Email validation on textField in iOS

Question

In iOS App, how to add Email validation on UITextField?

Answer 1

A version using NSRegularExpression and regex pattern copied from OWASP_Validation_Regex_Repository

+ (BOOL) isValidEmail:(NSString *)emailString {
        NSError *error = NULL;
        /**
         * @see OWASP_Validation_Regex_Repository
         */
        NSString *emailPattern = @"^[a-zA-Z0-9_+&*-]+(?:\\.[a-zA-Z0-9_+&*-]+)*@(?:[a-zA-Z0-9-]+\\.)+[a-zA-Z]{2,7}$";
        NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:emailPattern
                                                                               options:NSRegularExpressionCaseInsensitive
                                                                                 error:&error];
        NSUInteger matchCount = [regex numberOfMatchesInString:emailString options:0 range:NSMakeRange(0, [emailString length])];
        return matchCount > 0;
    }