Unity如何检测sprite mssing?或为空? [英] Unity How to detect sprite mssing? or null?
问题描述
我想检测图像精灵是缺少"还是无"
I want to detect image sprite is "Missing" or "None"
当我得到这个精灵时,他们都像这样空", 那么,我怎么知道它是缺失"还是无"?
When I Get this sprite , They all got "null" like this , So How do I know it is "Missing" or "None" ?
PS:我想知道它丢失了还是没有,对我来说是不同的情况.
PS : I want to know it is missing or none , it is different situations for me.
推荐答案
由于尝试访问引用时引用null
的原因不同,Unity会引发不同的异常!
Unity throws different exceptions for different reasons why the reference is null
when trying to access them!
这也是您应已覆盖行为类型为Object
的== null
(基本上是大多数Unity内置类型的父类),即使对象看起来是null
,它仍会存储一些信息,如前所述-其原因null
.
This is also the reason why you should strongly avoid someObject == null
checks. Unity has overwritten the behavior of == null
for the type Object
(basically the mother class of most Unity built-in types) and even if an object appears to be null
it still stores some information like - as just mentioned - the reason why it is null
.
因此,您可以使用一些技巧",然后只需尝试访问一个字段并检查您在try - catch
块中确切地获得了哪个异常:
So you could use a little "trick" and simply try to access a field and check which exception exactly you get within try - catch
blocks:
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!");
}
}
示例
Example
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!");
}
}
}
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