title: How to fill SliverList with API data
body: <p>I'm building a weather forecast app in which SliverAppBar shows current weather and SliverList shows daily forecast in form of cards. I get data from DarkSky API as a <em>Map</em>.</p>
  
  <p>I have completed the current weather part with FutureBuilder, but now I'm having a trouble finding how to fill SliverList. I tried to do it with FutureBuilder as well, but without success.</p>
  
  <p><strong>This is my code</strong></p>
  
  <pre class="lang-dart prettyprint-override"><code>class HomeScreen extends StatefulWidget {
    @override
    _HomeScreenState createState() =&gt; _HomeScreenState();
  }
  
  class _HomeScreenState extends State&lt;HomeScreen&gt; {
  
    @override
    Widget build(BuildContext context) {
      return new Scaffold(
  
          body: new CustomScrollView(
            slivers: &lt;Widget&gt;[
              new SliverAppBar(
                brightness: Brightness.dark,
                centerTitle: true,
                title: Text('Weather'),
                expandedHeight: 300,
                floating: true,
                pinned: true,
                snap: true,
                flexibleSpace: FlexibleSpaceBar(
                    background: new Container(
                  child: updateCurrentWeather(), //METHOD CONSTRUCTING CONTENT OF SliverAppBar
                )),
              ),
              SliverList(
                delegate: SliverChildBuilderDelegate(
                    (context, index) =&gt; Card(
                          margin: EdgeInsets.fromLTRB(30, 3, 30, 3),
                          color: Colors.black12,
                          child: new ListTile(
                            leading: Icon(Icons.watch_later),
                            title: new Text('$index',
                                style: new TextStyle(color: Colors.white)),
                            subtitle: new Text('29 °C'),
                          ),
                        ),
                    childCount: 20),
              )
            ],
          ));
    }
  
    Future&lt;Map&gt; getWeather(String key, double lat, double lon) async {
      String apiUrl =
          'https://api.darksky.net/forecast/$key/$lat,$lon?lang=sk&amp;units=si';
      http.Response response = await http.get(apiUrl);
      return json.decode(response.body);
    }
  </code></pre>
  
  <p><strong>How can I fill the SliverList with the map I get?</strong></p>