Java 在类PurseMain中将对象调用到ArrayList中

好的，这个程序的目标是在类钱包中的ArrayList钱包中输入字符串值，例如penny、dime、quarter和nickel。然后，一旦通过PurseMain类执行了钱包，那么Coin类就应该获取添加到ArrayList钱包中的硬币名称的字符串值，并将它们的美元值相加。我的教授告诉我们在第三类中创建硬币值，称为硬币，并在PurseMain中创建另一个ArrayList。但实际上我的主要问题是，如何将Coin类中创建的对象调用到PurseMain中的ArrayList中？任何帮助都将不胜感激。谢谢

package purse;
import java.util.Scanner;
import java.util.ArrayList;



/**
* The Purse program creates an ArrayList called purse that gets printed out,
 reversed, and transfered into another ArrayList called purse2. 
 *     
 *               - ArrayList purse 
 *               - ArrayList purse2
 *               - Scanner coin - the Scanner that is used to type the                             contents of ArrayList purse
 *               - Scanner coin2- the Scanner that is used to type the  contents of ArrayList purse2
 *               - String input - contains Scanner coin and is used to fill    ArrayList purse
 *               - String input2- contains Scanner coin2 and is used to fill  ArrayList purse2
 *               - String end - sentinel for ending the process inputting    strings into Scanner coin and Scanner coin2
 *      
 */
public class Purse  
{ 
  ArrayList<String> purse = new ArrayList<>(); 


   /**
   *  fills ArrayList purse and purse2 with U.S coin names 
   *  purse gets printed out and then again is printed in reverse
   *  purse2 is printed

   */

  public void addCoin()
  { 



   String penny = "penny";
   String nickel = "nickel";
  String dime = "dime";
  String quarter = "quarter";
  String end = "done";

  Scanner coin = new Scanner (System.in); 
   String input = " ";
  System.out.println("Please put as many coins of U.S currency as you like into the purse, hit the ENTER button after each coin and, type 'done' when finished: ");

  while (!input.equalsIgnoreCase ("done"))
  {  input = ( coin.nextLine());
   if   (input.equalsIgnoreCase("penny")||input.equalsIgnoreCase("nickel")||input.equals IgnoreCase("dime")||input.equalsIgnoreCase("quarter")||input.equalsIgnoreCase(en d))
   {
        purse.add(input);
        purse.remove(end);
    }
   else{
       System.out.println("Please input a coin of U.S currency.");
    }
    }
  }

  /**
  @return ArrayList purse
  */
 public ArrayList<String> printPurseContents()
  { 
      System.out.println("Contents of the purse: " + purse);
      return purse;  
  }

     /** checks whether purse2 has the same coins in the same order as purse
     * @return 
     * @param purse2
   */



  public boolean sameContents(Purse purse2)
  {

      if (purse2.purse.equals(purse)) 
      {
          return true; 
  } 
  else
  {
      return false;
  }   

 }
  /**
  * checks whether purse2 has the same coins as in purse, disregarding the  order
  * @param purse2
  * @return 
 */

 public boolean sameCoins(Purse purse2) 
{

   if( purse2.purse.containsAll(purse))
  {
      return true; 
  }    
    else
  {
     return false;
  }
 } 


/**
* adds contents of purse into purse2 and clears purse of its contents
 * @param purse2    
*/
public void transfer(Purse purse2)  
{
           purse2.purse.addAll(purse);
            purse.clear();

 System.out.println("The second purse now has: " + purse2.purse );
 System.out.println("and the first purse has: " + purse);


 }


}

---

你需要在钱包里放一个新的硬币袋（根据需要）。所以，要有一个硬币袋，里面有一张硬币清单。由于钱包有硬币袋，它将是你钱包的财产

public class Coin{
   private String type;
   private String currencyType;
//more fields and getters and setters
}

public class Purse{  

  ArrayList<String> purse = new ArrayList<>(); 
  List<Coins> coinPouch = new ArrayList<>();//contains coin objects
.
.
.
.

   private void addCoins(String coinType){
      Coin coin = new Coin();
      coin.setType(coinType);

      coinPouch.add(coin);
   }
}

---

好吧，我基本上理解你在做什么，但是setType是从哪里来的呢？您是否在某处创建了另一个方法或类，或者是从Java库中调用的？除此之外，尽管我理解。Coin类有一个我已经给出的属性类型。我添加了一条注释，上面写着-//更多字段、getter和setter。我没有为属性添加setter方法，因为它会使代码变得冗长。您可以添加SETTER方法和GETTER方法。如果给出了您想要的，请考虑标记答案为关闭/投票。谢谢

 package purse;

/*
   * To change this license header, choose License Headers in Project Properties.
     * To change this template file, choose Tools | Templates
     * and open the template in the editor.
  */

  /** private string name;
     * private double value;
     * sum up value method
     *
      * @author
  */
 public class Coin 
{

   private String Penny = "penny";
   private String Nickel = "nickel";
   private String Dime = "dime";
   private String Quarter = "quarter";
   private double penny = 0.01;
   private double nickel = 0.05;
   private double dime = 0.10;
   private double quarter = 0.25;    

   public void SumUpValue()
   {

   }



 } 

public class Coin{
   private String type;
   private String currencyType;
//more fields and getters and setters
}

public class Purse{  

  ArrayList<String> purse = new ArrayList<>(); 
  List<Coins> coinPouch = new ArrayList<>();//contains coin objects
.
.
.
.

   private void addCoins(String coinType){
      Coin coin = new Coin();
      coin.setType(coinType);

      coinPouch.add(coin);
   }
}

if (input.equalsIgnoreCase("penny")|| input.equalsIgnoreCase("nickel")  ||input.equalsIgnoreCase("dime")||input.equalsIgnoreCase("quarter")||input.equalsIgnoreCase(end)){
   addCoins(input);//Adds coins to the list of coins objects and the purse now has the coin pouch :D
   purse.remove(end);
}
else{
   System.out.println("Please input a coin of U.S currency.");
}