【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: 

1. 自身类做为事件监听器
2. 外部类作为事件监听器
3. 匿名内部类作为事件监听器
4. 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:

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

    //ActionListener:java.awt.event.ActionListener(interface),用来监听Action事件
    class ThisClassEvent extends JFrame implements ActionListener
    { 
        JButton btn;  

        public ThisClassEvent()
        {
            super("Java事件监听机制");
            setLayout(new FlowLayout());
            setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);


            btn=new JButton("点击");
            //addActionListerner()原型为:public void addActionListener(ActionListener l)
            btn.addActionListener(this);
            getContentPane().add(btn);


            setBounds(200,200,300,160);
            setVisible(true);
        }


        /------------------------------
        //actionPerformed函数是从ActionListener中继承来的.

        public void actionPerformed (ActionEvent e)
        {
            Container c=getContentPane();
            c.setBackground(Color.red);
        } 


        /------------------------------
        public static void main(String args[])
        { 
            new ThisClassEvent();
        }
    } 

    2. 外部类作为事件监听器:

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


    class OuterClassEvent extends JFrame
    { 
        JButton btn; 
        public OuterClassEvent()
        {
             super("Java事件监听机制");
             setLayout(new FlowLayout());
             setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);


             btn=new JButton("点击");

             //addActionListerner()原型为:public void addActionListener(ActionListener l)
             //new OuterClass(this)是OuterClass的实例,而OuterClass是从ActionListener继承来的
             btn.addActionListener(new OuterClass(this));
             getContentPane().add(btn);


             setBounds(200,200,300,160);
             setVisible(true);
        }


        public static void main(String args[])
        {
             new OuterClassEvent();
        }
    } 


    //外部类------------------------------

    //OuterClass从ActionListener继承
    class OuterClass implements ActionListener
    {
         OuterClassEvent oce;
         public OuterClass(OuterClassEvent oce)
         {
             this.oce = oce;
         }

 

         //actionPerformed函数是从ActionListener中继承来的.
         public void actionPerformed(ActionEvent e)
         {
             Container c=oce.getContentPane();
             c.setBackground(Color.red);
         }
    }

 

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

    3. 匿名内部类作为事件监听器:

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


    class AnonymousEvent extends JFrame
    { 
        JButton btn;


        public AnonymousEvent()
        { 
            super("Java事件监听机制");
            setLayout(new FlowLayout());
            setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);


            btn=new JButton("点击");


            //匿名内部类---------------------------
            //addActionListerner()原型为:public void addActionListener(ActionListener l)
            btn.addActionListener
            (
                //new ActionListener()声明了ActionListener的一个实例
                new ActionListener()
                {

                    //actionPerformed函数是从ActionListener中继承来的.
                    public void actionPerformed(ActionEvent e)
                    {
                        Container c=getContentPane();
                        c.setBackground(Color.red);
                    }
                }
            );
 
            //------------------------------
            getContentPane().add(btn); 
            setBounds(200,200,300,160);
            setVisible(true); 

        }


        public static void main(String args[])
        {
            new AnonymousEvent();
        }
    }

 

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

    4.内部类作为事件监听器：

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


    class InnerClassEvent extends JFrame

    { 
        JButton btn;
        public InnerClassEvent()

        { 
            super("Java事件监听机制");
            setLayout(new FlowLayout());
            setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);


            btn=new JButton("点击");

            //addActionListerner()原型为:public void addActionListener(ActionListener l)
            btn.addActionListener(new InnerClass());
            getContentPane().add(btn);


            setBounds(200,200,300,160);
            setVisible(true);
        }


        //内部类---------------------------
        //InnerClass继承了ActionListener
        class InnerClass implements ActionListener
        {

            //actionPerformed函数是从ActionListener中继承来的.
            public void actionPerformed (ActionEvent e)
            {
                Container c=getContentPane();
                c.setBackground(Color.red);
            }
        }

 
        //------------------------------
        public static void main(String args[])

        {
            new InnerClassEvent();
        }
    }

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