FNames

常用作标识符等不变的字符串（如：资源路径/资源文件类型/骨骼名称/表格行名等）

• 比较字符串操作非常快

• 即使多个相同的字符串，也只在内存存储一份副本，避免了冗余的内存分配操作

• 不区分大小写

• 初始化

  FName TestHUDName = FName(TEXT("ThisIsMyTestFName"));

• 比较

  CompareFloat = TestFName.Compare(OtherFName);

• 搜索

  if( FName(TEXT("pelvis"), FNAME_Find) != NAME_None ){}

• FString <-> FName

  TestHUDName = FName(*TestHUDString);
  TestHUDString = TestHUDName.ToString();

FText

FText 是一种静态字符串，在UE4中可以负责处理文本本地化、UI 文本显示等

• 支持文本本地化

• 提高文本渲染的性能

• 较快的copy操作

• FString <-> FText

  TestHUDText = FText::FromString(TestHUDString);
  TestHUDString = TestHUDText.ToString();

• FName -> FText

  TestHUDText = FText::FromName(TestHUDName);

• 比较

FString

FString str1("Hello!");

FString str2 = TEXT("Hello World!");

FString str3 = FString::Printf(TEXT("I am %d years old"), 18);


if(MyFString.Equals(OtherFString, ESearchCase::CaseSensitive)){...} // 大小写敏感
if(MyFString.Equals(OtherFString, ESearchCase::IgnoreCase)){...}
if(MyFString == OtherFString){...}


FString str4 = TEXT("Hello World!");
str4 += FString("UE4");

float value = 1.0f;
FString str5 = FString::Printf(TEXT("Current Value: %f"),value);


FString str6 = TEXT("Blueprint, C++, Material");
TArray<FString> strList;
str6.ParseIntoArray(strList, TEXT(","), true);

• FString <-> int32/float

  // FString -> int32/float
  FString TheString = "233";
  int32 MyShinyNewInt = FCString::Atoi(*TheString);
  
  FString TheString = "233.3";
  float MyStringtoFloat = FCString::Atof(*TheString);
  
  // int32/float -> FString
  FString NewString = FString::FromInt(233);
  FString NewString = FString::SanitizeFloat(233.3f);

• FString <-> TCHAR* 自动隐式转换

  const FString MyFString;
  const TCHAR *TCharString = *MyFString;
  
  const FString MyFString=TCharString;

• FString → char *

  // 1
  char *plainText= TCHAR_TO_ANSI(*str);
  
  // 2
  FString str
  string t = TCHAR_TO_UTF8(*str);
  char * returnvalue = (char *)malloc(sizeof(char) * (t.length() + 1));
  strncpy_s(returnvalue, t.length() , t.c_str(), t.length());  

• FString <-> std::string

  // FString -> std::string
  FString UE4Str = "Flowers";
  std::string MyStdString(TCHAR_TO_UTF8(*UE4Str));
  
  // std::string -> FString
  std::string TestString = "Happy";
  FString HappyString(TestString.c_str());

• FString <-> TArray

  // FString -> TArray<uint8>
  FString JsonStr;
  TArray<uint8> content;
  content.SetNum(JsonStr.Len());
  memcpy(content.GetData(), TCHAR_TO_ANSI(*JsonStr), JsonStr.Len()); 
  
  //TArray<uint8> ****-> FString
  TArray<uint8> content;
  const std::string cstr(reinterpret_cast<const char*>(content.GetData()), content.Num());
  FString frameAsFString = cstr.c_str();
  UE_LOG(VRSLog, Warning, TEXT("%s"), *frameAsFString);

• FArrayReaderPtr -> FString

  uint8 data[512];
  FMemory::Memzero(data, 512);
  FMemory::Memcpy(data, ArrayReaderPtr->GetData(), ArrayReaderPtr->Num());
  FString str = ((const char*)data);

• 数值 -> std::to_string

  std::string to_string( long value );
  std::string to_string( long long value );
  std::string to_string( unsigned value );
  std::string to_string( unsigned long value );
  std::string to_string( unsigned long long value );
  std::string to_string( float value );
  std::string to_string( double value );
  std::string to_string( long double value );

• std::string <-> std::wstring

  • WideCharToMultiByte

    // std::wstring -> std::string
    std::string WStringToString(const std::wstring wstr)
    {
    std::string str;
    int len = WideCharToMultiByte(CP_UTF8, 0, wstr.c_str(), wstr.size(), NULL, 0, NULL,NULL);
    char*buffer = new char[len + 1];
    WideCharToMultiByte(CP_UTF8, 0, wstr.c_str(), wstr.size(), buffer, len, NULL, NULL);
    buffer[len] = '\0';
    str.append(buffer);
    delete[]buffer;
    return str;
    }

    // std::string -> std::wstring
    std::string str_path=TCHAR_TO_UTF8(*AppPath);
    std::wstring wstr_path;
    wstr_path.assign(str_path.begin(), str_path.end());

• 中文乱码

• UE4 Source Header References

  CString.h
  UnrealString.h
  NameTypes.h
  StringConv.h (TCHAR_TO_ANSI etc)

• CString.h可以查到更多，如

  toi64 (string to int64)
  Atod    (string to double precision float)

• 更多关于FString的操作可以到UnrealString.h找到.

参考

• 虚幻引擎4 官方文档 | 字符串
• UE4 C++基础教程 - 字符串和本地化