Put it all together - Private chat - (Unreal Engine module)

Last updated on September 4, 2025

Connect the UI with private chat​

In this tutorial, you will connect your implementation in PrivateChatSubsystem_Starter to the private chat widget.

  1. Open the PrivateChatWidget_Starter CPP file and start with connecting the UI to send private chat messages. Replace the SendPrivateChatMessage() code with the following code:

    void UPrivateChatWidget_Starter::SendPrivateChatMessage(const FText& MessageText)
    {
        if (!PrivateChatSubsystem)
        {
            UE_LOG_PRIVATECHAT(Warning, TEXT("Cannot send private chat message. Private Chat subsystem is not valid."));
            return;
        }

        if (!ensure(GetOwningPlayer()))
        {
            UE_LOG_PRIVATECHAT(Warning, TEXT("Cannot send private chat message. PlayerController is not valid."));
            return;
        }

        const ULocalPlayer* LocalPlayer = GetOwningPlayer()->GetLocalPlayer();
        if (!ensure(LocalPlayer))
        {
            UE_LOG_PRIVATECHAT(Warning, TEXT("Cannot send private chat message. LocalPlayer is not valid."));
            return;
        }

        // Send private private chat message.
        PrivateChatSubsystem->SendPrivateChatMessage(
            LocalPlayer->GetPreferredUniqueNetId().GetUniqueNetId(),
            PrivateChatRecipientUserId,
            MessageText.ToString());
    }

  2. Replace the GetLastPrivateChatMessages() function with the code below to get and display the chat message history:

    void UPrivateChatWidget_Starter::GetLastPrivateChatMessages() const
    {
        if (!PrivateChatSubsystem)
        {
            UE_LOG_PRIVATECHAT(Warning, TEXT("Cannot get last private chat messages. Private Chat subsystem is not valid."));
            return;
        }

        if (!ensure(GetOwningPlayer()))
        {
            UE_LOG_PRIVATECHAT(Warning, TEXT("Cannot get last private chat messages. PlayerController is not valid."));
            return;
        }

        const ULocalPlayer* LocalPlayer = GetOwningPlayer()->GetLocalPlayer();
        if (!ensure(LocalPlayer))
        {
            UE_LOG_PRIVATECHAT(Warning, TEXT("Cannot get last private chat messages. LocalPlayer is not valid."));
            return;
        }

        // Get chat room id.
        const FString ChatRoomId = PrivateChatSubsystem->GetPrivateChatRoomId(
            LocalPlayer->GetPreferredUniqueNetId().GetUniqueNetId(),
            PrivateChatRecipientUserId);

        // Abort if room id was not found.
        if (ChatRoomId.IsEmpty())
        {
            W_Chat->SetWidgetState(EAccelByteWarsWidgetSwitcherState::Empty, NO_CHAT_MESSAGE);
            return;
        }

        // Get last private chat messages.
        TArray<TSharedRef<FChatMessage>> OutMessages;
        if (PrivateChatSubsystem->GetLastPrivateChatMessages(
            LocalPlayer->GetPreferredUniqueNetId().GetUniqueNetId(),
            ChatRoomId,
            W_Chat->GetMaxChatHistory(),
            OutMessages))
        {
            // Abort if last messages is empty.
            if (OutMessages.IsEmpty())
            {
                W_Chat->SetWidgetState(EAccelByteWarsWidgetSwitcherState::Empty, NO_CHAT_MESSAGE);
                return;
            }

            // Display last chat messages.
            Algo::Reverse(OutMessages);
            for (const TSharedRef<FChatMessage>& Message : OutMessages)
            {
                AppendChatMessage(Message.Get());
            }
        }
        // Show error message if failed.
        else 
        {
            W_Chat->SetWidgetState(EAccelByteWarsWidgetSwitcherState::Error, FAILED_TO_LOAD_CHAT_MESSAGE);
        }
    }

  3. Next, replace the AppendChatMessage() function with the code below to append the chat message to be displayed with additional safeguards:

    void UPrivateChatWidget_Starter::AppendChatMessage(const FChatMessage& Message) const
    {
        if (!PrivateChatSubsystem)
        {
            UE_LOG_PRIVATECHAT(Warning, TEXT("Cannot append a private chat message to display. Private Chat subsystem is not valid."));
            return;
        }

        if (!ensure(GetOwningPlayer()))
        {
            UE_LOG_PRIVATECHAT(Warning, TEXT("Cannot append a private chat message to display. PlayerController is not valid."));
            return;
        }

        const ULocalPlayer* LocalPlayer = GetOwningPlayer()->GetLocalPlayer();
        if (!ensure(LocalPlayer))
        {
            UE_LOG_PRIVATECHAT(Warning, TEXT("Cannot append a private chat message to display. LocalPlayer is not valid."));
            return;
        }

        const FUniqueNetIdAccelByteUserRef SenderABId = StaticCastSharedRef<const FUniqueNetIdAccelByteUser>(Message.GetUserId());
        if (!SenderABId.Get().IsValid())
        {
            UE_LOG_PRIVATECHAT(Warning, TEXT("Cannot append a private chat message to display. Sender User Id is invalid."));
            return;
        }

        // Construct chat message.
        UChatData* ChatData = NewObject<UChatData>();
        ChatData->Message = Message.GetBody();
        ChatData->bIsSenderLocal = PrivateChatSubsystem->IsMessageFromLocalUser(LocalPlayer->GetPreferredUniqueNetId().GetUniqueNetId(), Message);

        // If the sender doesn't have display name, then use the default display name.
        ChatData->Sender = Message.GetNickname();
        if (ChatData->Sender.IsEmpty() || SenderABId.Get().GetAccelByteId().Equals(ChatData->Sender))
        {
            ChatData->Sender = UTutorialModuleOnlineUtility::GetUserDefaultDisplayName(Message.GetUserId().Get());
        }

        // Display chat message.
        W_Chat->AppendChatMessage(ChatData);
    }

  4. Now, complete the code by binding the chat events with the widget. To do this, replace the pre-defined NativeOnActivated() function with the following code:

    void UPrivateChatWidget_Starter::NativeOnActivated()
    {
        Super::NativeOnActivated();

        // Reset chat widget
        W_Chat->ClearChatMessages();
        W_Chat->ClearInput();

        // Setup widget
        W_Chat->OnSubmitDelegates.AddUObject(this, &ThisClass::SendPrivateChatMessage);
        Btn_Back->OnClicked().AddUObject(this, &ThisClass::DeactivateWidget);

        if (PrivateChatSubsystem)
        {
            PrivateChatSubsystem->GetOnSendPrivateChatCompleteDelegates()->AddUObject(this, &ThisClass::OnSendPrivateChatComplete);
            PrivateChatSubsystem->GetOnPrivateChatMessageReceivedDelegates()->AddUObject(this, &ThisClass::OnPrivateChatMessageReceived);
        }

        // Display default state.
        GetLastPrivateChatMessages();
    }

  5. Finally, unbind those events when the widget is closed. To this, replace the pre-defined NativeOnDeactivated() function with the following code:

    void UPrivateChatWidget_Starter::NativeOnDeactivated()
    {
        PrivateChatRecipientUserId = nullptr;

        // Cleanup widget
        W_Chat->OnSubmitDelegates.RemoveAll(this);
        Btn_Back->OnClicked().RemoveAll(this);

        // Unbind chat events.
        if (PrivateChatSubsystem)
        {
            PrivateChatSubsystem->GetOnSendPrivateChatCompleteDelegates()->RemoveAll(this);
            PrivateChatSubsystem->GetOnPrivateChatMessageReceivedDelegates()->RemoveAll(this);
        }

        Super::NativeOnDeactivated();
    }

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