Работает функционал переключения валют, остались правки по ui

lib/base/base_state.dart

@@ -41,7 +41,6 @@ abstract class BaseState<T extends StatefulWidget> extends State<T> {
         }
       });
     }
-
     return getMainWidget();
   }
 

lib/base/settings_base_state.dart

@@ -5,9 +5,15 @@ import 'package:flutter/material.dart';
 
 abstract class SettingsBaseState<T extends StatefulWidget> extends BaseState<T> {
 
+  int selectedItem;
+
   @override
   Widget getScreenContent() {
 
+    print('getScreenContent: $selectedItem');
+    getSelectedValue();
+
+
     List<Widget> widgets = new List();
 
     for (String option in getOptions()) {
@@ -19,6 +25,10 @@ abstract class SettingsBaseState<T extends StatefulWidget> extends BaseState<T>
 
   List<String> getOptions();
 
+  void saveOption();
+
+  void getSelectedValue();
+
   @override
   List<Widget> getMenuButtons() {
     return null;
@@ -27,16 +37,21 @@ abstract class SettingsBaseState<T extends StatefulWidget> extends BaseState<T>
   Widget getItem(String option) {
     return new Container(
         height: 56.0,
-        child: (new FlatButton(onPressed: null,
+        child: (new FlatButton(onPressed: () {
+          saveOption();
+          setState(() {
+            selectedItem = getOptions().indexOf(option);
+          });
+        },
             child: new Row(children: <Widget>[
               new Expanded(child: new Text(option)),
-              getCheckMark()]))));
+              getCheckMark(getOptions().indexOf(option))]))));
   }
 
-  Widget getCheckMark() {
-    return new Image.asset(check_png,
+  Widget getCheckMark(int index) {
+    return index == selectedItem ? new Image.asset(check_png,
         width: 28.0,
-        height: 28.0);
+        height: 28.0) : new Image.asset(check_png, color: new Color(0xffffff));
   }
 
   @override