Ensure User has entered email address string in correct format?

Question

i have a text field in Contact screen and the user need to enter email address to send me message. Whats the best way to ensure the user has entered a valid email address su

Answer 1

Use this textField delegate function as this will be called on every text entered:

 - (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
 {
      NSString *strEnteredText = textField.text;
     if(strEnteredText.length>0) 
     {
       if([self validateEmail:strEnteredText])
       {
          //Valid email 
          //Use UILabel to give message
         // BOOL email = true to know email is valid when submit button tapped
       }
       else
       {
          //Not Valid email
          //Use UILabel to give message
          // BOOl emaiL = false to know email is valid when submit button tapped
        }
     }
 }

Add this method .h file

 - (BOOL) validateEmail: (NSString *) enteredText 
 {
   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:enteredText];
 }