fix #350

lib/app.dart

@@ -94,6 +94,7 @@ class _AppState extends State<App> with WidgetsBindingObserver {
       listenable: context.watch<SettingsChangeProvider>(),
       builder: (BuildContext context, Widget? child) {
         return MaterialApp(
+          scaffoldMessengerKey: globalRootScaffoldMessengerKey,
           restorationScopeId: 'app',
           localizationsDelegates: const [
             AppLocalizations.delegate,

lib/globals.dart

@@ -1,6 +1,5 @@
-import 'dart:ui';
-
 import 'package:camera/camera.dart';
+import 'package:flutter/material.dart';
 import 'package:twonly/src/database/twonly.db.dart';
 import 'package:twonly/src/model/json/userdata.dart';
 import 'package:twonly/src/services/api.service.dart';
@@ -37,3 +36,6 @@ bool globalAllowErrorTrackingViaSentry = false;
 
 late String globalApplicationCacheDirectory;
 late String globalApplicationSupportDirectory;
+
+final GlobalKey<ScaffoldMessengerState> globalRootScaffoldMessengerKey =
+    GlobalKey<ScaffoldMessengerState>();

lib/src/localization/app_de.arb

@@ -458,5 +458,6 @@
     "couldNotVerifyUsername": "{username} konnte nicht verifiziert werden",
     "linkPubkeyDoesNotMatch": "Der öffentliche Schlüssel im Link stimmt nicht mit dem für diesen Kontakt gespeicherten öffentlichen Schlüssel überein. Triff die Person persönlich und scanne den QR-Code direkt!",
     "startWithCameraOpen": "Mit geöffneter Kamera starten",
-    "showImagePreviewWhenSending": "Bildvorschau bei der Auswahl von Empfängern anzeigen"
+    "showImagePreviewWhenSending": "Bildvorschau bei der Auswahl von Empfängern anzeigen",
+    "verifiedPublicKey": "Der öffentliche Schlüssel von {username} wurde überprüft und ist gültig."
 }

lib/src/localization/app_en.arb

@@ -488,5 +488,6 @@
   "couldNotVerifyUsername": "Could not verify {username}",
   "linkPubkeyDoesNotMatch": "The public key in the link does not match the public key stored for this contact. Try to meet your friend in person and scan the QR code directly!",
   "startWithCameraOpen": "Start with camera open",
-  "showImagePreviewWhenSending": "Display image preview when selecting recipients"
+  "showImagePreviewWhenSending": "Display image preview when selecting recipients",
+  "verifiedPublicKey": "The public key of {username} has been verified and is valid."
 }

lib/src/localization/generated/app_localizations.dart

@@ -2851,6 +2851,12 @@ abstract class AppLocalizations {
   /// In en, this message translates to:
   /// **'Display image preview when selecting recipients'**
   String get showImagePreviewWhenSending;
+
+  /// No description provided for @verifiedPublicKey.
+  ///
+  /// In en, this message translates to:
+  /// **'The public key of {username} has been verified and is valid.'**
+  String verifiedPublicKey(Object username);
 }
 
 class _AppLocalizationsDelegate

lib/src/localization/generated/app_localizations_de.dart

@@ -1577,4 +1577,9 @@ class AppLocalizationsDe extends AppLocalizations {
   @override
   String get showImagePreviewWhenSending =>
       'Bildvorschau bei der Auswahl von Empfängern anzeigen';
+
+  @override
+  String verifiedPublicKey(Object username) {
+    return 'Der öffentliche Schlüssel von $username wurde überprüft und ist gültig.';
+  }
 }

lib/src/localization/generated/app_localizations_en.dart

@@ -1567,4 +1567,9 @@ class AppLocalizationsEn extends AppLocalizations {
   @override
   String get showImagePreviewWhenSending =>
       'Display image preview when selecting recipients';
+
+  @override
+  String verifiedPublicKey(Object username) {
+    return 'The public key of $username has been verified and is valid.';
+  }
 }

lib/src/views/camera/camera_preview_components/main_camera_controller.dart

@@ -2,14 +2,16 @@ import 'dart:io';
 import 'package:camera/camera.dart';
 import 'package:collection/collection.dart';
 import 'package:drift/drift.dart' show Value;
+import 'package:flutter/material.dart';
 import 'package:flutter/services.dart';
-import 'package:flutter/widgets.dart';
 import 'package:google_mlkit_barcode_scanning/google_mlkit_barcode_scanning.dart';
 import 'package:twonly/globals.dart';
+import 'package:twonly/src/database/daos/contacts.dao.dart';
 import 'package:twonly/src/database/twonly.db.dart';
 import 'package:twonly/src/model/protobuf/client/generated/qr.pb.dart';
 import 'package:twonly/src/services/signal/session.signal.dart';
 import 'package:twonly/src/utils/log.dart';
+import 'package:twonly/src/utils/misc.dart';
 import 'package:twonly/src/utils/qr.dart';
 import 'package:twonly/src/utils/screenshot.dart';
 import 'package:twonly/src/views/camera/camera_preview_components/camera_preview_controller_view.dart';
@@ -219,6 +221,19 @@ class MainCameraController {
                 );
               }
               await HapticFeedback.heavyImpact();
+              if (verificationOk) {
+                globalRootScaffoldMessengerKey.currentState?.showSnackBar(
+                  SnackBar(
+                    content: Text(
+                      globalRootScaffoldMessengerKey.currentContext?.lang
+                              .verifiedPublicKey(
+                                  getContactDisplayName(contact)) ??
+                          '',
+                    ),
+                    duration: const Duration(seconds: 6),
+                  ),
+                );
+              }
             }
           }
         } else {