add an array list to my java code so that when the button is clicked, it will add the value of (ChoixPizza*NumPizza)+(NumTopping, the topping price depends on what size the pizza is)+(ChoixBreuvage*NumBreuvage) to an list which can then be shown on the textarea list: import java.awt.EventQueue;

import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.border.EmptyBorder;
import javax.swing.JLabel;
import java.awt.Font;
import javax.swing.SwingConstants;
import javax.swing.border.TitledBorder;
import javax.swing.border.EtchedBorder;
import java.awt.Color;
import javax.swing.border.BevelBorder;
import javax.swing.border.CompoundBorder;
import javax.swing.border.LineBorder;
import javax.swing.UIManager;
import javax.swing.border.SoftBevelBorder;
import javax.swing.border.MatteBorder;
import java.awt.GridLayout;
import javax.swing.ImageIcon;
import javax.swing.JComboBox;
import javax.swing.DefaultComboBoxModel;
import javax.swing.BoxLayout;
import java.awt.FlowLayout;
import javax.swing.JTextField;
import javax.swing.JButton;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;

public class PizzaOrder extends JFrame {


	private JPanel contentPane;
	private JPanel ToppingSelect;
	private JTextField NumPizza;
	private JTextField NumTopping;
	private JTextField NumBreuvage;
	private JButton Ajouter;


	public static void main(String[] args) {
		EventQueue.invokeLater(new Runnable() {
			public void run() {
				try {
					PizzaOrder frame = new PizzaOrder();
					frame.setVisible(true);
				} catch (Exception e) {
					e.printStackTrace();

				}
			}
		});

	}



	public PizzaOrder() {

		setTitle("Order");
		setResizable(false);
		setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		setBounds(100, 100, 630, 689);
		contentPane = new JPanel();
		contentPane.setBackground(new Color(255, 147, 0));
		contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));

		setContentPane(contentPane);
		contentPane.setLayout(null);

		JPanel Menu = new JPanel();
		Menu.setBackground(new Color(255, 147, 0));
		Menu.setBorder(new TitledBorder(new LineBorder(new Color(0, 0, 0)), "Menu", TitledBorder.LEADING, TitledBorder.TOP, null, new Color(0, 0, 0)));
		Menu.setBounds(6, 6, 618, 158);
		contentPane.add(Menu);
		Menu.setLayout(new GridLayout(0, 3, 0, 0));

		JPanel PizzaPrice = new JPanel();
		PizzaPrice.setBackground(new Color(255, 147, 0));
		PizzaPrice.setBorder(new TitledBorder(new EtchedBorder(EtchedBorder.LOWERED, null, null), "Pizza", TitledBorder.LEADING, TitledBorder.TOP, null, null));
		Menu.add(PizzaPrice);
		PizzaPrice.setLayout(null);

		JLabel PetitPizza = new JLabel("Petit: 6.79$");
		PetitPizza.setBounds(17, 21, 72, 16);
		PizzaPrice.add(PetitPizza);

		JLabel MoyenPizza = new JLabel("Moyen: 8.29$");
		MoyenPizza.setBounds(17, 40, 85, 16);
		PizzaPrice.add(MoyenPizza);

		JLabel LargePizza = new JLabel("Large: 9.49$");
		LargePizza.setBounds(17, 59, 85, 16);
		PizzaPrice.add(LargePizza);

		JLabel ExtraLargePizza = new JLabel("Extra Large: 10.29$");
		ExtraLargePizza.setBounds(17, 78, 127, 16);
		PizzaPrice.add(ExtraLargePizza);

		JLabel FetePizza = new JLabel("Fete: 15.99$");
		FetePizza.setBounds(17, 97, 93, 16);
		PizzaPrice.add(FetePizza);

		JPanel ToppingPrice = new JPanel();
		ToppingPrice.setBackground(new Color(255, 147, 0));
		ToppingPrice.setLayout(null);
		ToppingPrice.setBorder(new TitledBorder(new EtchedBorder(EtchedBorder.LOWERED, null, null), "Toppings", TitledBorder.LEADING, TitledBorder.TOP, null, new Color(0, 0, 0)));
		Menu.add(ToppingPrice);

		JLabel Petittopping = new JLabel("Petit: 1.20$");
		Petittopping.setBounds(17, 21, 72, 16);
		ToppingPrice.add(Petittopping);

		JLabel Moyentopping = new JLabel("Moyen: 1.40$");
		Moyentopping.setBounds(17, 40, 85, 16);
		ToppingPrice.add(Moyentopping);

		JLabel Largetopping = new JLabel("Large: 1.60$");
		Largetopping.setBounds(17, 59, 85, 16);
		ToppingPrice.add(Largetopping);

		JLabel ExtraLargetopping = new JLabel("Extra Large: 1.80$");
		ExtraLargetopping.setBounds(17, 78, 127, 16);
		ToppingPrice.add(ExtraLargetopping);

		JLabel Fetetopping = new JLabel("Fete: 2.30$");
		Fetetopping.setBounds(17, 97, 93, 16);
		ToppingPrice.add(Fetetopping);

		JPanel BreuvagePrice = new JPanel();
		BreuvagePrice.setBackground(new Color(255, 147, 0));
		BreuvagePrice.setLayout(null);
		BreuvagePrice.setBorder(new TitledBorder(new EtchedBorder(EtchedBorder.LOWERED, null, null), "Breuvages", TitledBorder.LEADING, TitledBorder.TOP, null, new Color(0, 0, 0)));
		Menu.add(BreuvagePrice);

		JLabel Pop = new JLabel("Pop: 1.10$");
		Pop.setBounds(17, 21, 72, 16);
		BreuvagePrice.add(Pop);

		JLabel Jus = new JLabel("Jus: 1.35$");
		Jus.setBounds(17, 40, 85, 16);
		BreuvagePrice.add(Jus);

		JLabel Eau = new JLabel("Eau: 1.00$");
		Eau.setBounds(17, 59, 85, 16);
		BreuvagePrice.add(Eau);

		JPanel PizzaSelect = new JPanel();
		PizzaSelect.setBorder(new SoftBevelBorder(BevelBorder.LOWERED, null, null, null, null));
		PizzaSelect.setBackground(new Color(255, 147, 0));
		PizzaSelect.setBounds(16, 187, 350, 300);
		contentPane.add(PizzaSelect);
		PizzaSelect.setLayout(null);

		JLabel NombrePizzaTitle = new JLabel("Choix Pizza");
		NombrePizzaTitle.setForeground(new Color(0, 252, 255));
		NombrePizzaTitle.setFont(new Font("Hiragino Sans GB", Font.BOLD, 15));
		NombrePizzaTitle.setBounds(139, 6, 90, 27);
		PizzaSelect.add(NombrePizzaTitle);


		JComboBox<String> ChoixPizza = new JComboBox<String>();
		ChoixPizza.setModel(new DefaultComboBoxModel(PizzaSize.values()));
		ChoixPizza.setBounds(122, 90, 126, 27);
		ChoixPizza.setMaximumRowCount(5);
		PizzaSelect.add(ChoixPizza);


		NumPizza = new JTextField();
		NumPizza.setBounds(122, 129, 130, 26);
		PizzaSelect.add(NumPizza);
		NumPizza.setColumns(10);

		JLabel PizzaIcon = new JLabel("");
		PizzaIcon.setBounds(6, 6, 350, 279);
		PizzaSelect.add(PizzaIcon);
		PizzaIcon.setIcon(new ImageIcon(PizzaOrder.class.getResource("/Image/PizzaImage.png")));

		JPanel ToppingSelect;
		ToppingSelect = new JPanel();
		ToppingSelect.setBorder(new SoftBevelBorder(BevelBorder.LOWERED, null, null, null, null));
		ToppingSelect.setBackground(new Color(255, 147, 0));
		ToppingSelect.setBounds(400, 187, 208, 129);
		contentPane.add(ToppingSelect);
		ToppingSelect.setLayout(null);;

		JLabel NombreToppingTitle = new JLabel("Nombre de topping");
		NombreToppingTitle.setForeground(new Color(0, 252, 255));
		NombreToppingTitle.setFont(new Font("Hiragino Sans GB", Font.BOLD, 15));
		NombreToppingTitle.setBounds(29, 23, 150, 27);
		ToppingSelect.add(NombreToppingTitle);

		NumTopping = new JTextField();
		NumTopping.setBounds(39, 50, 130, 26);
		NumTopping.setColumns(10);
		ToppingSelect.add(NumTopping);

		JLabel ToppingIcon = new JLabel("");
		ToppingIcon.setIcon(new ImageIcon(PizzaOrder.class.getResource("/Image/ToppingImage.png")));
		ToppingIcon.setBounds(6, 8, 208, 109);
		ToppingSelect.add(ToppingIcon);

		JPanel BreuvageSelect = new JPanel();
		BreuvageSelect.setBorder(new SoftBevelBorder(BevelBorder.LOWERED, null, null, null, null));
		BreuvageSelect.setBackground(new Color(255, 147, 0));
		BreuvageSelect.setBounds(400, 358, 208, 129);
		contentPane.add(BreuvageSelect);
		BreuvageSelect.setLayout(null);;

		JLabel NombreToppingTitle_1 = new JLabel("Choix de breuvages");
		NombreToppingTitle_1.setBounds(34, 6, 150, 27);
		BreuvageSelect.add(NombreToppingTitle_1);
		NombreToppingTitle_1.setForeground(new Color(0, 252, 255));
		NombreToppingTitle_1.setFont(new Font("Hiragino Sans GB", Font.BOLD, 15));

		NumBreuvage = new JTextField();
		NumBreuvage.setBounds(47, 62, 130, 26);
		NumBreuvage.setColumns(10);
		BreuvageSelect.add(NumBreuvage);

		JComboBox<String> ChoixBreuvage = new JComboBox<String>();
		ChoixBreuvage.setModel(new DefaultComboBoxModel(Breuvages.values()));
		ChoixBreuvage.setBounds(65, 34, 79, 27);
		ChoixBreuvage.setMaximumRowCount(3);
		BreuvageSelect.add(ChoixBreuvage);

		JLabel BreuvageIcon = new JLabel("");
		BreuvageIcon.setIcon(new ImageIcon(PizzaOrder.class.getResource("/Image/BreuvageImage.png")));
		BreuvageIcon.setBounds(0, 0, 209, 129);
		BreuvageSelect.add(BreuvageIcon);


		JButton Quitter = new JButton("Quitter");
		Quitter.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent e) {
				System.exit(0);
			}
		});
		Quitter.setBounds(33, 552, 160, 50);
		contentPane.add(Quitter);


		Ajouter = new JButton("Ajouter");
		JButton jButton = new JButton();
		jButton.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent e) {

			}});
		Ajouter.setBounds(234, 552, 160, 50);
		contentPane.add(Ajouter);




		JButton Payer = new JButton("Payer");
		Payer.setBounds(431, 552, 160, 50);
		contentPane.add(Payer);

		Payer.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent e) {
				Receipt receipt = new Receipt(); 
				receipt.setVisible(true);  
				dispose();  
			}
		});
		setVisible(false);
	}
}import java.awt.EventQueue;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.border.EmptyBorder;
import javax.swing.JLabel;
import javax.swing.border.TitledBorder;
import javax.swing.ImageIcon;
import javax.swing.JList;
import javax.swing.border.LineBorder;
import java.awt.Color;
import java.awt.Font;
import javax.swing.BoxLayout;
import javax.swing.JButton;

public class Receipt extends JFrame {

    private JPanel contentPane;

    /**
     * Launch the application.
     */
    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {
            public void run() {
                try {
                    Receipt frame = new Receipt();
                    frame.setVisible(true);
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        });
    }

    /**
     * Create the frame.
     */
    public Receipt() {
        setResizable(false);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setBounds(100, 100, 474, 521);
        contentPane = new JPanel();
        contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));

        setContentPane(contentPane);
        contentPane.setLayout(null);

        JPanel Panel1 = new JPanel();
        Panel1.setBounds(0, 0, 474, 493);
        contentPane.add(Panel1);
        Panel1.setLayout(null);

        JLabel TitleCommande = new JLabel("Commande");
        TitleCommande.setFont(new Font("Noteworthy", Font.PLAIN, 25));
        TitleCommande.setBounds(175, 6, 108, 31);
        Panel1.add(TitleCommande);

        JList list = new JList();
        list.setBounds(30, 49, 408, 241);
        Panel1.add(list);

        JLabel Subtotale = new JLabel("SubTotales: ");
        Subtotale.setBounds(57, 338, 143, 24);
        Panel1.add(Subtotale);

        JLabel Totale = new JLabel("Totales: ");
        Totale.setBounds(57, 374, 143, 24);
        Panel1.add(Totale);

        JButton ShowTax = new JButton("+Tax(13%)");
        ShowTax.setBounds(199, 337, 117, 29);
        Panel1.add(ShowTax);

        JButton ModifyCommande = new JButton("Modifier la Commande");
        ModifyCommande.setBounds(30, 435, 170, 31);
        Panel1.add(ModifyCommande);
        // Add action listener to the "Modifier la Commande" button
        ModifyCommande.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                // Close the Receipt window
                dispose();

                // Show the PizzaOrder window
                PizzaOrder pizzaOrder = new PizzaOrder();
                pizzaOrder.setVisible(true);
            }
        });
        
        
 
        JButton Fermer = new JButton("Fermer");
        Fermer.setBounds(268, 436, 170, 31);
        Panel1.add(Fermer);

        // Add action listener to the "Fermer" button
        Fermer.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                // Close the current window
                dispose();

                // Terminate the entire application
                System.exit(0);
            }
        });

       
    }
}
public enum Breuvages {
    Pop(1.10), Jus(1.35), Eau(1.00);

    private final double value;

    private Breuvages(double value) {
        this.value = value;
    }

    public double getValue() {
        return value;
    }
}
public enum PizzaSize {
    Small(6.79), Medium(8.29), Large(9.49), ExtraLarge(10.29), Fete(15.99);

    private final double price;

    private PizzaSize(double price) {
        this.price = price;
    }

    public double getPrice() {
        return price;
    }

	static PizzaSize getSelectedItem() {
		// TODO Auto-generated method stub
		return null;
	}
}