Email validation in objective c

If your are designing signup screen in iOS app, you need to validate email provided by user. In this post we will learn ho validate email and show alert if provided email is wrong.

For this we will use NSPredicate and regular expression.

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

}

Now show alert if email is invalid

if(![self validateEmail:[aTextField text]]) {
        // user entered invalid email address
        UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Error" message:@"Enter a valid email address." delegate:self cancelButtonTitle:nil otherButtonTitles:@"OK", nil];
        [alert show]; 
        [alert release]; //if ARC is disable then write this line otherwise not
 }