PlaceActors 需在引擎初始化之后

但，单为这一个功能，更改整个模块的启动顺序，也不太划算

更好的办法是，启动顺序保持正常（如"LoadingPhase": "Default" ），然后通过监听引擎初始化完成的回调事件来实现

FCoreDelegates::OnPostEngineInit.AddRaw(this, &FAdvModModule::RegisterPlaceActors);

1、模块启动时，绑定回调事件

void FAdvModModule::StartupModule()
{
	FCoreDelegates::OnPostEngineInit.AddRaw(this, &FAdvModModule::RegisterPlaceActors);
}

2、模块关闭时，卸载

void FAdvModModule::ShutdownModule()
{
	UnregisterPlaceActors();
}

void FAdvModModule::UnregisterPlaceActors()
{
	// 注意，直接判断模块是否有效
	if (!IPlacementModeModule::IsAvailable())
	{
		return;
	}

	IPlacementModeModule& PlacementModeModule = IPlacementModeModule::Get();
	PlacementModeModule.UnregisterPlacementCategory(FName("ExtendPlaceActors"));
}

3、注册

void FAdvModModule::RegisterPlaceActors()
{
	// 判断模块是否已加载
	IPlacementModeModule& PlacementModeModule = IPlacementModeModule::Get();
	if (!PlacementModeModule.IsAvailable())
	{
		return;
	}

	// 注册分类
	int32 SortOrder = 0;
	FPlacementCategoryInfo AdvCategoryInfo(FText::FromString("ExtendActors"), FSlateIcon(), FName("ExtendPlaceActors"), "ExtendActors", SortOrder += 10);
	PlacementModeModule.RegisterPlacementCategory(AdvCategoryInfo);
	
	// 创建子项
	FPlaceableItem* Item01 = new FPlaceableItem(nullptr, FAssetData(AStaticMeshActor::StaticClass()), SortOrder += 10);
	FPlaceableItem* Item02 = new FPlaceableItem(nullptr, FAssetData(ASkeletalMeshActor::StaticClass()), SortOrder += 10);
	FPlaceableItem* SKM_Manny = new FPlaceableItem(nullptr, FAssetData(LoadObject<USkeletalMesh>(nullptr, TEXT("/Game/Characters/Mannequins/Meshes/SKM_Manny.SKM_Manny"))), SortOrder += 10);
	FPlaceableItem* SKM_Quinn = new FPlaceableItem(nullptr, FAssetData(LoadObject<USkeletalMesh>(nullptr, TEXT("/Game/Characters/Mannequins/Meshes/SKM_Quinn.SKM_Quinn"))), SortOrder += 10);
	FPlaceableItem* ABP_Manny = new FPlaceableItem(nullptr, FAssetData(LoadObject<UAnimBlueprint>(nullptr, TEXT("/Game/Characters/Mannequins/Animations/ABP_Manny.ABP_Manny"))), SortOrder += 10);
	FPlaceableItem* ABP_Quinn = new FPlaceableItem(nullptr, FAssetData(LoadObject<UAnimBlueprint>(nullptr, TEXT("/Game/Characters/Mannequins/Animations/ABP_Quinn.ABP_Quinn"))), SortOrder += 10);
	FPlaceableItem* Item_Material = new FPlaceableItem(nullptr, FAssetData(LoadObject<UMaterial>(nullptr, TEXT("/Game/Characters/Mannequins/Materials/M_Mannequin.M_Mannequin"))), SortOrder += 10);

	// 将子项添加到分类中
	PlacementModeModule.RegisterPlaceableItem(AdvCategoryInfo.UniqueHandle, MakeShareable(Item01));
	PlacementModeModule.RegisterPlaceableItem(AdvCategoryInfo.UniqueHandle, MakeShareable(Item02));
	PlacementModeModule.RegisterPlaceableItem(AdvCategoryInfo.UniqueHandle, MakeShareable(SKM_Manny));
	PlacementModeModule.RegisterPlaceableItem(AdvCategoryInfo.UniqueHandle, MakeShareable(SKM_Quinn));
	PlacementModeModule.RegisterPlaceableItem(AdvCategoryInfo.UniqueHandle, MakeShareable(ABP_Manny));
	PlacementModeModule.RegisterPlaceableItem(AdvCategoryInfo.UniqueHandle, MakeShareable(ABP_Quinn));
	PlacementModeModule.RegisterPlaceableItem(AdvCategoryInfo.UniqueHandle, MakeShareable(Item_Material));
	
}