NSStringEncoding到字符串

Question

代码

NSString* strFromWeb = [NSString stringWithContentsOfURL:url usedEncoding:&enc error:&error];
NSLog(@"%d", enc);

这个打印4，因为

NSUTF8StringEncoding  = 4,

有什么内置函数可以打印NSUTF8StringEncoding之类的吗？

Answer 1

您可以将NSStringEncoding转换为CFStringEncoding，然后从中获取名称：

NSStringEncoding enc;
NSString* strFromWeb = [NSString stringWithContentsOfURL:url usedEncoding:&enc error:&error];
if (strFromWeb) {
    CFStringEncoding cfEnc = CFStringConvertNSStringEncodingToEncoding(enc);
    NSString *name = (NSString *)CFStringGetNameOfEncoding(cfEnc);
    NSLog(@"Encoding = %@", name);
} else {
    // log error
}

Answer 2

没有办法直接从它的值中获取枚举名称作为字符串。

对于字符串编码，您可以深入到Core层，它有CFStringGetNameOfEncoding，它接受与NSStringEncoding不同的CFStringEncoding。但是使用CFStringConvertNSStringEncodingToEncoding，您可以转换编码值。不过，这并不是所有编码的名称。

Answer 3

这可能令人感兴趣：

NSStringEncoding encoding;
NSString* strFromWeb = [NSString stringWithContentsOfURL:url usedEncoding:&encoding error:&error];
NSLog(@"%d", encoding);

可用编码：

*/
enum {
    NSASCIIStringEncoding = 1,      /* 0..127 only */
    NSNEXTSTEPStringEncoding = 2,
    NSJapaneseEUCStringEncoding = 3,
    NSUTF8StringEncoding = 4,
    NSISOLatin1StringEncoding = 5,
    NSSymbolStringEncoding = 6,
    NSNonLossyASCIIStringEncoding = 7,
    NSShiftJISStringEncoding = 8,          /* kCFStringEncodingDOSJapanese */
    NSISOLatin2StringEncoding = 9,
    NSUnicodeStringEncoding = 10,
    NSWindowsCP1251StringEncoding = 11,    /* Cyrillic; same as AdobeStandardCyrillic */
    NSWindowsCP1252StringEncoding = 12,    /* WinLatin1 */
    NSWindowsCP1253StringEncoding = 13,    /* Greek */
    NSWindowsCP1254StringEncoding = 14,    /* Turkish */
    NSWindowsCP1250StringEncoding = 15,    /* WinLatin2 */
    NSISO2022JPStringEncoding = 21,        /* ISO 2022 Japanese encoding for e-mail */
    NSMacOSRomanStringEncoding = 30,

    NSUTF16StringEncoding = NSUnicodeStringEncoding,      /* An alias for NSUnicodeStringEncoding */

    NSUTF16BigEndianStringEncoding = 0x90000100,          /* NSUTF16StringEncoding encoding with explicit endianness specified */
    NSUTF16LittleEndianStringEncoding = 0x94000100,       /* NSUTF16StringEncoding encoding with explicit endianness specified */

    NSUTF32StringEncoding = 0x8c000100,                   
    NSUTF32BigEndianStringEncoding = 0x98000100,          /* NSUTF32StringEncoding encoding with explicit endianness specified */
    NSUTF32LittleEndianStringEncoding = 0x9c000100        /* NSUTF32StringEncoding encoding with explicit endianness specified */
};
typedef NSUInteger NSStringEncoding;

来源：NSUTF8StringEncoding returns nil NSString