Cw 188 fix grey screen (#537)

* Fix late initialization exception when using late with Mobx
Fix index out of range exception in picker

* Add haven account list class to configure file to be generated in haven.dart

lib/src/screens/settings/widgets/settings_picker_cell.dart

@@ -53,7 +53,10 @@ class SettingsPickerCell<ItemType extends Object> extends StandardListRow {
       displayItem?.call(selectedItem) ?? selectedItem.toString(),
       textAlign: TextAlign.right,
       style: TextStyle(
-          fontSize: 14.0, fontWeight: FontWeight.w500, color: Theme.of(context).primaryTextTheme!.overline!.color!),
+        fontSize: 14.0,
+        fontWeight: FontWeight.w500,
+        color: Theme.of(context).primaryTextTheme.overline?.color,
+      ),
     );
   }
 }

lib/src/widgets/picker.dart

@@ -1,3 +1,5 @@
+// ignore_for_file: deprecated_member_use
+
 import 'package:flutter/material.dart';
 import 'package:cake_wallet/src/widgets/alert_background.dart';
 import 'package:cake_wallet/src/widgets/alert_close_button.dart';
@@ -34,11 +36,11 @@ class Picker<Item extends Object> extends StatefulWidget {
   final bool Function(Item, String)? matchingCriteria;
 
   @override
-  PickerState createState() => PickerState<Item>(items, images, onItemSelected);
+  _PickerState<Item> createState() => _PickerState<Item>(items, images, onItemSelected);
 }
 
-class PickerState<Item> extends State<Picker> {
-  PickerState(this.items, this.images, this.onItemSelected);
+class _PickerState<Item> extends State<Picker> {
+  _PickerState(this.items, this.images, this.onItemSelected);
 
   final Function(Item) onItemSelected;
   List<Item> items;
@@ -94,7 +96,7 @@ class PickerState<Item> extends State<Picker> {
                 child: ClipRRect(
                   borderRadius: BorderRadius.all(Radius.circular(30)),
                   child: Container(
-                    color: Theme.of(context).accentTextTheme!.headline6!.color!,
+                    color: Theme.of(context).accentTextTheme.headline6!.color!,
                     child: ConstrainedBox(
                       constraints: BoxConstraints(
                         maxHeight: MediaQuery.of(context).size.height * 0.65,
@@ -107,12 +109,12 @@ class PickerState<Item> extends State<Picker> {
                               padding: const EdgeInsets.all(16),
                               child: TextFormField(
                                 controller: searchController,
-                                style: TextStyle(color: Theme.of(context).primaryTextTheme!.headline6!.color!),
+                                style: TextStyle(color: Theme.of(context).primaryTextTheme.headline6!.color!),
                                 decoration: InputDecoration(
                                   hintText: widget.hintText,
                                   prefixIcon: Image.asset("assets/images/search_icon.png"),
                                   filled: true,
-                                  fillColor: Theme.of(context).accentTextTheme!.headline3!.color!,
+                                  fillColor: Theme.of(context).accentTextTheme.headline3!.color!,
                                   alignLabelWithHint: false,
                                   contentPadding: const EdgeInsets.symmetric(vertical: 4, horizontal: 16),
                                   enabledBorder: OutlineInputBorder(
@@ -129,7 +131,7 @@ class PickerState<Item> extends State<Picker> {
                               ),
                             ),
                           Divider(
-                            color: Theme.of(context).accentTextTheme!.headline6!.backgroundColor!,
+                            color: Theme.of(context).accentTextTheme.headline6!.backgroundColor!,
                             height: 1,
                           ),
                           if (widget.selectedAtIndex != -1) buildSelectedItem(),
@@ -137,7 +139,7 @@ class PickerState<Item> extends State<Picker> {
                             child: Stack(
                               alignment: Alignment.center,
                               children: <Widget>[
-                                (items?.length ?? 0) > 3 ? Scrollbar(
+                                items.length > 3 ? Scrollbar(
                                   controller: controller,
                                   child: itemsList(),
                                 ) : itemsList(),
@@ -154,7 +156,7 @@ class PickerState<Item> extends State<Picker> {
                                             fontWeight: FontWeight.w500,
                                             fontFamily: 'Lato',
                                             decoration: TextDecoration.none,
-                                            color: Theme.of(context).primaryTextTheme!.headline6!.color!,
+                                            color: Theme.of(context).primaryTextTheme.headline6!.color!,
                                           ),
                                         ),
                                       )
@@ -178,13 +180,13 @@ class PickerState<Item> extends State<Picker> {
 
   Widget itemsList() {
     return Container(
-      color: Theme.of(context).accentTextTheme!.headline6!.backgroundColor!,
+      color: Theme.of(context).accentTextTheme.headline6!.backgroundColor!,
       child: widget.isGridView
           ? GridView.builder(
               padding: EdgeInsets.zero,
               controller: controller,
               shrinkWrap: true,
-              itemCount: items == null || items.isEmpty ? 0 : items.length,
+              itemCount: items.isEmpty ? 0 : items.length,
               gridDelegate: SliverGridDelegateWithFixedCrossAxisCount(
                 crossAxisCount: 2,
                 crossAxisSpacing: 2,
@@ -198,11 +200,11 @@ class PickerState<Item> extends State<Picker> {
               shrinkWrap: true,
               separatorBuilder: (context, index) => widget.isSeparated
                   ? Divider(
-                      color: Theme.of(context).accentTextTheme!.headline6!.backgroundColor!,
+                      color: Theme.of(context).accentTextTheme.headline6!.backgroundColor!,
                       height: 1,
                     )
                   : const SizedBox(),
-              itemCount: items == null || items.isEmpty ? 0 : items.length,
+              itemCount: items.isEmpty ? 0 : items.length,
               itemBuilder: (context, index) => buildItem(index),
             ),
     );
@@ -215,19 +217,16 @@ class PickerState<Item> extends State<Picker> {
     }
 
     final item = items[index];
-    final image = images != null ? images[index] : null;
+    final image = images.isNotEmpty ? images[index] : null;
 
     return GestureDetector(
       onTap: () {
-        if (onItemSelected == null) {
-          return;
-        }
         Navigator.of(context).pop();
         onItemSelected(item);
       },
       child: Container(
         height: 55,
-        color: Theme.of(context).accentTextTheme!.headline6!.color!,
+        color: Theme.of(context).accentTextTheme.headline6!.color!,
         padding: EdgeInsets.only(left: 24, right: 24),
         child: Row(
           mainAxisSize: MainAxisSize.max,
@@ -239,13 +238,13 @@ class PickerState<Item> extends State<Picker> {
               child: Padding(
                 padding: EdgeInsets.only(left: image != null ? 12 : 0),
                 child: Text(
-                  // What a hack (item as) ? 
+                  // What a hack (item as) ?
                   widget.displayItem?.call(item as Object) ?? item.toString(),
                   style: TextStyle(
                     fontSize: 14,
                     fontFamily: 'Lato',
                     fontWeight: FontWeight.w600,
-                    color: Theme.of(context).primaryTextTheme!.headline6!.color!,
+                    color: Theme.of(context).primaryTextTheme.headline6!.color!,
                     decoration: TextDecoration.none,
                   ),
                 ),
@@ -259,11 +258,11 @@ class PickerState<Item> extends State<Picker> {
 
   Widget buildSelectedItem() {
     final item = widget.items[widget.selectedAtIndex];
-    final image = images != null ? widget.images[widget.selectedAtIndex] : null;
+    final image = images.isNotEmpty ? widget.images[widget.selectedAtIndex] : null;
 
     return Container(
       height: 55,
-      color: Theme.of(context).accentTextTheme!.headline6!.color!,
+      color: Theme.of(context).accentTextTheme.headline6!.color!,
       padding: EdgeInsets.only(left: 24, right: 24),
       child: Row(
         mainAxisSize: MainAxisSize.max,
@@ -280,13 +279,13 @@ class PickerState<Item> extends State<Picker> {
                   fontSize: 16,
                   fontFamily: 'Lato',
                   fontWeight: FontWeight.w700,
-                  color: Theme.of(context).primaryTextTheme!.headline6!.color!,
+                  color: Theme.of(context).primaryTextTheme.headline6!.color!,
                   decoration: TextDecoration.none,
                 ),
               ),
             ),
           ),
-          Icon(Icons.check_circle, color: Theme.of(context).accentTextTheme!.bodyText1!.color!),
+          Icon(Icons.check_circle, color: Theme.of(context).accentTextTheme.bodyText1!.color!),
         ],
       ),
     );

lib/view_model/buy/buy_amount_view_model.dart

@@ -9,22 +9,21 @@ class BuyAmountViewModel = BuyAmountViewModelBase with _$BuyAmountViewModel;
 
 abstract class BuyAmountViewModelBase with Store {
   BuyAmountViewModelBase()
-    : amount = '' {
+      : amount = '',
+        fiatCurrency = FiatCurrency.usd {
     int selectedIndex = FiatCurrency.currenciesAvailableToBuyWith
         .indexOf(getIt.get<SettingsStore>().fiatCurrency);
 
-    if (selectedIndex == -1) {
-      selectedIndex = FiatCurrency.currenciesAvailableToBuyWith
-          .indexOf(FiatCurrency.usd);
+    if (selectedIndex != -1) {
+      fiatCurrency = FiatCurrency.currenciesAvailableToBuyWith[selectedIndex];
     }
-    fiatCurrency = FiatCurrency.currenciesAvailableToBuyWith[selectedIndex];
   }
 
   @observable
   String amount;
 
   @observable
-  late FiatCurrency fiatCurrency;
+  FiatCurrency fiatCurrency;
 
   @computed
   double get doubleAmount {