migrated this app to the V2 embedding

android/app/build.gradle

@@ -26,7 +26,7 @@ apply plugin: 'kotlin-android'
 apply from: "$flutterRoot/packages/flutter_tools/gradle/flutter.gradle"
 
 android {
-    compileSdkVersion 28
+    compileSdkVersion 31
 
     sourceSets {
         main.java.srcDirs += 'src/main/kotlin'

android/app/src/main/AndroidManifest.xml

@@ -6,11 +6,12 @@
          additional functionality it is fine to subclass or reimplement
          FlutterApplication and put your custom class here. -->
     <application
-        android:name="io.flutter.app.FlutterApplication"
+        android:name="${applicationName}"
         android:label="flutter_chat_ui"
         android:icon="@mipmap/ic_launcher">
         <activity
             android:name=".MainActivity"
+            android:exported="true"
             android:launchMode="singleTop"
             android:theme="@style/LaunchTheme"
             android:configChanges="orientation|keyboardHidden|keyboard|screenSize|locale|layoutDirection|fontScale|screenLayout|density|uiMode"
@@ -21,12 +22,16 @@
                  there is no splash screen (such as the default splash screen
                  defined in @style/LaunchTheme). -->
             <meta-data
-                android:name="io.flutter.app.android.SplashScreenUntilFirstFrame"
-                android:value="true" />
+                android:name="io.flutter.embedding.android.NormalTheme"
+                android:resource="@style/NormalTheme"
+                />
             <intent-filter>
                 <action android:name="android.intent.action.MAIN"/>
                 <category android:name="android.intent.category.LAUNCHER"/>
             </intent-filter>
         </activity>
+        <meta-data
+            android:name="flutterEmbedding"
+            android:value="2" />
     </application>
 </manifest>

android/app/src/main/kotlin/com/example/flutter_chat_ui/MainActivity.kt

@@ -1,12 +1,8 @@
 package com.example.flutter_chat_ui
 
-import android.os.Bundle
-import io.flutter.app.FlutterActivity
-import io.flutter.plugins.GeneratedPluginRegistrant
+import io.flutter.embedding.android.FlutterActivity
+
 
 class MainActivity: FlutterActivity() {
-  override fun onCreate(savedInstanceState: Bundle?) {
-    super.onCreate(savedInstanceState)
-    GeneratedPluginRegistrant.registerWith(this)
-  }
+
 }

android/app/src/main/res/values/styles.xml

@@ -1,8 +1,18 @@
 <?xml version="1.0" encoding="utf-8"?>
 <resources>
-    <style name="LaunchTheme" parent="@android:style/Theme.Black.NoTitleBar">
+    <!-- Theme applied to the Android Window while the process is starting when the OS's Dark Mode setting is off -->
+    <style name="LaunchTheme" parent="@android:style/Theme.Light.NoTitleBar">
         <!-- Show a splash screen on the activity. Automatically removed when
-             Flutter draws its first frame -->
+             the Flutter engine draws its first frame -->
         <item name="android:windowBackground">@drawable/launch_background</item>
     </style>
+    <!-- Theme applied to the Android Window as soon as the process has started.
+         This theme determines the color of the Android Window while your
+         Flutter UI initializes, as well as behind your Flutter UI while its
+         running.
+
+         This Theme is only used starting with V2 of Flutter's Android embedding. -->
+    <style name="NormalTheme" parent="@android:style/Theme.Light.NoTitleBar">
+        <item name="android:windowBackground">?android:colorBackground</item>
+    </style>
 </resources>

android/build.gradle

@@ -1,12 +1,12 @@
 buildscript {
-    ext.kotlin_version = '1.3.50'
+    ext.kotlin_version = '1.7.10'
     repositories {
         google()
         jcenter()
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:3.5.0'
+        classpath 'com.android.tools.build:gradle:7.2.0'
         classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
     }
 }

android/gradle/wrapper/gradle-wrapper.properties

@@ -3,4 +3,4 @@ distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-5.6.2-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-7.3.3-all.zip

lib/models/message_model.dart

@@ -9,11 +9,11 @@ class Message {
   final bool unread;
 
   Message({
-    this.sender,
-    this.time,
-    this.text,
-    this.isLiked,
-    this.unread,
+    required this.sender,
+    required this.time,
+    required this.text,
+    required this.isLiked,
+    required this.unread,
   });
 }
 

lib/models/user_model.dart

@@ -4,8 +4,8 @@ class User {
   final String imageUrl;
 
   User({
-    this.id,
-    this.name,
-    this.imageUrl,
+    required this.id,
+    required this.name,
+    required this.imageUrl,
   });
 }

lib/screens/chat_screen.dart

@@ -5,7 +5,7 @@ import 'package:flutter_chat_ui/models/user_model.dart';
 class ChatScreen extends StatefulWidget {
   final User user;
 
-  ChatScreen({this.user});
+  ChatScreen({required this.user});
 
   @override
   _ChatScreenState createState() => _ChatScreenState();