All done. Need fix logout.

lib/screens/splash.dart

@@ -173,31 +173,39 @@ class _SplashScreenState extends BaseState<SplashScreen> {
     SqliteHelper helper) {
     // Канал ловит вызовы методов из "нативной" части приложения.
     // Могут быть вызваны либо exit либо faq, либо purchase.
-    platform.setMethodCallHandler((MethodCall call) {
+    platform.setMethodCallHandler((MethodCall call) async {
       print(this.toString());
       if (call.method == 'findUser') {
-        String cardPhone = call.arguments[0];
-        var userResponse = getUser(call.arguments[1], cardPhone, token);
 
-        if (userResponse != null) {
-          userResponse.then((response) {
-            List<Map> users;
+        try {
 
+          Response userResponse;
 
+          switch (call.arguments[1]) {
+            case 'card':
+              userResponse = await getUserByCard(call.arguments[0], token);
+              break;
+            case 'phone':
+              userResponse = await getUserByPhone(call.arguments[0], token);
+              break;
+          }
 
-            try {
-              users = JSON.decode(response.body);
-            } catch (error) {
-              print(error);
-            }
-
+          if (userResponse != null) {
+            print('I have user in method handler!');
+            List<Map> users = JSON.decode(userResponse.body);
             if (users.length > 0) {
               return users[0];
             } else {
               throw new FlutterError("Users not found");
             }
-          });
+          } else {
+            throw new FlutterError("Users not found");
+          }
+        } catch (error) {
+          print(error.toString());
+          throw new FlutterError("Users not found");
         }
+
       } else if (call.method == 'faq') {
         faq(helper, app, context, true);
       } else if (call.method == 'settings') {
@@ -209,20 +217,12 @@ class _SplashScreenState extends BaseState<SplashScreen> {
             });
           });
       } else {
-        String userString;
-
-        if (call.arguments[0] is String) {
-          userString = call.arguments[0];
-        } else {
-          userString = JSON.encode(call.arguments[0]);
-        }
-
+        String userString = call.arguments[0] is String
+          ? call.arguments[0]
+          : JSON.encode(call.arguments[0]);
         print(userString);
-
         String card = call.arguments[1];
-        print('$userString, $card');
-
-        startScanner(token, userString, card);
+        purchase(token, userString, card);
       }
     });
 
@@ -242,7 +242,7 @@ class _SplashScreenState extends BaseState<SplashScreen> {
     });
   }
 
-  startScanner(String token, String userString, String card) {
+  purchase(String token, String userString, String card) {
     new Future.delayed(const Duration(milliseconds: 200), () {
       var route = new MaterialPageRoute<Null>(
         builder: (BuildContext context) => new PurchaseScreen(helper, app, userString, card), fullscreenDialog: true);
@@ -251,22 +251,4 @@ class _SplashScreenState extends BaseState<SplashScreen> {
       });
     });
   }
-
-  Future<Response> getUser(String type, String cardPhone, String token) {
-    try {
-      switch (type) {
-        case 'card':
-          return getUserByCard(cardPhone, token);
-          break;
-        case 'phone':
-          return getUserByPhone(cardPhone, token);
-          break;
-        default:
-          return null;
-      }
-    } catch (error) {
-      print(error.toString());
-      return null;
-    }
-  }
 }