How to do it...

Open the stopwatch.dart file and dive right into the ListView code:

1. Let's replace ListView with one of its variants, ListView.builder. Replace the existing implementation of _buildLapDisplay with this one:

Widget _buildLapDisplay() {
  return ListView.builder(
    itemCount: laps.length,
    itemBuilder: (context, index) {
      final milliseconds = laps[index];
      return ListTile(
        contentPadding: EdgeInsets.symmetric(horizontal: 50),
        title: Text('Lap ${index + 1}'),
        trailing: Text(_secondsText(milliseconds)),
      );
    },
  );
}

2. ScrollViews can get too big, so it's usually a good idea to show the user their position in the list. Wrap ListView in a Scrollbar widget. There aren't any special properties to enter since this widget is entirely context aware:

return Scrollbar(
  child: ListView.builder(
    itemCount: laps.length,

3. Finally, add a quick new feature for...