java - 如何向位于子类的父类(super class)中的 Jbutton 添加功能？

Question

我正在尝试使用子类向 Jbutton 添加功能，但是 Jbutton 实际上是在父类(super class)中声明和定义的。这是我的代码:

 JButton zz=new JButton(ss);
         zz.setBounds(470,70,35,35);
         zz.setBorder(oo);
         zz.setBackground(new Color(0,170,120));
         l.add(zz);

这是我的 Jbutton，位于我的项目中名为 realestate 的父类(super class)中。我创建了子类，我试图在其中为此按钮添加 Action 监听器。这是我的子类:

public class assan extends RealEstate{
zz.addActionListener(new ActionListener(){
   public void actionPerformed(ActionEvent u)
   {
       System.out.println("kk");
   }
});}

但我运行这个程序时遇到了不同类型的错误，例如:包 'zz' 不存在 等等。这是我的完整代码:

 package realestate;

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

public class Realestate extends JFrame {
 Realestate()
 {
    JLabel l=new JLabel(new ImageIcon("C:\\Users\\MUHAMMAD SHAHAB\\Documents\\NetBeansProjects\\Real Estate\\src\\real\\estate\\file (2).jpg"));
                   l.setBounds(100,50,300,250);
                   add(l); 
                    ImageIcon ss=new ImageIcon("C:\\Users\\MUHAMMAD SHAHAB\\Documents\\NetBeansProjects\\Real Estate\\src\\real\\estate\\1470672145_Help_mark_query_question_support_talk.png");
                public  JButton zz=new JButton(ss);
             zz.setBounds(470,70,35,35);
             zz.setBackground(new Color(0,170,120));
             l.add(zz);
 }
    public class assan extends Realestate{
        zz.addActionListener(new ActionListener(){
           public void actionPerformed(ActionEvent o)
           {
               System.out.println("Cena");
           }
        });
    }
    public static void main(String[] args) {
      RealEstate v=new RealEstate();
         v.setUndecorated(true);
         v.setVisible(true);
         v.setBounds(350,200,600,350);
         v.setForeground(Color.WHITE);
assan n=new assan();
    }

}

我做错了什么？

Answer 1

Imagine that this is the superclass:

public class RealEstate{
    public JButton button = new JButton("Button Name");
}

And this the subclass:

public class SubClass extends RealEstate{

   /**
   * Constructor
   */
   public SubClass(){

       //The Button is public so it is visible to the subclass
       button.addActionListener(new ActionListener(){
              public void actionPerformed(ActionEvent u){
                 System.out.println("Hello World!");
              }
       });
   }  
}

也看看这个 ( tutorial )

A minimal example of the code you may need:

import java.awt.Color;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.BorderFactory;
import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.border.Border;

public class RealEstate extends JFrame {

    public JButton button = new JButton("Button");

    /**
     * Constructor
     */
    public RealEstate() {


  //Button
       button.setText("I am a JButton");

        // ...rest of the code below
    }

    /**
     * The SubClass
     */
    protected class SubClass extends RealEstate {

        /**
         * Constructor
         */
        public SubClass() {

            //accessing the button from the SubClass
            button.addActionListener(new ActionListener() {
                public void actionPerformed(ActionEvent u) {
                    System.out.println("Hello World!");
                }
            });
        }

    }

    /**
     * Main Method
     * 
     * @param args
     */
    public static void main(String[] args) {
        RealEstate v = new RealEstate();
        v.setUndecorated(true);
        v.setVisible(true);
        v.setSize(600,600);
        v.setForeground(Color.WHITE);

        v.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    }
}