someObject == null
检查的原因。Unity已经覆盖了类型Object
(大多数Unity内置类型的母类)的== null
行为,即使一个对象看起来是null
,它仍然存储一些信息,比如刚才提到的它为什么是null
的原因。
因此,你可以使用一个小“技巧”,只需尝试访问一个字段,并检查在try-catch
块中确切得到了哪个异常:
public void CheckReference(Object reference)
{
try
{
var blarf = reference.name;
}
catch (MissingReferenceException) // General Object like GameObject/Sprite etc
{
Debug.LogError("The provided reference is missing!");
}
catch (MissingComponentException) // Specific for objects of type Component
{
Debug.LogError("The provided reference is missing!");
}
catch (UnassignedReferenceException) // Specific for unassigned fields
{
Debug.LogWarning("The provided reference is null!");
}
catch (NullReferenceException) // Any other null reference like for local variables
{
Debug.LogWarning("The provided reference is null!");
}
}
例子
public class Example : MonoBehaviour
{
public Renderer renderer;
public Collider collider;
private void Awake()
{
renderer = GetComponent<Renderer>();
Destroy(renderer);
}
private void Update()
{
if (!Input.GetKeyDown(KeyCode.Space)) return;
CheckReference(renderer); // MissingComponentException
CheckReference(collider); // UnassignedReferenceException
Sprite sprite = null;
CheckReference(sprite); // NullReferenceException
sprite = Sprite.Create(new Texture2D(1, 1), new Rect(0, 0, 1, 1), Vector2.zero);
DestroyImmediate(sprite);
CheckReference(sprite); // MissingReferenceException
}
public void CheckReference(Object reference)
{
try
{
var blarf = reference.name;
}
catch (MissingReferenceException) // General Object like GameObject/Sprite etc
{
Debug.LogError("The provided reference is missing!");
}
catch (MissingComponentException) // Specific for objects of type Component
{
Debug.LogError("The provided reference is missing!");
}
catch (UnassignedReferenceException) // Specific for unassigned fields
{
Debug.LogWarning("The provided reference is null!");
}
catch (NullReferenceException) // Any other null reference like for local variables
{
Debug.LogWarning("The provided reference is null!");
}
}
}
whatever.sprite == null
,Unity 会重写==
运算符和Equals
方法,以使您更轻松地进行操作。 - Draco18s no longer trusts SE