添加到运行总变量？

Question

我正在尝试制作一个餐厅菜单选择器 我有一个订单课程和另一个连接到选择饮料菜单的课程

我的订单类（表）有一个运行总变量。 我试图将一个项目的价格添加到运行总计中，但语法有问题

selectedItem.getPrice();

        Table tbl = new Table();
        tbl.setRunningTotal() + selectedItem.getPrice();

我在创建表类的“实例”然后使用设置的运行总计“setter”并将其添加到选定的 fooditems 获取价格方法中是否正确？

这是完整的“表格”类

package sample;

import java.util.ArrayList;

public class Table {
   private ArrayList<FoodDrinkController> customers;
   private String tablenumber;
   private ArrayList order;
   private double runningTotal;
   private double totalCalories;

   public Table(ArrayList<FoodDrinkController> customers, String tablenumber, ArrayList order, double runningTotal, double totalCalories) {
      this.customers = customers;
      this.tablenumber = tablenumber;
      this.order = order;
      this.runningTotal = runningTotal;
      this.totalCalories = totalCalories;
   }

   public Table() {

   }

   public ArrayList<FoodDrinkController> getCustomers() {
      return customers;
   }

   public void setCustomers(ArrayList<FoodDrinkController> customers) {
      this.customers = customers;
   }

   public String getTablenumber() {
      return tablenumber;
   }

   public void setTablenumber(String tablenumber) {
      this.tablenumber = tablenumber;
   }

   public ArrayList getOrder() {
      return order;
   }

   public void setOrder(ArrayList order) {
      this.order = order;
   }

   public double getRunningTotal() {
      return runningTotal;
   }

   public void setRunningTotal(double runningTotal) {
      this.runningTotal = runningTotal;
   }

   public double getTotalCalories() {
      return totalCalories;
   }

   public void setTotalCalories(double totalCalories) {
      this.totalCalories = totalCalories;
   }


}

任何帮助将不胜感激 我要做的就是将食品价格属性添加到另一个类的运行总属性中

****编辑****

这是 SelectDrinkControlleerGUI 类

package sample;

import javafx.application.Application;
import javafx.collections.FXCollections;
import javafx.collections.ObservableList;
import javafx.event.ActionEvent;
import javafx.fxml.FXML;
import javafx.scene.control.ListView;
import javafx.stage.Stage;

import java.util.ArrayList;

public class SelectDrinkControllerGUI extends Application {




    public ListView<FoodDrink> lvDrinks;
    private FoodDrinkController fdc = new FoodDrinkController();
    private Table table;











    public SelectDrinkControllerGUI() {


    }

    @Override
    public void start(Stage stage) throws Exception {

    }


    // Filters the menu items so i just displays drinks in the listview
    @FXML
    public void initialize() {
        System.out.println("initialize");
        ObservableList<FoodDrink> items = fdc.filterByType(Global.itemtype.DRINK);
        ArrayList<FoodDrink> stringList = new ArrayList<>();
        //System.out.println(items);
        for (FoodDrink item : items) {
            stringList.add(item);


        }

        lvDrinks.setItems(FXCollections.observableList(stringList));

    }

    // Button that adds the selected item to the order array
    public void addEntry(ActionEvent actionEvent){
        FoodDrink selectedItem = lvDrinks.getSelectionModel().getSelectedItem();
        fdc.order.add(selectedItem);

        selectedItem.getPrice();

        Table tbl = new Table();
        tbl.setRunningTotal(tbl.getRunningTotal() + selectedItem.getPrice());

        System.out.println("" + tbl.getRunningTotal());

        System.out.println(fdc.order);



    }
}

这是处理所有类型食物的 FoodDrinkController 类

package sample;

import javafx.collections.FXCollections;
import javafx.collections.ObservableList;

import java.util.ArrayList;

public class FoodDrinkController {
    private ArrayList<FoodDrink> fullList = new ArrayList<>();




    public ArrayList<FoodDrink> order = new ArrayList<FoodDrink>();








    //constructor with some stuff in it
    public FoodDrinkController(){

        FoodDrink cola = new FoodDrink("Coca Cola", 2.99, Global.itemtype.DRINK);
        FoodDrink pepsi = new FoodDrink("Pepsi", 2.99, Global.itemtype.DRINK);
        FoodDrink lemmonade = new FoodDrink("Lemmonade", 2.99, Global.itemtype.DRINK);
        FoodDrink garlicbread = new FoodDrink("Garlic Bread", 4.99, Global.itemtype.STARTER);

        FoodDrink burger = new FoodDrink("burger", 7.99, Global.itemtype.MAIN);

        fullList.add(cola);
        fullList.add(pepsi);
        fullList.add(lemmonade);
        fullList.add(burger);
        fullList.add(garlicbread);



    }


    public ObservableList<FoodDrink> filterByType(Global.itemtype itemtype){
        ArrayList<FoodDrink> subList = new ArrayList<>();
        for (FoodDrink listItem : fullList){
            if(listItem.getItemtype().equals(itemtype)){
                subList.add(listItem);
            }
        }
        return FXCollections.observableArrayList(subList);
    }



    //plain old main method
    public static void main(String[] args) {
        //SelectDrinkController fbtd = new SelectDrinkController();
        //System.out.println(fbtd.filterByType("DRINK"));

        FoodDrinkController fdc = new FoodDrinkController();
        //System.out.println(fdc.filterByType(Global.itemtype.DRINK));

    }
}

Answer 1

您的问题是每次添加条目时都会创建 Table 的另一个实例。

你想创建一次Table（我猜。）可能在SelectDrinkControllerGUI的构造函数中：

您已经在SelectDrinkControllerGUI 中有一个实例变量table，所以只需将您的构造函数更改为：

public SelectDrinkControllerGUI() {
    this.table = new Table();
}

然后更新addEntry(...):

public void addEntry(ActionEvent actionEvent){
    FoodDrink selectedItem = lvDrinks.getSelectionModel().getSelectedItem();
    fdc.order.add(selectedItem);

    table.setRunningTotal(table.getRunningTotal() + selectedItem.getPrice());

    System.out.println(table.getRunningTotal());

    System.out.println(fdc.order);
}

另外，您不需要"" + 来打印双打。做我上面做的：

System.out.println(tbl.getRunningTotal());

如果您仍有问题，请告诉我。