Unhandled exception when running code

Development Programming & Scripting
1

The program is meant to log a message whenever the player presses a key, but when i run the code , i get the following error.

Unhandled exception at 0x000007FEE193791A (UE4Editor-Engine.dll) in UE4Editor.exe: 0xC0000005: Access violation reading location 0x00000000000000B8.

The code is:

#include "ClientMessage.h"
#include "MyPawn.h"


AMyPawn::AMyPawn(const class FPostConstructInitializeProperties& PCIP)
	: Super(PCIP)
{
	SetupInputComponent();
}
void AMyPawn::SetupInputComponent()
{
	InputComponent->BindAction("printStuff", IE_Pressed, this, &AMyPawn::printMessage);
}
void AMyPawn::printMessage()
{
	GEngine->AddOnScreenDebugMessage(-1, 5.f, FColor::Red, TEXT("This is an on screen message!"));
}

And this is the header file:

#pragma once

#include "GameFramework/Pawn.h"
#include "MyPawn.generated.h"

/**
 * 
 */
UCLASS()
class CLIENTMESSAGE_API AMyPawn : public APawn
{
	GENERATED_UCLASS_BODY()
	void SetupInputComponent();
	void printMessage();
	
	
};
2

Did you add in the Edit->Project Settings->Input->Action Mappings the printStuff and set it to the buttons you want it to register?

3

Also call Super::SetupInputComponent(); in the beginning of your setupinputcomponent function.

4

yes i did.

5

my SetupInputComponent wasnt overridden from the base class , because when i did i got a build error saying that the base class did not contain a function named SetupInputComponent.

6

Not sure but shouldn’t this input handling be in a player controller? And if you move it there tag it as virtual void SetupInp…

7

Sorry ignore this and try first setting your functions to public.

8

That fixed it , thanks.

9

Same happened for me. The AGameController constructor is too early for registration, because the InputComponent was nullptr, because AActor::EnableInput(APlayerController* PlayerController) is not called. I tried that manually, now this is not throwing an exception, but did not work (4.7.2):

UCLASS()
class BUTTONFOOTBALL_API AGameController : public APlayerController
{
	GENERATED_BODY()
	
public:
	AGameController(const FObjectInitializer& ObjectInitializer);
	virtual void SetupInputComponent() override;
	void OnFirePressed();
};

.

AGameController::AGameController(const FObjectInitializer& ObjectInitializer)
	: Super(ObjectInitializer)
{
	SetupInputComponent();
}

void AGameController::OnFirePressed()
{
	GEngine->AddOnScreenDebugMessage(-1, 5.f, FColor::Red, FString::Printf(TEXT("%s"), __FUNCTION__));
}

void AGameController::SetupInputComponent()
{
	AActor::EnableInput(this);
	InputComponent->BindAction("F", IE_Pressed, this, &AGameController::OnFirePressed);
}

Any ideas?

(and how can set the syntax highlighting for this code?)

10

Move it to BeginPlay instead of constructor perhaps.

11

The constructor isn’t the problem. I already tried the beginplay and the InputComponent was nullptr… If I call the hack(??) (AActor::EnableInput(this)), I got some assert and it did not response to my action

12

Is that controller possessing or spawning a pawn? You should be feeding the input you get to a pawn you are controlling or referencing instead of calling that function.

13

link text, read up a bit about pawns and controllers to get an idea of what is happening. I haven’t looked it up but I believe you are referencing a non static function in a static way, ie what actor are you trying to enable input on, and what are you trying to do as a whole. There are many examples out there that can help you get started on setting up controllers.