zha_map WIP: get inital data

lib/pages/play_media.page.dart

@@ -57,7 +57,7 @@ class _PlayMediaPageState extends State<PlayMediaPage> {
         _loaded = false;
       });
     } else {
-      _isMediaExtractorExist = HomeAssistant().services.containsKey("media_extractor");
+      _isMediaExtractorExist = HomeAssistant().isServiceExist("media_extractor");
       //_useMediaExtractor = _isMediaExtractorExist;
       _players = HomeAssistant().entities.getByDomains(domains: ["media_player"]);
       setState(() {

lib/pages/zha_page.dart

@@ -0,0 +1,90 @@
+part of '../main.dart';
+
+class ZhaPage extends StatefulWidget {
+  ZhaPage({Key key}) : super(key: key);
+
+  @override
+  _ZhaPageState createState() => new _ZhaPageState();
+}
+
+class _ZhaPageState extends State<ZhaPage> {
+
+  List data = [];
+  String error = "";
+
+  @override
+  void initState() {
+    super.initState();
+    _loadData();
+  }
+
+  _loadData() async {
+    setState(() {
+      data.clear();
+      error = "";
+    });
+    ConnectionManager().sendSocketMessage(
+      type: 'zha_map/devices'
+    ).then((response){
+      setState(() {
+        data = response['devices'];
+      });
+    }).catchError((e){
+      setState(() {
+        error = '$e';
+      });
+    });
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    Widget body;
+    if (error.isNotEmpty) {
+      body = PageLoadingError(errorText: error,);
+    } else if (data.isEmpty) {
+      body = PageLoadingIndicator();
+    } else {
+      List<Widget> devicesListWindet = [];
+      data.forEach((device) {
+        devicesListWindet.add(
+          Card(
+            child: Column(
+              mainAxisSize: MainAxisSize.min,
+              children: <Widget>[
+                CardHeader(
+                  name: '${device['ieee']}',
+                  subtitle: Text('${device['manufacturer']}'),
+                ),
+                Text('${device['device_type']}'),
+                Text('model: ${device['model']}'),
+                Text('offline: ${device['offline']}'),
+                Text('neighbours: ${device['neighbours'].length}'),
+                Text('raw: $device'),
+              ],
+            ),
+          )
+        );
+      });
+      body = ListView(
+        children: devicesListWindet
+      );
+    }
+    return new Scaffold(
+      appBar: new AppBar(
+        leading: IconButton(icon: Icon(Icons.arrow_back), onPressed: (){
+          Navigator.pop(context);
+        }),
+        actions: <Widget>[
+          IconButton(
+            icon: Icon(Icons.refresh),
+            onPressed: () => _loadData(),
+          )
+        ],
+        // Here we take the value from the MyHomePage object that was created by
+        // the App.build method, and use it to set our appbar title.
+        title: new Text('ZHA'),
+      ),
+      body: body
+    );
+  }
+}