UE4 C++学习笔记之C++输出字符串及FString字符串转换

本篇文章将和大家介绍UE4中C++输出字符串和FString字符串转换，有不清楚的可以看看。

C++输出枚举值

UE_LOG(LogTemp, Warning, TEXT("EnumType:  %s"), *StaticEnum()->GetNameStringByValue((uint8)EnumName));

C++输出字符串

输出字符串到output log中

FString filePath
UE_LOG(LogTemp, Log, TEXT("%s"), *filePath);
UE_LOG(LogTemp, Error, TEXT("Hello,World!"));

输出字符串到屏幕上

FString filePath;
GEngine->AddOnScreenDebugMessage(-1, 5.f, FColor::Green, FString::Printf(TEXT("DLL_Init")));
GEngine->AddOnScreenDebugMessage(-1, 5.f, FColor::Green, FString::Printf(TEXT("%s"), *filePath));

字符串转换

FString to Others

FString to FNames

FString TheString = "UE4_C++_IS_Awesome";
FName ConvertedFString = FName(*TheString);

 FString to FText

FString TheString = "Hello，world";
FText ConvertedFSting=FText::FromSting(TheString);

FString to Integer 

FString TheString = "123.021";
int32 MyShinyNewInt = FCString::Atoi(*TheString);

FString to Float

FString TheString = "123.021";
int32 MyShinyNewInt = FCString::Atof(*TheString);

FString to std::string

#include 
//....
FString UE4Str = "Flowers";
std::string MyStdString(TCHAR_TO_UTF8(*UE4Str));

Others to FString

FText to FString

FString Name = NameDesc->GetText().ToString(); 

 Float/Integer to FString

FString NewString = FString::FromInt(YourInt);
FString VeryCleanString = FString::SanitizeFloat(YourFloat);

std::string to FString

#include 
//....
std::string TestString = "Happy"; 
FString HappyString(TestString.c_str());

不常用先记着

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

atoi64 (string to int64)
Atod    (string to double precision float)

更多关于FString的操作可以到UnrealString.h找到。

Converting FArrayReaderPtr to FString

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

Converting Array to FString

TArray content;  
...  
const std::string cstr(reinterpret_cast(content.GetData()), content.Num());  
FString frameAsFString = cstr.c_str();  
UE_LOG(VRSLog, Warning, TEXT("%s"), *frameAsFString);  

Converting FString to Array

FString JsonStr;  
TArray content;  
content.SetNum(JsonStr.Len());  
memcpy(content.GetData(), TCHAR_TO_ANSI(*JsonStr), JsonStr.Len());   

FString StrData;  
const TCHAR* StrPtr = *StrData;  
FTCHARToUTF8 UTF8String(StrPtr);  
int32 CTXSize = UTF8String.Length();  
TArray URLData;  
URLData.SetNum(CTXSize);  
memcpy(URLData.GetData(), UTF8String.Get(), CTXSize);  

Converting FString to char *

///1
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());  
///2
int ARPG_Database::BP_GetColumnIndex(int resultSet, FString columnName)
｛
    return GetColumnIndex(resultSet, TCHAR_TO_ANSI(*columnName));
｝
int ARPG_Database::GetColumnIndex(int iResult, const char* columnName)
｛
｝

Converting FString to const char *

const char *plainText= TCHAR_TO_ANSI(*aes_content);

Converting FString to TCHAR *

 int ARPG_Database::BP_GetColumnIndex(int resultSet, FString columnName)
 ｛
     return GetColumnIndex(resultSet, *columnName);
 ｝
 int ARPG_Database::GetColumnIndex(int iResult, const TCHAR* columnName)
 ｛
 ｝