import 'package:flutter/material.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: Scaffold(appBar: AppBar(), body: ListViewBug()),
    );
  }
}

class ListViewBug extends StatefulWidget {
  const ListViewBug({Key key}) : super(key: key);

  @override
  _ListViewBugState createState() => _ListViewBugState();
}

class _ListViewBugState extends State<ListViewBug> {
  List<String> _originalProductList = [
    "Product 1",
    "Product 2",
    "Product 3",
  ];

  List<String> _productList;

  @override
  initState() {
    super.initState();
    _productList = _originalProductList;
    _filtered = false;
  }

  bool _filtered;

  toggleFilter() {
    setState(() {
      _filtered = !_filtered;
      if (_filtered) {
        _productList = _originalProductList.getRange(1, 3).toList();
      } else {
        _productList = _originalProductList;
      }
    });
  }

  @override
  Widget build(BuildContext context) {
    return Wrap(
      children: <Widget>[
        FlatButton(
            child: Text("Toggle filter"), onPressed: () => toggleFilter()),
        Container(
          child: ListView(
            shrinkWrap: true,
            children: _productList
                .map(
                  (item) => Chip(
                    key: Key(item),
                    label: Text(
                      item,
                    ),
                  ),
                )
                .toList(),
          ),
        ),
      ],
    );
  }
}