[UE4]C++实现动态加载的问题:LoadClass()和LoadObject() 及 静态加载问题:ConstructorHelpers::FClassFinder()和FObjectFinder()

时间:2021-01-19 14:57:13

转自:http://aigo.iteye.com/blog/2281558

动态加载UObject和动态加载UClass分别用LoadObject<T>(),和LoadClass<T>() ,两者均在在UObjectGlobals.h中。

另外注意:LoadClass<T>的模版名称,不能直接写UBlueprint,例如:LoadClass<UBlueprint>是错误的,创建蓝图时选择的是什么父类,则写对应的父类名,假如是Actor,那么要写成:LoadClass<AActor>,否则无法加载成功。

路径名也必须带_C后缀(LoadObject不需要带_C后缀),例如,蓝图路径是:Blueprint'/Game/Blueprints/MyBP.MyBP'

加后缀以后,则是:Blueprint'/Game/Blueprints/MyBP.MyBP_C',

例子:

UClass* Test = LoadClass<AActor>(NULL, TEXT("Blueprint'/Game/Blueprints/MapPathBrush_BP.MapPathBrush_BP_C'"));  

官方还没出文档,只能先看代码注释:

// Load an object.
template< class T >
inline T* LoadObject( UObject* Outer, const TCHAR* Name, const TCHAR* Filename=nullptr, uint32 LoadFlags=LOAD_None, UPackageMap* Sandbox=nullptr )
{
return (T*)StaticLoadObject( T::StaticClass(), Outer, Name, Filename, LoadFlags, Sandbox );
}
// Load a class object.
template< class T >
inline UClass* LoadClass( UObject* Outer, const TCHAR* Name, const TCHAR* Filename=nullptr, uint32 LoadFlags=LOAD_None, UPackageMap* Sandbox=nullptr )
{
return StaticLoadClass( T::StaticClass(), Outer, Name, Filename, LoadFlags, Sandbox );
}
/**
* Find or load an object by string name with optional outer and filename specifications.
* These are optional because the InName can contain all of the necessary information.
*
* @param ObjectClass The class (or a superclass) of the object to be loaded.
* @param InOuter An optional object to narrow where to find/load the object from
* @param InName String name of the object. If it's not fully qualified, InOuter and/or Filename will be needed
* @param Filename An optional file to load from (or find in the file's package object)
* @param LoadFlags Flags controlling how to handle loading from disk
* @param Sandbox A list of packages to restrict the search for the object
* @param bAllowObjectReconciliation Whether to allow the object to be found via FindObject in the case of seek free loading
*
* @return The object that was loaded or found. NULL for a failure.
*/
COREUOBJECT_API UObject* StaticLoadObject( UClass* Class, UObject* InOuter, const TCHAR* Name, const TCHAR* Filename = NULL, uint32 LoadFlags = LOAD_None, UPackageMap* Sandbox = NULL, bool bAllowObjectReconciliation = true );
COREUOBJECT_API UClass* StaticLoadClass(UClass* BaseClass, UObject* InOuter, const TCHAR* Name, const TCHAR* Filename = NULL, uint32 LoadFlags = LOAD_None, UPackageMap* Sandbox = NULL);

 LoadObject加载例子,不需要添加后缀:

可以用LoadObject加载的文件包括:

Texture、Material、SoundWave、SoundCue、ParticlesSystem、AnimMontage、BlendSpace(1D,2D,3D)、AnimSequence、AnimBlueprint、SkeletalMesh等等。这些文件的父类都是UObject,所以也可以先加载为UObject*然后再强转为具体的类型,例如: