GameInstance C++ troubles

Development Programming & Scripting C++
1

I’m trying to rewrite CCGToolkit from 100% Blueprints to C++ (as much as possible) and there are some problems I’ve encounter with.

  1. On original project there is an BeginPlay function in CardGameInstance (which derived from GameInstance).
    When I try to override BeginPlay() in CardGameInstance2 (on C++), it says that

CardGameInstance2.h:76:18: error: ‘BeginPlay’ marked ‘override’ but does not override any member functions
[2020.05.31-16.53.27:002][696]CompilerResultsLog: virtual void BeginPlay() override;

So, where should I put code from blueprint BeginPlay? To constructor GameInstance::GameInstance? or GameInstance::Init?

  1. Have some troubles with widgets on c++.
    I have in constructor:


static ConstructorHelpers::FClassFinder<UUserWidget> WidgetUIBPClass(TEXT("/Game/CCGToolkit/Blueprints/Widgets/Menu/Test.Test_C"));
WidgetUIClass = WidgetUIBPClass.Class;

and then in CardGameInstance::ShowMenu I have:



WidgetUI = CreateWidget<UWidgetUI>(this, WidgetUIClass);
if (WidgetUI == nullptr)
{
UE_LOG(LogTemp, Error, TEXT("WidgetUI: EMPTY!"));
return;
}
WidgetUI->AddToViewport();

Everything goes smoothly, without any errors, but I don’t see my Widget on screen.
Of course Test widget derived from my WidgetUI class. WidgetUI contains almost nothing. Should I put some code in here?

What’s the problem? Can I summon Widgets from GameInstance?
I’ve try following:



WidgetUI = CreateWidget<UWidgetUI>(GetWorld(), WidgetUIClass);

and



APlayerController* PlayerController = GetWorld()->GetFirstPlayerController();
WidgetUI = CreateWidget<UWidgetUI>(PlayerController, WidgetUIClass);

same result. Black screen, no Widget is showing.

2

Use this instead of BeginPlay()


virtual void Init() override;

I have this running from my gamestate class and it works fine:


HudGame = CreateWidget<UHudGame>(GetWorld(), SpawnHudGame);
HudGame->AddToViewport();

It should be possible to spawn form anywhere, as long as GetWorld is using the right world. Is your game instance properly set up in the project settings?

3

Intentionally keeping widgets in the game instance seems like a bad idea, and I’m not sure how reliable that will be in PIE. The Game Instance is often used as a last-resort place to store a widget when a player can’t be found.

A good place to store widgets and references to widget assets is in the HUD class, and you can properly give them owning players too. This matters a lot in multiplayer for example, so it’s a good habit to get into.