NullReferenceException: Object reference not set to an insta

IndieDoroid

Version : spine-unity-3.8-2021-07-02.unitypackage
Unity 2021.1.12f1

Unity pops up the error for Spine from time to time. Any idea why I'm getting this? :think:

Seems to have to do with this line of code

if (string.IsNullOrEmpty(value)) {
   state.ClearTrack(0);
} else {
   var animationObject = skeletonDataAsset.GetSkeletonData(false).FindAnimation(value);
   if (animationObject != null)
      state.SetAnimation(0, animationObject, loop);
}

This line specifically

state.SetAnimation(0, animationObject, loop);

Thanks for the help!

Harald

IndieDoroid ：
Unity pops up the error for Spine from time to time. Any idea why I'm getting this? :think:

When exactly do you receive this error message? E.g. do you receive it when opening a scene (or after opening a project in Unity), when entering play mode, or when selecting a SkeletonDataAsset in the project?

IndieDoroid

Hi Harald

It happens once I enter play mode.

The super strange thing is, it throws this red error once, but if I EXIT then immediately ENTER again, the red error doesn't happen.

Have you seen this before? I wonder if it has anything to do with the way Unity refreshes their scenes? The editor has been suffering performance issues lately.

UPDATE
I think this is what's causing it .. which never was an issue prior to this posting. :think: Somehow it's now a problem. I was calling this at Start on another script. Am I doing something wrong ? :wounded:

 
  string _idle = "Idle";
void Start()
{
           _skeletonAnimation.AnimationName = _idle;
}

DarkTI

Looks like a matter of execution order, if you do this

state.SetAnimation(0, animationObject, loop);

in Start() as well.

If so, you need to do this

_skeletonAnimation.AnimationName = _idle;

in Awake() for example.

Harald

The problem is due to Unity Project Settings - Editor - Enter Play Mode Settings Enter Play Mode Options being enabled and Reload Scene being disabled. This will not call Awake on ExecuteAlways and ExecuteInEditorMode components (which is kind of an annoying asymmetric design :rolleyes🙂, as described here. Now SkeletonAnimation.Awake() is not called, and due to bad luck in script execution order SkeletonAnimation.Start() is called after your script's Start() call.

Now to fix this error, you would need to call skeletonAnimation.Initialize(false); once in Start() before calling _skeletonAnimation.AnimationName = _idle;.

We will add an automatic call to Initialize(false); to these Properties on the 3.8 and 4.0 branches, as this does not break existing behaviour (it has no effect when everything was correct beforehand, a null reference exception would occur anyway when not).

We have just committed the bugfix. New 3.8 and 4.0 unitypackages are available for download here as usual:
Spine Unity Download
Thanks for reporting!

For reference: this issue has been tracked under this issue ticket:
https://github.com/EsotericSoftware/spine-runtimes/issues/1919

IndieDoroid

Harald ：
The problem is due to Unity Project Settings - Editor - Enter Play Mode Settings Enter Play Mode Options being enabled and Reload Scene being disabled. This will not call Awake on ExecuteAlways and ExecuteInEditorMode components (which is kind of an annoying asymmetric design :rolleyes🙂, as described here. Now SkeletonAnimation.Awake() is not called, and due to bad luck in script execution order SkeletonAnimation.Start() is called after your script's Start() call.

Now to fix this error, you would need to call skeletonAnimation.Initialize(false); once in Start() before calling _skeletonAnimation.AnimationName = _idle;.

We will add an automatic call to Initialize(false); to these Properties on the 3.8 and 4.0 branches, as this does not break existing behaviour (it has no effect when everything was correct beforehand, a null reference exception would occur anyway when not).

We have just committed the bugfix. New 3.8 and 4.0 unitypackages are available for download here as usual:
Spine Unity Download
Thanks for reporting!

For reference: this issue has been tracked under this issue ticket:
https://github.com/EsotericSoftware/spine-runtimes/issues/1919

Thanks Harald, I'll install the latest runtime for 3.8. If I run into issues, I'll come back here. It's just so strange that suddenly it's a red error after months of nothing. :zipper:

DarkTI ：

Looks like a matter of execution order, if you do this

state.SetAnimation(0, animationObject, loop);

in Start() as well.

If so, you need to do this

_skeletonAnimation.AnimationName = _idle;

in Awake() for example.

Thanks for tip!