Did Interfaces change in 4.7.x?

Development Programming & Scripting C++
1

It seems to be a bit out of date, especially when we now have different syntax for constructors.

Has anyone figured out how to create interfaces in 4.7.x?

 #pragma once #include "Interact.generated.h" /** Class needed to support InterfaceCast<IToStringInterface>(Object) */ UINTERFACE(MinimalAPI) class UInteract : public UInterface {	GENERATED_UINTERFACE_BODY() }; class IInteract {	GENERATED_IINTERFACE_BODY() IInteract(const FObjectInitializer& obj = FObjectInitializer::Get()); virtual void Interact(); }; 
 #include "ShooterGame.h" #include "Interact.h" IInteract::IInteract(const FObjectInitializer& obj) { } void IInteract::Interact() { }

But this code results in a linker error

 error LNK2019: unresolved external symbol "public: __cdecl UInteract::UInteract(class FObjectInitializer const &)" (??0UInteract@@QEAA@AEBVFObjectInitializer@@@Z) referenced in function "void __cdecl InternalConstructor<class UInteract>(class FObjectInitializer const &)" (??$InternalConstructor@VUInteract@@@@YAXAEBVFObjectInitializer@@@Z)
2

You need to change the decleration and defenition.

 IInteract::IInteract(const FObjectInitializer& obj); IInteract::IInteract(const FObjectInitializer& obj = FObjectInitializer::Get()) { }

is a example.

 UINTERFACE(Blueprintable, Category = "Event Brain, Interfaces") class MYGAME_API UTimeOfDayEventInterface : public UInterface {	GENERATED_UINTERFACE_BODY() public: }; class ITimeOfDayEventInterface {	GENERATED_IINTERFACE_BODY() public:	ITimeOfDayEventInterface(const FObjectInitializer & PCIP); .. }; 
 UTimeOfDayEventInterface::UTimeOfDayEventInterface(const FObjectInitializer & PCIP)	: Super(PCIP) { .. } // Not sure if this is safe tough, never done it my self but it compiles. ITimeOfDayEventInterface::ITimeOfDayEventInterface(const FObjectInitializer & PCIP = FObjectInitializer::Get()) { .. }

Hope it helps. :slight_smile:

3

Thanks for the help. The problem was that the constructor had to be from USomeInterface not ISomeInterface. I should learn to read.