In-depth parsing of coding conversion methods in IOS development

IOS developmentMediumEncoding conversionThe method is the content to be introduced in this article, mainly to learnEncoding conversionFor more information, see the details. You can use the following methodsEncoding conversion.

 
 

  
  
NSString* str2 = [NSString stringWithCString:str1 encoding:enc1]; 
 
 

Call the cStringUsingEncoding: enc2 of NSString to convert from enc1 to enc2.

However, it is difficult to obtain the enc enumerated values.

1. Only the following encoding values are defined in NSString. h.

 
 

  
  
enum {  
  
  
    NSASCIIStringEncoding = 1,                 
  
  
    NSNEXTSTEPStringEncoding = 2,  
  
  
    NSJapaneseEUCStringEncoding = 3,  
  
  
    NSUTF8StringEncoding = 4,  
  
  
    NSISOLatin1StringEncoding = 5,  
  
  
    NSSymbolStringEncoding = 6,  
  
  
    NSNonLossyASCIIStringEncoding = 7,  
  
  
    NSShiftJISStringEncoding = 8,           
  
  
    NSISOLatin2StringEncoding = 9,  
  
  
    NSUnicodeStringEncoding = 10,  
  
  
    NSWindowsCP1251StringEncoding = 11,     
  
  
    NSWindowsCP1252StringEncoding = 12,     
  
  
    NSWindowsCP1253StringEncoding = 13,     
  
  
    NSWindowsCP1254StringEncoding = 14,     
  
  
    NSWindowsCP1250StringEncoding = 15,     
  
  
    NSISO2022JPStringEncoding = 21,          
  
  
    NSMacOSRomanStringEncoding = 30,  
  
  
 
  
  
    NSUTF16StringEncoding = NSUnicodeStringEncoding,        
  
  
 
  
  
#if MAC_OS_X_VERSION_10_4 <= MAC_OS_X_VERSION_MAX_ALLOWED || __IPHONE_2_0 <= __IPHONE_OS_VERSION_MAX_ALLOWED  
  
  
    NSUTF16BigEndianStringEncoding = 0x90000100,           
  
  
    NSUTF16LittleEndianStringEncoding = 0x94000100,        
  
  
 
  
  
    NSUTF32StringEncoding = 0x8c000100,                     
  
  
    NSUTF32BigEndianStringEncoding = 0x98000100,           
  
  
    NSUTF32LittleEndianStringEncoding = 0x9c000100          
  
  
#endif  
  
  
}; 
 
 

Is Chinese in iphone not supported yet? No, right?

2. The iphone must support Chinese characters, but this enumeration value is not defined in NSString. We can obtain this enumeration value in two ways. The first method is CFStringConvertEncodingToNSStringEncoding.
For example:

 
 

  
  
NSStringEncoding enc = CFStringConvertEncodingToNSStringEncoding(kCFStringEncodingGB_18030_2000);  
  
  
NSString* str2 = [NSString stringWithCString:str1 encoding:enc]; 
 
 

For all kCFStringEncoding definitions, see CFStringEncodingExt. h. CFStringConvertIANACharSetNameToEncoding is also useful.

3. Another method is

 
 

  
  
const NSStringEncoding *encodings = [NSString availableStringEncodings];  
  
  
NSMutableString *str = [[NSMutableString alloc] init];  
  
  
NSStringEncoding encoding;  
  
  
while ((encoding = *encodings++) != 0)  
  
  
{  
  
  
         [str appendFormat: @"%@ === %in", [NSString localizedNameOfStringEncoding:encoding], encoding];  
  
  
} 
 
 

Print the str array, and you can know the enumerated value of each encoding, for example,-2147482063 in Chinese.

Summary: in-depth analysisIOS developmentMediumEncoding conversionThe content of this method has been introduced. I hope this article will help you!