用初始化的对象填充数组列表

Question

我在Class Deck中有ArrayList套牌。我想用Card对象填充ArrayList。

我还想填充卡片对象的属性。

我添加了一个 for 循环来查看结果，并且 ArrayList 有 5 个对象，名称为 NULL，值为 0。

(FillDeck 已在主函数中调用(

import java.util.ArrayList;

public class Deck {
    private ArrayList<Card> deck=new ArrayList();

      public Deck(){
    }

      public Deck(ArrayList<Card> deck ){
        this.deck = deck;
    }
          //hearts,spades,diamonds,clubs  
        Card card1 = new Card("A hearts",11,true);
        Card card2 = new Card("2 hearts",2,true);
        Card card3 = new Card("3 hearts",3,true);
        Card card4 = new Card("4 hearts",4,true);    
        Card card5 = new Card("5 hearts",5,true);


    public void filldeck(){


        deck.add(card1);       
        deck.add(card2);       
        deck.add(card3);      
        deck.add(card4);     
        deck.add(card5);       

          for (int i=0; i<deck.size(); i++){
              System.out.println(deck.get(i).getName());
              System.out.println(deck.get(i).getValue());

          }
    }

}


public class Card {

    private String name;
    private int value;
    private boolean samecard = true ;
    public Card(){
    }
    public Card(String name,int value,boolean samecard){
        name = this.name;
        value = this.value;
        samecard = this.samecard;
    }
    public String getName(){
        return name;
    }
    public int getValue(){
        return value;
    }
    public boolean getSamecard(){
        return samecard;
    }
}

Answer 1

因为您看到的是字段的默认值。要解决此问题，您必须实际分配值，例如

public Card(String name,int value,boolean samecard){
    this.name = name;
    this.value = value;
    this.samecard = samecard;
}

Answer 2

您的Card(String name, int value, boolean samecard)有错误的实现，您无法将实例变量分配给构造函数参数。

需要明确的是，这是错误的：name = this.name

这是正确的：this.name = name

这是一个正确的实现：

    public Card(String name,int value,boolean samecard){
        this.name = name;
        this.value = value;
        this.samecard = samecard;
    }

Answer 3

你在 Card 类中搞砸了构造函数，将构造函数变量赋值更改为：

this.name = name;
this.value = value;
this.samecard = samecard;

Answer 4

您正在限定作业的右侧，在这种情况下是不正确的：

public Card(String name,int value,boolean samecard){
    name = this.name;
    value = this.value;
    samecard = this.samecard;
}

它必须是

public Card(String name,int value,boolean samecard){
    this.name = name;
    this.value = value;
    this.samecard = samecard;
}

Answer 5

您的承包商有问题。它看起来像这样：

public Card(String name,int value,boolean samecard){
    name = this.name;
    value = this.value;
    samecard = this.samecard;
}

它应该是这样的：

public Card(String name,int value,boolean samecard){
    this.name = name;
    this.value = value;
    this.samecard = samecard;
}