【UE4 C++】打印字符串与输出日志

打印屏幕

• 默认打印屏幕

  // 打印至屏幕
  FString screenMessage = "(AddOnScreenDebugMessage)    Hello world!";
  GEngine->AddOnScreenDebugMessage(-1, 1.f, FColor::Green, screenMessage);
  
  // 打印至屏幕
  UKismetSystemLibrary::PrintString(this, "(UKismetSystemLibrary::PrintString)   Hello world!");
  
  

  

输出log

• 默认类别打印log

  UE_LOG(LogTemp, Log, TEXT("(UE_LOG-logTemp)    Hello world!"));
  

• 自定义类别打印log

  // .h 自定义日志分类
  DECLARE_LOG_CATEGORY_CLASS(GMDebugLog, Log, All);
  
  // .cpp 输出日志 自定义分类
  UE_LOG(GMDebugLog, Warning, TEXT("(UE_LOG-logTemp)    Hello world!"));
  UE_LOG(GMDebugLog, Error, TEXT("(UE_LOG-GMDebugLog)    Hello world!"));
  

• 带变量打印log

  
  //创建FString 变量 FString::Printf
  FString playerName = "User";
  int32 healthValue = 100;
  FString outputMessage1 = FString::Printf(TEXT("Name is %s, health value is %d"), *playerName, healthValue);
  UE_LOG(LogTemp, Warning, TEXT("FStringFormatArg: %s"), *outputMessage1);
  
  //创建FString变量 FString::Format
  TArray<FStringFormatArg> args;
  args.Add(FStringFormatArg(playerName));
  args.Add(FStringFormatArg(healthValue));
  
  FString outputMessage2 = FString::Format(TEXT("Name is {0}, health value is  {1}"), args);
  UE_LOG(LogTemp, Warning, TEXT("FString::Format: %s"), *outputMessage2);