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

03-UnrealEngine/Gameplay/UObject/UnrealSpecifiers/Meta/Scene/AllowedLocators.md

@@ -0,0 +1,58 @@
+# AllowedLocators
+
+- **功能描述：** 用来给Sequencer定位可绑定的对象
+- **使用位置：** UPROPERTY
+- **引擎模块：** Scene
+- **元数据类型：** string="abc"
+- **限制类型：** FUniversalObjectLocator
+- **常用程度：** ★
+
+用来给Sequencer定位可绑定的对象。
+
+看起来是Sequencer用来定位Actor做属性绑定的辅助定位器。只用在FUniversalObjectLocator 这个写好的属性里，一般我们用不到去扩展这部分，因此只是OnlyInternal。
+
+## 源码中搜索得到：
+
+```cpp
+
+	// Helper struct for Binding Properties UI for locators.
+USTRUCT()
+struct FMovieSceneUniversalLocatorInfo
+{
+	GENERATED_BODY()
+
+	// Locator for the entry
+	UPROPERTY(EditAnywhere, Category = "Default", meta=(AllowedLocators="Actor"))
+	FUniversalObjectLocator Locator;
+
+	// Flags for how to resolve the locator
+	UPROPERTY()
+	ELocatorResolveFlags ResolveFlags = ELocatorResolveFlags::None;
+};
+```
+
+看起来是允许定位的对象类型。
+
+## 原理：
+
+```cpp
+TMap<FName, TSharedPtr<ILocatorEditor>> ApplicableLocators;
+
+void FUniversalObjectLocatorCustomization::CustomizeHeader(TSharedRef<IPropertyHandle> StructPropertyHandle, FDetailWidgetRow& HeaderRow, IPropertyTypeCustomizationUtils& StructCustomizationUtils)
+{
+		TArray<FString> AllowedTypes;
+		if (PropertyHandle->HasMetaData("AllowedLocators"))
+		{
+			PropertyHandle->GetMetaData("AllowedLocators").ParseIntoArray(AllowedTypes, TEXT(","));
+		}
+}
+
+FUniversalObjectLocatorEditorModule& Module = FModuleManager::Get().LoadModuleChecked<FUniversalObjectLocatorEditorModule>("UniversalObjectLocatorEditor");
+for (TPair<FName, TSharedPtr<ILocatorEditor>> Pair : Module.LocatorEditors)
+{
+	if (AllowedTypes.Num() == 0 || AllowedTypes.Contains(Pair.Key.ToString()))
+	{
+		ApplicableLocators.Add(Pair.Key, Pair.Value);
+	}
+}
+```