title: Add item to ListView withoud losing data in textField
body: <p>When screen build first time I fetch data with API and use Future builder. Build listView with initialated text in the text field. Under each item in listView I have button 'add' which add new item to listView. When I add new Item, textField that has been changed by the user is not saved.
  It happen because screen build due to state, how can I add item and save data in textField.</p>
  <p>'add' Function in button:</p>
  <pre><code>    onPressed: () {
      setState(() { snapshot.data!['items'].add({});});
  },
  </code></pre>
  <p>How I initial text in textField</p>
  <pre><code> TextEditingController _controller = TextEditingController();
    @override
    void initState() {
      super.initState();
      _controller = TextEditingController(text: widget.link);
    }
  </code></pre>