交通灯应用程序：在自己的类中实现ActionListener

Question

我将如何修改此程序？该程序用于模拟交通灯，点击按钮即可更改灯光。我已经使程序在赋值的参数下工作得很好。该任务需要4个类，一个JFrame和两个嵌套的JPanel（一个用于trafficcontrol，一个用于trafficlight面板）。我似乎无法回答关于如何将动作侦听器的内部类别分离到其自己的separete实体的最后一个问题，并且仍然可以让程序工作。

问题

内部类用于促进两个类之间的通信 有亲密的关系。使内部类（ChangeListener）成为常规类 从TrafficControlPanel中取出并观察所涉及的并发症 让他们沟通和两个阶级的亲​​密关系。

这是程序

Package traffic.light;
import javax.swing.JFrame;

public class TrafficLight extends JFrame
{
  public static void main (String[] args)
  {
    JFrame frame = new JFrame("Traffic Light");
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setSize(150, 230);
    frame.add(new TrafficControlPanel());
    frame.pack();
    frame.setVisible(true);
  }
}






package traffic.light;

import java.awt.*; 
import javax.swing.*;
import java.awt.event.*;
public class TrafficLightPanel extends JPanel 
{ 
 private int currentState = 0; 
 private final int NUM_LIGHTS = 3; // the number of lights 
 private final int X = 50, Y = 10, WIDTH = 50, HEIGHT = 130; //box size 
 private final int DIAMETER = 30; // light diameter 
 private final int X_OFFSET = 10, Y_OFFSET = 10; // offsets to position the lights in the box 
 private final int PANEL_WIDTH = 150, PANEL_HEIGHT = 230; // the size of a traffic control panel 

 //----------------------------------------------------------------- 
 // Creates the traffic light panel 
 //----------------------------------------------------------------- 
 public void TrafficLightPanel() 
 { 
 setPreferredSize(new Dimension(150, 230)); 
 setLayout(new BorderLayout());
 } 

 public void paintComponent(Graphics page) 
 { 
 super.paintComponent(page); 
 int lightOn = currentState % NUM_LIGHTS; 
 setBackground(Color.white); 
 page.setColor(Color.lightGray); 
 page.fillRect(X, Y, WIDTH, HEIGHT); 


 switch (lightOn)
         {
             case 0:
 page.setColor(Color.red);
 page.fillOval((X+X_OFFSET),(Y+Y_OFFSET), 30, 30);
 page.setColor(Color.darkGray);
 page.fillOval((X+X_OFFSET),60 , 30, 30);
 page.setColor(Color.darkGray);
 page.fillOval((X+X_OFFSET),100, 30, 30);

                 break;
             case 1:
page.setColor(Color.darkGray);
 page.fillOval((X+X_OFFSET),20, 30, 30);
 page.setColor(Color.yellow);
 page.fillOval((X+X_OFFSET),60 , 30, 30);
 page.setColor(Color.darkGray);
 page.fillOval((X+X_OFFSET),100, 30, 30);
                 break;
             case 2 :
 page.setColor(Color.darkGray);
 page.fillOval((X+X_OFFSET),(Y+Y_OFFSET), 30, 30);
 page.setColor(Color.darkGray);
 page.fillOval((X+X_OFFSET),60 , 30, 30);
 page.setColor(Color.green);
 page.fillOval((X+X_OFFSET),100, 30, 30);
                 break;

 }

 }


 public void change(int clickcount ) 
 { 
 currentState = clickcount ; 
 repaint();
 } 

}







package traffic.light;

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

class TrafficControlPanel extends JPanel {
    private JButton push;
    private TrafficLightPanel LightPanel;
    int click = 0;

    public TrafficControlPanel() {

        setLayout(new BorderLayout());
        LightPanel = new TrafficLightPanel();

        push = new JButton("Change Light");
        push.addActionListener(new TrafficControlPanel.ChangeListener());
        setPreferredSize(new Dimension(150, 230));
        setBackground(Color.white);
        add(LightPanel, BorderLayout.CENTER);
        add(push, BorderLayout.SOUTH);


    }

      // this needs to be deleted and put into the ChangeListener class below
    private class ChangeListener implements ActionListener {
        int click = 0;

        public void actionPerformed(ActionEvent event) {
            click++;
            LightPanel.change(click);
        }
    }
}






package traffic.light;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class ChangeListener implements ActionListener{

      public void actionPerformed(ActionEvent event) {
          // what goes here?
        }
    }

Answer 1

问题中提出了挑战：

  

...观察使他们进行沟通的复杂性   这两个班级的亲密关系。

当ChangeListener无法访问内部变量时，任务的重点是让你看到通信变得更加复杂。

为您提供一些提示：您需要能够在LightPanel.Change内拨打ChangeListener。如何将LightPanel的引用发送给ChangeListener？