- (BOOL)textFieldShouldReturn:(UITextField*)textField;

- (BOOL)textFieldShouldReturn:(UITextField*)textField {
    NSInteger nextTag = textField.tag + 1;
    UIResponder* nextResponder = [textField.superview viewWithTag:nextTag];

    if (nextResponder) {
        [nextResponder becomeFirstResponder];
    } else {
        [textField resignFirstResponder];
    }
    return NO;
}

- (BOOL)textFieldShouldReturn:(UITextField*)textField {
    NSUInteger nextIndex = [arrayWithResponders indexOfObject:textField]+1 % [arrayWithResponders count];
    UIResponder* nextResponder = [arrayWithTextFields objectAtIndex: nextIndex];

    if (nextResponder) {
        [nextResponder becomeFirstResponder];
    } else {
        [textField resignFirstResponder];
    }
    return NO;
}