Problem with ActionEvent not doing anything

Hi, I've been learning the basics of Java on and off for a few years, and I am currently attempting to learn how to code GUI stuff. I'm brand new to coding GUIs, only having started using it yesterday. I was trying to use action listeners to respond to button presses. I had some success, although some of my code works and some doesn't. I've commented next to the bit I think is wrong, but I'm unsure what I need to do to fix it. Basically, the nextOne ActionEvent doesn't work. I popped in a System.out.println in there to see if it even 'triggered' at all, but nothing happens.

Code Java:

---

import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JLabel;
import javax.swing.JButton;
import javax.swing.BoxLayout;
import javax.swing.ImageIcon;
import java.awt.BorderLayout;
import javax.swing.BorderFactory;
import javax.swing.border.Border;
import java.awt.Dimension;
import javax.swing.JSeparator;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
 
public class simpleCardGame implements ActionListener{
 
	JButton higher, lower, nextOne;
	JPanel mainPane, topPane;
 
	public JFrame setupGame(){
		Border empty = BorderFactory.createEmptyBorder(10, 10, 10, 10);
		JFrame frame = new JFrame("Nic's simple card game");
		frame.setPreferredSize(new Dimension(600, 350));
 
    		mainPane = new JPanel();
    		mainPane.setLayout(new BoxLayout(mainPane, BoxLayout.Y_AXIS));	
	        topPane = new JPanel();
 
        	JLabel cardPile = new JLabel("", new ImageIcon("cardback.jpg"), JLabel.LEADING);
	        cardPile.setBorder(empty);
        	cardPile.setVerticalTextPosition(JLabel.TOP);
         	cardPile.setHorizontalTextPosition(JLabel.CENTER);
 
         	JLabel firstCard = new JLabel("",new ImageIcon("card.jpg"), JLabel.LEADING);
                topPane.add(firstCard);
	 	topPane.add(cardPile);
 
   		JPanel buttonPanel = new JPanel();
		buttonPanel.setLayout(new BoxLayout(buttonPanel, BoxLayout.X_AXIS));
 
		higher = new JButton("Higher");
		higher.setSize(400,800);
		higher.addActionListener(this);
 
		lower = new JButton("Lower");
		lower.setSize(200,800);
		lower.addActionListener(this);
 
		buttonPanel.add(higher);
		buttonPanel.add(lower);   
 
		mainPane.add(topPane);
		mainPane.add(buttonPanel);
		frame.setContentPane(mainPane);
    		frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		frame.pack();
 
   		return frame;
	}
 
	public void showAnswer(){
		mainPane.removeAll();
		topPane = new JPanel();
 
     		JLabel firstCard = new JLabel("",new ImageIcon("card.jpg"), JLabel.LEADING);
    		topPane.add(firstCard);
 
    		JLabel revealCard = new JLabel("",new ImageIcon("card2.jpg"), JLabel.LEADING);
    		topPane.add(revealCard);
    		JPanel answerPanel = new JPanel();
		answerPanel.setLayout(new BoxLayout(answerPanel, BoxLayout.X_AXIS));
 
		JLabel answer = new JLabel("Correct!  Or incorrect! Please code this properly!", JLabel.LEADING);
 
		JButton nextOne = new JButton("Next");
		nextOne.addActionListener(this);
 
		answerPanel.add(answer);
		answerPanel.add(nextOne);
		mainPane.add(topPane);
		mainPane.add(answerPanel);
		mainPane.updateUI();
	}
 
	String choice = null;
	public void actionPerformed(ActionEvent e) {
      		if(e.getSource() == higher) {
          		choice = "higher";
         		showAnswer();
			System.out.println("higher clicked");
      		}
      		else if(e.getSource() == lower){
          		choice = "lower";
          		showAnswer();
         		System.out.println("lower clicked");
      		}
 
/** THIS IS PROBABLY WHERE I'VE GONE WRONG */
 
 		else if(e.getSource() == nextOne){
      			System.out.println("Next clicked");
      			mainPane.removeAll();
      			JFrame anotherFrame = setupGame();
      			showGame(anotherFrame);
      		}
  	}
 
	public void showGame(JFrame frame){
		frame.setVisible(true); 
	}
}

---

And, probably irrelevant here, but this is the code I use to actually run this...

Code Java:

---

import javax.swing.JFrame;
 
public class cardTest {
 
	public static void main(String[] args) {
 
		simpleCardGame myGame = new simpleCardGame();
		JFrame thisFrame = myGame.setupGame();
		myGame.showGame(thisFrame);
 
	}
}

---

Thanks! :)

The JButton you're adding the ActionListener to is not the same JButton you're checking against in your ActionListener.

When you do:

Code java:

---

JButton nextOne = new JButton("Next");

---

That's "hiding" the nextOne variable that's global, that you're using in your ActionListener.

Ah, awesome, that would have taken me a very long time to figure out myself! Thanks for your help :)