UE多人射击游戏CreateSession与JoinSession自定义房间名调试

问题根源 #

1. 原代码仅按Presence搜索会话，未针对自定义名称添加过滤逻辑，无法精准定位目标会话
2. 使用FName存储用户输入的自定义名称，受FName命名规则限制（特殊字符/空格会被截断、大小写统一转换），易出现名称不匹配
3. 缺少“输入名称→搜索对应会话→加入”的完整流程衔接

代码修改步骤 #

1. 重构CreateSession函数 #

改用FString接收自定义名称，避免FName的规则限制，同时将名称存入会话设置：

void UMultiplayerSessionsSubsystem::CreateSession(int32 NumPublicConnections, FString MatchType, FString CustomSessionName)
{
    if (!SessionInterface.IsValid())
    {
        return;
    }

    // 将输入名称安全转换为FName作为内部会话标识（自动处理非法字符）
    FName InternalSessionName = FName(*CustomSessionName);
    auto ExistingSession = SessionInterface->GetNamedSession(InternalSessionName);
    if (ExistingSession != nullptr)
    {
        SessionInterface->DestroySession(InternalSessionName);
    }

    CreateSessionCompleteDelegateHandle = SessionInterface->AddOnCreateSessionCompleteDelegate_Handle(CreateSessionCompleteDelegate);

    LastSessionSettings = MakeShareable(new FOnlineSessionSettings());
    LastSessionSettings->bIsLANMatch = IOnlineSubsystem::Get()->GetSubsystemName() == "Null" ? true : false;
    LastSessionSettings->NumPublicConnections = NumPublicConnections;
    LastSessionSettings->bAllowJoinInProgress = true;
    LastSessionSettings->bAllowJoinViaPresence = true;
    LastSessionSettings->bUseLobbiesIfAvailable = true;
    LastSessionSettings->bShouldAdvertise = true;
    LastSessionSettings->bUsesPresence = true;
    LastSessionSettings->Set(FName("MatchType"), MatchType, EOnlineDataAdvertisementType::ViaOnlineServiceAndPing);

    // 用FString存储原始自定义名称，避免FName的规则限制
    LastSessionSettings->Set(FName("CustomSessionName"), CustomSessionName, EOnlineDataAdvertisementType::ViaOnlineServiceAndPing);
        
    const ULocalPlayer* LocalPlayer = GetWorld()->GetFirstLocalPlayerFromController();
    if(!SessionInterface->CreateSession(*LocalPlayer->GetPreferredUniqueNetId(), InternalSessionName, *LastSessionSettings))
    {
        SessionInterface->ClearOnCreateSessionCompleteDelegate_Handle(CreateSessionCompleteDelegateHandle);
        MultiplayerOnCreateSessionComplete.Broadcast(false);
    }   
}

2. 修改FindSessions函数，支持按名称过滤 #

新增参数接收目标会话名称，添加过滤条件：

void UMultiplayerSessionsSubsystem::FindSessions(int32 MaxSearchResult, FString TargetSessionName)
{
    if(!SessionInterface.IsValid())
    {
        if (GEngine)
        {
            GEngine->AddOnScreenDebugMessage(-1, 1.0f, FColor::Cyan, TEXT("OnlineSessionInterface Is not Valid"));
        }
        return;
    }

    FindSessionsCompleteDelegateHandle = SessionInterface->AddOnFindSessionsCompleteDelegate_Handle(FindSessionsCompleteDelegate);
    LastSessionSearch = MakeShareable(new FOnlineSessionSearch());
    LastSessionSearch->MaxSearchResults = MaxSearchResult;
    LastSessionSearch->bIsLanQuery = IOnlineSubsystem::Get()->GetSubsystemName() == "Null" ? true : false;
    LastSessionSearch->QuerySettings.Set(SEARCH_PRESENCE, true, EOnlineComparisonOp::Equals);

    // 添加自定义名称过滤，仅搜索匹配的会话
    if(!TargetSessionName.IsEmpty())
    {
        LastSessionSearch->QuerySettings.Set(FName("CustomSessionName"), TargetSessionName, EOnlineComparisonOp::Equals);
    }

    const ULocalPlayer* LocalPlayer = GetWorld()->GetFirstLocalPlayerFromController();
    if(!SessionInterface->FindSessions(*LocalPlayer->GetPreferredUniqueNetId(), LastSessionSearch.ToSharedRef()))
    {
        SessionInterface->ClearOnFindSessionsCompleteDelegate_Handle(FindSessionsCompleteDelegateHandle);
        MultiplayerOnFindSessionsComplete.Broadcast(TArray<FOnlineSessionSearchResult>(), false);
        if(GEngine)
        {
            GEngine->AddOnScreenDebugMessage(-1, 1.0f, FColor::Cyan, TEXT("FindSessionFailed"));
        }
    }
}

3. UI层流程衔接 #

• 给房主添加文本输入框，输入自定义名称后调用CreateSession传入该名称
• 给加入者添加文本输入框，输入目标名称后调用FindSessions传入该名称
• 在MultiplayerOnFindSessionsComplete回调中，若搜索到结果，调用JoinSession加入第一个匹配的会话

额外注意事项 #

• 测试LAN模式时，确保设备在同一网络，关闭防火墙限制
• 若需要支持特殊字符/空格的会话名称，必须用FString存储，不要用FName
• 可在搜索结果回调中，将会话名称展示到UI列表，让用户选择加入（可选优化）

内容的提问来源于stack exchange，提问作者Paul Miller