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

03-UnrealEngine/Gameplay/UObject/UnrealSpecifiers/Specifier/UPROPERTY/Blueprint/BlueprintSetter.md

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+# BlueprintSetter
+
+- **功能描述：** 采用一个自定义的set函数来读取。
+
+- **元数据类型：** string="abc"
+- **引擎模块：** Blueprint
+- **作用机制：** 在PropertyFlags中加入[CPF_BlueprintVisible](../../../Flags/EPropertyFlags/CPF_BlueprintVisible.md)，在Meta中加入[BlueprintSetter](../../../Meta/Blueprint/BlueprintSetter.md)
+- **常用程度：** ★★★
+
+采用一个自定义的set函数来读取。
+
+会默认设置BlueprintReadWrite。
+
+## 测试代码：
+
+```cpp
+public:
+	//(BlueprintGetter = , Category = Blueprint, ModuleRelativePath = Property/MyProperty_Test.h)
+	UFUNCTION(BlueprintGetter, Category = Blueprint)	//or BlueprintPure
+		int32 MyInt_Getter()const { return MyInt_WithGetter * 2; }
+
+	//(BlueprintSetter = , Category = Blueprint, ModuleRelativePath = Property/MyProperty_Test.h)
+	UFUNCTION(BlueprintSetter, Category = Blueprint)	//or BlueprintCallable
+		void MyInt_Setter(int NewValue) { MyInt_WithSetter = NewValue / 4; }
+private:
+	//(BlueprintGetter = MyInt_Getter, Category = Blueprint, ModuleRelativePath = Property/MyProperty_Test.h)
+	//PropertyFlags:	CPF_BlueprintVisible | CPF_BlueprintReadOnly | CPF_ZeroConstructor | CPF_IsPlainOldData | CPF_NoDestructor | CPF_HasGetValueTypeHash | CPF_NativeAccessSpecifierPrivate 
+	UPROPERTY(BlueprintGetter = MyInt_Getter, Category = Blueprint)
+		int32 MyInt_WithGetter = 123;
+
+	//(BlueprintSetter = MyInt_Setter, Category = Blueprint, ModuleRelativePath = Property/MyProperty_Test.h)
+	//PropertyFlags:	CPF_BlueprintVisible | CPF_ZeroConstructor | CPF_IsPlainOldData | CPF_NoDestructor | CPF_HasGetValueTypeHash | CPF_NativeAccessSpecifierPrivate 
+	UPROPERTY(BlueprintSetter = MyInt_Setter, Category = Blueprint)
+		int32 MyInt_WithSetter = 123;
+```
+
+## 蓝图表现：
+
+![Untitled](BlueprintGetter/Untitled.png)
+
+## 原理：
+
+如果有MD_PropertySetFunction则用它来作为Set的调用。
+
+```cpp
+void UK2Node_VariableSet::ExpandNode(class FKismetCompilerContext& CompilerContext, UEdGraph* SourceGraph)
+{
+		// If property has a BlueprintSetter accessor, then replace the variable get node with a call function
+		if (VariableProperty)
+		{
+			// todo check with BP team if we need to test if the variable has native Setter
+			const FString& SetFunctionName = VariableProperty->GetMetaData(FBlueprintMetadata::MD_PropertySetFunction);
+			if (!SetFunctionName.IsEmpty())
+			{
+			}
+		}
+}
+```