如何实现 ArrayList 以将“房间”对象添加到“房屋”对象列表中？ [关闭]

Question

我目前正在做作业，我有两个班级房间和房子。作为作业的一部分，我需要启用房屋类将房间存储在ArrayList：

实现从键盘读取House 类中的房间信息的方法——这应该根据需要调用Room 构造函数。创建一个零参数的 House 构造函数来调用这个新方法。

如果这含糊不清或已在其他地方得到回答，但我试图理解其他类似查询的解释，我不知道如何将它们应用于我的情况，我深表歉意。

我如何将Room 的ArrayList 应用到house 类？

House:

import java.util.ArrayList;
import java.util.Scanner;

public class House {

private int idNum;
private static int internalCount = 0; 
private ArrayList rooms = new ArrayList();
private String address;
private int numRooms;
private String houseType; 

public House (String address, int numRooms, String houseType) {
idNum = internalCount++;

this.address = address;
this.numRooms = numRooms;
this.houseType = houseType;     
}


public House () {
int i = 0;  
idNum = ++internalCount;

Scanner scan = new Scanner(System.in);
scan.useDelimiter("\n");

System.out.println("Enter address of house:");   
address = scan.next();

System.out.println("Enter number of rooms:");   //Number of rooms in the House
numRooms = scan.nextInt();

 while (i < numRooms)  //This will loop until all rooms have been described
 {
 add.room = new Room[100]; //I understand this is incorrect but I don't know what  I should have in here
 i++;
 }

 System.out.println("Enter type of house:");
 houseType = scan.next();
 }
 public void addroom(String description, double length, double width)
 {

 }

 int getIdNum() {
 return idNum;
 }


 @Override

 public String toString()
 {
  String report = "~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~\n";
  report += "Address: " + address + "\n";
  report += "No. of Rooms: " + numRooms + "\n";
  report += "House Type: " + houseType+ "\n";
  report += "~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~\n";

  return report;
 }
 }

Room:

import java.util.Scanner;

public class Room {

private String description;
private double length;
private double width;

public Room (String description, double length, double width) {
this.description = description;
this.length = length;
this.width = width;     
}

public Room () {
Scanner scan = new Scanner(System.in);
scan.useDelimiter("\n");

System.out.println("Enter description of room:");
description = scan.next();

System.out.println("Enter length of room:");
length = scan.nextDouble();

 System.out.println("Enter width of room:");
 width = scan.nextDouble();
 }

 /*
 * Calculates and returns area of Room
 */
 public double getArea () {
 return length*width;
 }


 @Override
 public String toString() {
 return description + "- Length: " + length + "m; Width: " + width + 'm';
 }   
}

Answer 1

您检查过API 的ArrayList 吗？

你需要这样的东西：

rooms.add(new Room());

此外，我将使用 Java 泛型并这样定义列表：

private ArrayList<Room> rooms;

这利用了generics，并确保这只能是房间列表，而不是杂项对象。它会为您省去一些麻烦，因为您不会无意中将房屋添加到您的房间列表中（通过编程错误）

Answer 2

由于这是作业，我不会全部解决，但会给你一个工作的基础......

public class House {
  private List<Room> rooms;

  public House() {
    rooms = new ArrayList<Room>();
  }

  public void addRoom(...) {
    Room room = new Room(...);
    rooms.add(room);
  }

  public int numRooms() {
    return rooms.size();
  }

  public Room getRoom(int roomNumber) {
    return rooms.get(roomNumber);
  }
}

public class Room {
  public Room(...) {
    ...
  }
}

问题？

Answer 3

使用特化列表到Room 类型

List<Room> rooms = new ArrayList<Room>();

while (i < numRooms)  //This will loop until all rooms have been described
{
  rooms.add(new Room()); //this is correct 
  i++;
}

Answer 4

ArrayList<Room> rooms = new ArrayList<Room>();
rooms.add(new Room());

Answer 5

更改您的构造函数方法，添加一些关于您的房间的代码ArrayList。

public House(..., ArrayList aRooms) {

 ...
 rooms = aRooms;
}

public House() {

 ...
 // It's better to instantiate the rooms array here.
 rooms = new ArrayList<Room>();
}

要将房间添加到您的房间ArrayList，只需执行类似操作（不要忘记检查ArrayList API、http://docs.oracle.com/javase/6/docs/api/java/util/ArrayList.html）。

ArrayList<Room> rooms = new ArrayList<Room>();
rooms.add(new Room(...));
// Add here all the rooms you need.

House house = new House(rooms);

// You can also create a method into the House class to allow adding new rooms once you have created a House object.
public void addRoom(Room room) {

 this.rooms.add(room);
}

Answer 6

改变这个循环：

while (i < numRooms)  //This will loop until all rooms have been described
{
  add.room = new Room[100]; //I understand this is incorrect but I don't know what I  should have in here
 i++;
}

收件人：

while (i < numRooms) 
{
Room newRoom = new Room();
rooms.add(newRoom);
i++;
}