iOS开发 - 实现过滤字符串中的Emoji表情

一、前提介绍

在我们平时iOS开发中有一些情况需要我们的客户端用户不能输入Emoji表情，或者需要自动过滤掉用户输入的Emoji表情，因为服务器无法识别这些用户输入的表情，这个时候我们就需要办法解决这种情况了。
相信大家如果在遇到这种问题，上谷歌百度都搜索看过这段代码，

+ (BOOL)stringContainsEmoji:(NSString *)string
{    
    __block BOOL returnValue = NO;    
    [string enumerateSubstringsInRange:NSMakeRange(0, [string length]) 
options:NSStringEnumerationByComposedCharacterSequences usingBlock:
^(NSString *substring, NSRange substringRange, NSRange enclosingRange, BOOL *stop) { 
        const unichar hs = [substring characterAtIndex:0]; 
        // surrogate pair        
        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 {      
                  // 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;
}

(NSString *)converStrEmoji:(NSString *)emojiStr
{
NSString *tempStr = [[NSString alloc]init];
NSMutableString *kksstr = [[NSMutableString alloc]init];
NSMutableArray *array = [NSMutableArray arrayWithCapacity:10];
NSMutableString *strMu = [[NSMutableString alloc]init];
for(int i =0; i < [emojiStr length]; i++)
{
tempStr = [emojiStr substringWithRange:NSMakeRange(i, 1)];
[strMu appendString:tempStr];
if ([self stringContainsEmoji:strMu]) {
strMu = [[strMu substringToIndex:([strMu length]-2)] mutableCopy];
[array removeLastObject];
continue;
}else
[array addObject:tempStr];
}
for (NSString *strs in array) {
[kksstr appendString:strs];
}
return kksstr;
}