java如何实现ArrayList以将“Room”对象添加到“House”对象列表中？

Question

我目前正在做一项作业，我有两门课，一间教室，一间房子。作为任务的一部分，我需要启用house类将房间存储在ArrayList中：

Implement a method to read in room information in the House class from the keyboard — this should call the Room constructor as required. Create a zero-argument House constructor to call this new method.

我很抱歉，如果这是含糊不清的，或者已经在其他地方得到了回答，但在试图理解其他类似问题的解释后，我不知道如何将它们应用到我的情况中

如何将Room的ArrayList应用于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

将列表专门化为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 2

更改此循环：

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++;
}

致：

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

Answer 3

更改构造函数方法，添加有关房间的代码ArrayList

public House(..., ArrayList aRooms) {

 ...
 rooms = aRooms;
}

public House() {

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

要将文件室添加到文件室ArrayList，只需执行类似操作（不要忘记检查ArrayListAPI，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 4

因为这是家庭作业，我不会完全解决它，但给你一个工作的基础。p>

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(...) {
    ...
  }
}

有问题吗

Answer 5

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

Answer 6

你检查过ArrayList的API了吗

你需要像这样的东西：

rooms.add(new Room());

此外，我将使用Java泛型并定义列表：

private ArrayList<Room> rooms;

这将使用generics，并确保这只能是房间列表，而不是其他对象。它将为您节省一些悲伤，因为您不能无意中将房屋添加到房间列表中（通过编程错误）