【转】转帖并注释:Java中的事件处理机制--事件监听器的四种实现方式

原文地址：http://blog.sina.com.cn/s/blog_4b650d650100nqws.html

Java中四种事件监听器的实现方式分别为:

自身类做为事件监听器
外部类作为事件监听器
匿名内部类作为事件监听器
内部类作为事件监听器.

下面分别描述:

//---------------------------------------------------------------------

1. 自身类作为事件监听器:

 1  import javax.swing.*;
 2  import java.awt.*;
 3  import java.awt.event.*;
 4 
 5     //ActionListener:java.awt.event.ActionListener(interface),用来监听Action事件
 6     class ThisClassEvent extends JFrame implements ActionListener
 7     { 
 8         JButton btn;  
 9 
10         public ThisClassEvent()
11         {
12             super("Java事件监听机制");
13             setLayout(new FlowLayout());
14             setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
15 
16 
17             btn=new JButton("点击");
18             //addActionListerner()原型为:public void addActionListener(ActionListener l)
19             btn.addActionListener(this);
20             getContentPane().add(btn);
21 
22 
23             setBounds(200,200,300,160);
24             setVisible(true);
25         }
26 
27 
28         /------------------------------
29         //actionPerformed函数是从ActionListener中继承来的.
30 
31         public void actionPerformed (ActionEvent e)
32         {
33             Container c=getContentPane();
34             c.setBackground(Color.red);
35         } 
36 
37 
38         /------------------------------
39         public static void main(String args[])
40         { 
41             new ThisClassEvent();
42         }
43     }

2. 外部类作为事件监听器:

 1   import java.awt.*; 
 2     import java.awt.event.*;
 3     import javax.swing.*;
 4 
 5 
 6     class OuterClassEvent extends JFrame
 7     { 
 8         JButton btn; 
 9         public OuterClassEvent()
10         {
11              super("Java事件监听机制");
12              setLayout(new FlowLayout());
13              setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
14 
15 
16              btn=new JButton("点击");
17 
18              //addActionListerner()原型为:public void addActionListener(ActionListener l)
19              //new OuterClass(this)是OuterClass的实例,而OuterClass是从ActionListener继承来的
20              btn.addActionListener(new OuterClass(this));
21              getContentPane().add(btn);
22 
23 
24              setBounds(200,200,300,160);
25              setVisible(true);
26         }
27 
28 
29         public static void main(String args[])
30         {
31              new OuterClassEvent();
32         }
33     } 
34 
35 
36     //外部类------------------------------
37 
38     //OuterClass从ActionListener继承
39     class OuterClass implements ActionListener
40     {
41          OuterClassEvent oce;
42          public OuterClass(OuterClassEvent oce)
43          {
44              this.oce = oce;
45          }
46 
47  
48 
49          //actionPerformed函数是从ActionListener中继承来的.
50          public void actionPerformed(ActionEvent e)
51          {
52              Container c=oce.getContentPane();
53              c.setBackground(Color.red);
54          }
55     }
56 
57  
58 
59     //---------------------------------------------------------------------

3. 匿名内部类作为事件监听器:

 1   import java.awt.*;
 2     import java.awt.event.*;
 3     import javax.swing.*;
 4 
 5 
 6     class AnonymousEvent extends JFrame
 7     { 
 8         JButton btn;
 9 
10 
11         public AnonymousEvent()
12         { 
13             super("Java事件监听机制");
14             setLayout(new FlowLayout());
15             setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
16 
17 
18             btn=new JButton("点击");
19 
20 
21             //匿名内部类---------------------------
22             //addActionListerner()原型为:public void addActionListener(ActionListener l)
23             btn.addActionListener
24             (
25                 //new ActionListener()声明了ActionListener的一个实例
26                 new ActionListener()
27                 {
28 
29                     //actionPerformed函数是从ActionListener中继承来的.
30                     public void actionPerformed(ActionEvent e)
31                     {
32                         Container c=getContentPane();
33                         c.setBackground(Color.red);
34                     }
35                 }
36             );
37  
38             //------------------------------
39             getContentPane().add(btn); 
40             setBounds(200,200,300,160);
41             setVisible(true); 
42 
43         }
44 
45 
46         public static void main(String args[])
47         {
48             new AnonymousEvent();
49         }
50     }
51 
52  
53 
54     //---------------------------------------------------------------------

4.内部类作为事件监听器：

 1    import java.awt.*;
 2     import java.awt.event.*;
 3     import javax.swing.*;
 4 
 5 
 6     class InnerClassEvent extends JFrame
 7 
 8     { 
 9         JButton btn;
10         public InnerClassEvent()
11 
12         { 
13             super("Java事件监听机制");
14             setLayout(new FlowLayout());
15             setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
16 
17 
18             btn=new JButton("点击");
19 
20             //addActionListerner()原型为:public void addActionListener(ActionListener l)
21             btn.addActionListener(new InnerClass());
22             getContentPane().add(btn);
23 
24 
25             setBounds(200,200,300,160);
26             setVisible(true);
27         }
28 
29 
30         //内部类---------------------------
31         //InnerClass继承了ActionListener
32         class InnerClass implements ActionListener
33         {
34 
35             //actionPerformed函数是从ActionListener中继承来的.
36             public void actionPerformed (ActionEvent e)
37             {
38                 Container c=getContentPane();
39                 c.setBackground(Color.red);
40             }
41         }
42 
43  
44         //------------------------------
45         public static void main(String args[])
46 
47         {
48             new InnerClassEvent();
49         }
50     }
51 
52     //---------------------------------------------------------------------