GetAssetPreview 总是返回 null

Question

I have a small unity editor script that gets asset previews from unity and saves them to a folder. It works well for my machine but it doesn't work on another machine that has the same project. Here is the code I use:

GameObject[] objs = Resources.LoadAll<GameObject>("");
foreach (GameObject obj in objs)
{
    Texture2D previewImage = null;
    while (previewImage == null)
    {
        previewImage = AssetPreview.GetAssetPreview(obj);
        Thread.Sleep(100);
    }
    System.IO.File.WriteAllBytes(previewImage.name + ".png", previewImage.EncodeToPNG());
}

The code stays in an infinite loop where it says previewImage == null . Any ideas ?

Answer 1

I know this is an old post, but I have been struggling with the same issue and what seems to work really well for me is the following code:

AssetDatabase.ImportAsset(AssetDatabase.GetAssetPath(prefab), ImportAssetOptions.ForceUpdate);

This will cause a bit of lag for large asset databases, but not too much.

Another way of solving this issue is to use:

EditorUtility.SetDirty(prefab);

This however is sooo much slower...

Check both and see which one fits your needs, but I would go with the first one.

Answer 2

EditorUtility.SetDirty(prefab);

Worked for me! Thanks! For textures it returns whole atlas, but with 3d model worked good. I needed a couple of hacks to prevent application failure:

1. Max tries counter.

2. Sprites dictionary for not calling SetDirty() every time.

    public static Texture2D GetPreviewForced(Object obj) { if (obj == null) return null; int instanceId = obj.GetInstanceID(); if (_itemsPreviews.ContainsKey(obj)) { return _itemsPreviews[obj]; } else { if (Application.isPlaying) EditorUtility.SetDirty(obj); Texture2D result = AssetPreview.GetAssetPreview(obj); int tries = 1000; while (AssetPreview.IsLoadingAssetPreview(instanceId) && tries > 0) { tries--; } if (tries != 0) _itemsPreviews.Add(obj, result); return result; } }