iOS 与十六进制转换

• 普通字符串转换为十六进制的。
  - (NSString *)hexStringFromString:(NSString *)string{
  NSData *myD = [string dataUsingEncoding:NSUTF8StringEncoding];
  Byte *bytes = (Byte *)[myD bytes];
  //下面是Byte 转换为16进制。
  NSString *hexStr=@"";
  for(int i=0;i<[myD length];i++)
  {
  NSString *newHexStr = [NSString stringWithFormat:@"%x",bytes[i]&0xff];///16进制数
  if ([newHexStr length]==1)
  hexStr = [NSString stringWithFormat:@"%@0%@",hexStr,newHexStr];
  else
  hexStr = [NSString stringWithFormat:@"%@%@",hexStr,newHexStr];
  }
  return hexStr;
  }

• 十六进制转换为普通字符串的。
  - (NSString *)stringFromHexString:(NSString *)hexString {
  char *myBuffer = (char *)malloc((int)[hexString length] / 2 + 1);
  bzero(myBuffer, [hexString length] / 2 + 1);
  for (int i = 0; i < [hexString length] - 1; i += 2) {
  unsigned int anInt;
  NSString * hexCharStr = [hexString substringWithRange:NSMakeRange(i, 2)];
  NSScanner * scanner = [[NSScanner alloc] initWithString:hexCharStr];
  [scanner scanHexInt:&anInt];
  myBuffer[i / 2] = (char)anInt;
  }
  NSString *unicodeString = [NSString stringWithCString:myBuffer encoding:4];
  NSLog(@"字符串%@",unicodeString);
  return unicodeString;
  }

• 数字转十六进制字符串
  - (NSString *)stringWithHexNumber:(NSUInteger)hexNumber{
  char hexChar[6];
  sprintf(hexChar, "%x", (int)hexNumber);
  NSString *hexString = [NSString stringWithCString:hexChar encoding:NSUTF8StringEncoding];
  return hexString;
  }

• 十六进制字符串转数字
  - (NSInteger)numberWithHexString:(NSString *)hexString{
  const char *hexChar = [hexString cStringUsingEncoding:NSUTF8StringEncoding];
  int hexNumber;
  sscanf(hexChar, "%x", &hexNumber);
  return (NSInteger)hexNumber;
  }

• 将NSData转换成十六进制的字符串
  - (NSString *)convertDataToHexStr:(NSData *)data {
  if (!data || [data length] == 0) {
  return @"";
  }
  NSMutableString *string = [[NSMutableString alloc] initWithCapacity:[data length]];
  [data enumerateByteRangesUsingBlock:^(const void *bytes, NSRange byteRange, BOOL *stop) {
  unsigned char dataBytes = (unsigned char)bytes;
  for (NSInteger i = 0; i < byteRange.length; i++) {
  NSString *hexStr = [NSString stringWithFormat:@"%x", (dataBytes[i]) & 0xff];
  if ([hexStr length] == 2) {
  [string appendString:hexStr];
  } else {
  [string appendFormat:@"0%@", hexStr];
  }
  }
  }];
  return string;
  }

• 将十六进制字符串转换成NSData
  - (NSData *)convertHexStrToData:(NSString *)str {
  if (!str || [str length] == 0) {
  return nil;
  }
  NSMutableData *hexData = [[NSMutableData alloc] initWithCapacity:8];
  NSRange range;
  if ([str length] % 2 == 0){
  range = NSMakeRange(0, 2);
  } else range = NSMakeRange(0, 1);
  for (NSInteger i = range.location; i < [str length]; i += 2) {
  unsigned int anInt;
  NSString *hexCharStr = [str substringWithRange:range];
  NSScanner *scanner = [[NSScanner alloc] initWithString:hexCharStr];
  [scanner scanHexInt:&anInt];
  NSData *entity = [[NSData alloc] initWithBytes:&anInt length:1];
  [hexData appendData:entity];
  range.location += range.length;
  range.length = 2;
  }
  NSLog(@"hexdata: %@", hexData);
  return hexData;
  }