因為emoji編碼在android或者pc設備沒有很好的支持，所以有時候為了禁止emoji表情的輸入，因為關閉不了系統emoji的鍵盤，那只能根據編碼把emoji表情過濾掉，寫了一個NSString的拓展，用來判斷是不是emoji編碼：
@implementation NSString(Emoji)
+(BOOL)isContainsEmoji:(NSString *)string {
__block BOOL isEomji = NO;
[string enumerateSubstringsInRange:NSMakeRange(0, [string length]) options:NSStringEnumerationByComposedCharacterSequencesusingBlock:
^(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) {
isEomji = YES;
}
}
} else if (substring.length > 1) {
const unichar ls = [substring characterAtIndex:1];
if (ls == 0x20e3) {
isEomji = YES;
}
} else {
// non surrogate
if (0x2100 <= hs && hs <= 0x27ff && hs != 0x263b) {
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;
}
這樣在textview或textfield的delegate判斷一下，即可禁止輸入emoji，如下：
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
//emoji無效
if([NSString isContainsEmoji:string])
{
return NO;
}
}
當然，最好的方法還是做一套emoji的編碼解碼，以支持其他非ios設備。不然禁止這個功能有點說不過去。