Fiat api fix (#1070)

* Cw 474 linux swapping wallets btc then xmr still shows btc receive qr code (#1068)

* feat: improve address page txt field

* fix: switching wallets from the desktop dropdown updates dashboard pages

* Revert "feat: improve address page txt field"

This reverts commit 0a30e6d9e1d13795219b66a6fdf2c1d218479089.

* refactor: rename to WalletChangeListener

* fix: _init also behaves on wallet change

* Fix Fiat conversion API parsing
Cherry pick fix for Desktop switching wallets not updating dashboard screens

* Minor indentations fix [skip ci]

---------

Co-authored-by: Rafael Saes <76502841+saltrafael@users.noreply.github.com>

lib/core/fiat_conversion_service.dart

@@ -21,7 +21,7 @@ Future<double> _fetchPrice(Map<String, dynamic> args) async {
     'key': secrets.fiatApiKey,
   };
 
-  double price = 0.0;
+  num price = 0.0;
 
   try {
     late final Uri uri;
@@ -41,12 +41,12 @@ Future<double> _fetchPrice(Map<String, dynamic> args) async {
     final results = responseJSON['results'] as Map<String, dynamic>;
 
     if (results.isNotEmpty) {
-      price = results.values.first as double;
+      price = results.values.first as num;
     }
 
-    return price;
+    return price.toDouble();
   } catch (e) {
-    return price;
+    return price.toDouble();
   }
 }
 

lib/core/wallet_change_listener_view_model.dart

@@ -0,0 +1,30 @@
+import 'package:cw_core/balance.dart';
+import 'package:cw_core/transaction_history.dart';
+import 'package:cw_core/transaction_info.dart';
+import 'package:mobx/mobx.dart';
+import 'package:cw_core/wallet_base.dart';
+import 'package:cake_wallet/store/app_store.dart';
+
+part 'wallet_change_listener_view_model.g.dart';
+
+class WalletChangeListenerViewModel = WalletChangeListenerViewModelBase
+    with _$WalletChangeListenerViewModel;
+
+abstract class WalletChangeListenerViewModelBase with Store {
+  WalletChangeListenerViewModelBase({
+    required AppStore appStore,
+  }) : _wallet = appStore.wallet! {
+    reaction((_) => appStore.wallet, (WalletBase? wallet) {
+      _wallet = wallet!;
+      onWalletChange(wallet);
+    });
+  }
+
+  void onWalletChange(WalletBase wallet) {}
+
+  @observable
+  WalletBase<Balance, TransactionHistoryBase<TransactionInfo>, TransactionInfo> _wallet;
+  @computed
+  WalletBase<Balance, TransactionHistoryBase<TransactionInfo>, TransactionInfo> get wallet =>
+      _wallet;
+}