Stack Listviews

import 'package:flutter/foundation.dart';
import 'package:flutter/material.dart';
import 'package:cryptick/data/crypto_data.dart';
import 'package:cryptick/modules/crypto_presenter.dart';
import 'package:shimmer/shimmer.dart';
import 'dart:async';
import 'package:path_provider/path_provider.dart';
import 'dart:io';



class HomePage extends StatefulWidget {
  @override
  _HomePageState createState() => new _HomePageState();
}

class MoreInfoScreen extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return new Scaffold(
      appBar: new AppBar(
        centerTitle: true,
        backgroundColor: Colors.black,
        title: new Text("More Info",
          style: new TextStyle(
            fontFamily: 'PlayfairDisplay',
            letterSpacing: 0.8
          )
        ),
      ),
      body: new Center(
        child: new Card(
          child: new Column(
          children: [
            new ListTile(
              title: new Text('Squared Software London',
                  style: new TextStyle(fontWeight: FontWeight.w500)),
              subtitle: new Text('Cryp-Tick Exchange'),
              leading: new CircleAvatar(
                radius: 18.5,
                backgroundImage: new NetworkImage('https://instagram.flhr4-2.fna.fbcdn.net/vp/d5dfc743e547f88c553af0b9bdc33ece/5BCDB00D/t51.2885-19/s150x150/34885182_217909492157471_8233391730213257216_n.jpg'),
              )
            ),
            new ListTile(
              subtitle: new Text('Contact us at: squaredsoftwarelondon@gmail.com',
                  style: new TextStyle(fontWeight: FontWeight.w500)),
              leading: new Icon(
                Icons.alternate_email,
                color: Colors.red[500],
              ),
            ),
            new Divider(),
            new ListTile(
              title: new Text('Cryp-Tick Exchange uses the Public Ticker V1 API available from: https://coinmarketcap.com/api/',
                  style: new TextStyle(fontWeight: FontWeight.w500)),
            ),
          ],
        ),
        ),
      ),
    );

  }
}


class SettingsScreen extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return new Scaffold(
      appBar: new AppBar(
        centerTitle: true,
        backgroundColor: Colors.black,
        title: new Text("Settings",
          style: new TextStyle(
            fontFamily: 'PlayfairDisplay',
            letterSpacing: 0.8
          )
        ),
      ),
      body: new Center(
          child: new Column(
          children: [
            new ListTile(
              title: new MaterialButton(
              child: new Text(
                    'Fiat Currencies',
                    textAlign: TextAlign.center,
                    style: new TextStyle(
                      fontSize: 20.0,
                      letterSpacing: 0.8,
                      fontFamily: 'PlayfairDisplay'
                    ),
                  ),
              onPressed: (){
                Navigator.push(
                context,
                new MaterialPageRoute(builder: (context) => new CurrencyScreen()),
            );
              }
            ),
            ),
            new Divider(),
            new ListTile(
              title: new MaterialButton(
              child: new Text(
                    'Fill with more options',
                    textAlign: TextAlign.center,
                    style: new TextStyle(
                      fontSize: 20.0,
                      letterSpacing: 0.8,
                      fontFamily: 'PlayfairDisplay'
                    ),
                  ),
              onPressed: (){
                Navigator.push(
                context,
                new MaterialPageRoute(builder: (context) => new SettingsScreen()),
            );
              }
            ),
            ),
          ],
        ),
      ),
    );

  }
}

class CurrencyScreen extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return new Scaffold(
      appBar: new AppBar(
        centerTitle: true,
        backgroundColor: Colors.black,
        title: new Text("Choose your fiat exchange currency",
          style: new TextStyle(
            fontFamily: 'PlayfairDisplay',
            letterSpacing: 0.8
          )
        ),
      ),
      body: new Center(

          child: new Column(
          children: [
            new ListTile(
              title: new Text('British Pound Sterling',
                  style: new TextStyle(fontWeight: FontWeight.w500)),

              leading: new Text('£',
                  style: new TextStyle(fontWeight: FontWeight.w500, fontSize: 30.0)),
            ),
            new Divider(),
            new ListTile(
              title: new Text('United States Dollar',
                  style: new TextStyle(fontWeight: FontWeight.w500)),

              leading: new Text("US\$",
                  style: new TextStyle(fontWeight: FontWeight.w500, fontSize: 15.0)),
            ),
            new Divider(),
            new ListTile(
              title: new Text('Euro',
                  style: new TextStyle(fontWeight: FontWeight.w500)),

              leading: new Text("€",
                  style: new TextStyle(fontWeight: FontWeight.w500, fontSize: 30.0)),
            ),
            new Divider(),
            new ListTile(
              title: new Text('Japanese yen',
                  style: new TextStyle(fontWeight: FontWeight.w500)),

              leading: new Text("¥",
                  style: new TextStyle(fontWeight: FontWeight.w500, fontSize: 30.0)),
            ),
            new Divider(),
            new ListTile(
              title: new Text('Australian Dollar',
                  style: new TextStyle(fontWeight: FontWeight.w500)),

              leading: new Text("A\$",
                  style: new TextStyle(fontWeight: FontWeight.w500, fontSize: 20.0),
              )
            ),
            new Divider(),
            new ListTile(
              title: new Text('Canadian Dollar',
                  style: new TextStyle(fontWeight: FontWeight.w500)),

              leading: new Text("A\$",
                  style: new TextStyle(fontWeight: FontWeight.w500, fontSize: 20.0),
              )
            ),
            new Divider(),
            new ListTile(
              title: new Text('Swiss Franc',
                  style: new TextStyle(fontWeight: FontWeight.w500)),

              leading: new Text("CHF",
                  style: new TextStyle(fontWeight: FontWeight.w500, fontSize: 15.0),
              )
            ),
          ],
        ),
      ),
    );

  }
}

class _HomePageState extends State<HomePage> implements CryptoListViewContract {
  CryptoListPresenter _presenter;
  List<Crypto> _currencies;
  bool _isLoading;
  final List<MaterialColor> _colors = [Colors.blue, Colors.indigo, Colors.red];

  _HomePageState() {
    _presenter = new CryptoListPresenter(this);
  }

  var refreshKey = new GlobalKey<RefreshIndicatorState>();

  @override
  void initState() {
    super.initState();
    _isLoading = true;
    _presenter.loadCurrencies();
    refreshList();
  }

  Future<Null> refreshList() async {

    refreshKey.currentState?.show(atTop: false);
    await new Future.delayed(new Duration(seconds: 1));
      _presenter.loadCurrencies();
      Scaffold.of(context).showSnackBar(
            new SnackBar(
              duration: new Duration(seconds: 3),
              backgroundColor: Colors.black,
              content: new Text(
                    'Refresh available every 60 seconds',
                    textAlign: TextAlign.center,
                    style: new TextStyle(
                      letterSpacing: 0.8,
                      fontFamily: 'PlayfairDisplay'
                    ),
                  ),
              ),
            );
    setState(() {
    });
    return null;
  }

  @override
  Widget build(BuildContext context) {
    return new Scaffold(
        appBar: new AppBar(
          centerTitle: true,
          backgroundColor: Colors.black,
          title: new Text("Cryp-Tick Exchange",
          style: new TextStyle(
            fontFamily: 'PlayfairDisplay',
            letterSpacing: 0.8
          )
          ),
          elevation: defaultTargetPlatform == TargetPlatform.iOS ? 0.0 : 5.0,
        ),
        drawer: new Drawer(
        child: new ListView(
          padding: EdgeInsets.zero,
          children: <Widget>[
            new DrawerHeader(
              child: new CircleAvatar(
              child: new Image.asset('images/ctavatar.png'),
              ),
              decoration: new BoxDecoration(
                color: Colors.black,
              ),
            ),
            new MaterialButton(
              child: new Text(
                    'More Info',
                    textAlign: TextAlign.center,
                    style: new TextStyle(
                      fontSize: 20.0,
                      letterSpacing: 0.8,
                      fontFamily: 'PlayfairDisplay'
                    ),
                  ),
              onPressed: (){
                Navigator.push(
                context,
                new MaterialPageRoute(builder: (context) => new MoreInfoScreen()),
            );
              }
            ),
            new Divider(),
            new MaterialButton(
              child: new Text(
                    'Settings',
                    textAlign: TextAlign.center,
                    style: new TextStyle(
                      fontSize: 20.0,
                      letterSpacing: 0.8,
                      fontFamily: 'PlayfairDisplay'
                    ),
                  ),
              onPressed: (){
                Navigator.push(
                context,
                new MaterialPageRoute(builder: (context) => new SettingsScreen()),
            );
              }
            ),
          ]
        ),
      ),
        body: _isLoading
            ? new Center(
          child: new CircularProgressIndicator(),
        )
            : _cryptoWidget()
      );

  }



  Widget _cryptoWidget() {
    return new Container(
        child: new Column(
          children: <Widget>[
            new Flexible(
              child: new ListView.builder(
                  scrollDirection: Axis.horizontal,
                  itemBuilder: (BuildContext context, int index) {
                  return _listViewFiller();
                }
              ),
            ),
            new Flexible(
              child: new RefreshIndicator(
              key: refreshKey,
              child: new ListView.builder(
                scrollDirection: Axis.horizontal,
                itemCount: _currencies.length,
                itemBuilder: (BuildContext context, int index) {
                  final int i = index ~/ 2;
                  final Crypto currency = _currencies[i];
                  final MaterialColor color = _colors[i % _colors.length];
                  if (index.isOdd) {
                    return new Divider();
                  }
                  return _getListItemUi(currency, color);
                },
              ),
              onRefresh:refreshList,
            ),
            )
          ],
        )
      );
  }

  ListTile _getListItemUi(Crypto currency, MaterialColor color) {
    return new ListTile(
      leading: new Image.asset("cryptoiconsWhite/"+currency.symbol.toLowerCase()+"@2x.png"),
      title: new Text(currency.name,
          style: new TextStyle(fontWeight: FontWeight.bold)),
      subtitle:
      _getSubtitleText(currency.price_usd, currency.percent_change_1h),
      isThreeLine: true,
      trailing: new IconButton(
        icon: new Icon(Icons.add),
        onPressed: () async { Directory appDocDir = await getApplicationDocumentsDirectory();
        String appDocPath = appDocDir.path;
        var myFile = new File('$appDocPath/my_file.txt')
        ..writeAsStringSync('myVar: $_currencies');
        print(myFile.absolute.path);
        }
      ),
    );
  }

  Card _listViewFiller() {
    new BorderRadius.circular(30.0);
    return new Card(
      child: new SizedBox(
        height: 300.0,
        width: 300.0,
        child: new SizedBox(
          child: new Image.network(
            'https://proxy.duckduckgo.com/iu/?u=http%3A%2F%2Fwww.personaltouchcolorado.com%2Fwp-content%2Fuploads%2F2013%2F01%2FGoodner-Waterfall1-e1362453084645.jpg&f=1'
            ),
          ),
        ),
      );
    }


  Widget _getSubtitleText(String priceUSD, String percentageChange) {
    TextSpan priceTextWidget = new TextSpan(
        text: "\$$priceUSD\n", style: new TextStyle(color: Colors.black));
    String percentageChangeText = "1 hour: $percentageChange%";
    TextSpan percentageChangeTextWidget;

    if (double.parse(percentageChange) > 0) {
      percentageChangeTextWidget = new TextSpan(
          text: percentageChangeText,
          style: new TextStyle(color: Colors.green ));
    } else {
      percentageChangeTextWidget = new TextSpan(
          text: percentageChangeText, style: new TextStyle(color: Colors.red));
    }

    return new RichText(
        text: new TextSpan(
            children: [priceTextWidget, percentageChangeTextWidget]));
  }

  @override
  void onLoadCryptoComplete(List<Crypto> items) {
    // TODO: implement onLoadCryptoComplete

    setState(() {
      _currencies = items;
      _isLoading = false;
    });
  }

  @override
  void onLoadCryptoError() {
    // TODO: implement onLoadCryptoError
  }
}