すべてを統合する - デバイス ID でログインする - (Unreal Engine モジュール)

Last updated on March 24, 2025

Connect the UI to let player log in with device ID

In this tutorial, you will learn how to connect the login menu widget with the login implementation we created in the previous section.

We have already provide you with the reference to AuthEssentialsSubsystem_Starter in the LoginWidget_Starter class CPP file, in the NativeConstruct() function, as seen in the snippet code below.

void ULoginWidget_Starter::NativeConstruct()
{
    Super::NativeConstruct();

    GameInstance = Cast<UAccelByteWarsGameInstance>(GetGameInstance());
    ensure(GameInstance);

    AuthSubsystem = GameInstance->GetSubsystem<UAuthEssentialsSubsystem_Starter>();
    ensure(AuthSubsystem);

    PromptSubsystem = GameInstance->GetSubsystem<UPromptSubsystem>();
    ensure(PromptSubsystem);

    SetLoginState(ELoginState::Default);
    OnRetryLoginDelegate.Clear();
}

You are going to set up the callback function to listen when login process is completed, set up the login credentials, and send the login request.

1. Since the declaration is already made, go straight to the LoginWidget_Starter CPP file and navigate to OnLoginComplete(). This function will be the callback for when the login process is completed. This function will display main menu widget on login success or display an error message on login fails:

   void ULoginWidget_Starter::OnLoginComplete(bool bWasSuccessful, const FString& ErrorMessage)
   {
       if (bWasSuccessful) 
       {
           // Broadcast on-login success event.
           if (UAuthEssentialsModels::OnLoginSuccessDelegate.IsBound())
           {
               UAuthEssentialsModels::OnLoginSuccessDelegate.Broadcast(GetOwningPlayer());
           }
   
           // When login success, open Main Menu widget.
           OpenMainMenu();
       }
       else 
       {
           // When login failed, show error message.
           Tb_FailedMessage->SetText(FText::FromString(ErrorMessage));
           SetLoginState(ELoginState::Failed);
       }
   }

2. Now, you can start to send the login request. Still in the CPP file, navigate to OnLoginWithDeviceIdButtonClicked() and replace the existing implementation with the following:

   void ULoginWidget_Starter::OnLoginWithDeviceIdButtonClicked()
   {
       SetLoginState(ELoginState::LoggingIn);
       OnRetryLoginDelegate.AddUObject(this, &ThisClass::OnLoginWithDeviceIdButtonClicked);
   
       APlayerController* PC = GetWorld()->GetFirstPlayerController();
       ensure(PC);
   
       ensure(AuthSubsystem);
       AuthSubsystem->SetAuthCredentials(EAccelByteLoginType::DeviceId, TEXT(""), TEXT(""));
       AuthSubsystem->Login(PC, FAuthOnLoginCompleteDelegate::CreateUObject(this, &ThisClass::OnLoginComplete));
   }

3. Compile your project and make sure there are no errors.