我正在尝试从 ArrayList 中删除一个对象。每个 Item 对象有 3 个属性;1. itemNum 2. 信息 3. 成本。我也有 3 个类, 1. Item 类定义了存储在目录中的单个项目。2. Catalog 类维护Item 对象的列表。3 客户端类 w/main 方法。我在 Item 类中有集合和获取,并且在 Catalog 中有 ArrayList。在客户端中,我会提示“输入要删除的 itemNum。如何根据对 itemNum 的搜索从 ArrayList 中正确删除 Item 对象?以下是我的代码以及到目前为止我尝试过的代码。
Public class Item
{
private int itemNum;
private String info;
private double cost;
private int itemNum;
public Item()
{ //start constructor
itemNum = 0; //default values
info = "x";
cost = 0;
} //end constructor
public CatalogItem(int newItemNum, String newInfo, double newCost)
{ //start overload constructor
this.itemNum = newItemNum;
this.info = newInfo;
this.cost = newCost;
} //end overload constructor
//下面是itemNum的设置/获取。我也有成本和信息的设置/获取,但选择不包括对空间的操作
public int getItemNum()
{ //start itemNum accessor
return itemNum;
} //end getItemNum
public void setItemNum(int newItemNum)
{ //start itemNum mutator
this.itemNum = newItemNum;
} //end setItemNum
} //end Item class
public boolean equals(CatalogItem obj)
{ //start equals
if (itemId == obj.itemId)
return true;
else
return false;
} //end equals
//下面是我的目录类
import java.util.*;
public class Catalog
{ //start class
private ArrayList<CatalogItem> listOfObjects = new ArrayList<CatalogItem>(100); //creates ArrayList
Item newItem = new Item(newItemNum, newInfo, newCost);
public void remove(int id)
{ //start remove
int item = id;
for (int index = 0; index < listOfObjects.size(); index++)
if (newItem.getItemId() == item) //if item in the inventory matches the item number passed
listOfObjects.remove(index); //removes based on index, I’ve also tried listOfObjects.remove(item);
/* I’ve also tried an enhanced for loop
for (CatalogItem obj : listOfObjects)
if (newItem.getItemId() == item)
listOfObjects.remove(newItem); */
} //end remove
}
//下面是主要的。它接收用户关于 itemNum、info 和 cost 的输入
import java.util.*; //allows use of Scanner class
public class Client
{ //start client class
public static void main(String[] args)
{ //start main
Catalog serv = new Catalog(); //creates instance of Catalog class
Scanner scan = new Scanner(System.in); //creates instance of Scanner class called scan
System.out.print("\nEnter in the Item ID you want to remove: ");
id = scan.nextInt();
serv.remove(id); //sends id to Catalog Class to be removed
} //end main
} //end class
它编译得很好,但不会根据找到的索引删除。任何帮助都会很棒。