{
buttonPanel.setBackground(backgroundColor);
}
}
}
输出结果：
测试程序2：
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();//构建一个PlafFrame类对象
frame.setTitle("PlafTest");//设置Title属性，确定框架标题栏中的文字
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);//设置默认关闭操作，退出并关闭
frame.setVisible(true);//设置Visible属性，组件可见
});
}
}
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();//获得一个用于描述已安装的观感实现的对象数组
for (UIManager.LookAndFeelInfo info : infos)
makeButton(info.getName(), info.getClassName());//返回观感的显示名称，返回观感实现类的名称
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)
{
// 添加按钮到面板
JButton button = new JButton(name);
buttonPanel.add(button);
// 设置按钮事件
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();
}
});
}//使用辅助方法makeButton和匿名内部类指定按钮动作
}
输出结果：
测试程序3：
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();//构建一个ActionFrame类对象
frame.setTitle("ActionTest");//设置Title属性，确定框架标题栏中的文字
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);//设置默认关闭操作，退出并关闭
frame.setVisible(true);//设置Visible属性，组件可见
});
}
}
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();
// 定义操作
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));
// 将面板添加到框架
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);//获得将按键映射到动作键的输入映射
imap.put(KeyStroke.getKeyStroke("ctrl Y"), "panel.yellow");//根据一个便于人们阅读的说明创建一个按钮（由空格分隔的字符串序列）
imap.put(KeyStroke.getKeyStroke("ctrl B"), "panel.blue");
imap.put(KeyStroke.getKeyStroke("ctrl R"), "panel.red");
// 将名称与操作关联起来
ActionMap amap = buttonPanel.getActionMap();//返回关联动作映射键和动作对象的映射
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);//将名/值放置在动作对象内
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");//返回被存储的名对的值
buttonPanel.setBackground(c);
}
}
}
输出结果：
测试程序4：
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();//构建一个MouseFrame类对象
frame.setTitle("MouseTest");//设置Title属性，确定框架标题栏中的文字
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);//设置默认关闭操作，退出并关闭
frame.setVisible(true);//设置Visible属性，组件可见
});
}
}
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;
// 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)
{
// 如果鼠标指针在内部，则将其设置为十字线
// 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();
// 拖动当前矩形到(x, y)的中心
current.setFrame(x - SIDELENGTH / 2, y - SIDELENGTH / 2, SIDELENGTH, SIDELENGTH);
repaint();
}
}
}
}
输出结果：
实验2：结对编程练习
结对编程伙伴：冯志霞
import java.util.*;
import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
import java.awt.Frame;
import java.io.File;
import java.io.FileNotFoundException;
public class Dianmingqi extends JFrame implements ActionListener {
private JButton but;
private JButton show;
private static boolean flag = true;
public static void main(String arguments[]) {
new Dianmingqi();
}
public Dianmingqi() {
but = new JButton("START");
but.setBounds(100, 150, 100, 40);
show = new JButton("开始点名");
show.setBounds(80, 80, 180, 30);
show.setFont(new Font("宋体", Font.BOLD, 30));
add(but);
add(show);
setLayout(null);// 布局管理器必须先初始化为空才能赋值
setVisible(true);
setResizable(false);
setBounds(100, 100, 300, 300);
//setBackground(Color.red);不起作用
this.getContentPane().setBackground(Color.cyan);
setTitle("START");
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
but.addActionListener(this);
}
public void actionPerformed(ActionEvent e) {
int i = 0;
String names[] = new String[50];
try {
Scanner in = new Scanner(new File("studentnamelist.txt"));
while (in.hasNextLine()) {
names[i] = in.nextLine();
i++;
}
} catch (FileNotFoundException e1) {
e1.printStackTrace();
}
if (but.getText() == "START") {
show.setBackground(Color.BLUE);
flag = true;
new Thread() {
public void run() {
while (Dianmingqi.flag) {
Random r = new Random();
int i = r.nextInt(47);
show.setText(names[i]);
}
}
}.start();
but.setText("STOP");// 更改文本内容
but.setBackground(Color.YELLOW);
} else if (but.getText() == "STOP") {
flag = false;
but.setText("START");
but.setBackground(Color.WHITE);
show.setBackground(Color.GREEN);
}
}
}
实验总结：
这个周的结对编程练习，由于对很多知识的不理解，无法完全实现编程题的内容，我深感自己的不足。对于代码中的一些方法还不是能够完全理解。
package 点名器; import java.io.*; import java.awt.*; import java.awt.event.*; import java.util.List; import javax.swing.JFrame; import java.util.ArrayList; public class RollCaller extends JFrame{ private String fileName="studentnamelist.txt"; private File f; private FileReader fr; private BufferedReader br; private List<String> names=new ArrayList<String>(); private String Name; private Label labelName; private Button button; public static void main(String[] args) { RollCaller rollcaller=new RollCaller(); rollcaller.newFrame(); rollcaller.read(); } public void newFrame() { labelName=new Label("随机点名"); button=new Button("START"); this.setLocation(300,300); this.setResizable(true);//设置此窗体是否可由用户调整大小。 this.setSize(1000,800); this.add(labelName,BorderLayout.NORTH); this.add(button,BorderLayout.CENTER); this.pack(); this.setVisible(true); setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); button.addActionListener(new ButtonAction()); } public void read() { try{ f=new File(fileName); if(!f.exists()){ f.createNewFile(); } fr=new FileReader(f); br=new BufferedReader(fr); String str=br.readLine(); while(str!=null){ names.add(str); str=br.readLine(); } }catch(Exception e){ e.printStackTrace(); } } public void name() { try{ int index=(int)(Math.random()*names.size()); Name=names.get(index); }catch(Exception e){ e.printStackTrace(); } } private class ButtonAction implements ActionListener{ public void actionPerformed(ActionEvent e){ name(); labelName.setText(Name); } } }
这次的作业，我在网络中查询了很多，
通过在网上查询，我查到了BufferedReader由Reader类扩展而来，提供文本读取。
还有label对象是一个可在容器中放置文本的组件。一个标签只显示一行只读文本。文本可由应用程序更改，但是用户不能直接对其进行编辑。
但是这个代码还存在着很多问题，对于很多知识我还需更多的掌握，不论是从程序的实用，还是外观，都还需更加深入的学习。