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03-UnrealEngine/Gameplay/UObject/UnrealSpecifiers/Meta/AnimationGraph/CustomizeProperty/CustomizeProperty.md

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+# CustomizeProperty
+
+- **功能描述：** 使用在FAnimNode的成员属性上，告诉编辑器不要为它生成默认Details面板控件，后续会在DetailsCustomization里自定义创建相应的编辑控件。
+- **使用位置：** UPROPERTY
+- **引擎模块：** AnimationGraph
+- **元数据类型：** bool
+- **限制类型：** FAnimNode里的属性
+- **常用程度：** ★
+
+使用在FAnimNode的成员属性上，告诉编辑器不要为它生成默认Details面板控件，后续会在DetailsCustomization里自定义创建相应的编辑控件。
+
+和AllowEditInlineCustomization的作用有点像，都只是做个标记提示编辑器会在别的地方进行自定义，不用为它生成默认Details面板控件。
+
+## 源码中例子：
+
+在源码里能见到挺多例子，常见的就是在AnimBP中的节点上的属性，其在细节面板需要专门的定制化编辑。最常见的例子是Slot这个节点，其SlotName只是个FString类型，但是在细节面板里显示的却是个ComboString。这是因为它标上了CustomizeProperty，告知默认的动画节点细节面板生成器*（FAnimGraphNodeDetails）先不要为这个属性创建编辑控件，之后会在自己的定制化（FAnimGraphNodeSlotDetails）里为SlotName再创建自定义UI。
+
+```cpp
+struct FAnimNode_Slot : public FAnimNode_Base
+{
+	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category=Settings, meta=(CustomizeProperty))
+	FName SlotName;
+}
+
+void FPersonaModule::CustomizeBlueprintEditorDetails(const TSharedRef<class IDetailsView>& InDetailsView, FOnInvokeTab InOnInvokeTab)
+{
+	InDetailsView->RegisterInstancedCustomPropertyLayout(UAnimGraphNode_Slot::StaticClass(),
+		FOnGetDetailCustomizationInstance::CreateStatic(&FAnimGraphNodeSlotDetails::MakeInstance, InOnInvokeTab));
+
+	InDetailsView->SetExtensionHandler(MakeShared<FAnimGraphNodeBindingExtension>());
+}
+
+```
+
+## 测试代码：
+
+```cpp
+USTRUCT(BlueprintInternalUseOnly)
+struct INSIDER_API FAnimNode_MyCustomProperty : public FAnimNode_Base
+{
+	GENERATED_USTRUCT_BODY()
+public:
+	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = CustomProperty)
+	FString MyString_Default;
+	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = CustomProperty, meta = (CustomizeProperty))
+	FString MyString_CustomizeProperty;
+	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = CustomProperty, meta = (CustomizeProperty))
+	FString MyString_CustomizeProperty_Other;
+};
+
+UCLASS()
+class INSIDEREDITOR_API UAnimGraphNode_MyCustomProperty : public UAnimGraphNode_Base
+{
+	GENERATED_UCLASS_BODY()
+
+	UPROPERTY(EditAnywhere, Category = Settings)
+	FAnimNode_MyCustomProperty Node;
+};
+
+//再创建一个定制化，生成自定义UI
+void FMyAnimNode_MyCustomPropertyCustomization::CustomizeDetails(class IDetailLayoutBuilder& DetailBuilder)
+{
+	TSharedPtr<IPropertyHandle> PropertyHandle = DetailBuilder.GetProperty(TEXT("Node.MyString_CustomProperty"));
+	
+	//Just for test
+	ComboListItems.Empty();
+	ComboListItems.Add(MakeShareable(new FString(TEXT("First"))));
+	ComboListItems.Add(MakeShareable(new FString(TEXT("Second"))));
+	ComboListItems.Add(MakeShareable(new FString(TEXT("Third"))));
+	const TSharedPtr<FString> ComboBoxSelectedItem = ComboListItems[0];
+
+	IDetailCategoryBuilder& Group = DetailBuilder.EditCategory(TEXT("CustomProperty"));
+	Group.AddCustomRow(INVTEXT("CustomProperty"))
+		.NameContent()
+		[
+			PropertyHandle->CreatePropertyNameWidget()
+		]
+		.ValueContent()
+		[
+			SNew(STextComboBox)
+				.OptionsSource(&ComboListItems)
+				.InitiallySelectedItem(ComboBoxSelectedItem)
+				.ContentPadding(2.f)
+				.ToolTipText(FText::FromString(*ComboBoxSelectedItem))
+		];
+}
+
+//注册定制化
+PropertyModule.RegisterCustomClassLayout(TEXT("AnimGraphNode_MyCustomProperty"), FOnGetDetailCustomizationInstance::CreateStatic(&FMyAnimNode_MyCustomPropertyCustomization::MakeInstance));
+
+```
+
+## 测试效果：
+
+SlotName的效果如右侧所示。
+
+我们自己模仿的例子可见MyString_Default依然只是个默认String，而MyString_CustomizeProperty则为它创建了自定义UI。
+
+作为对比，MyString_CustomizeProperty_Other我们标上了CustomizeProperty但是没有为它创建UI，则没有显示出来，说明引擎默认的机制因此就把它的UI默认创建流程给跳过了。
+
+![Untitled](Untitled.png)
+
+## 原理：
+
+CustomizeProperty其实会会改变Pin的bPropertyIsCustomized 属性（GetRecordDefaults中体现），然后在创建流程的过程中不创建默认的widget，这个可见CustomizeDetails中的bPropertyIsCustomized判断得知。
+
+```cpp
+void FAnimBlueprintNodeOptionalPinManager::GetRecordDefaults(FProperty* TestProperty, FOptionalPinFromProperty& Record) const
+{
+	const UAnimationGraphSchema* Schema = GetDefault<UAnimationGraphSchema>();
+
+	// Determine if this is a pose or array of poses
+	FArrayProperty* ArrayProp = CastField<FArrayProperty>(TestProperty);
+	FStructProperty* StructProp = CastField<FStructProperty>(ArrayProp ? ArrayProp->Inner : TestProperty);
+	const bool bIsPoseInput = (StructProp  && StructProp->Struct->IsChildOf(FPoseLinkBase::StaticStruct()));
+
+	//@TODO: Error if they specified two or more of these flags
+	const bool bAlwaysShow = TestProperty->HasMetaData(Schema->NAME_AlwaysAsPin) || bIsPoseInput;
+	const bool bOptional_ShowByDefault = TestProperty->HasMetaData(Schema->NAME_PinShownByDefault);
+	const bool bOptional_HideByDefault = TestProperty->HasMetaData(Schema->NAME_PinHiddenByDefault);
+	const bool bNeverShow = TestProperty->HasMetaData(Schema->NAME_NeverAsPin);
+	const bool bPropertyIsCustomized = TestProperty->HasMetaData(Schema->NAME_CustomizeProperty);
+	const bool bCanTreatPropertyAsOptional = CanTreatPropertyAsOptional(TestProperty);
+
+	Record.bCanToggleVisibility = bCanTreatPropertyAsOptional && (bOptional_ShowByDefault || bOptional_HideByDefault);
+	Record.bShowPin = bAlwaysShow || bOptional_ShowByDefault;
+	Record.bPropertyIsCustomized = bPropertyIsCustomized;
+}
+
+//这个是在AnimBP中选中一个节点然后在右侧细节面板中的属性
+void FAnimGraphNodeDetails::CustomizeDetails(class IDetailLayoutBuilder& DetailBuilder)
+{
+		// sometimes because of order of customization
+		// this gets called first for the node you'd like to customize
+		// then the above statement won't work
+		// so you can mark certain property to have meta data "CustomizeProperty"
+		// which will trigger below statement
+		if (OptionalPin.bPropertyIsCustomized)
+		{
+						continue;
+		}
+		TSharedRef<SWidget> InternalCustomWidget = CreatePropertyWidget(TargetProperty, TargetPropertyHandle.ToSharedRef(), AnimGraphNode->GetClass());
+}
+```