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03-UnrealEngine/Gameplay/UObject/UnrealSpecifiers/Specifier/UCLASS/Blueprint/HideFunctions/HideFunctions.md

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+# HideFunctions
+
+- **功能描述：** 在子类的函数覆盖列表里隐藏掉某些函数。
+- **引擎模块：** Blueprint
+- **元数据类型：** strings=(abc，"d|e"，"x|y|z")
+- **作用机制：** 在Meta中增加[HideFunctions](../../../../Meta/Blueprint/HideFunctions.md)
+- **关联项：** [ShowFunctions](../ShowFunctions.md)
+- **常用程度：** ★★
+
+在子类的函数覆盖列表里隐藏掉某些函数。
+
+- 在蓝图中鼠标右键依然可以查看到该类下BlueprintCallable的函数，依然可以调用，本标记只是用在类的函数覆盖列表上。
+- HideFunctions其实只能填函数名字，想要隐藏一个目录下的函数，是需要HideCategories再额外定义的。
+
+源码中只有一个地方用到，一个很好的示例是UCameraComponent中定义的SetFieldOfView和SetAspectRatio，对UCineCameraComponent 来说是无意义的，因此隐藏掉会更好。
+
+```cpp
+class ENGINE_API UCameraComponent : public USceneComponent
+{
+UFUNCTION(BlueprintCallable, Category = Camera)
+	virtual void SetFieldOfView(float InFieldOfView) { FieldOfView = InFieldOfView; }
+UFUNCTION(BlueprintCallable, Category = Camera)
+	void SetAspectRatio(float InAspectRatio) { AspectRatio = InAspectRatio; }
+}
+
+UCLASS(HideCategories = (CameraSettings), HideFunctions = (SetFieldOfView, SetAspectRatio), Blueprintable, ClassGroup = Camera, meta = (BlueprintSpawnableComponent), Config = Engine)
+class CINEMATICCAMERA_API UCineCameraComponent : public UCameraComponent
+```
+
+## 示例代码：
+
+```cpp
+UCLASS(Blueprintable, HideFunctions = (MyFunc1, MyEvent2),hideCategories= EventCategory2)
+class INSIDER_API AMyClass_HideFunctions :public AActor
+{
+	GENERATED_BODY()
+public:
+	UFUNCTION(BlueprintCallable)
+		void MyFunc1() {}
+
+	UFUNCTION(BlueprintCallable)
+		void MyFunc2() {}
+
+	UFUNCTION(BlueprintCallable, Category = "FuncCategory1")
+		void MyFuncInCategory1() {}
+
+	UFUNCTION(BlueprintCallable, Category = "FuncCategory2")
+		void MyFuncInCategory2() {}
+
+public:
+UFUNCTION(BlueprintImplementableEvent)
+		void MyEvent1();
+
+	UFUNCTION(BlueprintImplementableEvent)
+		void MyEvent2();
+
+	UFUNCTION(BlueprintImplementableEvent, Category = "EventCategory1")
+		void MyEventInCategory1();
+
+	UFUNCTION(BlueprintImplementableEvent, Category = "EventCategory2")
+		void MyEventInCategory2();
+};
+
+UCLASS(Blueprintable, ShowFunctions = (MyEvent2),showCategories= EventCategory2)
+class INSIDER_API AMyClass_ShowFunctions :public AMyClass_HideFunctions
+{
+	GENERATED_BODY()
+public:
+
+};
+```
+
+## 示例效果：
+
+发现Callable的函数是依然可以调用的。
+
+![Untitled](Untitled.png)
+
+在HideFunction子类里，函数重载会发现少两个
+
+![Untitled](Untitled%201.png)
+
+在ShowFunction的子类里可以重新打开Event2和EventCategory2
+
+![Untitled](Untitled%202.png)
+
+## 原理：
+
+原理显示，HideFunctions其实只能填函数名字，想要隐藏一个目录下的函数，是需要HideCategories再额外定义的。
+
+```cpp
+bool IsFunctionHiddenFromClass( const UFunction* InFunction,const UClass* Class )
+	{
+		bool bResult = false;
+		if( InFunction )
+		{
+			bResult = Class->IsFunctionHidden( *InFunction->GetName() );
+
+			static const FName FunctionCategory(TEXT("Category")); // FBlueprintMetadata::MD_FunctionCategory
+			if( !bResult && InFunction->HasMetaData( FunctionCategory ) )
+			{
+				FString const& FuncCategory = InFunction->GetMetaData(FunctionCategory);
+				bResult = FEditorCategoryUtils::IsCategoryHiddenFromClass(Class, FuncCategory);
+			}
+		}
+		return bResult;
+	}
+```