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03-UnrealEngine/Gameplay/UObject/UnrealSpecifiers/Meta/Object/ShowOnlyInnerProperties/ShowOnlyInnerProperties.md

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+# ShowOnlyInnerProperties
+
+- **功能描述：** 把结构属性的内部属性直接上提一个层级直接展示
+- **使用位置：** UPROPERTY
+- **元数据类型：** bool
+- **限制类型：** FStruct属性
+- **关联项：** [ShowInnerProperties](../ShowInnerProperties/ShowInnerProperties.md)
+- **常用程度：** ★★★
+
+把结构属性的内部属性直接上提一个层级直接展示，而不是像默认一样归属于一个可展开的父级结构。
+
+## 测试代码：
+
+```cpp
+UPROPERTY(EditAnywhere, BlueprintReadWrite)
+FMyPropertyInner InnerStruct;
+
+UPROPERTY(EditAnywhere, BlueprintReadWrite, meta = (ShowOnlyInnerProperties))
+FMyPropertyInner InnerStruct_ShowOnlyInnerProperties;
+```
+
+## 效果对比：
+
+![Untitled](Untitled.png)
+
+可以发现InnerStruct_ShowOnlyInnerProperties的内部属性直接就显示在对象的当前层级上，而InnerStruct的属性有一个结构名称作为Category来展开。
+
+## 原理：
+
+在遇见FStructProperty的时候，会开始判断ShowOnlyInnerProperties来决定是否要创建一个可展开的Category，或者还是直接把内部属性展示出来。有了ShowOnlyInnerProperties，就会直接递归迭代到其内部属性。
+
+```cpp
+void DetailLayoutHelpers::UpdateSinglePropertyMapRecursive(FPropertyNode& InNode, FName CurCategory, FComplexPropertyNode* CurObjectNode, FUpdatePropertyMapArgs& InUpdateArgs)
+{
+		static FName ShowOnlyInners("ShowOnlyInnerProperties");
+		// Whether or not to push out struct properties to their own categories or show them inside an expandable struct
+		// This recursively applies for any nested structs that have the ShowOnlyInners metadata 
+		const bool bPushOutStructProps = bIsStruct && !bIsCustomizedStruct && Property->HasMetaData(ShowOnlyInners);
+		
+		if (bRecurseIntoChildren || LocalUpdateFavoriteSystemOnly)
+		{
+						// Built in struct properties or children of arras 
+						UpdateSinglePropertyMapRecursive(ChildNode, CurCategory, CurObjectNode, ChildArgs);
+		}
+
+}
+
+void FObjectPropertyNode::GetCategoryProperties(const TSet<UClass*>& ClassesToConsider, const FProperty* CurrentProperty, bool bShouldShowDisableEditOnInstance, bool bShouldShowHiddenProperties,
+	const TSet<FName>& CategoriesFromBlueprints, TSet<FName>& CategoriesFromProperties, TArray<FName>& SortedCategories)
+	{
+			if (CurrentProperty->HasMetaData(Name_ShowOnlyInnerProperties))
+			{
+				const FStructProperty* StructProperty = CastField<const FStructProperty>(CurrentProperty);
+				if (StructProperty)
+				{
+					for (TFieldIterator<FProperty> It(StructProperty->Struct); It; ++It)
+					{
+						GetCategoryProperties(ClassesToConsider, *It, bShouldShowDisableEditOnInstance, bShouldShowHiddenProperties, CategoriesFromBlueprints, CategoriesFromProperties, SortedCategories);
+					}
+				}
+			}
+			
+}
+```