iOS限制UITextView长度，表情符号输入

- (BOOL)textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range replacementText:(NSString *)text {
    
    NSInteger maxLength = 200;
    
    if ([text isEqualToString:@"\n"]){ //判断输入的字是否是回车，即按下return
          [self.textView resignFirstResponder];
          return false;
      }
      if ([self stringContainsEmoji:text]) {
          return false;
      }
      if (textView.text.length + text.length > maxLength) {
          //NSString *allText = [textView.text stringByReplacingCharactersInRange:range withString:text];
          NSString *allText = [NSString stringWithFormat:@"%@%@",textView.text,text];
          textView.text = [allText substringToIndex:maxLength];
          return false;
      }
      return true;
}

/// 判断是否有emoji
- (BOOL)stringContainsEmoji:(NSString *)string {
    
    // 过滤所有表情
    __block BOOL containsEmoji = NO;
    
    //九宫格 汉字 获取到的是圈123这样的 要可以输入
    if ([string isEqualToString:@"➋"]||[string isEqualToString:@"➌"]||[string isEqualToString:@"➍"]||[string isEqualToString:@"➎"]||[string isEqualToString:@"➏"]||[string isEqualToString:@"➐"]||[string isEqualToString:@"➑"]||[string isEqualToString:@"➒"]) {
        return containsEmoji;
    }
    
    
    [string enumerateSubstringsInRange:NSMakeRange(0, [string 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 <= 0x1F9FF) {// <=0x1f77f <=0x1f9c0 <=0x1F9FF
                    containsEmoji = YES;
                }
            }
        }
        else if (substring.length > 1) {
            const unichar ls = [substring characterAtIndex:1];
            if (ls == 0x20e3 || ls == 0xfe0f || ls == 0xd83c) {
                containsEmoji = YES;
            }
        } else {
            if (0x2100 <= hs && hs <= 0x27ff) {
                containsEmoji = YES;
            }
            else if (0x2B05 <= hs && hs <= 0x2b07) {
                containsEmoji = YES;
            }
            else if (0x2934 <= hs && hs <= 0x2935) {
                containsEmoji = YES;
            }
            else if (0x3297 <= hs && hs <= 0x3299) {
                containsEmoji = YES;
            } else if (hs == 0xa9 || hs == 0xae || hs == 0x303d || hs == 0x3030 || hs == 0x2b55 || hs == 0x2b1c || hs == 0x2b1b || hs == 0x2b50) {
                containsEmoji = YES;
            }
        }
        
        if (containsEmoji) {
            *stop = YES;
        }
    }];
    return containsEmoji;
}