Question

一段时间以来，我一直没有编写代码，试图让一个简单的项目重新投入我的工作，但我陷入了困境。

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class Dungeon : MonoBehaviour
{
    public Tile[,] map = new Tile[40, 40];

    void Start() {
        for (int y = 0; y < 40; y++) {
           for (int x = 0; x < 40; x++){
                map[x, y].ceiling = 0;
                map[x, y].northWall = 0;
                map[x, y].westWall = 0;
                map[x, y].floor = 0;
            }
        }
     }
 }

它不会运行，给我一个错误，提示：“ NullReferenceException：对象引用未设置为对象的实例”

我应该提到，Tile类只是天花板，northWall，westWall和地板的支架。它们都是整数，我依赖于隐式构造函数。这是代码：

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class Tile : MonoBehaviour
{
    public int ceiling { get; set; }
    public int northWall { get; set; }
    public int westWall { get; set; }
    public int floor { get; set; }
}

Answer 1

您的Tile类型为MonoBehaviour！ MonoBehaviours不能像普通分类那样创建，只能通过使用AddComponent将它们添加到某个GameObject来创建；如果不附加到GameObject，它们将不存在。

因此，您的行

public Tile[,] map = new Tile[40, 40];

实际上不创建具有默认值的实例的填充数组，而是创建一个由null 引用 strong>，而不是实例。

我想您想要的是：

瓷砖

Tile

和

// use this tag to make it // serializable and e.g. visiable in the inspector [System.Serializable] public class Tile { // use fields instead of properties // since also properties are not serialzed public int ceiling; public int northWall; public int westWall; public int floor; }

但是我个人总是希望拥有适当的构造函数和字段名称（public => PascalCase）

public class Dungeon : MonoBehaviour { public Tile[,] map = new Tile[40, 40]; private void Start() { for (int y = 0; y < 40; y++) { for (int x = 0; x < 40; x++) { // For simple types like e.g. int, string etc there are default values // so the array would be filled with those values. // However your class Tile has the default value null // So you have to create Tile instances using the default constructor like map[x, y] = new Tile(); // And than optionally give it values // though they will be 0 by default of course map[x, y].ceiling = 0; map[x, y].northWall = 0; map[x, y].westWall = 0; map[x, y].floor = 0; // or alternatively map[x, y] = new Tile() { ceiling = 0, northWall = 0, westWall = 0, floor = 0 }; } } } }

并使用

[System.Serializable] public class Tile { public int Ceiling ; public int NorthWall; public int WestWall; public int Floor; public Tile(int ceiling, int northWall, int westWall, int floor) { Ceiling = ceiling; NorthWall = northWall; WestWall = westWall; Floor = floor; } }

Answer 2

derHugo使我自己做出了花生酱吐司面包所需的时间。 derHugo的出路！

这是我的Tile课。它不需要所有MonoBehavior东西，我按照建议添加了一个构造函数：

public class Tile
{
    public int ceiling { get; set; }
    public int northWall { get; set; }
    public int westWall { get; set; }
    public int floor { get; set; }

    public Tile(int c, int n, int w, int f)
    {
        ceiling = c;
        northWall = n;
        westWall = w;
        floor = f;
    }
}

这是使用Tile类的函数：

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class Dungeon : MonoBehaviour
{
    public Tile[,] map = new Tile[40, 40];

void Start()
{
    for (int y = 0; y < 40; y++) {
       for (int x = 0; x < 40; x++){
            map[x, y] = new Tile(0, 0, 0, 0);
            }
        }
    }
}

现在它可以运行了！

2维Class对象数组给出错误：空引用异常：对象引用未设置为对象的实例

2 个答案: