Can't display widgets (nameplates) in full c++ (but it works in derived BP)

Development Programming & Scripting C++
1

Hello,

I manage to add a WidgetComponent to an Actor in a blueprint to display a nameplate.
I’m trying to do the same in full C ++ with this code

TargetWidget = CreateDefaultSubobject<UWidgetComponent>("Widget");

static ConstructorHelpers::FClassFinder<UUserWidget> hudWidgetObj(TEXT("/Game/UI/UI_Nameplate"));

if (hudWidgetObj.Succeeded())
{
TargetWidget->SetWidgetClass(hudWidgetObj.Class);
TargetWidget->SetWidgetSpace(EWidgetSpace::Screen);
TargetWidget->SetRelativeLocation(FVector(0.0f, 0.0f, 0.0f));
TargetWidget->SetDrawSize(FVector2D(500.0f, 700.0f));
TargetWidget->SetVisibility(true);
TargetWidget->AttachToComponent(CollisionComponent, FAttachmentTransformRules::KeepRelativeTransform);
}

When I launch my game, the nameplate is not displayed on my actor.

But if i create a Blueprint deriving from my c ++ class (without modifying my c ++ code and without modifying the blueprint), the actor using this blueprint displays the nameplate.

Why ? How can i fix the problem in C++ ?

2

May be this will help:

.h
UPROPERTY(EditDefaultsOnly, BlueprintReadOnly, Category = MyActorCat, meta = (AllowPrivateAccess = "true"))
UWidgetComponent* MessageComponent;

.cpp
MessageComponent = CreateDefaultSubobject<UWidgetComponent>(TEXT("MessageComponent"));
MessageComponent->SetupAttachment(RootComponent);

static ConstructorHelpers::FClassFinder<UUserWidget> Widget(TEXT("WidgetBlueprint'/Game/Widgets/Health/MessageWidget'"));
if (Widget.Succeeded())
{
    MessageComponent->SetWidgetClass(Widget.Class);

    static ConstructorHelpers::FObjectFinder<UMaterialInstance> MessageMaterial(TEXT("MaterialInstanceConstant'/Engine/EngineMaterials/Widget3DPassThrough_Masked_OneSided.Widget3DPassThrough_Masked_OneSided'"));
    if (MessageMaterial.Succeeded())
    {
        MessageComponent->SetMaterial(0, MessageMaterial.Object);
    }
}

There is a MessageWidget.uasset in the folder. Sadly I cannot open my project and view its parent class or setup. My build is broken at the moment.

3

Thanks.
I modify my code follow your code. It works.
Maybe it was because of AttachToComponent instead of SetupAttachment.

Here i my new code:

// .h
UPROPERTY(VisibleAnywhere, Category = "Components")
class UWidgetComponent* TargetWidgetComponent;

// .cpp
TargetWidgetComponent = CreateDefaultSubobject<UWidgetComponent>("WidgetComponent");
TargetWidgetComponent->SetupAttachment(CollisionComponent);

static ConstructorHelpers::FClassFinder<UUserWidget> userWidget(TEXT("WidgetBlueprint'/Game/UI/UI_Nameplate'"));
if (userWidget.Succeeded())
{
		TargetWidgetComponent->SetWidgetClass(userWidget.Class);
		
		static ConstructorHelpers::FObjectFinder<UMaterialInstance> MessageMaterial(TEXT("MaterialInstanceConstant'/Engine/EngineMaterials/Widget3DPassThrough_Masked_OneSided.Widget3DPassThrough_Masked_OneSided'"));
		if (MessageMaterial.Succeeded())
		{
			TargetWidgetComponent->SetMaterial(0, MessageMaterial.Object);
		}

		TargetWidgetComponent->SetWidgetSpace(EWidgetSpace::Screen);
		TargetWidgetComponent->SetRelativeLocation(FVector(0.0f, 0.0f, 0.0f));
		TargetWidgetComponent->SetDrawSize(FVector2D(500.0f, 700.0f));
		TargetWidgetComponent->SetVisibility(true);
}
4

:slight_smile: