常用的几种监听器

1.键盘监听器：

 1 class KeyFrame extends Frame {
 2     public KeyFrame() {
 3         setBounds(1,2,300,400);
 4         setVisible(true);
 5         
 6         this.addKeyListener(new KeyAdapter() {
 7             //键盘按下
 8             public void keyPressed(KeyEvent e) {
 9                 int keyCode = e.getKeyCode();
10                 if (keyCode == KeyEvent.VK_UP) {
11                     System.out.println("按了上键");
12                 }
13             }
14         });
15     }

2.鼠标监听器：

 1 //适配器模式
 2     private class MyMouseListener extends MouseAdapter{
 3         public void mousePressed(MouseEvent e) {
 4             MyFrame frame = (MyFrame)e.getSource();
 5             //鼠标点击时，将会在界面上产生一个点
 6             //这个点就是鼠标的点
 7             frame.addPoint(new Point(e.getX(),e.getY()));
 8             
 9             //每次点击鼠标都重新画一遍
10             frame.repaint();
11         }
12     }

通过鼠标监听器实现画笔的功能：

 1 class MyFrame extends Frame{
 2     ArrayList points;
 3     //需要画笔，需要监听鼠标当前的位置，需要集合存储这个点
 4     public MyFrame(String title) {
 5         super(title);
 6         setBounds(200,200,400,300);
 7         setVisible(true);
 8         //存鼠标点击的点
 9         points = new ArrayList<>();
10         //添加一个鼠标监听器
11         this.addMouseListener(new MyMouseListener());
12     }
13     
14     public void paint(Graphics g) {
15         //画画，监听鼠标的事件
16         Iterator iterator = points.iterator();
17         while (iterator.hasNext()) {
18             Point point = (Point) iterator.next();
19             g.setColor(Color.BLUE);
20             g.fillOval(point.x, point.y, 10, 10);
21         }
22     }
23     
24     //添加一个点到界面上
25     public void addPoint(Point point) {
26         points.add(point);
27     }
28     
29     //适配器模式
30     private class MyMouseListener extends MouseAdapter{
31         public void mousePressed(MouseEvent e) {
32             MyFrame frame = (MyFrame)e.getSource();
33             //鼠标点击时，将会在界面上产生一个点
34             //这个点就是鼠标的点
35             frame.addPoint(new Point(e.getX(),e.getY()));
36             
37             //每次点击鼠标都重新画一遍
38             frame.repaint();
39         }
40     }
41 }

3.窗口监听器：

1 class MyWindowListener extends WindowAdapter {
2         public void windowClosing(WindowEvent e) {
3             setVisible(false);
4             System.exit(0);
5         }
6         
7     }

实例使用：

 1 class WindowFrame extends Frame{
 2     public WindowFrame() {
 3         setBackground(Color.blue);
 4         setBounds(100,100,200,200);
 5         setVisible(true);
 6         addWindowListener(new MyWindowListener() {
 7             public void windowClosing(WindowEvent e) {
 8                 setVisible(false);
 9             }
10             
11             public void windowActiated(WindowEvent e) {
12                 System.out.println("windowActivated");
13             }
14         });
15     }
16     
17     class MyWindowListener extends WindowAdapter {
18         public void windowClosing(WindowEvent e) {
19             setVisible(false);
20             System.exit(0);
21         }
22         
23     }
24 }