UI Toolkit at Package Level?

This might be a dumb question, but I'm about to start with UI Toolkit, and I'm adding it to a package, not a project. So I create a new Editor Window, which creates the three files (.cs, .uss and .uxml), and following the tutorial I want to link the USS to my window, which results in "Asset at path {cut-off path} is not a StyleSheet".

Creating a new USS results in "Could not find a part of the path {cut-off path}" in the console. It seems to me that your tooling is not set up for supporting package-level UI. Is there a workaround or something I'm missing?

 

I'm on 2021.2.14f.

I played around some more, and when you create a new UXML through the editor, the generated .cs actually loads the style sheet via code. Here, the package file path works. So I'm not sure what the UI Builder is supposed to do actually when you add style sheets there.

 

Yes, it's an editor window. And the result is functional. It's just that in the tutorial, it says, quote

In StyleSheet, click Add Existing USS and select DragAndDropWindow.uss​

Which doesn't work for an USS located in a package, but isn't necessary, because the stylesheet is already assigned through the generated .cs.

I'll try to add the stylesheet through the markup as you suggested later.

In any case, thanks for your quick help, really appreciated!

 

Alright, thanks for checking!

 

A workaround is to add it from C#, but that won't show it in the editor.

Hope they backport the fix if it ever comes -.-

 

Update for this? I would like to refer to a package path when adding a uss file

 

Had this issue too, though with visual tree assets, though found a simple work around that should work with style sheets assets too:

• Serialize a VisualTreeAsset/StyleSheet field in your editor window
• Select your script asset, and assign a reference through the default value fields
• The values will be assigned when the window is open, so you can apply them via C# easily

 

I had a similar problem where I was developing an asset library and then using it as a package within another project. I just check to see if the package's virtual path is valid using AssetDatabase API and if it is I simply switch the base path. See example below.

Add this script into an Editor folder:

Code (CSharp):

1. public static class AssetPaths
2. {
3.     public static string packageRootDir
4.     {
5.         get
6.         {
7.             // regular assets path
8.             string rootDir = "Assets/whatever/";
9.  
10.             // IMPORTANT: this is linked to the "name" property of the package manifest json file
11.             string packagesDir = "Packages/com.whatever/";
12.  
13.             if (AssetDatabase.IsValidFolder(packagesDir))
14.                 rootDir = packagesDir;
15.  
16.             return rootDir;
17.         }
18.     }
19. }

Then you can use the correct path like so:

Code (CSharp):

1. protected void CreateGUI()
2. {
3.     // build GUI from UXML
4.     VisualTreeAsset visualTree = AssetDatabase.LoadAssetAtPath<VisualTreeAsset>(
5.         AssetPaths.packageRootDir + "Editor/MyCustomEditorWindow.uxml"
6.     );
7.     visualTree.CloneTree(rootVisualElement);
8.  
9.     // add stylesheet
10.     StyleSheet styleSheet = AssetDatabase.LoadAssetAtPath<StyleSheet>(
11.         AssetPaths.packageRootDir + "Editor/MyCustomEditorWindow.uss"
12.     );
13.    
14.     if (styleSheet != null)
15.         rootVisualElement.styleSheets.Add(styleSheet);
16. }

This does not affect UIBuilder, you can still use it like normal.

 

This Bug is over a year old and still not fixed...
It is really annoying that you cannot use stylesheet files with the ui builder when working in a package...

 

It works with the UI builder if you add the style file in the uxml via text editor and with relative path to the uxml.

Code (CSharp):

1. <ui:UXML ...>
2.     <Style src="styles.uss" />
3.     <ui:VisualElement name="root" />
4. </ui:UXML>

like this when they are in the same folder

 

Is there any ETA on this now? Been 1 1/2 years and with the recommended workflow of using packages this feature is pretty much necessary.

 

I would like to +1 this issue, in our project we are building a framework of packages where each package features its own UI assets; but currently we cannot bring it together in the project due to this issue

 

@mvriel Have you tried my suggestion above? I am able to use the UI Builder to design Editor UI in a package and I can import it just fine in other projects.