Navigation between screens without previous states showing.

lib/screens/purchase.dart

@@ -39,10 +39,17 @@ class PurchaseScreenState<T> extends BaseState<PurchaseScreen> {
   }
 
   @override
-  Widget build(BuildContext ctx) {
+  void initState() {
+
     setState(() {
       requestAsyncData(user);
     });
+
+    super.initState();
+  }
+
+  @override
+  Widget build(BuildContext ctx) {
     return getMainWidget();
   }
 
@@ -172,7 +179,7 @@ class PurchaseScreenState<T> extends BaseState<PurchaseScreen> {
         child: new FlatButton(
             child: new Text(title, style: new TextStyle(color: textColor)),
           //    FIXME:  onPressed: () => startScanner(context, app, helper)),
-            onPressed: () => print('startScanner')),
+            onPressed: () => Navigator.of(context).pop(true)),
         decoration: new BoxDecoration(
             border: new Border.all(
                 color: Resources.getButtonColor(app), width: 1.0),