(iOS) - DatePicker as keyboard

dpkeyboard.mm

- (void) initializeTextFieldInputView {
    UIDatePicker *datePicker = [[UIDatePicker alloc] initWithFrame:CGRectZero];
    datePicker.datePickerMode = UIDatePickerModeDate;
    datePicker.minuteInterval = 5;
    datePicker.backgroundColor = [UIColor whiteColor];
    [datePicker addTarget:self action:@selector(dateUpdated:) forControlEvents:UIControlEventValueChanged];
    self.textField.inputView = datePicker;
    
    //Add done button
    UIToolbar *toolbar = [[UIToolbar alloc] init];
    UIBarButtonItem *doneButton = [[UIBarButtonItem alloc] initWithTitle:@"Done" style:UIBarButtonItemStyleDone target:self action:@selector(doneButtonWasPressed:)];
    UIBarButtonItem *flexibleSeparator = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemFlexibleSpace target:nil action:nil];
    toolbar.items = @[flexibleSeparator, doneButton];
    self.textField.inputAccessoryView = toolbar;
}

- (void) dateUpdated:(UIDatePicker *)datePicker {
    NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
    [formatter setDateFormat:@"yyyy-MM-dd"];
    self.textField.text = [formatter stringFromDate:datePicker.date];
}