java - 在 JScrollPane 中显示对象 ArrayList 中的变量

Question

一个具有静态 ArrayList，一个具有已设置的 UI，我想显示每个对象 foodName 的列表，因为这将是可以在在线菜单 GUI 上选择和订购的食品项目.

    public class MenuItem
    {  
        private String foodName;
        private String foodType;
        private float price;
        private int calories;    

        /**
         * Constructor for objects of class MenuItem
         */
        public MenuItem(String nameFood, String typeFood, float foodPrice, int caloryCount)

        {     
        foodName = nameFood;
        foodType = typeFood;
        price = foodPrice;
        calories = caloryCount;

       } 

       public String foodName()   
       {
         return foodName;       
       }

       public String foodType()   
       {
          return foodType; 
       }

       public float price()
       {
           return price;
       }

       public int  calories()
       {
           return calories;
        }
    }

上面是我为每个 MenuItem 编写的类。

import java.util.ArrayList;


/**
 * 
 * ArrayList for the class, will hold all food items
 * @author Jonathan
 * @version 1.0
 *
 */

public class RestaurantArrayList extends MenuItem
{


    public RestaurantArrayList(String nameFood, String typeFood, float foodPrice, int caloryCount) {
        super(nameFood, typeFood, foodPrice, caloryCount);

    }

    public static final ArrayList<MenuItem> items;

    static 
    {
        items = new ArrayList<>();
        items.add(new MenuItem("Coca Cola", "Drink", 3.00f, 38));
        items.add(new MenuItem("Fanta Orange", "Drink", 3.00f, 31 ));
        items.add(new MenuItem("Glass of Red Wine", "Drink", 5.00f, 85));
        items.add(new MenuItem("Glass of White Wine", "Drink", 5.00f, 82));
        items.add(new MenuItem("Carling", "Drink", 3.50f, 189));
        items.add(new MenuItem("Fosters", "Drink", 3.50f, 378));
        items.add(new MenuItem("Water", "Drink", 0.00f, 0));
        items.add(new MenuItem("Breads", "Starter", 5.00f, 150));
        items.add(new MenuItem("Cold Meat", "Starter", 5.00f, 150));
        items.add(new MenuItem("Potato Skins and Barbeque Sauce", "Starter", 5.00f, 500));
        items.add(new MenuItem("Cold Meat", "Starter", 5.00f, 400));
        items.add(new MenuItem("Garlic Bread and Cheese", "Starter", 4.50f, 450));
        items.add(new MenuItem("Steak", "Main", 13.50f, 750));
        items.add(new MenuItem("Cheese and Bacon Burger", "Main", 8.00f, 850));
        items.add(new MenuItem("Spaghetti Cabonara", "Main", 7.00f, 675));
        items.add(new MenuItem("Steak", "Main", 13.50f, 378));
        items.add(new MenuItem("Seafood Paella", "Main", 10.00f, 850));
    }
}

这是我也设置的 ArrayList 类。我想在文本区域中显示食物的名称，但我不知道该怎么做。如果有人可以提供帮助那就太好了。谢谢

JScrollPane scrollPane_1 = new JScrollPane();
        scrollPane_1.setBounds(219, 50, 134, 309);
        contentPane.add(scrollPane_1);

这是设置 JScrollPane 的一小段代码，我希望在其内部显示信息，该信息位于其自己的 GUI 类中。

Answer 1

我会使用JList与定制DefaultListCellRenderer 。单元格渲染器确定单元格中对象的显示方式，因此在您的情况下，您需要 JList 中的 MenuItem 对象，并且渲染器应提取名称字符串以进行显示。这是我起草的:

创建一个 JList 并将其添加到 JScrollPane 的视口(viewport)中:

JList foodList = new JList(RestaurantArrayList.items.toArray());
foodList.setCellRenderer(new FoodListRenderer());
JScrollPane scr = new JScrollPane(foodList);

和自定义ListCellRenderer类:

class FoodListRenderer extends DefaultListCellRenderer {

@Override
public Component getListCellRendererComponent(JList list, Object value, int index, boolean isSelected, boolean cellHasFocus) {
    String name = ((MenuItem) value).foodName();
    return super.getListCellRendererComponent(list, name, index, isSelected, cellHasFocus);
}}