Email validation on textField in iOS

Question

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

Answer 1

Use NSPredicate and Regex:

- (BOOL)validateEmailWithString:(NSString*)email {     NSString *emailRegex = @"[A-Z0-9a-z._%+-]+@[A-Za-z0-9.-]+\\.[A-Za-z]{2,4}";      NSPredicate *emailTest = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", emailRegex];      return [emailTest evaluateWithObject:email]; } 

For a bunch of emails separated by a comma:

- (NSMutableArray*)validateEmailWithString:(NSString*)emails {     NSMutableArray *validEmails = [[NSMutableArray alloc] init];     NSArray *emailArray = [emails componentsSeparatedByString:@","];     for (NSString *email in emailArray)     {         NSString *emailRegex = @"[A-Z0-9a-z._%+-]+@[A-Za-z0-9.-]+\\.[A-Za-z]{2,4}";          NSPredicate *emailTest = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", emailRegex];          if ([emailTest evaluateWithObject:email])             [validEmails addObject:email];     }     return [validEmails autorelease]; } 

Edited Answer: (It also validates extra dots )

- (BOOL)validateEmailWithString:(NSString*)checkString {     BOOL stricterFilter = NO; // Discussion http://blog.logichigh.com/2010/09/02/validating-an-e-mail-address/     NSString *stricterFilterString = @"[A-Z0-9a-z\\._%+-]+@([A-Za-z0-9-]+\\.)+[A-Za-z]{2,4}";     NSString *laxString = @".+@([A-Za-z0-9-]+\\.)+[A-Za-z]{2}[A-Za-z]*";     NSString *emailRegex = stricterFilter ? stricterFilterString : laxString;     NSPredicate *emailTest = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", emailRegex];     return [emailTest evaluateWithObject:checkString]; }