Upgrade Flutter framework and dependencies

android/gradle.properties

@@ -2,5 +2,5 @@ org.gradle.jvmargs=-Xmx1536M
 android.enableR8=true
 android.useAndroidX=true
 android.enableJetifier=true
-app.versionName=1.0.10
-app.versionCode=11
+app.versionName=1.0.11
+app.versionCode=12

lib/data/data.dart

 import 'package:memory/models/TileModel.dart';
 
 String selectedTile = "";
-int selectedIndex;
+int selectedIndex = 0;
 bool selected = true;
 int points = 0;
 

lib/main.dart

@@ -145,9 +145,9 @@ class _HomeState extends State<Home> {
 class Tile extends StatefulWidget {
   final String imagePathUrl;
   final int tileIndex;
-  final _HomeState parent;
+  final _HomeState? parent;
 
-  Tile({this.imagePathUrl, this.tileIndex, this.parent});
+  Tile({this.imagePathUrl: '', this.tileIndex: 0, this.parent});
 
   @override
   _TileState createState() => _TileState();
@@ -177,7 +177,7 @@ class _TileState extends State<Tile> {
                 myPairs[widget.tileIndex] = tileModel;
                 print(selectedIndex);
                 myPairs[selectedIndex] = tileModel;
-                this.widget.parent.setState(() {});
+                this.widget.parent?.setState(() {});
                 setState(() {
                   selected = false;
                 });
@@ -190,7 +190,7 @@ class _TileState extends State<Tile> {
               print(selectedIndex);
               selected = true;
               Future.delayed(const Duration(seconds: 2), () {
-                this.widget.parent.setState(() {
+                this.widget.parent?.setState(() {
                   myPairs[widget.tileIndex].setIsSelected(false);
                   myPairs[selectedIndex].setIsSelected(false);
                 });

lib/models/TileModel.dart

 class TileModel {
-  String imageAssetPath;
-  bool isSelected;
+  String imageAssetPath = "";
+  bool isSelected = false;
 
-  TileModel({this.imageAssetPath, this.isSelected});
+  TileModel({this.imageAssetPath: "", this.isSelected: false});
 
   void setImageAssetPath(String getImageAssetPath) {
     imageAssetPath = getImageAssetPath;

pubspec.lock

@@ -49,7 +49,7 @@ packages:
       name: cupertino_icons
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.1.3"
+    version: "1.0.5"
   fake_async:
     dependency: transitive
     description:

pubspec.yaml

@@ -4,12 +4,12 @@ description: A simple and classic memory game.
 version: 1.0.0+1
 
 environment:
-  sdk: ">=2.1.0 <3.0.0"
+  sdk: ">=2.16.1 <3.0.0"
 
 dependencies:
   flutter:
     sdk: flutter
-  cupertino_icons: ^0.1.2
+  cupertino_icons: ^1.0.5
 
 dev_dependencies:
   flutter_test: