Unreal Engine 4.19 C++ 未声明的标识符错误，但它的代码已声明

Question

这也发布到 Unreal 的 AnswerHub，但他们的响应速度很慢，我想知道这是 Unreal Engine 错误还是 Visual Studio 2013/C++ 通用错误。我想如果这是一个一般性错误，那么 Whosebug 会指出来。

基本上无缘无故 Visual Studio 开始在正确检测代码时遇到问题，说空函数中有未知符号，然后它开始说已经工作的代码中有未声明的标识符，或者“->”不是'已知等。另一个文件给我这些错误 http://i.imgur.com/AVrbdTS.png?1 下面是我用来显示我的问题的代码。再次尝试时，它说无法打开 ToggleForBP.generated.h

这是 Visual Studio 2013 还是 Unreal Engine 的错误？

#pragma once

#include "GameFramework/Actor.h"
#include "ToggleForBP.generated.h"

UCLASS()
class PLAYGROUND_API AToggleForBP : public AActor
{
    GENERATED_BODY()

public: 
    // Sets default values for this actor's properties
    AToggleForBP();

    // Called when the game starts or when spawned
    virtual void BeginPlay() override;

    // Called every frame
    virtual void Tick(float DeltaSeconds) override;


    //Toggles between on and off
    void SwitchOnOff();

    bool UniqueValueBlah;


};

我的.cpp

// Fill out your copyright notice in the Description page of Project Settings.

#include "Playground.h"
#include "ToggleForBP.h"


// Sets default values
AToggleForBP::AToggleForBP()
{
    // Set this actor to call Tick() every frame.  You can turn this off to improve performance if you don't need it.
    PrimaryActorTick.bCanEverTick = true;

}

void SwitchOnOff()
{

    UniqueValueBlah = true;
}

// Called when the game starts or when spawned
void AToggleForBP::BeginPlay()
{
    Super::BeginPlay();

}

// Called every frame
void AToggleForBP::Tick( float DeltaTime )
{
    Super::Tick( DeltaTime );

}

我从上面的代码得到的错误：

Error   2   error : Failed to produce item: D:\Unreal Projects\Playground\Binaries\Win64\UE4Editor-Playground-3827.dll  D:\Unreal Projects\Playground\Intermediate\ProjectFiles\ERROR   Playground
Error   1   error C2065: 'UniqueValueBlah' : undeclared identifier  D:\Unreal Projects\Playground\Source\Playground\ToggleForBP.cpp 18  1   Playground
Error   3   error MSB3073: The command ""D:\Programs\Epic Games\Epic Games.9\Engine\Build\BatchFiles\Build.bat" PlaygroundEditor Win64 Development "D:\Unreal Projects\Playground\Playground.uproject" -rocket -waitmutex" exited with code -1.   C:\Program Files (x86)\MSBuild\Microsoft.Cpp\v4.0\V120\Microsoft.MakeFile.Targets   38  5   Playground
    4   IntelliSense: identifier "UniqueValueBlah" is undefined d:\Unreal Projects\Playground\Source\Playground\ToggleForBP.cpp 18  2   Playground

Answer 1

将您的函数签名更改为：

void AToggleForBP::SwitchOnOff()
{

    UniqueValueBlah = true;
}

没有把它做成成员函数，编译器认为它是一个全局函数。

Unreal Engine 4.19 C++ 未声明的标识符错误，但它的代码已声明

Unreal Engine 4.19 C++ Undeclared Identifier error, but it code IS declared

c++

undeclared-identifier

unreal-engine4