我的ActionListener如何在JButton中访问另一个类中的变量？ [英] How can my ActionListener for a JButton access variables in another class?

问题描述

我正在为一个项目做一台老虎机。我无法获取 JButton 从我的 ArrayList 生成新的随机数。我可以在程序启动时随机化数字并设置 actionlistener ，但它不能满足我的需要。它仅用于测试目的。

I am doing a slot machine for a project. I am having trouble getting my JButton to generate new random numbers from my ArrayList. I can randomize the numbers when the program starts and have an actionlistener set up, but it doesn't do what I need. It was merely for testing purposes.

我的 Actionlistener 位于不同的Java文件中。一切正常，我无法弄清楚如何在 plc1 ， plc2 的占位符中生成新的randoms，以及单击按钮时 plc3 。

My Actionlistener is in a different Java file. Everything works, I just can't figure out how to generate new randoms in the placeholder of plc1, plc2, and plc3 when the button is clicked.

我刚刚开始真正编码大约3周前。
请不要讨厌，这是我的第一个项目。

package GGCGuiLotto;

import java.util.ArrayList;
import java.awt.Color;
import java.awt.Image;
import java.awt.BorderLayout; 
import java.awt.Image;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.Icon;
import javax.swing.JOptionPane;
import javax.swing.JLabel;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JButton;
import javax.swing.JPanel;
import javax.swing.JTextField;

import java.util.Random;


public class GGCGuiLotto {

public static void main(String[] args) {    

//Arraylist of images

ImageIcon pic0 = new ImageIcon("pics/pic1.png");
ImageIcon pic1 = new ImageIcon("pics/pic2.png");
ImageIcon pic2 = new ImageIcon("pics/pic3.png");
ImageIcon pic3 = new ImageIcon("pics/pic4.png");
ImageIcon pic4 = new ImageIcon("pics/pic5.png");
ImageIcon pic5 = new ImageIcon("pics/pic6.png");
ImageIcon pic6 = new ImageIcon("pics/pic7.png");

final ArrayList<ImageIcon> slotlist = new ArrayList<ImageIcon>();   
    slotlist.add(pic0);
    slotlist.add(pic1);
    slotlist.add(pic2);
    slotlist.add(pic3);
    slotlist.add(pic4);
    slotlist.add(pic5);
    slotlist.add(pic6);

    Random ran = new Random();

    int plc1 = ran.nextInt(4);
    int plc2 = ran.nextInt(4);
    int plc3 = ran.nextInt(4);

    //generates the frame and the labels are added.

    JFrame frame = new JFrame();
    frame.setSize (400,275);
    frame.setTitle("GGC Lotto Slots Rcorbin");
    frame.setResizable(false);
    frame.setVisible(true);

    JPanel pnlReels = new JPanel();
    frame.add(pnlReels);

    JPanel aReel1 = new JPanel();
    aReel1.setBackground(new Color(25,25,112));
    aReel1.setBounds(15,10,100,100);

    JPanel bReel2 = new JPanel();
    bReel2.setBackground(new Color(25,25,112));
    bReel2.setBounds(145,10,100,100);

    JPanel cReel3 = new JPanel();
    cReel3.setBackground(new Color(25,25,112));
    cReel3.setBounds(275,10,100,100);   

        pnlReels.add(aReel1);
    pnlReels.add(bReel2);
    pnlReels.add(cReel3);   

    JLabel aReel1lbl = new JLabel();
    JLabel bReel2lbl = new JLabel();
    JLabel cReel3lbl = new JLabel();

    aReel1.add(aReel1lbl);
    bReel2.add(bReel2lbl);
    cReel3.add(cReel3lbl);  

    aReel1lbl.setIcon(slotlist.get(plc1));
    bReel2lbl.setIcon(slotlist.get(plc2));
    cReel3lbl.setIcon(slotlist.get(plc3));  

    //jbutton 
    JButton slotbtn1 = new JButton();
    slotbtn1.setText("GGC LOTTO Click ME");
    pnlReels.add(slotbtn1);
    slotbtn1.setBounds(145,50,100,75);
    //FirstGuiListener act = new FirstGuiListener();
    //slotbtn1.addActionListener((ActionListener) act); 

GenPLCListener genPLC = new GenPLCListener();
slotbtn1.addActionListener((genPLC));
    {}
    if (plc1 == plc2 && plc1 == plc3 && plc2 == plc3)
    {
        JOptionPane.showConfirmDialog(null,"Winner! Play Again? ","GGC Lotto Slots RCorbin ",JOptionPane.YES_NO_OPTION);
        //System.out.println("Winner");
    }
    else
    {
        //JOptionPane.showMessageDialog(null,"No Winner Winner Chicken Dinner ! ");
        System.out.println("Crazy");    }

}
}

---

---

package GGCGuiLotto;

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.Random;

import javax.swing.JOptionPane;

class GenPLCListener extends GGCGuiLotto implements ActionListener{
public void actionPerformed(ActionEvent event){
        System.out.println("Works");

JOptionPane.showConfirmDialog(null,"Choose Wisely. ","Click If you Trust!",JOptionPane.YES_NO_OPTION);
}
}

推荐答案

尝试到扩展GGCGuiLotto 不会按照你认为的那样做，这可以让你访问相同的实例变量。所以摆脱它。相反，您可以传递引用，即 GGCGuiLotto 的当前实例给您的侦听器。并让一些getter和setter从 GGCGuiLotto 类中访问所需的变量。我的意思是这样的事情（不完全确定你想要完成什么，所以这只是一个例子）。

Trying to extends GGCGuiLotto isn't going to do what you think it's supposed to, which is give you access to the same instance variables. So get rid of that. Instead you can pass-by-reference, the current instance of GGCGuiLotto to your listener. And have some getters and setters to access the variables you need from the GGCGuiLotto class. What I mean is maybe something like this (not completely sure what you're trying to accomplish, so this is just an example).

public class GenPLCListener implements ActionListener {
    private GGCGuiLotto lotto;

    public GenPLCListener(GGCGuiLotto lotto) {
        this.lotto = lotto;
    }

    @Override
    public void actionPerfomred(ActionEvent e) {
        List<ImageIcon> slotList = lotto.getSlotList();
        Collections.shuffle(slotList);  // shuffle the list
        // do something else if need be.
    }
}

创建监听器时，传递这个。 此是 GGCGuiLotto的实例

When you create the listener, pass this to it. this being the instance of GGCGuiLotto

几个侧面笔记

• Swing程序不像控制台程式。您不希望在 main 方法中执行所有操作。对于初学者来说， main 方法中的代码可以放入构造函数中。然后在 main 方法中创建 GGCGuiLotto 的实例。

• Swing programs aren't like console programs. You don't want to do everything inside your main method. For starters, the code in your main method, you could put in the constructor instead. Then create an instance of GGCGuiLotto in the main method.

应该在Event Dispatch Thread上运行Swing应用程序。请参阅初始主题

Swing apps should be run on the Event Dispatch Thread. See Initial Threads

也许更合适的解决方案你的问题是有一个接口，你可以在中覆盖 pullSlot 方法GGCGuiLotto 类，只需将接口传递给监听器，并调用 pullSlot 方法。 的actionPerformed 。这样的东西

Maybe a more proper solution to your problem would be to have an interface with the pullSlot method that you can override in the GGCGuiLotto class and just pass the interface to the listener and call the pullSlot method inf your actionPerformed. Something like this

public interface PullInterface {
    public void pullSlot();
}

public class GGCGuiLotto implements PullInterface {
    ArrayList<ImageIcon> slotList = new ArrayList<>();  // global scope.
    JLabel aReel1lbl = new JLabel();
    JLabel bReel2lbl = new JLabel();
    JLabel cReel3lbl = new JLabel();
    Random rand = new Random();

    public GGCGuiLotto() {
        GenPLCListener listener = new GenPLCListener(this);
    }

    @Override
    public void pullSlot() {
        // do what you need to do here to implement a pulling of the lever
        int r1 = rand.nextInt(slotList.size());
        int r2 = rand.nextInt(slotList.size());
        int r3 = rand.nextInt(slotList.size());

        reel1lbl.setIcon(slotList.get(r1));
    }
}

public class GenPLCListener implement ActionListener {
    private PullInterface pull;

    public GenPLCListener(PullInterface pull) {
        this.pull = pull;
    }

    @Override
    public void actionPerformed(ActionEvent e) {
        pull.pullSlot();
    }
}

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