void MainWindow::addItem() {
  bool ok;
  QString text = QInputDialog::getText(this, tr("New Item"), tr("New Item:"),
                                       QLineEdit::Normal, "", &ok);
  if (ok && !text.isEmpty()) {
    if (m_pItem == nullptr) {
      QStringList lst = {text};
      QTreeWidgetItem *item =
          new QTreeWidgetItem(static_cast<QTreeWidget *>(nullptr), lst);
      ui->treeWidget->addTopLevelItem(item);
    } else {
      QTreeWidgetItem *newItem = new QTreeWidgetItem(m_pItem);
      newItem->setText(0, text);
      m_pItem->setExpanded(true);
    }
  }
}