vault backup: 2024-10-12 17:19:45

03-UnrealEngine/Gameplay/UObject/UnrealSpecifiers/Meta/Pin/InternalUseParam/InternalUseParam.md

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+# InternalUseParam
+
+- **功能描述：** 用在函数调用上，指定要隐藏的参数名称，也可以隐藏返回值。可以隐藏多个参数
+- **使用位置：** UFUNCTION
+- **引擎模块：** Pin
+- **元数据类型：** strings="a，b，c"
+- **关联项：** [HidePin](../HidePin/HidePin.md)
+- **常用程度：** ★★
+
+该元数据和HidePin是等价的。
+
+## C++测试代码：
+
+```cpp
+UCLASS(Blueprintable, BlueprintType)
+class INSIDER_API AMyFunction_HidePinfTest :public AActor
+{
+public:
+	GENERATED_BODY()
+public:
+	UFUNCTION(BlueprintCallable)
+	int MyFunc_Default(FName name, float value, FString options) { return 0; }
+
+	UFUNCTION(BlueprintCallable, meta = (HidePin = "options"))
+	int MyFunc_HidePin(FName name, float value, FString options) { return 0; }
+
+	UFUNCTION(BlueprintCallable, meta = (InternalUseParam = "options,comment"))
+	int MyFunc_HidePin2(FName name, float value, FString options,FString comment) { return 0; }
+
+	UFUNCTION(BlueprintCallable, meta = (InternalUseParam = "options"))
+	int MyFunc_InternalUseParam(FName name, float value, FString options) { return 0; }
+
+	UFUNCTION(BlueprintCallable, meta = (HidePin = "ReturnValue"))
+	int MyFunc_HideReturn(FName name, float value, FString options, FString& otherReturn) { return 0; }
+
+public:
+	UFUNCTION(BlueprintPure)
+	int MyPure_Default(FName name, float value, FString options) { return 0; }
+
+	UFUNCTION(BlueprintPure, meta = (HidePin = "options"))
+	int MyPure_HidePin(FName name, float value, FString options) { return 0; }
+
+	UFUNCTION(BlueprintPure, meta = (InternalUseParam = "options"))
+	int MyPure_InternalUseParam(FName name, float value, FString options) { return 0; }
+
+	UFUNCTION(BlueprintPure, meta = (HidePin = "ReturnValue"))
+	int MyPure_HideReturn(FName name, float value, FString options, FString& otherReturn) { return 0; }
+
+public:
+	UFUNCTION(BlueprintCallable, meta = (InternalUseParam = "options,comment"))
+	int MyFunc_InternalUseParams2(FName name, float value, FString options,FString comment) { return 0; }
+
+	UFUNCTION(BlueprintCallable, meta = (InternalUseParam = "options,comment,ReturnValue"))
+	int MyFunc_InternalUseParams3(FName name, float value, FString options,FString comment) { return 0; }
+
+};
+```
+
+## 蓝图测试结果：
+
+![Untitled](Untitled.png)
+
+可以看出BlueprintCallable和BlueprintPure其实都可以。另外ReturnValue是默认的返回值的名字，也可以通过这个来隐藏掉。
+
+## 原理：
+
+可见MD_InternalUseParam的使用也是在隐藏引脚。
+
+```cpp
+// Gets a list of pins that should hidden for a given function
+void FBlueprintEditorUtils::GetHiddenPinsForFunction(UEdGraph const* Graph, UFunction const* Function, TSet<FName>& HiddenPins, TSet<FName>* OutInternalPins)
+{
+	check(Function != nullptr);
+	TMap<FName, FString>* MetaData = UMetaData::GetMapForObject(Function);	
+	if (MetaData != nullptr)
+	{
+		for (TMap<FName, FString>::TConstIterator It(*MetaData); It; ++It)
+		{
+			const FName& Key = It.Key();
+
+			if (Key == FBlueprintMetadata::MD_LatentInfo)
+			{
+				HiddenPins.Add(*It.Value());
+			}
+			else if (Key == FBlueprintMetadata::MD_HidePin)
+			{
+				TArray<FString> HiddenPinNames;
+				It.Value().ParseIntoArray(HiddenPinNames, TEXT(","));
+				for (FString& HiddenPinName : HiddenPinNames)
+				{
+					HiddenPinName.TrimStartAndEndInline();
+					HiddenPins.Add(*HiddenPinName);
+				}
+			}
+			else if (Key == FBlueprintMetadata::MD_ExpandEnumAsExecs ||
+					Key == FBlueprintMetadata::MD_ExpandBoolAsExecs)
+			{
+				TArray<FName> EnumPinNames;
+				UK2Node_CallFunction::GetExpandEnumPinNames(Function, EnumPinNames);
+				
+				for (const FName& EnumName : EnumPinNames)
+				{
+					HiddenPins.Add(EnumName);
+				}
+			}
+			else if (Key == FBlueprintMetadata::MD_InternalUseParam)
+			{
+				TArray<FString> HiddenPinNames;
+				It.Value().ParseIntoArray(HiddenPinNames, TEXT(","));
+				for (FString& HiddenPinName : HiddenPinNames)
+				{
+					HiddenPinName.TrimStartAndEndInline();
+
+					FName HiddenPinFName(*HiddenPinName);
+					HiddenPins.Add(HiddenPinFName);
+
+					if (OutInternalPins)
+					{
+						OutInternalPins->Add(HiddenPinFName);
+					}
+				}
+			}
+			else if (Key == FBlueprintMetadata::MD_WorldContext)
+			{
+				const UEdGraphSchema_K2* K2Schema = GetDefault<UEdGraphSchema_K2>();
+				if(!K2Schema->IsStaticFunctionGraph(Graph))
+				{
+					bool bHasIntrinsicWorldContext = false;
+
+					UBlueprint const* CallingContext = FindBlueprintForGraph(Graph);
+					if (CallingContext && CallingContext->ParentClass)
+					{
+						UClass* NativeOwner = CallingContext->ParentClass;
+						while(NativeOwner && !NativeOwner->IsNative())
+						{
+							NativeOwner = NativeOwner->GetSuperClass();
+						}
+
+						if(NativeOwner)
+						{
+							bHasIntrinsicWorldContext = NativeOwner->GetDefaultObject()->ImplementsGetWorld();
+						}
+					}
+
+					// if the blueprint has world context that we can lookup with "self", 
+					// then we can hide this pin (and default it to self)
+					if (bHasIntrinsicWorldContext)
+					{
+						HiddenPins.Add(*It.Value());
+					}
+				}
+			}
+		}
+	}
+}
+```