Thread: need some help with this error

i just learned GUI applications in my class but im getting an error i dont know why

package Chapter7;
import javax.swing.*;
import java.awt.event.*;
import java.awt.*;
 
public class RetalPrice extends JFrame {
 
	int itemCost;
	double markupPercentage;
	JTextField answer;
	JTextField answer2;
	JButton button;
 
	public RetalPrice()
	{
		int width = 400;
		int length = 150;
 
		setTitle("Retail Price Calculator");
		setSize(width,length);
 
		JLabel question = new JLabel("What is the item's cost");
		JLabel question2 = new JLabel("what is the mark up percentage");
		answer = new JTextField(10);
		answer2 = new JTextField(10);
		button = new JButton("calculate");
		button.addActionListener(new CalcButtonListener()); //Line where im getting the error
		JPanel panel = new JPanel();
 
		panel.add(question);
		panel.add(answer);
		panel.add(question2);
		panel.add(answer2);
		panel.add(button);
		add(panel);
		setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		setVisible(true);
 
	}
 
	private class CalcButtonListener implements ActionListener
	{
		public void actionPerformed(ActionEvent e)
		{
			int price;
			int tax;
			double finalPrice;
			String input;
			price = Integer.parseInt(answer.getText());
			tax = Integer.parseInt(answer2.getText());
			finalPrice = price + price * (tax/100);
 
			JOptionPane.showMessageDialog(null, "the final price is " + finalPrice);
		}
	}
 
	public static void main (String[]args)
	{
		RetalPrice tax = new RetalPrice();
	}
}

the error says The method addActionListener(ActionListener) in the type AbstractButton is not applicable for the arguement RetalPrice.CalcButtonListener)

thank you in advance