Object reference not set to an instance of an object, Unity

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英文:

Object reference not set to an instance of an object, Unity

问题

当敌人生成时，我尝试在这里初始化他 enemy.Init();，但出现了错误“Object reference not set to an instance of an object”（对象引用未设置为对象的实例）。但在这里 Debug.Log(enemy._enemyHealth);，我能够获取到敌人的生命值。如果敌人是类 'Usual Enemy' 并且它是从 'Enemy' 类继承的，而且我将会有更多的敌人子类，我如何从这里初始化我的敌人呢？

你可以尝试使用以下方法来解决这个问题：

  1. 确保预制件正确配置： 确保你的敌人预制件（Prefab）已正确配置，并且在预制件上已经附加了相应的脚本组件。确保 enemy.Init(); 中的 enemy 不为 null。

  2. 检查子类的初始化方法： 如果你有多个敌人子类，确保每个子类都实现了 Init() 方法。你可以在每个子类中重写 Init() 方法，以确保它们的初始化逻辑正确执行。

  3. 使用多态： 你可以使用多态来确保调用适当的子类的 Init() 方法。这样，无论你使用哪个子类的实例，都会调用正确的初始化方法。

例如，如果你的 enemy 变量是 Enemy 类型的引用，但实际上它是一个子类的实例，那么你可以这样调用 Init() 方法：

  1. enemy.Init();

这将根据实际的对象类型调用正确的 Init() 方法。

确保在你的子类中正确实现了 Init() 方法，以便它可以执行所需的初始化逻辑。如果你仍然遇到问题，可以提供更多的代码或信息，以便我可以提供更具体的帮助。

英文:

So when enemy is spawned i try to init him here enemy.Init(); but had error Object reference not set to an instance of an object. But here Debug.Log(enemy._enemyHealth); i get number of enemy health. How i can Init my enemy from here if enemy has class 'Usual Enemy' and it extends from this class 'Enemy' and i wiil have more enemy child cllases?

I vave class Enemy

  1. using System.Collections;
  2. using System.Collections.Generic;
  3. using UnityEngine;
  4. using UnityEngine.AI;
  6. public abstract class Enemy : MonoBehaviour
  7. {
  9.     private GameObject _player;
  10.     private Animator _animator;
  11.     private Rigidbody _rigidbody;
  12.     private bool _isSpawned;
  13.     private const int _enemySpavnTime = 5;
  14.     [SerializeField] public float _enemyHealth;
  15.     [SerializeField] protected float _rotationSpeed = 10f;
  16.     [SerializeField] protected float _moveSpeed;
  17.     [SerializeField] protected float _damage;
  18.     [SerializeField] protected DamageBox _damageBox;
  19.     [SerializeField] protected TriggerBox _triggerBox;
  20.     private EnemyCondition _enemyCondition = EnemyCondition.Dead;
  21.     
  22.     private enum EnemyCondition 
  23.     {
  24.         Spawn,
  25.         Run,
  26.         Attack,
  27.         Dead
  28.     }
  31.     void Start()
  32.     {
  33.         _rigidbody = GetComponent<Rigidbody>();
  34.         _animator = GetComponent<Animator>();
  35.         _player = GameObject.FindWithTag("Hero");
  36.         _damageBox.HeroHited += enemyAttack;
  37.         _triggerBox.HeroInAttackRange += enemyGetAngry;
  38.         _triggerBox.HeroOutAttackRange += enemyGetChill;
  39.     }
  41.     void Update()
  42.     {   
  43.         if (_player != null) 
  44.         {
  45.             if (_enemyCondition == EnemyCondition.Run)
  46.             {
  47.                 EnemyPlayerRotation(_player);
  49.             } else if (_enemyCondition == EnemyCondition.Attack)
  50.             {
  51.                 EnemyPlayerRotation(_player);
  52.             }
  53.         }
  54.         
  55.     }
  57.     void FixedUpdate() {
  58.         if (_enemyCondition == EnemyCondition.Run)
  59.         {
  60.             EnemyPlayerFollow();
  61.         }   
  62.     }
  64.     public virtual void Init() {
  65.         enemySpawn();
  66.     }
  68.     protected virtual void EnemyPlayerFollow() {
  69.         Vector3 direction = transform.TransformDirection(new Vector3(0, 0, 1));
  70.         _rigidbody.velocity = direction * _moveSpeed;
  71.     }
  73.     protected virtual void EnemyPlayerRotation(GameObject target) {
  74.         Vector3 direction = (target.transform.position - transform.position).normalized;
  75.         Quaternion lookRotation = Quaternion.LookRotation(new Vector3(direction.x, 0, direction.z));
  76.         transform.rotation = Quaternion.Slerp(transform.rotation, lookRotation, Time.deltaTime * _rotationSpeed);
  77.      }
  79.     public virtual void EnemyDamage(float damage)
  80.     {
  81.         _enemyHealth -= damage;
  82.         if (_enemyHealth <= 0) {
  83.             PoolManager.Instanse.Despawn(gameObject);
  84.         }
  85.     }
  87.     public virtual void enemySpawned() {
  88.         _enemyCondition = EnemyCondition.Run;
  89.         _rigidbody.isKinematic = false;
  90.         _animator.SetTrigger("Run");
  91.         StopCoroutine(SpawnMoveUp());
  92.         Debug.Log("enemySpawned");
  93.     }
  95.     protected virtual void enemyAttack(Hero trigger) 
  96.     {   
  97.         if (_enemyCondition == EnemyCondition.Attack) {
  98.             trigger.HeroDamage(_damage);
  99.         }
  100.     }
  102.     protected virtual void enemyGetAngry() {
  103.         _enemyCondition = EnemyCondition.Attack;
  104.         _animator.SetTrigger("Attack");
  105.     }
  107.     protected virtual void enemyGetChill() {
  108.         _enemyCondition = EnemyCondition.Run;
  109.         _animator.SetTrigger("Run");
  110.     }
  112.     protected virtual void enemySpawn() {
  113.         _animator.SetTrigger("Spawn");
  114.         _animator.speed = 0.0f;
  115.         StartCoroutine(SpawnMoveUp());
  116.     }
  118.     IEnumerator SpawnMoveUp()
  119.     {  
  120.         float spawnStage = 0.0f;
  121.         Vector3 startPoint = transform.position;
  122.         while(spawnStage <= 1.0f) {
  123.             transform.position = Vector3.Slerp(startPoint, new Vector3(transform.position.x, 0, transform.position.z), spawnStage);
  124.             spawnStage += Time.deltaTime/_enemySpavnTime;
  125.             yield return null;
  126.         }
  127.         _animator.speed = 1.0f;
  128.         
  129.     }
  130.     
  131. }

And I have class that spawns enemies

  1. using System.Collections;
  2. using System.Collections.Generic;
  3. using UnityEngine;
  5. public class EnemiesSpawner : MonoBehaviour
  6. {
  7.     [SerializeField] private Levels[] _levelsList;
  8.     private List<GameObject> _enemiesQueue = new List<GameObject>();
  9.     private List<GameObject> _levelEnemiesList = new List<GameObject>();
  10.     private List<int> _levelEnemiesCount = new List<int>();
  12.     private bool _isBossSpawned = false;
  13.     // private int _currentLevel = PlayerPrefs.GetInt("currentLevel") - 1;
  14.     private int _currentLevelNumber = 0;
  15.     private float _reloadPause = 0;
  16.     private int currentEnemiesListPos = 0;
  17.     private int allEnemiesCount = 0;
  19.     private float _reloadTime;
  20.     private float _spawnRadius;
  21.     private float _spawnOfsetRadius = 2f;
  23.     [SerializeField] private GameObject _boss;
  24.     [SerializeField] private GameObject _spawnPoint;
  26.     void Start() {
  27.         Levels currentLevelObj = _levelsList[_currentLevelNumber];
  28.         _levelEnemiesCount.AddRange(currentLevelObj.enemiesCount.ToArray());
  29.         _levelEnemiesList = currentLevelObj.enemiesPrefabs;
  30.         _spawnRadius = currentLevelObj.spawnRadius;
  31.         _reloadTime = currentLevelObj.spawnReload;
  33.         foreach(int num in _levelEnemiesCount) {
  34.             allEnemiesCount += num;
  35.         }
  37.         while(_enemiesQueue.Count < allEnemiesCount){
  38.             int randomIndex = Random.Range(0, _levelEnemiesCount.Count);
  39.             if (_levelEnemiesCount[randomIndex] == 0) {
  40.                 continue;
  41.             } else {
  42.                 _enemiesQueue.Add(_levelEnemiesList[randomIndex]);
  43.                 _levelEnemiesCount[randomIndex] --;
  44.             }
  45.         }
  46.     }
  48.     public void SetPlayerForSpawn (GameObject player) {
  49.         _spawnPoint = player;
  50.     }
  52.     void Update ()
  53.     {           
  54.         if (_spawnPoint != null){
  55.             SpawnEnemies();
  56.         }
  57.         
  58.     }
  60.     public void SpawnEnemies() 
  61.     {
  62.         _reloadPause += Time.deltaTime;
  63.         if (_reloadPause >= _reloadTime && currentEnemiesListPos < allEnemiesCount) {
  64.             GameObject go = PoolManager.Instanse.Spawn(_enemiesQueue[currentEnemiesListPos],new Vector3((Random.value < 0.5f) ? Random.Range(_spawnPoint.transform.position.x + _spawnOfsetRadius, _spawnPoint.transform.position.x + _spawnRadius) : Random.Range(_spawnPoint.transform.position.x - _spawnOfsetRadius, _spawnPoint.transform.position.x - _spawnRadius), -5, (Random.value < 0.5f) ? Random.Range(_spawnPoint.transform.position.z + _spawnOfsetRadius, _spawnPoint.transform.position.z + _spawnRadius) : Random.Range(_spawnPoint.transform.position.z - _spawnOfsetRadius, _spawnPoint.transform.position.z - _spawnRadius)), Quaternion.identity);
  65.             Enemy enemy = go.GetComponent<Enemy>();
  66.             Debug.Log(enemy._enemyHealth);
  67.             enemy.Init();
  68.             _reloadPause = 0;
  69.             currentEnemiesListPos ++;
  70.         } else if (currentEnemiesListPos == allEnemiesCount && _isBossSpawned == true) {
  71.             Instantiate(_boss,new Vector3(0,0,0), Quaternion.identity);
  72.             _isBossSpawned = true;
  73.         }
  74.         
  75.     }
  76. }

So when enemy is spawned i try to init him here enemy.Init(); but had error Object reference not set to an instance of an object. But here Debug.Log(enemy._enemyHealth); i get number of enemy health. How i can Init my enemy from here if enemy has class 'Usual Enemy' and it extends from this class 'Enemy' and i wiil have more enemy child cllases?

答案1

得分: 0

问题不在于“敌人”对象。它不是空的。如果你看一下调用栈中的最后一个引用，你会发现它是“_animator”字段。

这可能是因为你在Unity引擎调用“敌人”对象的“Start”方法之前调用了“Init”函数。

英文:

The problem is not about "enemy" object. It is not null. If you look at the last reference on your call stack, you see that it is "_animator" field.

It's probably because you call the "Init" function before the "enemy" object's "Start" method called by Unity engine.

huangapple
  • 本文由 发表于 2023年6月1日 18:54:24
  • 转载请务必保留本文链接：https://go.coder-hub.com/76381166.html
  • c#
  • oop
  • unity-game-engine
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