import 'package:flutter/material.dart';

class InputContainerDemo extends StatefulWidget {
  @override
  _InputContainerDemoState createState() => new _InputContainerDemoState();
}

class _InputContainerDemoState extends State<InputContainerDemo> {
  static final List<String> _dropdownItems = <String>['One', 'Two', 'Free', 'Four'];
  String _dropdownValue = null;

  @override
  Widget build(BuildContext context) {
    return new Scaffold(
      appBar: new AppBar(title: new Text('InputContainer Demo')),
      body: new Padding(
        padding: const EdgeInsets.all(32.0),
        child: new DropdownButtonHideUnderline(
          child: new Column(
            crossAxisAlignment: CrossAxisAlignment.stretch,
            children: <Widget>[
              new InputContainer(
                labelText: _dropdownValue == null ? 'Where are you from' : 'From',
                isEmpty: _dropdownValue == null,
                child: new DropdownButton<String>(
                  value: _dropdownValue,
                  isDense: true,
                  onChanged: (String newValue) {
                    setState(() {
                      _dropdownValue = newValue;
                    });
                  },
                  items: _dropdownItems.map((String value) {
                    return new DropdownMenuItem<String>(
                      value: value,
                      child: new Text(value),
                    );
                  }).toList(),
                ),
              ),
              new SizedBox(height: 32.0),
              new Center(
                child: new RaisedButton(
                  onPressed: () {
                    setState((){
                      _dropdownValue = null;
                    });
                  },
                  child: new Text('CLEAR'),
                ),
              ),
            ],
          ),
        ),
      )
    );
  }
}

void main() {
  runApp(new MaterialApp(home: new InputContainerDemo()));
}