Java 简单GUI | JButton，按下时，显示由另一个类的“方法|调试帮助”定义的字符串变量文本？

本质上，我创建了一个程序，旨在为用户提供一个包含一个按钮的界面。当按下按钮时，程序将根据一个简单的随机变量和一个开关大小写生成一个字符串，然后显示您绘制的+该字符串变量

除了MTGgui类中的方法showDialogMessage在调用时没有显示字符串cardName之外，所有功能都按预期运行，该字符串定义为其各自类中另一个名为card的私有变量。关于如何解决这个问题，有什么建议吗？

试试这个：

****// --------------------------------
package Practice;
import java.util.Random;

public class Card
{
    Random gen = new Random();
    private Card[] Deck = new Card[60];
    private int i = 0;
    private int drawnCard;
    public static String cardName = "";

    // Constructor to return String variable "cardName",    
    // which is later used by the MTGgui class.
    public String Draw(String cardName)
    {   
        if (i < Deck.length)
        {
            drawnCard = gen.nextInt(5) + 0;

            switch (drawnCard)
            {
            case 0: cardName = "Instant";
            case 1: cardName = "Sorcery";
            case 2: cardName = "Creature";
            case 3: cardName = "Enchantment";
            case 4: cardName = "Land";
            case 5: cardName = "Artifact";
            default: cardName = "Nothing!";
            }

            Card.cardName = this.cardName;
        }
        return Card.cardName;
    }
}
// Card class.
//--------------------------------




// --------------------------------
package Practice;
import javax.swing.JFrame;

public class MTGInterface extends JFrame
{
    public static void main (String[] args)
    {
        MTGgui MTG = new MTGgui();
        MTG.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        MTG.setSize(300, 200);
        MTG.setVisible(true);
    }
}

// Main class.
// --------------------------------




// --------------------------------------------------
package Practice;
import java.awt.FlowLayout;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;

import javax.swing.JFrame;
import javax.swing.JButton;
import javax.swing.Icon;
import javax.swing.ImageIcon;
import javax.swing.JOptionPane;
// Importing required assets.

public class MTGgui extends JFrame // Code to set up the user interface.
{
    // JButton variable that appears on-screen.
    private JButton DrawCard;

    // Constructor for this class.
    public MTGgui()
    {
        super("MTG Deck Drawing Simulator : Mega Awesome Edition!!!");

        setLayout(new FlowLayout());

        DrawCard = new JButton("Draw a card");
        add(DrawCard);

        // Building an event handler for actions caused by button.
        HandlerClass Handler = new HandlerClass();
        DrawCard.addActionListener(Handler);
    }

    // Private class within MTGgui for event handling.
    private class HandlerClass implements ActionListener
    {
        // Initializing private String variable that is the same 
        // as the "Card" class' variable - cardName.
        private String card = Card.cardName;

        public void actionPerformed(ActionEvent Event) 
        {
            JOptionPane.showMessageDialog(null, "You drew a(n)" + card);
        }

    }
}

// MTGgui class
//--------------------------------------------------****

公务舱卡 {

}

---

这个解决方案有很多静态/非静态变量/方法，这不是最好的编程方式，但它很有效。

为了吸引正确的注意：1我们都知道您在寻求帮助。写一个简短的标题，说明你的问题。把你的第一段放在代码前面。好的，我将在以后的帖子中遵循这些步骤。谢谢你的建议！我仍在学习更先进的技术，因此代码目前可以正常工作。非常感谢你！我很感激！我还意识到我在Card类中忽略了增加整数I。我的错误。

private class HandlerClass implements ActionListener
{
    // Initializing private String variable that is the same 
    // as the "Card" class' variable - cardName.
    //        private String card = Card.cardName;

    public void actionPerformed(ActionEvent Event) 
    {
        JOptionPane.showMessageDialog(null, "You drew a(n) " + Card.draw());
    }
}

private static Card[] Deck = new Card[60];

// Constructor to return String variable "cardName",    
// which is later used by the MTGgui class.
public static String draw()
{   
    Random gen = new Random();

    String returningCardName = "";

    int i = 0;
    // i will be always 0...
    if (i < Deck.length)
    {
        int drawnCard = gen.nextInt(5) + 0;

        switch (drawnCard)
        {
        case 0: returningCardName = "Instant"; break;
        case 1: returningCardName = "Sorcery"; break;
        case 2: returningCardName = "Creature"; break;
        case 3: returningCardName = "Enchantment"; break;
        case 4: returningCardName = "Land"; break;
        case 5: returningCardName = "Artifact"; break;
        default: returningCardName = "Nothing!"; break;
        }

    }
    return returningCardName;
}