logout, индикатор загрузки на экране регистрации

lib/registration.dart

@@ -12,6 +12,7 @@ class RegistrationScreen extends StatefulWidget {
 class _RegistrationScreenState extends BaseState<RegistrationScreen> {
 
   String _merchantID = "";
+  bool _loading = false;
 
   @override Widget build(BuildContext context) {
     return new Scaffold(appBar: _getAppBar(), body: _getScreen(context));
@@ -19,16 +20,14 @@ class _RegistrationScreenState extends BaseState<RegistrationScreen> {
 
   AppBar _getAppBar() {
     return new AppBar(title: new Text("Регистрация"),
-        backgroundColor: primaryColor,  actions: <Widget>[
-          new IconButton(
-            icon: new Icon(Icons.help_outline),
-            tooltip: 'Air it',
-            onPressed: faq,
-          )
-        ]);
+      actions: <Widget>[new IconButton(icon: new Icon(Icons.help_outline), onPressed: faq)]);
   }
 
   Widget _getScreen(BuildContext context) {
+    return new Stack(children: <Widget>[_getScreenContent(), _getProgressIndicator()]);
+  }
+
+  Widget _getScreenContent() {
     return new Container(height: 332.0,
         child: new ListView(reverse: true, children: <Widget>[
           new Center(child: new Column(children: <Widget>[
@@ -38,6 +37,10 @@ class _RegistrationScreenState extends BaseState<RegistrationScreen> {
         ].reversed.toList()));
   }
 
+  Widget _getProgressIndicator() {
+    return new Center(child: _loading ? new CircularProgressIndicator() : null);
+  }
+
   Widget _getLogo() {
     return new Container(height: 192.0, width: 156.0,
         child: new Image.asset(logo_png, height: 24.0, width: 156.0));
@@ -56,14 +59,6 @@ class _RegistrationScreenState extends BaseState<RegistrationScreen> {
         onChanged: (text) => _handleUserInput(text));
   }
 
-  void _handleUserInput(String text) {
-    if (text.length > 0) {
-      setState(() {
-        _merchantID = text;
-      });
-    }
-  }
-
   Decoration _getDecoraionForInputField() {
     return new BoxDecoration(color: Colors.white,
         border: new Border.all(color: const Color(0xffcfd8dc), width: 1.0,),
@@ -71,19 +66,35 @@ class _RegistrationScreenState extends BaseState<RegistrationScreen> {
   }
 
   Widget _getButton(BuildContext context) {
-    return  new Container(margin: new EdgeInsets.only(top: 36.0), height: 42.0, padding: new EdgeInsets.only(left: 40.0, right: 40.0),
+    return  new Container(margin: new EdgeInsets.only(top: 36.0), height: 42.0,
+     padding: new EdgeInsets.only(left: 40.0, right: 40.0),
             child: new RaisedButton(child: new Text('ЗАРЕГИСТРИРОВАТЬ',
                 style: new TextStyle(color: Colors.white)),
                 onPressed: _isValidMerchantID() ? () => _registerShop(context, _merchantID) : null,
                 color: primaryColor));
   }
 
-  bool _isValidMerchantID() {
+  Widget _getCircularProgressIndicator() {
+    return new Center(child: new CircularProgressIndicator());
+  }
+
+  _isValidMerchantID() {
     return _merchantID.length == 5;
   }
 
-  void _registerShop(BuildContext context, String merchantShop) {
-    _register(context, merchantShop);
+  _handleUserInput(String text) {
+    if (text.length > 0) {
+      setState(() {
+        _merchantID = text;
+      });
+    }
+  }
+
+  _registerShop(BuildContext context, String merchantShop) {
+    setState(() {
+      loading = true;
+      _register(context, merchantShop);
+    });
   }
 
   _register(BuildContext context, String merchantShop) async {
@@ -113,6 +124,9 @@ class _RegistrationScreenState extends BaseState<RegistrationScreen> {
       platform.invokeMethod('saveToken', {'token' : token}).then((value) {
         print(value.toString());
       });
+      setState(() {
+        loading = false;
+      });
       pushRoute(context, new FinishRegistrationScreen());
     }).catchError((error) {
       print(error.toString());