Request fix functionality

Question

MY TASK : Write a JavaFX GUI application that allows the user to pick a set of pizza toppings using a set of check boxes. Assuming each topping cost 50 cents, and a plain pizza costs $10, display the cost of the pizza. Note that, once a topping is checked or unchecked, the cost of pizza should update automatically.

FIX REQUEST : my pizza cost calculator fails to add cost for topping properly

For example, Extracheese checked and unchecked resulted in below base price $10 (ie; $7)

import javafx.application.Application;
import javafx.event.ActionEvent;
import javafx.event.EventHandler;
import javafx.scene.Scene;
import javafx.scene.control.CheckBox;
import javafx.scene.control.Label;
import javafx.scene.layout.VBox;
import javafx.scene.layout.HBox;
import javafx.scene.transform.Scale;
import javafx.stage.Stage;
import javafx.scene.text.Text;

import javafx.application.Application; 
import javafx.scene.Group; 
import javafx.scene.Scene; 
import javafx.stage.Stage; 
import javafx.scene.text.Font; 
import javafx.scene.text.FontPosture; 
import javafx.scene.text.FontWeight; 
import javafx.scene.text.Text; 

class PizzaCost extends VBox {

    private CheckBox ExtraCheeseCheckBox;
    private CheckBox GreenPepperCheckBox;

    private Label TotalPizzaCost;
    public double pizzaCost = 10.0;
    
    public PizzaCost(){
        Font font = new Font(13);
        
        ExtraCheeseCheckBox = new CheckBox("Extra Cheese");
        ExtraCheeseCheckBox.setOnAction(this::processCheckBoxAction);
        
        GreenPepperCheckBox = new CheckBox("GreenPepper");
        GreenPepperCheckBox.setOnAction(this::processCheckBoxAction);

        TotalPizzaCost = new Label(pizzaCost +"");
        TotalPizzaCost.setFont(font);
         

        HBox options = new HBox(ExtraCheeseCheckBox,GreenPepperCheckBox);
        getChildren().addAll(options,TotalPizzaCost);
    }
    
    public void processCheckBoxAction (ActionEvent event){
         if (ExtraCheeseCheckBox.isSelected()){
             pizzaCost += 0.5;
        }
        else {
             pizzaCost -= 0.5;
        }
        
        TotalPizzaCost.setText(pizzaCost+"");

    }
}

Answer 1

The following code works for me. The pizza cost never goes below $10.

import java.text.NumberFormat;

import javafx.application.Application;
import javafx.event.ActionEvent;
import javafx.geometry.Insets;
import javafx.geometry.Pos;
import javafx.scene.Scene;
import javafx.scene.control.CheckBox;
import javafx.scene.control.Label;
import javafx.scene.layout.HBox;
import javafx.scene.layout.VBox;
import javafx.scene.text.Font;
import javafx.stage.Stage;

public class PizzaCost extends Application {
    private static final double  TOPPING_COST = 0.5d;
    private static final NumberFormat COST_FORMAT = NumberFormat.getCurrencyInstance();
    private static final String  PIZZA_COST = "Pizza Cost: ";

    private double  pizzaCost = 10.0d;
    private Label  totalPizzaCostLabel;

    @Override
    public void start(Stage primaryStage) throws Exception {
        CheckBox extraCheesCheckBox = getCheckBox("Extra Cheese");
        CheckBox greenPepperCheckBox = getCheckBox("Green Pepper");
        HBox hBox = new HBox(20.0d, extraCheesCheckBox, greenPepperCheckBox);
        totalPizzaCostLabel = new Label(PIZZA_COST + COST_FORMAT.format(pizzaCost));
        totalPizzaCostLabel.setFont(new Font(13.0d));
        VBox root = new VBox(20.0d, hBox, totalPizzaCostLabel);
        root.setAlignment(Pos.CENTER);
        root.setPadding(new Insets(40.0d));
        Scene scene = new Scene(root);
        primaryStage.setScene(scene);
        primaryStage.setTitle("Pizza Cost");
        primaryStage.show();
    }

    private CheckBox getCheckBox(String text) {
        CheckBox cb = new CheckBox(text);
        cb.setOnAction(this::processCheckBoxAction);
        return cb;
    }

    private void processCheckBoxAction(ActionEvent event) {
        CheckBox cb = (CheckBox) event.getSource();
        if (cb.isSelected()) {
            pizzaCost += TOPPING_COST;
        }
        else {
            pizzaCost -= TOPPING_COST;
        }
        totalPizzaCostLabel.setText(PIZZA_COST + COST_FORMAT.format(pizzaCost));
    }

    public static void main(String[] args) {
        launch(args);
    }
}