判断是否为表情

/**
 *  判断是否是表情
 */
+ (BOOL)isEmoji:(NSString *)str
{
    //九宫格
    NSString * other = @"➋➌➍➎➏➐➑➒";
    for (NSInteger i = 0; i < str.length; i++)
    {
        if(([other rangeOfString:str].location != NSNotFound))
        {
            return NO;
        }
    }
    
    // 第三方输入法的表情
    NSString * pattern = @"[^\\u0020-\\u007E\\u00A0-\\u00BE\\u2E80-\\uA4CF\\uF900-\\uFAFF\\uFE30-\\uFE4F\\uFF00-\\uFFEF\\u0080-\\u009F\\u2000-\\u201f\r\n]";
    NSPredicate *pred = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", pattern];
    BOOL isMatch = [pred evaluateWithObject:str];
    
    if (isMatch)
    {
        return YES;
    }
    
    // 国际标准表情编码
    __block BOOL returnValue = NO;
    [str enumerateSubstringsInRange:NSMakeRange(0, [str length])
                               options:NSStringEnumerationByComposedCharacterSequences
                            usingBlock:^(NSString *substring, NSRange substringRange, NSRange enclosingRange, BOOL *stop) {
                                const unichar hs = [substring characterAtIndex:0];
                                if (0xd800 <= hs && hs <= 0xdbff) {
                                    if (substring.length > 1)
                                    {
                                        const unichar ls = [substring characterAtIndex:1];
                                        const int uc = ((hs - 0xd800) * 0x400) + (ls - 0xdc00) + 0x10000;
                                        if (0x1d000 <= uc && uc <= 0x1f77f)
                                        {
                                            returnValue = YES;
                                        }
                                    }
                                } else if (substring.length > 1) {
                                    const unichar ls = [substring characterAtIndex:1];
                                    if (ls == 0x20e3) {
                                        returnValue = YES;
                                    }
                                } else {
                                    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;
}

获取含有表情字符串的伪长度（一个表情算一个字）

- (NSInteger)getEmojiStringLength;
{
    __block NSInteger stringLength = 0;
    
    [self enumerateSubstringsInRange:NSMakeRange(0, [self length])
                               options:NSStringEnumerationByComposedCharacterSequences
                            usingBlock:^(NSString *substring, NSRange substringRange, NSRange enclosingRange, BOOL *stop)
     {
         const unichar hs = [substring characterAtIndex:0];
         if (0xd800 <= hs && hs <= 0xdbff)
         {
             if (substring.length > 1)
             {
                 const unichar ls = [substring characterAtIndex:1];
                 const int uc = ((hs - 0xd800) * 0x400) + (ls - 0xdc00) + 0x10000;
                 if (0x1d000 <= uc && uc <= 0x1f77f)
                 {
                     stringLength += 1;
                 }
                 else
                 {
                     stringLength += 1;
                 }
             }
             else
             {
                 stringLength += 1;
             }
         } else if (substring.length > 1)
         {
             const unichar ls = [substring characterAtIndex:1];
             if (ls == 0x20e3)
             {
                 stringLength += 1;
             }
             else
             {
                 stringLength += 1;
             }
         } else {
             if (0x2100 <= hs && hs <= 0x27ff)
             {
                 stringLength += 1;
             }
             else if (0x2B05 <= hs && hs <= 0x2b07)
             {
                 stringLength += 1;
             }
             else if (0x2934 <= hs && hs <= 0x2935)
             {
                 stringLength += 1;
             }
             else if (0x3297 <= hs && hs <= 0x3299)
             {
                 stringLength += 1;
             }
             else if (hs == 0xa9 || hs == 0xae || hs == 0x303d || hs == 0x3030 || hs == 0x2b55 || hs == 0x2b1c || hs == 0x2b1b || hs == 0x2b50)
             {
                 stringLength += 1;
             }
             else
             {
                 stringLength += 1;
             }
         }
     }];
    
    return stringLength;
}

根据限制字数截取后，获取含有表情的实际长度

- (NSInteger)getEmojiStringRealLength:(NSInteger)maxLength
{
    __block NSInteger stringLength = 0;
    __block NSInteger stringRealLength = 0;
    
    [self enumerateSubstringsInRange:NSMakeRange(0, [self length])
                             options:NSStringEnumerationByComposedCharacterSequences
                          usingBlock:^(NSString *substring, NSRange substringRange, NSRange enclosingRange, BOOL *stop)
     {
         const unichar hs = [substring characterAtIndex:0];
         if (0xd800 <= hs && hs <= 0xdbff)
         {
             if (substring.length > 1)
             {
                 const unichar ls = [substring characterAtIndex:1];
                 const int uc = ((hs - 0xd800) * 0x400) + (ls - 0xdc00) + 0x10000;
                 if (0x1d000 <= uc && uc <= 0x1f77f)
                 {
                     stringLength += 1;
                 }
                 else
                 {
                     stringLength += 1;
                 }
             }
             else
             {
                 stringLength += 1;
             }
         } else if (substring.length > 1)
         {
             const unichar ls = [substring characterAtIndex:1];
             if (ls == 0x20e3)
             {
                 stringLength += 1;
             }
             else
             {
                 stringLength += 1;
             }
         } else {
             if (0x2100 <= hs && hs <= 0x27ff)
             {
                 stringLength += 1;
             }
             else if (0x2B05 <= hs && hs <= 0x2b07)
             {
                 stringLength += 1;
             }
             else if (0x2934 <= hs && hs <= 0x2935)
             {
                 stringLength += 1;
             }
             else if (0x3297 <= hs && hs <= 0x3299)
             {
                 stringLength += 1;
             }
             else if (hs == 0xa9 || hs == 0xae || hs == 0x303d || hs == 0x3030 || hs == 0x2b55 || hs == 0x2b1c || hs == 0x2b1b || hs == 0x2b50)
             {
                 stringLength += 1;
             }
             else
             {
                 stringLength += 1;
             }
         }
         
         stringRealLength += substring.length;
         
         if (stringLength >= maxLength)
         {
             *stop = YES;
         }
     }];
    
    return stringRealLength;
}