初学java之事件响应（结合接口来设置在同一个界面上！）

 package wahaha;

 public class test_1 {

     public static void main( String args[] )

     {

         WindowActionEvent win = new WindowActionEvent();

         PoliceListen police = new PoliceListen(); //创建监视器

         win.setMyCommandListener(police);

         win.setBounds(100, 100, 460, 360);

         win.setTitle("处理ACtionEvent事件");

     }

 }

 package wahaha;

 import javax.swing.*;

 import java.awt.*;

 public class WindowActionEvent extends JFrame

 {

     JTextField inputText ;

     JTextArea testshow ;

     JButton button ;

     MyCommandListener listenner ;

     public WindowActionEvent()

     {

         init();

         setVisible(true);

         setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

     }

     void init()

     {

       setLayout(new FlowLayout());

       inputText =new JTextField(10);

       button =new JButton("确定");

       testshow = new JTextArea(9,30);

       add(inputText);

       add(button);

       add(new JScrollPane(testshow));

     }

     void setMyCommandListener(MyCommandListener listener)

     {

         this.listenner = listener ;

         listener.setJTextArea(testshow);

         listener.setJTextField(inputText);

                                     //inputText是事件源，listener是监视器

         button.addActionListener(listener) ;

                                     //button是事件源 ，listener是监视器

     }

 }

  package wahaha;

 //设置一个接口 implements/interface/extends

 import javax.swing.* ;

 import java.awt.event.* ;

 public interface MyCommandListener extends ActionListener    //子接口多给出了2个方法

 {

    public void setJTextField(JTextField text);

    public void setJTextArea(JTextArea area);

 }

   package wahaha;

   import javax.swing.*;

   import java.awt.event.*;

   public class PoliceListen implements MyCommandListener

   {

     JTextField textInput ;

     JTextArea textshow ;

    public void setJTextField( JTextField text )

    {

      textInput = text ;

    }

    public void setJTextArea(JTextArea area)

    {

        textshow = area;

    }

    public void actionPerformed( ActionEvent e)

    {

        String str=textInput.getText();

        textshow.append(str+"的长度："+str.length()+"\n");

    }

   }