Action Listener within Action Listener

Question

I'm creating a vending machine for a school project, and I have to update the numbers when user clicks A1, A2, B1, B2 etc. Everything after the decimal changes, but anything before that does not. So if I click A1 which is set to 4 dollars 50 cents, and I then choose D4 which is 1 dollar 5 cents, my JTextField shows as 4 dollars 5 cents.

This is the buttons on the GUI:

this is for buttons A and B

for buttons C and D

public void cost() {
    
     C_button.addActionListener (new ActionListener () {
         public void actionPerformed (ActionEvent e) {
          button_1.addActionListener (new ActionListener () {
             public void actionPerformed (ActionEvent e) {
                total_order = 2 + 0.5;
                cost_total.setText(String.valueOf(total_order));

             }
            });
          button_2.addActionListener (new ActionListener () {
             public void actionPerformed (ActionEvent e) {
                total_order = 2 + 0.25;
                cost_total.setText(String.valueOf(total_order));

             }
            });
          button_3.addActionListener (new ActionListener () {
             public void actionPerformed (ActionEvent e) {
                total_order = 2 + 0.10;
                cost_total.setText(String.valueOf(total_order));

             }
            });
          button_4.addActionListener (new ActionListener () {
             public void actionPerformed (ActionEvent e) {
                total_order = 2 + 0.05;
                cost_total.setText(String.valueOf(total_order));

             }
            });
         } 
        });

       D_button.addActionListener (new ActionListener () {
             public void actionPerformed (ActionEvent e) {
              button_1.addActionListener (new ActionListener () {
                 public void actionPerformed (ActionEvent e) {
                    total_order = 1 + 0.5;
                    cost_total.setText(String.valueOf(total_order));

                 }
                });
              button_2.addActionListener (new ActionListener () {
             public void actionPerformed (ActionEvent e) {
                total_order = 1 + 0.25;
                cost_total.setText(String.valueOf(total_order));

             }
            });
              button_3.addActionListener (new ActionListener () {
             public void actionPerformed (ActionEvent e) {
                total_order = 1 + 0.10;
                cost_total.setText(String.valueOf(total_order));

             }
            });
              button_4.addActionListener (new ActionListener () {
             public void actionPerformed (ActionEvent e) {
                total_order = 1 + 0.05;
                cost_total.setText(String.valueOf(total_order));

             }
            });
             }
            });

Answer 1

You're make this WAY more difficult than it should be. First, I'd create a map of all the value combinations and their costs, something like:

Map<String, Double> costMap = new HashMap<>();
costMap.put("A1", 4.5);
costMap.put("A2", 4.25);

Then I'd create a String somewhere to track user input:

String register = "";

Then create a Action to handle the basic key pressed for the bulk of your keys:

public class VendingAction extends AbstractAction {
    @Override
    public void actionPerformed(ActionEvent arg0) {
        register += getValue(Action.NAME);
        if (costMap.containsKey(register)) {
            costLabel.setText(costMap.get(register).toString());
            register = "";
        } else if (register.length() == 2) {
            //handle bad choice
            register = "";
        }
    }
}

Then when you create your buttons it would be something like:

JButton buttonA = new JButton(new VendingAction("A"));
JButton buttonB = new JButton(new VendingAction("B"));
//so on and so forth.