iOS 搜索高亮

NSString *originString = @"AaBbCcDd12345ABC abc";
NSString *searchKey = @"A";
NSMutableAttributedString *attributedString = [[NSMutableAttributedString alloc] initWithString:originString];

NSMutableAttributedString *attributedString = [[NSMutableAttributedString alloc] initWithString: originString];

NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern: searchKey options:NSRegularExpressionCaseInsensitive error:nil];

NSArray *searchResults = [regex matchesInString:originString options:0 range:NSMakeRange(0, originString.length)];

for (NSTextCheckingResult *result in searchResults) {
   [attributedString addAttribute:NSForegroundColorAttributeName value:UIColor.redColor range:result.range];
}

label.attributedText = attributedString;