E-Mail address validation in iOS app

Email validation custom method :

 -(BOOL) validEmailAddress:(NSString*) emailString {
    NSString *regExPattern = @"^[A-Z0-9._%+-]+@[A-Z0-9.-]+.[A-Z]{2,4}$";
    NSRegularExpression *regEx = [[NSRegularExpression alloc] initWithPattern:regExPattern options:NSRegularExpressionCaseInsensitive error:nil];
    NSUInteger regExMatches = [regEx numberOfMatchesInString:emailString options:0 range:NSMakeRange(0, [emailString length])];
    if (regExMatches == 0)
        return NO; // email invalid
     else
        return YES; // email valid
  }
Now, just call above method from where you want to validate email address (pass your email address as a emailString to this method).
For eg:

 if ([self validEmailAddress:yourEmailAddressText] == YES) {

      //email valid

}

else {

    //email invalid

}