我想从ArrayList中移除一个对象。每个Item对象都有3个属性; 1. itemNum 2. info 3.成本。我也有3个类,1. Item类定义存储在目录中的单个项目。 2. Catalog类维护Item对象的列表。 3客户类别/主要方法。 我有集合,并在Item类中获取,并且我在Catalog中有ArrayList。在客户端,我有一个提示“输入itemNum删除。如何根据itemNum的搜索从ArrayList中正确删除一个Item对象?下面是我的代码和我迄今为止尝试过的。如何正确地从ArrayList中删除一个对象?
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set/gets。我也有设置/获取成本和信息,但选择不包括做空间
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。它接收来自输入关于itemNum,信息用户,成本
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
它编译罚款,但不会删除基础上创建索引。任何帮助都会很棒。
什么是包含在您的目录中的项目的ID,你输入了什么ID删除 – gefei
我认为你应该实现一个构造函数3个参数为您的类,而不是重载之一。 – UrsulRosu
此外你的对象不是不可变的。这不是很好的风格。 – sk2212