Updated deprecated widgets with new one

Author: adarsh-technocrat

platform_channels/lib/src/method_channel_demo.dart

@@ -84,7 +84,7 @@ class _MethodChannelDemoState extends State<MethodChannelDemo> {
   }
 
   void showErrorMessage(BuildContext context, String errorMessage) {
-    Scaffold.of(context).showSnackBar(SnackBar(
+    ScaffoldMessenger.of(context).showSnackBar(SnackBar(
       content: Text(errorMessage),
     ));
   }

platform_channels/lib/src/pet_list_screen.dart

@@ -15,7 +15,7 @@ class PetListScreen extends StatefulWidget {
 
 class _PetListScreenState extends State<PetListScreen> {
   PetListModel petListModel;
-  final scaffoldKey = GlobalKey<ScaffoldState>();
+  final scaffoldMessengerKey = GlobalKey<ScaffoldMessengerState>();
 
   @override
   void initState() {
@@ -25,7 +25,7 @@ class _PetListScreenState extends State<PetListScreen> {
     BasicMessageChannel('stringCodecDemo', StringCodec())
         .setMessageHandler((message) async {
       if (message == null) {
-        scaffoldKey.currentState.showSnackBar(
+        scaffoldMessengerKey.currentState.showSnackBar(
           SnackBar(
               content:
                   const Text('An error occurred while adding pet details.')),
@@ -42,7 +42,7 @@ class _PetListScreenState extends State<PetListScreen> {
   @override
   Widget build(BuildContext context) {
     return Scaffold(
-      key: scaffoldKey,
+      key: scaffoldMessengerKey,
       appBar: AppBar(
         title: Text('Pet List'),
       ),
@@ -93,7 +93,7 @@ class BuildPetList extends StatelessWidget {
   }
 
   void showSnackBar(String message, BuildContext context) {
-    Scaffold.of(context).showSnackBar(SnackBar(
+    ScaffoldMessenger.of(context).showSnackBar(SnackBar(
       content: Text(message),
     ));
   }

platform_channels/pubspec.lock

@@ -7,42 +7,42 @@ packages:
       name: async
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.5.0-nullsafety.1"
+    version: "2.5.0-nullsafety.3"
   boolean_selector:
     dependency: transitive
     description:
       name: boolean_selector
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.1.0-nullsafety.1"
+    version: "2.1.0-nullsafety.3"
   characters:
     dependency: transitive
     description:
       name: characters
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.1.0-nullsafety.3"
+    version: "1.1.0-nullsafety.5"
   charcode:
     dependency: transitive
     description:
       name: charcode
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.2.0-nullsafety.1"
+    version: "1.2.0-nullsafety.3"
   clock:
     dependency: transitive
     description:
       name: clock
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.1.0-nullsafety.1"
+    version: "1.1.0-nullsafety.3"
   collection:
     dependency: transitive
     description:
       name: collection
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.15.0-nullsafety.3"
+    version: "1.15.0-nullsafety.5"
   cupertino_icons:
     dependency: "direct main"
     description:
@@ -56,7 +56,7 @@ packages:
       name: fake_async
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.2.0-nullsafety.1"
+    version: "1.2.0-nullsafety.3"
   flutter:
     dependency: "direct main"
     description: flutter
@@ -73,21 +73,21 @@ packages:
       name: matcher
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.12.10-nullsafety.1"
+    version: "0.12.10-nullsafety.3"
   meta:
     dependency: transitive
     description:
       name: meta
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.3.0-nullsafety.3"
+    version: "1.3.0-nullsafety.6"
   path:
     dependency: transitive
     description:
       name: path
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.8.0-nullsafety.1"
+    version: "1.8.0-nullsafety.3"
   pedantic:
     dependency: "direct dev"
     description:
@@ -106,55 +106,55 @@ packages:
       name: source_span
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.8.0-nullsafety.2"
+    version: "1.8.0-nullsafety.4"
   stack_trace:
     dependency: transitive
     description:
       name: stack_trace
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.10.0-nullsafety.1"
+    version: "1.10.0-nullsafety.6"
   stream_channel:
     dependency: transitive
     description:
       name: stream_channel
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.1.0-nullsafety.1"
+    version: "2.1.0-nullsafety.3"
   string_scanner:
     dependency: transitive
     description:
       name: string_scanner
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.1.0-nullsafety.1"
+    version: "1.1.0-nullsafety.3"
   term_glyph:
     dependency: transitive
     description:
       name: term_glyph
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.2.0-nullsafety.1"
+    version: "1.2.0-nullsafety.3"
   test_api:
     dependency: transitive
     description:
       name: test_api
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.2.19-nullsafety.2"
+    version: "0.2.19-nullsafety.6"
   typed_data:
     dependency: transitive
     description:
       name: typed_data
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.3.0-nullsafety.3"
+    version: "1.3.0-nullsafety.5"
   vector_math:
     dependency: transitive
     description:
       name: vector_math
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.1.0-nullsafety.3"
+    version: "2.1.0-nullsafety.5"
 sdks:
-  dart: ">=2.10.0-110 <2.11.0"
+  dart: ">=2.12.0-0.0 <3.0.0"