Unity3D:NullReferenceException:对象引用未设置为对象的实例

问题描述

我想从laserController.class访问Hero.class变量"aspect"，但收到错误消息:NullReferenceException: Object reference not set to an instance of an object.

I want to access Hero.class variable "aspect" from laserController.class, but I receive an error message : NullReferenceException: Object reference not set to an instance of an object.

Hero.class

Hero.class

using UnityEngine;
using System.Collections;

public class Hero : MonoBehaviour {

public float aspect = 0.1f;
void Update () {

    }
}

laserController.class

laserController.class

using UnityEngine;
using System.Collections;

public class laserController : MonoBehaviour {

public float health = 0f;
//public float aspect = 0.1f;

void OnCollisionEnter(Collision collision) {
    if(collision.gameObject.tag == "enemy"){
        Destroy(gameObject);
        Destroy(collision.gameObject);
    }
 }

void Update () {

    Hero direction = gameObject.GetComponent<Hero>();

    //LaserHealth
    health += Time.deltaTime;

    if(health > 7f){
        Destroy(gameObject);
    }
    //problem in here
    transform.Translate(Vector3.up * -direction.aspect);

    }
}

推荐答案

我想您的Hero组件未附加到与laserController相同的GameObject上.如果要强制该条件，可以使用RequireComponentAttribute:

I guess your Hero component isn't attached to the same GameObject where laserController is attached to.If you want to force that condition you can use a RequireComponentAttribute:

[RequireComponent(typeof(Hero))]
public class laserController : MonoBehaviour

其他一些不相关的考虑因素

Some other unrelated consideration:

• 定义一个空的Update方法是没有用的，并且会产生性能开销
• 尝试遵循类的一致性命名约定(驼峰式案例:laserController -> LaserController)

• Defining a empty Update method is useless and has performances overhead
• Try to follow consistence naming conventions for classes (camel case: laserController -> LaserController)

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