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()+"
");
   }
  }