從另一個類向ArrayList添加對象

Question

我對編程非常陌生，目前正在嘗試編寫汽車展示廳應用程序。 我有一個車輛班，一個陳列室班，並且我正在嘗試使用陳列室駕駛員進行輸入。

我在將車輛對象添加到我的arraylist時遇到問題。 有人可以指出我正確的方向。

我的代碼：

public class Vehicle {

    private String manufacturer;
    private String model;
    private String custName;
    private String vin;
    private String dateMan;
    private String dateSold;
    private Boolean sold;
    private char tax;
    private double cost;

    public Vehicle(String a, String b, String c, String d) {
        manufacturer = a;
        model = b;
        vin = c;
        dateMan = d;
    }

    public String toString() {
        String s = "Manufacturer: " + manufacturer + "  Model: "
                + model + "  vin: " + vin + "Date Manufactured:" + dateMan
                + "Cost: " + cost;
        return s;
    }

    public void buyVehicle(String a, String b) {  //buy method for the vehicle
        a = dateSold;
        b = custName;
        sold = true;
    }

    public String getManufacturer() {
        return manufacturer;
    }

    public String getModel() {
        return model;
    }

    public String getCustName() {
        return custName;
    }

    public String getVin() {
        return vin;
    }

    public String getDateMan() {
        return dateMan;
    }

    public String getDateSold() {
        return dateSold;
    }

    public Boolean getSold() {
        return sold;
    }

    public char getTax() {
        return tax;
    }

    public double getCost() {
        return cost;
    }
}

。

import java.util.ArrayList;

public class Showroom {

    private ArrayList<Showroom> theVehicles;

    public Showroom() {
        theVehicles = new ArrayList<Showroom>();
    }

    public boolean addVehicle(Showroom newVehicle) {
        theVehicles.add(newVehicle);
        return true;
    }
}

。

import java.util.*;

public class ShowroomDriver {

    public static void main(String[] args) {
        Vehicle v1 = new Vehicle("renault", "clio", "12", "290890");
        Showroom.addVehicle(v1);
    }
}

基本上，我對如何將車輛對象添加到陳列室類中的數組列表中感到困惑。 如果有人能指出正確的方向，我將不勝感激。

提前致謝。

Answer 1

您必須實例化Showroom類才能使用其屬性和方法

車輛的集合是車輛而不是陳列室。

package cars;

import java.util.ArrayList;
import java.util.List;

public class Showroom {

   private final List<Vehicle> theVehicles = new ArrayList<>();

   public boolean addVehicle( Vehicle newVehicle ) {
      theVehicles.add( newVehicle );
      return true;
   }

   public static void main( String[] args ) {
      final Showroom showroom = new Showroom();
      final Vehicle v1 = new Vehicle( "renault", "clio", "12", "290890" );
      showroom.addVehicle( v1 );
   }
}

在Vehicle類中，'='運算符周圍的一個錯誤，我想您想記住售出的價格和客戶名稱：

public void buyVehicle( String a, String b ) { // buy method for the vehicle
   dateSold = a;
   custName = b;
   sold = true;
}

Answer 2

我認為這

private ArrayList <Showroom> theVehicles;

應該是這個

private ArrayList <Vehicle> theVehicles;
theVehicles = new ArrayList <Vehicle> ();

和這個

public boolean addVehicle( Showroom newVehicle )

應該

public boolean addVehicle( Vehicle newVehicle )

您不想要Vehicle而不是ShowRoom的ArrayList嗎？

Answer 3

您的問題是您聲明了ShowRoom對象的ArrayList，但是想要的是Vehicle對象的ArrayList。

private ArrayList<Vehicle> theVehicles;

public boolean addVehicle(Vehicle v) {
    theVehicles.add(v);
    return true;
}