Camera.main空引用异常 [英] Camera.main null reference exception

问题描述

我是C#和Unity的新手，并且我已经阅读了整个论坛，但仍然很困惑.这是我得到的错误:

I am new to C# and Unity and I have read this entire forum and I am still stuck. This is the error I am getting:

NullReferenceException:对象引用未设置为对象的实例 ClickToMove.Update()(位于Assets/Scripts/ClickToMove.cs:27)

NullReferenceException: Object reference not set to an instance of an object ClickToMove.Update () (at Assets/Scripts/ClickToMove.cs:27)

这就是我所拥有的...

This is what I have...

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

 public class ClickToMove : MonoBehaviour {
     [Header("Stats")]
     public float attackDistance;
     public float attackRate;
     private float nextAttack;

     private NavMeshAgent navMeshAgent;
     private Animator anim;

     private Transform targetedEnemy;
     private bool enemyClicked;
     private bool walking;    
     void Awake ()
     {
         anim = GetComponent<Animator>();
         navMeshAgent = GetComponent<NavMeshAgent>();
     }

     // Update is called once per frame
     void Update ()
     {
         Ray ray = Camera.main.ScreenPointToRay(Input.mousePosition);
         RaycastHit hit;

         if (Input.GetButtonDown("Fire2"))
         {
             if (Physics.Raycast(ray, out hit, 1000))
             {
                 if (hit.collider.tag == "Enemy")
                 {
                     targetedEnemy = hit.transform;
                     enemyClicked = true;
                     //print("Enemy Hit");
                 }
                 else
                 {
                     walking = true;
                     enemyClicked = false;
                     navMeshAgent.isStopped = false;
                     navMeshAgent.destination = hit.point;
                 }
             }
         }
         if (enemyClicked)
         {
             MoveAndAttack();
         }

         if (navMeshAgent.remainingDistance <= navMeshAgent.stoppingDistance)
         {
             walking = false;
         }
         else
         {
             walking = true;
         }

         //anim.SetBool("isWalking", walking);
     }

     void MoveAndAttack()
     {
         if(targetedEnemy == null)
         {
             return;
         }

         navMeshAgent.destination = targetedEnemy.position;

         if(navMeshAgent.remainingDistance > attackDistance)
         {
             navMeshAgent.isStopped = false;
             walking = true;
         }
         else
         {
             transform.LookAt(targetedEnemy);
             Vector3 dirToAttack = targetedEnemy.transform.position - transform.position;

             if(Time.time > nextAttack)
             {
                 nextAttack = Time.time + attackRate;
             }
             navMeshAgent.isStopped = true;
             walking = false;
         }
     }
 }

第27行以"Ray ray = Camera.main.ScreenPointToRay ..."开头

Line 27 starts with "Ray ray = Camera.main.ScreenPointToRay..."

推荐答案

您需要在场景中使用带有MainCamera标签的摄像机才能调用Camera.main.ScreenPointToRay().没有这个，Camera.main将不存在，从而导致空引用异常.

You need to have a camera in your scene with the MainCamera tag in order to call Camera.main.ScreenPointToRay(). Without this, Camera.main does not exist, resulting in a null reference exception.

这篇关于Camera.main空引用异常的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！