自定义资源

新建插件StateMachine,然后手动拷贝一份StateMachineEditor用于编辑器模块，把里面的所有名称改为后缀为Editor版本

然后在Editor版本的Build.cs 的Private部分中加入如下模块 "UnrealEd", "AssetTools",Public部分加入 "StateMachine"模块

资源类

创建随意UObject 资源，可以保持默认，本例中为UStateMachineAsset

行为类

创建FAssetTypeActions_StateMachine类继承自FAssetTypeActions_Base，此类可以接管资源双击打开编辑器的动作，这个类需要在模块启动时注册，稍微会讲

此类建议创建在Editor模块

代码如下

#pragma once

#include "Developer/AssetTools/Public/AssetTypeActions_Base.h"

class FAssetTypeActions_StateMachine: public FAssetTypeActions_Base
{
public:
	FAssetTypeActions_StateMachine(EAssetTypeCategories::Type AsstCategory);
	~FAssetTypeActions_StateMachine();
	
	// IAssetTypeActions Implementation

	virtual FText GetName()const override;
	virtual FColor GetTypeColor()const override;;
	virtual UClass* GetSupportedClass()const override;
	virtual void OpenAssetEditor(const `TArray<UObject*>`& InObjects, `TSharedPtr<class IToolkitHost>` EditWithInLevelEditor = `TSharedPtr<IToolkitHost>`())override;

	virtual UThumbnailInfo* GetThumbnailInfo(UObject* Asset)const override;
	virtual uint32 GetCategories()override { return m_AssetCategory; }//自定义的标签，可以用系统自带的EAssetTypeCategories::Type

private:
	EAssetTypeCategories::Type m_AssetCategory;
};


#include "AssetTypeActions_StateMachine.h"
#include "BlueprintEditorUtils.h"
#include "AssetRegistryModule.h"

#include "StateMachineAsset.h"

#include "ThumbnailRendering/SceneThumbnailInfo.h"

#define LOCTEXT_NAMESPACE "AssetTypeActions"

FAssetTypeActions_StateMachine::FAssetTypeActions_StateMachine(EAssetTypeCategories::Type AssetCategory)
	:m_AssetCategory(AssetCategory)
{

}

FAssetTypeActions_StateMachine::~FAssetTypeActions_StateMachine()
{
	
}

FText FAssetTypeActions_StateMachine::GetName()const
{
	// Content里右键菜单创建的显示的可创建类型的名字
	return NSLOCTEXT("AssetTypeActions", "AssetTypeActions_StateMachine", "StateMachine Blueprint");
}

FColor FAssetTypeActions_StateMachine::GetTypeColor()const
{

	return FColor::Emerald;
}

UClass* FAssetTypeActions_StateMachine::GetSupportedClass()const
{
	return UStateMachineAsset::StaticClass();//创建的资源，即之前定义的UObject
}

//打开资源行为，通过这个方法可以打开其他视图
void FAssetTypeActions_StateMachine::OpenAssetEditor(const `TArray<UObject*>`& InObjects, `TSharedPtr<class IToolkitHost>` EditWithInLevelEditor)
{
	UE_LOG(LogTemp, Log, TEXT("FAssetTypeActions_StateMachine::OpenAssetEditor"));
//内容暂无
}

UThumbnailInfo* FAssetTypeActions_StateMachine::GetThumbnailInfo(UObject* Asset)const
{
	return NULL;
}

#undef LOCTEXT_NAMESPACE

工厂类

此类最好创建在Editor模块

此类是让引擎认识我们创建的这个资源和自定义标签，似乎定义了以后引擎就自动会识别，即上述两个类的功能

不创建的话连对应的自定义的标签也无法显示

#pragma once

#include "StateMachineAsset.h"
#include "Engine/Blueprint.h"
#include "Factories/Factory.h"
#include "UObject/Object.h"
#include "UObject/ObjectMacros.h"
#include "UObject/ScriptMacros.h"

#include "StateMachineFactory.generated.h"

UCLASS(HideCategories = Object,MinimalAPI)
class UStateMachineFactory : public UFactory
{
	GENERATED_BODY()

public:
	UStateMachineFactory(const FObjectInitializer& ObjectInitializer);
	virtual ~UStateMachineFactory();

public:
	UPROPERTY(EditAnywhere, Category = "StateMachineFactory")
		`TEnumAsByte<EBlueprintType>` mBlueprintType;

	UPROPERTY(EditAnywhere, Category = "StateMachineFactory")
		`TSubclassOf<UStateMachineAsset>` mSupportedClass;

public:
	// override UFactory function
	virtual bool ConfigureProperties()override;
	virtual UObject* FactoryCreateNew(UClass* InClass, UObject* InParent, FName InName, EObjectFlags InFlags, UObject* InContext, FFeedbackContext* InWarn,FName InCallingContext)override;
	virtual UObject* FactoryCreateNew(UClass* InClass, UObject* InParent, FName InName, EObjectFlags InFlags, UObject* InContext, FFeedbackContext* InWarn);
};


#include "StateMachineFactory.h"
#include "StateMachineAsset.h"

UStateMachineFactory::UStateMachineFactory(const FObjectInitializer& ObjectInitializer)
	:Super(ObjectInitializer), mSupportedClass(UStateMachineAsset::StaticClass())
{
	bCreateNew = true;
	bEditAfterNew = true;

	// 这个Factory托管的类型
	SupportedClass = mSupportedClass;
}

UStateMachineFactory::~UStateMachineFactory()
{

}

bool UStateMachineFactory::ConfigureProperties()
{
	return true;
}

UObject* UStateMachineFactory::FactoryCreateNew(UClass* InClass, UObject* InParent, FName InName, EObjectFlags InFlags, UObject* InContext, FFeedbackContext* InWarn,FName InCallingContext)
{
	return FactoryCreateNew(InClass, InParent, InName, InFlags, InContext, InWarn);
}

UObject* UStateMachineFactory::FactoryCreateNew(UClass* InClass,UObject* InParent,FName InName,EObjectFlags InFlags,UObject* InContext,FFeedbackContext* InWarn)
{
	UStateMachineAsset* NewStateMachineAssetItem = `NewObject<UStateMachineAsset>`(InParent, InClass, InName, InFlags);
	return NewStateMachineAssetItem;
}

模块

用于注册自定义标签以及我们之前创建的FAssetTypeActions_StateMachine类

// Copyright 1998-2019 Epic Games, Inc. All Rights Reserved.

#pragma once
#include "AssetTypeCategories.h"
#include "AssetToolsModule.h"

#include "CoreMinimal.h"
#include "Modules/ModuleManager.h"

class FStateMachineEditorModule : public IModuleInterface
{
public:

	/** IModuleInterface implementation */
	virtual void StartupModule() override;
	virtual void ShutdownModule() override;


	void RegisterAssetType(IAssetTools& AssetTools);
	void RegisterSetting();
	void UnRegisterSetting();


private:
	EAssetTypeCategories::Type m_StateMachineCategoryType;//自定义标签
	TArray<`TSharedPtr<IAssetTypeActions>`> m_CreatedAssetTypeActions;//Action数组
};

// Copyright 1998-2019 Epic Games, Inc. All Rights Reserved.

#include "StateMachineEditor.h"
#include "AssetTypeActions_StateMachine.h"
#include "ISettingsModule.h"

#define LOCTEXT_NAMESPACE "FStateMachineEditorModule"

void FStateMachineEditorModule::StartupModule()
{
	// This code will execute after your module is loaded into memory; the exact timing is specified in the .uplugin file per-module
	IAssetTools& AssetToolsInstance = FModuleManager::`LoadModuleChecked<FAssetToolsModule>`("AssetTools").Get();
    //创建自定义标签，可以本地化翻译
	m_StateMachineCategoryType= AssetToolsInstance.RegisterAdvancedAssetCategory(TEXT("StateMachine"), LOCTEXT("StateMachineAssetCategory", "StateMachine"));
	RegisterAssetType(AssetToolsInstance);
	RegisterSetting();

}

void FStateMachineEditorModule::ShutdownModule()
{
	// This function may be called during shutdown to clean up your module.  For modules that support dynamic reloading,
	// we call this function before unloading the module.

	UnRegisterSetting();
}

void FStateMachineEditorModule::RegisterAssetType(IAssetTools& AssetTools)
{
	`TSharedRef<IAssetTypeActions>` StateMachineBlueprint = MakeShareable(new FAssetTypeActions_StateMachine(m_StateMachineCategoryType));
    //注册资源行为类
	AssetTools.RegisterAssetTypeActions(StateMachineBlueprint);
	m_CreatedAssetTypeActions.Add(StateMachineBlueprint);
}

void FStateMachineEditorModule::RegisterSetting()
{
//暂时为空
}

void FStateMachineEditorModule::UnRegisterSetting()
{
//暂时为空
}

#undef LOCTEXT_NAMESPACE
	
IMPLEMENT_MODULE(FStateMachineEditorModule, StateMachineEditor)

然后我们在引擎Content目录下右键点击就出现我们要的效果