CAKE-185 | removed isValidAmount() from exchange_view_model.dart and exchange_page.dart; throw exception in the createTrade() (xmrto_exchange_provider.dart) if number of fractional digits of amount more than 8

lib/exchange/xmrto/xmrto_exchange_provider.dart

@@ -12,6 +12,7 @@ import 'package:cake_wallet/exchange/xmrto/xmrto_trade_request.dart';
 import 'package:cake_wallet/exchange/trade_not_created_exeption.dart';
 import 'package:cake_wallet/exchange/exchange_provider_description.dart';
 import 'package:cake_wallet/exchange/trade_not_found_exeption.dart';
+import 'package:cake_wallet/generated/i18n.dart';
 
 class XMRTOExchangeProvider extends ExchangeProvider {
   XMRTOExchangeProvider()
@@ -90,12 +91,25 @@ class XMRTOExchangeProvider extends ExchangeProvider {
   Future<Trade> createTrade({TradeRequest request}) async {
     final _request = request as XMRTOTradeRequest;
     final url = originalApiUri + _orderCreateUriSuffix;
-    final body = {
+    final _amount = _request.isBTCRequest
-      'amount':
+        ? _request.receiveAmount
-          _request.isBTCRequest ? _request.receiveAmount : _request.amount,
+        : _request.amount;
-      'amount_currency': _request.isBTCRequest
+
+    final _amountCurrency = _request.isBTCRequest
         ? _request.to.toString()
-          : _request.from.toString(),
+        : _request.from.toString();
+
+    final pattern = '^([0-9]+([.\,][0-9]{0,8})?|[.\,][0-9]{1,8})\$';
+    final isValid = RegExp(pattern).hasMatch(_amount);
+
+    if (!isValid) {
+      throw TradeNotCreatedException(description,
+          description: S.current.xmr_to_error_description);
+    }
+
+    final body = {
+      'amount': _amount,
+      'amount_currency': _amountCurrency,
       'btc_dest_address': _request.address
     };
     final response = await post(url,

lib/src/screens/exchange/exchange_page.dart

@@ -411,18 +411,7 @@ class ExchangePage extends BasePage {
                                   buttonAction: () => Navigator.of(context).pop());
                               });
                           } else {
-                            exchangeViewModel.isValidAmount()
+                            exchangeViewModel.createTrade();
-                            ? exchangeViewModel.createTrade()
-                            : showPopUp<void>(
-                                context: context,
-                                builder: (BuildContext context) {
-                                  return AlertWithOneAction(
-                                      alertTitle: S.of(context).xmr_to_error,
-                                      alertContent: S.of(context).xmr_to_error_description,
-                                      buttonText: S.of(context).ok,
-                                      buttonAction: () =>
-                                          Navigator.of(context).pop());
-                                });
                           }
                         }
                       },

lib/view_model/exchange/exchange_view_model.dart

@@ -311,20 +311,6 @@ abstract class ExchangeViewModelBase with Store {
   void removeTemplate({ExchangeTemplate template}) =>
       _exchangeTemplateStore.remove(template: template);
 
-  bool isValidAmount() {
-    bool isValid = true;
-
-    if (provider is XMRTOExchangeProvider) {
-      final amount = isReceiveAmountEntered
-          ? receiveAmount
-          : depositAmount;
-      final pattern = '^([0-9]+([.\,][0-9]{0,8})?|[.\,][0-9]{1,8})\$';
-      isValid = RegExp(pattern).hasMatch(amount);
-    }
-
-    return isValid;
-  }
-
   List<ExchangeProvider> providersForCurrentPair() {
     return _providersForPair(from: depositCurrency, to: receiveCurrency);
   }