Extending asset type actions

General Feedback & Requests
1

Extending various engine asset types is relatively straightforward and seems like an obvious starting point for many plugins. However, from what I can see, inheriting and extending associated asset type actions isn’t possible since they are all hidden away in private engine code and not exported. If we register a custom asset type actions object, then this overrides those registered for the engine asset class and so the in-built actions are no longer available.

Is there a reason why asset type actions have not been exported? Am I missing something that would allow me to extend them?

2

Heya kamrann! The proper api exposure for these classes has not yet been determined, but one thing you can do is:

In the GetActions function of your custom subclass of IAssetTypeActions (lets call it FFooActions for asset type UFooAsset), you can get the IAssetTypeActions of the engine-level asset that UFooAsset extends by using IAssetTools::GetAssetTypeActionsForClass() and passing in the parent class of UFooAsset.
Just call GetActions on the engine-level IAssetTypeActions before or after adding your own (which will determine menu order).

It would look like this:
void FFooActions::GetActions(const TArray<UObject*>& InObjects, FMenuBuilder& MenuBuilder)
{
FAssetToolsModule& AssetToolsModule = FModuleManager::LoadModuleChecked<FAssetToolsModule>(TEXT(“AssetTools”));
TSharedPtr<IAssetTypeActions> EngineActions = AssetToolsModule.Get().GetAssetTypeActionsForClass(GetSupportedClass()->GetSuperClass()).Pin();
if (EngineActions.IsValid())
{
EngineActions->GetActions(InObjects, MenuBuilder);
}

// Add more actions here

}

3

I’d missed that function in the module interface. Awesome, thanks Bob!

4

I’m trying to do something similar, but in my case I’m trying to add a custom action for USkeletalMesh. Doing it the way BobTellez suggested would require my tiny little IAssetActions-derived class to implement all the functions that FAssetTypeActions_SkeletalMesh overrides, finding the correct FAssetTypeActions_SkeletalMesh instance inside them and calling its implementation. This would be extremely brittle.

Is there a better way for me to simply add a single menu item that runs a tool on the selected USkeletalMesh asset in the content browser?

5

Also, isn’t there the possibility that GetAssetTypeActionsForClass() returns the same object you’re currently executing in? Resulting in an infinite loop?

6

If you aren’t wanting to create a whole new asset, you could just extend the content browser right-click menu using the menu extenders in FContentBrowserModule::GetAllAssetViewContextMenuExtenders().
You would just filter whether you apply your extension based on whether any of the selected items were of the type you want to handle.

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