How to Create Asset Right Click Menu In UE4

It would be wonderful if we can create our own asset menu to process assets. But it seems not that easy to achieve that. I always miss Unity when it comes to creation of a customized editor tool.

Prerequisites

First of all, it is recommended to you are guranteed to have these menus setup in the StartModule function:

void F***Module::StartupModule()
{
    // Set up your menus here.
}

It’s easy to know that we should release those menus in the ShutdownModule function:

void F***Module::ShutdownModule()
{
    // Release your menus here. 
}

The Content Browser module loaded if you want to create customized right click menu. As a result, we need to load this module by:

FContentBrowserModule& ContentBrowserModule = FModuleManager::LoadModuleChecked<FContentBrowserModule>(TEXT("ContentBrowser"));

Core Logic

Menu Extender

For a right click function in the content browser, a menu extender should be created and added to the current menu extender array by:

TArray<FContentBrowserMenuExtender_SelectedAssets>& CBMenuAssetExtenderDelegates = ContentBrowserModule.GetAllAssetViewContextMenuExtenders();
	CBMenuAssetExtenderDelegates.Add(FContentBrowserMenuExtender_SelectedAssets::CreateStatic(&YourOnExtendAssetSelectionMenu));

YourOnExtendAssetSelectionMenu is a static function that accepts a const TArray<FAssetData>& and returns a TSharedRef<FExtender>:

static TSharedRef<FExtender> YourOnExtendAssetSelectionMenu(const TArray<FAssetData>& SelectedAssets)
{
	TSharedRef<FExtender> Extender = MakeShared<FExtender>();
	Extender->AddMenuExtension(
		"CommonAssetActions",
		EExtensionHook::After,
		nullptr,
		FMenuExtensionDelegate::CreateStatic(&YourAssetExtenderFunc, SelectedAssets)
	);
	return Extender;
}

Here another function has just came to us. We still need an AssetExtenderFunction which accepts an FMenuBuilder& and an array of FAssetData. We add menu entry here to eventually add a button by:

static void YourAssetExtenderFunc(FMenuBuilder& MenuBuilder, const TArray<FAssetData> SelectedAssets)
{
    MenuBuilder.BeginSection("Your Asset Context", LOCTEXT("ASSET_CONTEXT", "Your Asset Context"));
    {
        // Add Menu Entry Here
    }
    MenuBuilder.EndSection();
}

Filtering the Selected Asset

We always need to add some menu to the specific asset. For example, Find Skeleton button would only appear in the right-click menu for a Animation Sequence Base asset:

We can filter asset data type in YourAssetExtenderFunc like this:

for (auto AssetIt = SelectedAssets.CreateConstIterator(); AssetIt; ++AssetIt)
{
    const FAssetData& Asset = *AssetIt;
    
    if (!Asset.IsRedirector() && Asset.AssetClass != NAME_Class && !(Asset.PackageFlags & PKG_FilterEditorOnly))
    {
        if (Asset.GetClass()->IsChildOf(UAnimSequenceBase::StaticClass()))
		{
            // ... 
		}
    }
}

Add Menu Entry

Simply use a Lambda function for this like:

MenuBuilder.AddMenuEntry(
	LOCTEXT("ButtonName", "ButtonName"),
	LOCTEXT("Button ToolTip", "Button ToolTip"),
	FSlateIcon(FLinterStyle::GetStyleSetName(), "Linter.Toolbar.Icon"),
	FUIAction(FExecuteAction::CreateLambda([SelectedAssets]()
	{
		// Do work here. 
	})),
	NAME_None,
	EUserInterfaceActionType::Button);

And that should work.