From 1dc7f9309a83a1fb79ab90b2847044b6725fbb36 Mon Sep 17 00:00:00 2001
From: cyan <cyjan@mrcyjanek.net>
Date: Wed, 5 Feb 2025 02:40:06 +0100
Subject: [PATCH] fix null check when user exits out of qr code scanner (#2002)

---
 lib/entities/qr_scanner.dart                                 | 4 ++--
 lib/src/screens/ur/animated_ur_page.dart                     | 2 ++
 lib/src/widgets/address_text_field.dart                      | 1 +
 lib/view_model/node_list/node_create_or_edit_view_model.dart | 4 +++-
 lib/view_model/restore/wallet_restore_from_qr_code.dart      | 3 ++-
 5 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/lib/entities/qr_scanner.dart b/lib/entities/qr_scanner.dart
index d8f7032d3..91c63a574 100644
--- a/lib/entities/qr_scanner.dart
+++ b/lib/entities/qr_scanner.dart
@@ -12,7 +12,7 @@ import 'package:flutter/scheduler.dart';
 
 var isQrScannerShown = false;
 
-Future<String> presentQRScanner(BuildContext context) async {
+Future<String?> presentQRScanner(BuildContext context) async {
   isQrScannerShown = true;
   try {
     final result = await Navigator.of(context).push<String>(
@@ -23,7 +23,7 @@ Future<String> presentQRScanner(BuildContext context) async {
       ),
     );
     isQrScannerShown = false;
-    return result!;
+    return result;
   } catch (e) {
     isQrScannerShown = false;
     rethrow;
diff --git a/lib/src/screens/ur/animated_ur_page.dart b/lib/src/screens/ur/animated_ur_page.dart
index dc40e6a12..cf9aa8509 100644
--- a/lib/src/screens/ur/animated_ur_page.dart
+++ b/lib/src/screens/ur/animated_ur_page.dart
@@ -100,6 +100,7 @@ class AnimatedURPage extends BasePage {
     switch (urQrType) {
       case "ur:xmr-txunsigned": // ur:xmr-txsigned
         final ur = await presentQRScanner(context);
+        if (ur == null) return;
         final result = await monero!.commitTransactionUR(animatedURmodel.wallet, ur);
         if (result) {
           Navigator.of(context).pop(true);
@@ -107,6 +108,7 @@ class AnimatedURPage extends BasePage {
         break;
       case "ur:xmr-output": // xmr-keyimage
         final ur = await presentQRScanner(context);
+        if (ur == null) return;
         final result = await monero!.importKeyImagesUR(animatedURmodel.wallet, ur);
         if (result) {
           Navigator.of(context).pop(true);
diff --git a/lib/src/widgets/address_text_field.dart b/lib/src/widgets/address_text_field.dart
index 9b407dedb..1f30e648b 100644
--- a/lib/src/widgets/address_text_field.dart
+++ b/lib/src/widgets/address_text_field.dart
@@ -233,6 +233,7 @@ class AddressTextField<T extends Currency> extends StatelessWidget{
         await PermissionHandler.checkPermission(Permission.camera, context);
     if (!isCameraPermissionGranted) return;
     final code = await presentQRScanner(context);
+    if (code == null) return;
     if (code.isEmpty) {
       return;
     }
diff --git a/lib/view_model/node_list/node_create_or_edit_view_model.dart b/lib/view_model/node_list/node_create_or_edit_view_model.dart
index 2fca12e95..71f996aff 100644
--- a/lib/view_model/node_list/node_create_or_edit_view_model.dart
+++ b/lib/view_model/node_list/node_create_or_edit_view_model.dart
@@ -215,7 +215,9 @@ abstract class NodeCreateOrEditViewModelBase with Store {
       bool isCameraPermissionGranted =
           await PermissionHandler.checkPermission(Permission.camera, context);
       if (!isCameraPermissionGranted) return;
-      String code = await presentQRScanner(context);
+      String? code = await presentQRScanner(context);
+      if (code == null) throw Exception("Unexpected QR code value: aborted");
+
       if (code.isEmpty) {
         throw Exception('Unexpected scan QR code value: value is empty');
       }
diff --git a/lib/view_model/restore/wallet_restore_from_qr_code.dart b/lib/view_model/restore/wallet_restore_from_qr_code.dart
index 0e4664f48..e28a429a4 100644
--- a/lib/view_model/restore/wallet_restore_from_qr_code.dart
+++ b/lib/view_model/restore/wallet_restore_from_qr_code.dart
@@ -89,7 +89,8 @@ class WalletRestoreFromQRCode {
   }
 
   static Future<RestoredWallet> scanQRCodeForRestoring(BuildContext context) async {
-    String code = await presentQRScanner(context);
+    String? code = await presentQRScanner(context);
+    if (code == null) throw Exception("Unexpected scan QR code value: aborted");
     if (code.isEmpty) throw Exception('Unexpected scan QR code value: value is empty');
 
     WalletType? walletType;