Question

<强势 > 类块

public class block {    
public enum size {SMALL,MEDIUM,LARGE,XLARGE}
    public String color;public size sz;

public block(String color, size sz) {
    super();
    this.color = color;
    this.sz = sz;
}
     public block() {
    this.color="White";
    this.sz=sz.SMALL;

}

public String toString() {
    String result="My color is " + color + " and size=" + sz;
    return result;}

< 坚固 > 分类行ofblock

public class rowofBlocks extends block{

        private block[] blocks;
private int numofBlocks;

public rowofBlocks(int numofBlocks){
    //super();
    this.numofBlocks=numofBlocks;
    generateBlocks() ;
}

private void generateBlocks() {

    this.blocks=new block[numofBlocks];

}

public String toString() {
    for(int a=0;a<blocks.length;a++)
    {

    System.out.print( blocks[a]);
    }
    String a="d";
    return a;
}
}

< 强势 > 类游戏Main

public class gameMain {

    public static void main(String[] args) {



block b=new block();
b.setSz(block.size.LARGE);
b.setColor("WHITE");

    rowofBlocks myrows=new rowofBlocks(3);
    System.out.println(b);
    System.out.println(myrows);
    }}

我的意思是,我只是看到无核核素而不是我的颜色是白色当我试图创建数组区块时。

Answer 1

您获得 null 值, 原因是您在 RowofBlocks 中不创建类中任何对象 block 。

创建数组后, 以 :

this.blocks = new block[numofBlocks];

在 generateBlocks () 的方法正文中

您必须绕过它并插入实际的区块 :

for(int i=0 ; i < this.blocks.length ; i++) {
     this.blocks[i] = new Block();
}

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