链接：http://www.jianshu.com/p/51deb78814e1
來源：简书
著作权归作者所有。商业转载请联系作者获得授权，非商业转载请注明出处。

感谢作者提供！
Swift:

import Foundation

extension String{

func emojiStr() -> String {
    //1.在一段字符串中查找十六进制的字符串
    let scanner = NSScanner(string: self)
    //2.将查找的字符串转换为十六进制的数字
    var value: UInt32 = 0
    scanner.scanHexInt(&value)
    //3.将十六进制的数字转化为 unicode字符
    let charCode = Character(UnicodeScalar(value))
    //4.将uniconde字符转换 字符串

    return "\(charCode)"

}

}
Objective-C:

.h

import <Foundation/Foundation.h>

@interface NSString (Emoji)
/**

• 将十六进制的编码转为emoji字符
  */

• (NSString *)emojiWithIntCode:(long)intCode;

/**

• 将十六进制的编码转为emoji字符
  */

• (NSString *)emojiWithStringCode:(NSString *)stringCode;

• (NSString *)emoji;

/**

• 是否为emoji字符
  */

• (BOOL)isEmoji;
  @end
  .m

import "NSString+Emoji.h"

define EmojiCodeToSymbol(c) ((((0x808080F0 | (c & 0x3F000) >> 4) | (c & 0xFC0) << 10) | (c & 0x1C0000) << 18) | (c & 0x3F) << 24)

@implementation NSString (Emoji)

• (NSString *)emojiWithIntCode:(long)intCode {
  NSString * s = [NSString stringWithFormat:@"%ld",intCode];
  int symbol = EmojiCodeToSymbol([s intValue]);
  NSString *string = [[NSString alloc] initWithBytes:&symbol length:sizeof(symbol) encoding:NSUTF8StringEncoding];
  if (string == nil) { // 新版Emoji
  string = [NSString stringWithFormat:@"%C", (unichar)intCode];
  }
  return string;
  }

• (NSString *)emoji
  {
  return [NSString emojiWithStringCode:self];
  }

• (NSString *)emojiWithStringCode:(NSString *)stringCode
  {
  char *charCode = (char *)stringCode.UTF8String;
  long intCode = strtol(charCode, NULL, 16);
  return [self emojiWithIntCode:intCode];
  }

// 判断是否是 emoji表情

• (BOOL)isEmoji
  {
  BOOL returnValue = NO;

  const unichar hs = [self characterAtIndex:0];
  // surrogate pair
  if (0xd800 <= hs && hs <= 0xdbff) {
  if (self.length > 1) {
  const unichar ls = [self characterAtIndex:1];
  const int uc = ((hs - 0xd800) * 0x400) + (ls - 0xdc00) + 0x10000;
  if (0x1d000 <= uc && uc <= 0x1f77f) {
  returnValue = YES;
  }
  }
  } else if (self.length > 1) {
  const unichar ls = [self characterAtIndex:1];
  if (ls == 0x20e3) {
  returnValue = YES;
  }
  } else {
  // non surrogate
  if (0x2100 <= hs && hs <= 0x27ff) {
  returnValue = YES;
  } else if (0x2B05 <= hs && hs <= 0x2b07) {
  returnValue = YES;
  } else if (0x2934 <= hs && hs <= 0x2935) {
  returnValue = YES;
  } else if (0x3297 <= hs && hs <= 0x3299) {
  returnValue = YES;
  } else if (hs == 0xa9 || hs == 0xae || hs == 0x303d || hs == 0x3030 || hs == 0x2b55 || hs == 0x2b1c || hs == 0x2b1b || hs == 0x2b50) {
  returnValue = YES;
  }
  }

  return returnValue;
  }
  @end