我是Java新手,需要弄清楚如何從另一個類訪問ArrayList。如何訪問另一個類的ArrayList
我有三類:Market
,StockEntry
和Print
我從市場調用打印類的打印方法和打印類從StockEntry類獲得的ArrayList的參考,但它不顯示任何信息。請看下圖:
市場類
public class Market {
StockEntry stock;
Print print;
Market() {
stock = new StockEntry();
print = new Print();
}
void addStock (String itemName,String name, int quantity, int price) {
stock.addStockOfItems(itemName, name, quantity, price);
}
void print() {
print.pr();
}
}
StockEntry類
import java.util.ArrayList;
public class StockEntry {
Fruit fruit;
ArrayList<Fruit> fruitList ;
StockEntry() {
fruit = new Fruit();
fruitList = new ArrayList<Fruit>();
}
void addStockOfItems(String itemName,String name, int quantity, int price) {
fruit.enterTheDetail(name, quantity, price);
fruitList.add(fruit);
}
}
打印類
import java.util.ArrayList;
public class Print {
StockEntry stock;
ArrayList<Fruit> fruitList;
Print() {
fruitList = new ArrayList<Fruit>();
}
void pr() {
for (Fruit fruit : stock.fruitList) {
System.out.println(fruit);
}
}
}
有人可以幫我弄清楚爲什麼這不起作用嗎?