iOS 禁止输入emoji

项目中原来使用的方法：

- (BOOL)ContainsEmoji:(NSString *)inputString 
{
    __block BOOL isEomji = NO;
    [inputString enumerateSubstringsInRange:NSMakeRange(0, [inputString 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) {
                    isEomji = YES;
                }
            }
        } else if (substring.length > 1) {
            const unichar ls = [substring characterAtIndex:1];
            if (ls == 0x20e3 || ls == 0xfe0f) {
                isEomji = YES;
            }
        } else {
            if (0x2100 <= hs && hs <= 0x27ff) {
                isEomji = YES;
            } else if (0x2B05 <= hs && hs <= 0x2b07) {
                isEomji = YES;
            } else if (0x2934 <= hs && hs <= 0x2935) {
                isEomji = YES;
            } else if (0x3297 <= hs && hs <= 0x3299) {
                isEomji = YES;
            } else if (hs == 0xa9 || hs == 0xae || hs == 0x303d || hs == 0x3030 || hs == 0x2b55 || hs == 0x2b1c || hs == 0x2b1b || hs == 0x2b50|| hs == 0x231a ) {
                isEomji = YES;
            }
        }
    }];
    return isEomji;
}

发现有一些emoji会遗漏过去，如：🤠 🤡 🧢 🪰 🪶 🪨 等；

调试发现，被识别出来的在 0x1d000 <= uc && uc <= 0x1F77F 这两个值之间，而🤠 的值更大。于是找到 UNICODE EMOJI，知道最新版本的emoji是14.0，发布日期：2021-08-25。

然后在文档中找到14.0版本中emoji编码的最大值：0x1FAF6，于是将识别的范围改为：0x1d000 <= uc && uc <= 0x1FAF6，测试过后，上述遗漏的emoji都被拦截了。

麻烦的点是emoji更新后，需要手动更新代码，有不对、遗漏的地方或者大家有更好的方法，希望不吝赐教。

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发现一个大佬用正则表达式写的简洁方法：

NSString *inputString = @"abcd123🤠 🤡 🧢 🪰 🪶 🪨";
NSRegularExpression *regularExpression = [NSRegularExpression regularExpressionWithPattern:@"[^\\u0020-\\u007e\\u00a0-\\u00be\\u2e80-\\ua4cf\\uf900-\\ufaff\\ufe30-\\ufe4f\\uff00-\\uffef\\u0080-\\u009f\\u2000-\\u201f\r\n]" options:0 error:nil];
NSString *result = [regularExpression stringByReplacingMatchesInString:inputString options:0 range:NSMakeRange(0, inputString.length) withTemplate:@""];

另外可以直接不让emoji输入，不过 currentInputMode 官方不建议使用了：

-(BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
    if ([[[UITextInputMode currentInputMode] primaryLanguage] isEqualToString:@"emoji"]) {
        return false;
    }
    return true;
}