[Solved] Asset picker widget for editor utility widget

[trashbyte]

I’m trying to add an asset picker (the same kind used all over the editor) to an editor utility widget, and I thought this would be simple but I guess there’s no support for it yet?

My research has led me down a Slate rabbit hole, with little to show for it. Apparently **SObjectPropertyEntryBox** is a slate widget type I could use? I made a UWidget subclass with **SNew(SObjectPropertyEntryBox)** etc in **RebuildWidget()** and that does result in an asset picker, but I can’t seem to get **OnObjectChanged** hooked up properly. It expects a reference to a callback function with **const FAssetData& Data** as a parameter, which seems pretty straightforward, but deep down in the slate codegen somewhere it calls **CreateSP(StaticCastSharedRef<UserClass>(InUserObject->AsShared()), InFunc, Vars...)** where **UserClass** is the widget type that gets passed to **OnObjectChanged** (my widget type), and **InUserObject is a **UserClass*. And the handler function in question is expected to be a member of that class, I think? e.g. .**OnObjectChanged(thi****s, &UMyAssetPickerWidget::OnAssetChanged)**. The problem is, my UWidget subclass isn’t **TSharedFromThis** so it doesn’t have **->AsShared()** and the compiler chokes there.

If there’s an easier way to do this, please let me know. Otherwise, how can I get a **SObjectPropertyEntryBox** or something similar into a widget I can use in UMG?

[trashbyte]

Okay, after a good night’s sleep I’ve figured it out. **OnObjectChanged has 22 (!) overloads, and the one I was using was for binding delegates on non-UObjects. There’s another overload, **OnObjectChanged(const FOnSetObject&) that takes a reference to a **FOnSetObject **which is a delegate type declared in **PropertyCustomizationHelpers.h**. So, I added a **FOnSetObject** delegate to my **UWidget** class, passed a reference to that into **OnObjectChanged** and used **BindUObject** on the delegate in my **UWidget** class’s constructor to bind that delegate to a member function that takes **const FAssetData&** and voilà! A working callback.

Edit:

Actually, there’s an even simpler way to do this. You can cut out the delegate middle man and just use the **OnObjectChanged_UObject()** variant which expects a UObject and its member function. It’s so much easier to figure this stuff out when intellisense actually decides to work.

[BlackFangTech]

@trashbyte

Okay, after a good night’s sleep I’ve figured it out. **OnObjectChanged has 22 (!) overloads, and the one I was using was for binding delegates on non-UObjects. There’s another overload, **OnObjectChanged(const FOnSetObject&) that takes a reference to a **FOnSetObject **which is a delegate type declared in **PropertyCustomizationHelpers.h**. So, I added a **FOnSetObject** delegate to my **UWidget** class, passed a reference to that into **OnObjectChanged** and used **BindUObject** on the delegate in my **UWidget** class’s constructor to bind that delegate to a member function that takes **const FAssetData&** and voilà! A working callback.

Edit:

Actually, there’s an even simpler way to do this. You can cut out the delegate middle man and just use the **OnObjectChanged_UObject()** variant which expects a UObject and its member function. It’s so much easier to figure this stuff out when intellisense actually decides to work.

Have you tried turning the thumbnail on and were you able to do so successfully? The thumbnail pool thing baffles me to this day.

[amu_mhr (Amit Mehar)]

@BlackFangTech if you are still looking for a solution for Thumbnails, you can try this:

FLevelEditorModule& LevelEditorModule = FModuleManager::LoadModuleChecked(“LevelEditor”);
TSharedPtr ThumbnailPool = LevelEditorModule.GetFirstLevelEditor()->GetThumbnailPool();

Pass that ThumbnailPool to SObjectPropertyEntryBox