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03-UnrealEngine/Gameplay/UObject/UnrealSpecifiers/Meta/DetailsPanel/AllowEditInlineCustomization/AllowEditInlineCustomization.md

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+# AllowEditInlineCustomization
+
+- **功能描述：** 允许EditInline的对象属性可以自定义属性细节面板来编辑该对象内的数据。
+- **使用位置：** UPROPERTY
+- **元数据类型：** string="abc"
+- **关联项：** [EditInline](../EditInline/EditInline.md)
+- **常用程度：** ★
+
+允许EditInline的对象属性可以自定义属性细节面板来编辑该对象内的数据。
+
+## 测试代码：
+
+```cpp
+UCLASS(Blueprintable, BlueprintType)
+class INSIDER_API UMyCommonObject :public UObject
+{
+	GENERATED_BODY()
+public:
+	UPROPERTY(BlueprintReadWrite, EditAnywhere)
+	int32 MyInt = 123;
+	UPROPERTY(BlueprintReadWrite, EditAnywhere)
+	FString MyString;
+};
+
+UCLASS(Blueprintable, BlueprintType)
+class INSIDER_API UMyCustomAsset :public UObject
+{
+	GENERATED_BODY()
+public:
+public:
+	UPROPERTY(EditAnywhere, BlueprintReadWrite, meta = (EditInline))
+	UMyCommonObject* MyCommonObject;
+
+	UPROPERTY(EditAnywhere, BlueprintReadWrite, meta = (EditInline,AllowEditInlineCustomization))
+	UMyCommonObject* MyCommonObject_Customization;
+};
+
+```
+
+## 效果：
+
+![Untitled](Untitled.png)
+
+要做到自定义EditInline的效果，采用自定义的IPropertyTypeCustomization和RegisterCustomPropertyTypeLayout也能做到。区别是，正如上面代码里的UMyCustomAsset里面有两个同类型的UMyCommonObject*对象，假如用IPropertyTypeCustomization的方式，就会导致两个变量都变成自定义的UI模式。而用AllowEditInlineCustomization就可以使得其中你想要的那个变成自定义方式，而其他的不做改变。
+
+在用法上，AllowEditInlineCustomization必须配合自定义的FAssetEditorToolkit来自己定义一个DetailView（而不是只自定义某个类型在引擎统一的DetailView的显示），然后再自定义IDetailCustomization来提供具体的Widget，最后用RegisterInstancedCustomPropertyLayout来关联起来。
+
+```cpp
+DetailsView->RegisterInstancedCustomPropertyLayout(UMyCommonObject::StaticClass(),FOnGetDetailCustomizationInstance::CreateStatic(&FMyCommonObjectDetailsCustomization::MakeInstance));
+```
+
+（这部分代码可参考MyCustomAsset的相关实现）
+
+## 源码：
+
+```cpp
+FDetailPropertyRow::FDetailPropertyRow(TSharedPtr<FPropertyNode> InPropertyNode, TSharedRef<FDetailCategoryImpl> InParentCategory, TSharedPtr<FComplexPropertyNode> InExternalRootNode)
+{
+		static FName InlineCustomizationKeyMeta("AllowEditInlineCustomization");
+		if (PropertyNode->AsComplexNode() && ExternalRootNode.IsValid()) // AsComplexNode works both for objects and structs
+		{
+			// We are showing an entirely different object inline.  Generate a layout for it now.
+			if (IDetailsViewPrivate* DetailsView = InParentCategory->GetDetailsView())
+			{
+				ExternalObjectLayout = MakeShared<FDetailLayoutData>();
+				DetailsView->UpdateSinglePropertyMap(InExternalRootNode, *ExternalObjectLayout, true);
+			}
+		}
+		else if (PropertyNode->HasNodeFlags(EPropertyNodeFlags::EditInlineNew) && PropertyNode->GetProperty()->HasMetaData(InlineCustomizationKeyMeta))
+		{
+			// Allow customization of 'edit inline new' objects if the metadata key has been specified.
+			// The child of this node, if set, will be an object node that we will want to treat as an 'external object layout'
+			TSharedPtr<FPropertyNode> ChildNode = PropertyNode->GetNumChildNodes() > 0 ? PropertyNode->GetChildNode(0) : nullptr;
+			TSharedPtr<FComplexPropertyNode> ComplexChildNode = StaticCastSharedPtr<FComplexPropertyNode>(ChildNode);
+			if (ComplexChildNode.IsValid())
+			{
+				// We are showing an entirely different object inline.  Generate a layout for it now.
+				if (IDetailsViewPrivate* DetailsView = InParentCategory->GetDetailsView())
+				{
+					ExternalObjectLayout = MakeShared<FDetailLayoutData>();
+					DetailsView->UpdateSinglePropertyMap(ComplexChildNode, *ExternalObjectLayout, true);
+				}
+			}
+		}
+		
+}
+```
+
+作用的原理是在创建FDetailPropertyRow的时候，即一个属性的在细节面板里的一行，如果有AllowEditInlineCustomization，就会创建ExternalObjectLayout ，之后在FDetailPropertyRow的创建孩子的时候，就会判断是否有ExternalObjectLayout，如果有就可以应用上我们之前的Customization，如果没有就会应用默认的设置。如下是使用ExternalObjectLayout的代码：
+
+```cpp
+void FDetailPropertyRow::GenerateChildrenForPropertyNode( TSharedPtr<FPropertyNode>& RootPropertyNode, FDetailNodeList& OutChildren )
+{
+	// Children should be disabled if we are disabled
+	TAttribute<bool> ParentEnabledState = TAttribute<bool>::CreateSP(this, &FDetailPropertyRow::GetEnabledState);
+
+	if( PropertyTypeLayoutBuilder.IsValid() && bShowCustomPropertyChildren )
+	{
+		const TArray< FDetailLayoutCustomization >& ChildRows = PropertyTypeLayoutBuilder->GetChildCustomizations();
+
+		for( int32 ChildIndex = 0; ChildIndex < ChildRows.Num(); ++ChildIndex )
+		{
+			TSharedRef<FDetailItemNode> ChildNodeItem = MakeShared<FDetailItemNode>(ChildRows[ChildIndex], ParentCategory.Pin().ToSharedRef(), ParentEnabledState);
+			ChildNodeItem->Initialize();
+			OutChildren.Add( ChildNodeItem );
+		}
+	}
+	else if (ExternalObjectLayout.IsValid() && ExternalObjectLayout->DetailLayout->HasDetails())
+	{
+		OutChildren.Append(ExternalObjectLayout->DetailLayout->GetAllRootTreeNodes());
+		//自定义的面板
+	}
+	else if ((bShowCustomPropertyChildren || !CustomPropertyWidget.IsValid()) && RootPropertyNode->GetNumChildNodes() > 0)
+{
+	//正常的默认创建孩子
+}
+```
+
+源码里使用的一个例子是LevelSequence上Bind Actor上的Binding Property的细节面板。
+
+假如我们采用一些代码去掉
+
+```cpp
+USTRUCT()
+struct FMovieSceneBindingPropertyInfo
+{
+	GENERATED_BODY()
+
+	// Locator for the entry
+	UPROPERTY(EditAnywhere, Category = "Default", meta=(AllowedLocators="Actor", DisplayName="Actor"))
+	FUniversalObjectLocator Locator;
+
+	// Flags for how to resolve the locator
+	UPROPERTY()
+	ELocatorResolveFlags ResolveFlags = ELocatorResolveFlags::None;
+
+	UPROPERTY(Instanced, VisibleAnywhere, Category = "Default", meta=(EditInline, AllowEditInlineCustomization, DisplayName="Custom Binding Type"))
+	UMovieSceneCustomBinding* CustomBinding = nullptr;
+};
+
+//自己Hack 代码
+UObject* obj = UInsiderLibrary::FindObjectWithNameSmart(TEXT("MovieSceneBindingPropertyInfo"));
+UScriptStruct* ss = Cast<UScriptStruct>(obj);
+FProperty* prop = ss->FindPropertyByName(TEXT("CustomBinding"));
+prop->RemoveMetaData(TEXT("AllowEditInlineCustomization"));
+```
+
+效果就会从左变到右边：
+
+![Untitled](AllowEditInlineCustomization/Untitled%201.png)
+
+注册的方式也不同：
+
+```cpp
+void ULevelSequenceEditorSubsystem::AddBindingDetailCustomizations(TSharedRef<IDetailsView> DetailsView, TSharedPtr<ISequencer> ActiveSequencer, FGuid BindingGuid)
+{
+	// TODO: Do we want to create a generalized way for folks to add instanced property layouts for other custom binding types so they can have access to sequencer context?
+	if (ActiveSequencer.IsValid())
+	{
+		UMovieSceneSequence* Sequence = ActiveSequencer->GetFocusedMovieSceneSequence();
+		UMovieScene* MovieScene = Sequence ? Sequence->GetMovieScene() : nullptr;
+		if (MovieScene)
+		{
+			FPropertyEditorModule& PropertyEditor = FModuleManager::Get().LoadModuleChecked<FPropertyEditorModule>(TEXT("PropertyEditor"));
+			DetailsView->RegisterInstancedCustomPropertyTypeLayout(FMovieSceneBindingPropertyInfo::StaticStruct()->GetFName(), FOnGetPropertyTypeCustomizationInstance::CreateLambda([](TWeakPtr<ISequencer> InSequencer, UMovieScene* InMovieScene, FGuid InBindingGuid, ULevelSequenceEditorSubsystem* LevelSequenceEditorSubsystem)
+				{
+					return MakeShared<FMovieSceneBindingPropertyInfoDetailCustomization>(InSequencer, InMovieScene, InBindingGuid, LevelSequenceEditorSubsystem);
+				}, ActiveSequencer.ToWeakPtr(), MovieScene, BindingGuid, this));
+			
+			DetailsView->RegisterInstancedCustomPropertyLayout(UMovieSceneSpawnableActorBinding::StaticClass(), FOnGetDetailCustomizationInstance::CreateStatic(&FMovieSceneSpawnableActorBindingBaseCustomization::MakeInstance, ActiveSequencer.ToWeakPtr(), MovieScene, BindingGuid));
+		}
+	}
+}
+```