Unreal Crashing And Giving Unhandled Exception: EXCEPTION_ACCESS_VIOLATION

[Suryansh]

Crash Screenshot:-

Mover.CPP file -

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

#include "Mover.h"
#include "Math/UnrealMathUtility.h"

// Sets default values for this component's properties
UMover::UMover()
{
	// Set this component to be initialized when the game starts, and to be ticked every frame.  You can turn these features
	// off to improve performance if you don't need them.
	PrimaryComponentTick.bCanEverTick = true;

	// ...
}


// Called when the game starts
void UMover::BeginPlay()
{
	Super::BeginPlay();
	// ...
	
	BeginPlaySetup();
}


// Called every frame
void UMover::TickComponent(float DeltaTime, ELevelTick TickType, FActorComponentTickFunction* ThisTickFunction)
{
	Super::TickComponent(DeltaTime, TickType, ThisTickFunction);
	// ...

	// if (!ObjectRefrence)
	// {
	// 	UE_LOG(LogTemp, Error, TEXT("Set ObjectRefrence For Mover Component In Blueprint."));
	// 	return;
	// }
	
	// if(ShouldRotate && Rotate)
	// {
	// 	RotateObject(DeltaTime);
	// }
	if(ShouldMove && Move)
	{
		MoveObject(DeltaTime);
	}
	
}

// void UMover::RotateObject(float DeltaTime) const
// {
// 	FRotator CurrentRotation = GetOwner()->GetActorRotation();
// 	FRotator TargetRotation = StartingRotation;

// 	if(ShouldRotate)
// 	{
// 		TargetRotation = StartingRotation + RotateOffset;
// 	}

// 	CurrentRotation = FMath::Lerp(CurrentRotation, TargetRotation, DeltaTime * RotateTime);
// 	GetOwner()->SetActorRotation(CurrentRotation);
// }

void UMover::MoveObject(float DeltaTime) const
{
	FVector CurrentVector = GetOwner()->GetActorLocation();
	FVector TargetLocation = StartingVector;

	if(ShouldMove)
	{
		TargetLocation = StartingVector + MoveOffset;
	}
	
	float Speed = MoveOffset.Length() / MoveTime;
	CurrentVector = FMath::VInterpConstantTo(CurrentVector, TargetLocation, DeltaTime, Speed);
	GetOwner()->SetActorLocation(CurrentVector);
}

void UMover::SetShouldMove(bool Should)
{
	ShouldMove = Should;
}

// void UMover::SetShouldRotate(bool Should)
// {
// 	ShouldRotate = Should;
// }

void UMover::BeginPlaySetup()
{
	StartingVector = GetOwner()->GetActorLocation();
	// StartingRotation = GetOwner()->GetActorRotation();
}

SecretWallTriggerComponent.CPP file -

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


#include "SecretWallTriggerComponent.h"


// Sets default values for this component's properties
USecretWallTriggerComponent::USecretWallTriggerComponent()
{
	// Set this component to be initialized when the game starts, and to be ticked every frame.  You can turn these features
	// off to improve performance if you don't need them.
	PrimaryComponentTick.bCanEverTick = true;
	// ...
}

// Called when the game starts
void USecretWallTriggerComponent::BeginPlay()
{
    Super::BeginPlay();
	UE_LOG(LogTemp, Warning, TEXT("Trigger Component Alive."));
}

void USecretWallTriggerComponent::TickComponent(float DeltaTime, ELevelTick TickType, FActorComponentTickFunction* ThisTickFunction)
{
	Super::TickComponent(DeltaTime, TickType, ThisTickFunction);

	AActor* AcceptableActor = GetAcceptableActor();

    if (AcceptableActor)
    {
        AcceptableActor->FindComponentByClass<UPrimitiveComponent>()->SetSimulatePhysics(false);
        AcceptableActor->AttachToComponent(this, FAttachmentTransformRules::KeepWorldTransform);

        Mover->SetShouldMove(true);
        // Mover->SetShouldRotate(true);
        
        UE_LOG(LogTemp, Display, TEXT("Unlocking!"))
    }
    else
    {
        Mover->SetShouldMove(false);
        // Mover->SetShouldRotate(false);
        
        UE_LOG(LogTemp, Display, TEXT("Locking!"))
    }
    
}

void USecretWallTriggerComponent::ActiveMover(UMover* NewMover)
{
    Mover = NewMover;
}

AActor* USecretWallTriggerComponent::GetAcceptableActor()
{
    TArray<AActor*> OverlappingActors;
    GetOverlappingActors(OverlappingActors);

    for (AActor* SingleActor : OverlappingActors)  
    {
        if (SingleActor->ActorHasTag(UnlockTag) && !(SingleActor->ActorHasTag("Grabbed")) )
        {
            return SingleActor;
        }
    }
    return nullptr;
}

As I press, the play button my unreal engine crashes and gives me the above error. I do not have a single clue why this error keeps showing. This code is from the Crypt Rider Section.

[DanM]

Mover is very likely to be nullptr. Where do you call ActiveMover?

[Suryansh]

I call ActiveMover in the blueprint for taking reference of mover for triggervolumecomponent.

[DanM]

Could you show that? Does adding this checks for Mover before dereferencing it stop the crashing?

[Suryansh]

I somehow gave the wrong reference to the Mover. Now everything is working fine. Thanks a lot for your help.