Flutter DropdownButton Example

flutter_dropdownbutton_example.dart

class _DropdownButtonBugState extends State<DropdownButtonBug> {

  final List<String> _items = ['One', 'Two', 'Three', 'Four'].toList();

  String _selection;

  @override
  void initState() {
    _selection = _items.first;
    super.initState();
  }

  @override
  Widget build(BuildContext context) {
    final dropdownMenuOptions = _items
      .map((String item) =>
        new DropdownMenuItem<String>(value: item, child: new Text(item))
      )
      .toList();

    return new Scaffold(
      body: new DropdownButton<String>(
        value: _selection,
        items: dropdownMenuOptions,
        onChanged: (s) {
          setState(() {
            _selection = s;
          });
        }
      )
    );
  }
}