UITextField, automatically move to next after 1 character

Question

Scenario: I have 4 UITextFields that only accept 1 character. Easy.

Problem: After I enter the 1 character, I want the next TextField to become active automatically with

Answer 1

Although it is an old question, I just came cross it and I came with simpler solution. assuming we doing this for pass code so each box (UITextField) max length is one char.

- (BOOL) textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string{
    if (![string isEqualToString:@""]) {
        textField.text = string;
        if ([textField isEqual:self.txtField1]) {
            [self.txtField2 becomeFirstResponder];
        }else if ([textField isEqual:self.txtField2]){
            [self.txtField3 becomeFirstResponder];
        }else if ([textField isEqual:self.txtField3]){
            [self.txtField4 becomeFirstResponder];
        }else{
            [textField resignFirstResponder];
        }
        return NO;
    }
    return YES;
}

-(BOOL)textFieldShouldBeginEditing:(UITextField *)textField{
    if (textField.text.length > 0) {
        textField.text = @"";
    }
    return YES;
}