Email validation on textField in iOS

Try this out
This checks exactly with top level domain names along with validation.

- (BOOL)validateEmail:(NSString *)inputText {
    NSString *emailRegex = @"[A-Z0-9a-z][A-Z0-9a-z._%+-]*@[A-Za-z0-9][A-Za-z0-9.-]*\\.[A-Za-z]{2,6}"; 
    NSPredicate *emailTest = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", emailRegex]; 
    NSRange aRange;
    if([emailTest evaluateWithObject:inputText]) {
        aRange = [inputText rangeOfString:@"." options:NSBackwardsSearch range:NSMakeRange(0, [inputText length])];
        int indexOfDot = aRange.location;
        //NSLog(@"aRange.location:%d - %d",aRange.location, indexOfDot);
        if(aRange.location != NSNotFound) {
            NSString *topLevelDomain = [inputText substringFromIndex:indexOfDot];
            topLevelDomain = [topLevelDomain lowercaseString];
            //NSLog(@"topleveldomains:%@",topLevelDomain);
            NSSet *TLD;
            TLD = [NSSet setWithObjects:@".aero", @".asia", @".biz", @".cat", @".com", @".coop", @".edu", @".gov", @".info", @".int", @".jobs", @".mil", @".mobi", @".museum", @".name", @".net", @".org", @".pro", @".tel", @".travel", @".ac", @".ad", @".ae", @".af", @".ag", @".ai", @".al", @".am", @".an", @".ao", @".aq", @".ar", @".as", @".at", @".au", @".aw", @".ax", @".az", @".ba", @".bb", @".bd", @".be", @".bf", @".bg", @".bh", @".bi", @".bj", @".bm", @".bn", @".bo", @".br", @".bs", @".bt", @".bv", @".bw", @".by", @".bz", @".ca", @".cc", @".cd", @".cf", @".cg", @".ch", @".ci", @".ck", @".cl", @".cm", @".cn", @".co", @".cr", @".cu", @".cv", @".cx", @".cy", @".cz", @".de", @".dj", @".dk", @".dm", @".do", @".dz", @".ec", @".ee", @".eg", @".er", @".es", @".et", @".eu", @".fi", @".fj", @".fk", @".fm", @".fo", @".fr", @".ga", @".gb", @".gd", @".ge", @".gf", @".gg", @".gh", @".gi", @".gl", @".gm", @".gn", @".gp", @".gq", @".gr", @".gs", @".gt", @".gu", @".gw", @".gy", @".hk", @".hm", @".hn", @".hr", @".ht", @".hu", @".id", @".ie", @" No", @".il", @".im", @".in", @".io", @".iq", @".ir", @".is", @".it", @".je", @".jm", @".jo", @".jp", @".ke", @".kg", @".kh", @".ki", @".km", @".kn", @".kp", @".kr", @".kw", @".ky", @".kz", @".la", @".lb", @".lc", @".li", @".lk", @".lr", @".ls", @".lt", @".lu", @".lv", @".ly", @".ma", @".mc", @".md", @".me", @".mg", @".mh", @".mk", @".ml", @".mm", @".mn", @".mo", @".mp", @".mq", @".mr", @".ms", @".mt", @".mu", @".mv", @".mw", @".mx", @".my", @".mz", @".na", @".nc", @".ne", @".nf", @".ng", @".ni", @".nl", @".no", @".np", @".nr", @".nu", @".nz", @".om", @".pa", @".pe", @".pf", @".pg", @".ph", @".pk", @".pl", @".pm", @".pn", @".pr", @".ps", @".pt", @".pw", @".py", @".qa", @".re", @".ro", @".rs", @".ru", @".rw", @".sa", @".sb", @".sc", @".sd", @".se", @".sg", @".sh", @".si", @".sj", @".sk", @".sl", @".sm", @".sn", @".so", @".sr", @".st", @".su", @".sv", @".sy", @".sz", @".tc", @".td", @".tf", @".tg", @".th", @".tj", @".tk", @".tl", @".tm", @".tn", @".to", @".tp", @".tr", @".tt", @".tv", @".tw", @".tz", @".ua", @".ug", @".uk", @".us", @".uy", @".uz", @".va", @".vc", @".ve", @".vg", @".vi", @".vn", @".vu", @".wf", @".ws", @".ye", @".yt", @".za", @".zm", @".zw", nil];
            if(topLevelDomain != nil && ([TLD containsObject:topLevelDomain])) {
                //NSLog(@"TLD contains topLevelDomain:%@",topLevelDomain);
                return TRUE;
            }
            /*else {
             NSLog(@"TLD DOEST NOT contains topLevelDomain:%@",topLevelDomain);
             }*/

        }
    }
    return FALSE;
}

Use Below code for "Swift language" For Email Validation

func ValidateEmailString (strEmail:NSString) -> Bool
{
   let emailRegex = "[A-Z0-9a-z._%+-]+@[A-Za-z0-9.-]+\\.[A-Za-z]{2,4}"
   let emailText = NSPredicate(format:"SELF MATCHES [c]%@",emailRegex)
   return (emailText.evaluate(with: strEmail))
} 

Thanks :)

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];
}

Use the below code:-

NSString *emailRegEx = @"[A-Z0-9a-z._%+-]+@[A-Za-z0-9.-]+\\.[A-Za-z]{2,4}";
NSPredicate *emailTest = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", emailRegEx];
//Valid email address

if ([emailTest evaluateWithObject:userMailTextField.text] == YES) 
{
     //Do Something
}
else
{
     NSLog(@"email not in proper format");
}

userMailTextField is the name of my textField (use your own).

I hope this code will help you!!!