chore: update get started with firebase source code

Author: PeterHdd

firebase_start_tutorial/android/app/build.gradle

@@ -27,7 +27,7 @@ apply plugin: 'com.google.gms.google-services' //this line
 apply from: "$flutterRoot/packages/flutter_tools/gradle/flutter.gradle"
 
 android {
-    compileSdkVersion 30
+    compileSdkVersion flutter.compileSdkVersion
 
     sourceSets {
         main.java.srcDirs += 'src/main/kotlin'

firebase_start_tutorial/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:4.1.0'
+        classpath 'com.android.tools.build:gradle:7.0.1'
         classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
         classpath 'com.google.gms:google-services:4.3.3'
     }
@@ -27,6 +27,6 @@ subprojects {
     project.evaluationDependsOn(':app')
 }
 
-task clean(type: Delete) {
+tasks.register("clean", Delete) {
     delete rootProject.buildDir
 }

firebase_start_tutorial/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-6.7-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-7.1-all.zip

firebase_start_tutorial/ios/Runner.xcodeproj/project.pbxproj

@@ -8,6 +8,7 @@
 
 /* Begin PBXBuildFile section */
 		1498D2341E8E89220040F4C2 /* GeneratedPluginRegistrant.m in Sources */ = {isa = PBXBuildFile; fileRef = 1498D2331E8E89220040F4C2 /* GeneratedPluginRegistrant.m */; };
+		2884022CCAE83A6EE2EB7D4F /* GoogleService-Info.plist in Resources */ = {isa = PBXBuildFile; fileRef = C7BA490C5F5ECF73E24F4223 /* GoogleService-Info.plist */; };
 		3B3967161E833CAA004F5970 /* AppFrameworkInfo.plist in Resources */ = {isa = PBXBuildFile; fileRef = 3B3967151E833CAA004F5970 /* AppFrameworkInfo.plist */; };
 		74858FAF1ED2DC5600515810 /* AppDelegate.swift in Sources */ = {isa = PBXBuildFile; fileRef = 74858FAE1ED2DC5600515810 /* AppDelegate.swift */; };
 		97C146FC1CF9000F007C117D /* Main.storyboard in Resources */ = {isa = PBXBuildFile; fileRef = 97C146FA1CF9000F007C117D /* Main.storyboard */; };
@@ -42,6 +43,7 @@
 		97C146FD1CF9000F007C117D /* Assets.xcassets */ = {isa = PBXFileReference; lastKnownFileType = folder.assetcatalog; path = Assets.xcassets; sourceTree = "<group>"; };
 		97C147001CF9000F007C117D /* Base */ = {isa = PBXFileReference; lastKnownFileType = file.storyboard; name = Base; path = Base.lproj/LaunchScreen.storyboard; sourceTree = "<group>"; };
 		97C147021CF9000F007C117D /* Info.plist */ = {isa = PBXFileReference; lastKnownFileType = text.plist.xml; path = Info.plist; sourceTree = "<group>"; };
+		C7BA490C5F5ECF73E24F4223 /* GoogleService-Info.plist */ = {isa = PBXFileReference; includeInIndex = 1; lastKnownFileType = text.plist.xml; name = "GoogleService-Info.plist"; path = "Runner/GoogleService-Info.plist"; sourceTree = "<group>"; };
 /* End PBXFileReference section */
 
 /* Begin PBXFrameworksBuildPhase section */
@@ -72,6 +74,7 @@
 				9740EEB11CF90186004384FC /* Flutter */,
 				97C146F01CF9000F007C117D /* Runner */,
 				97C146EF1CF9000F007C117D /* Products */,
+				C7BA490C5F5ECF73E24F4223 /* GoogleService-Info.plist */,
 			);
 			sourceTree = "<group>";
 		};
@@ -163,6 +166,7 @@
 				3B3967161E833CAA004F5970 /* AppFrameworkInfo.plist in Resources */,
 				97C146FE1CF9000F007C117D /* Assets.xcassets in Resources */,
 				97C146FC1CF9000F007C117D /* Main.storyboard in Resources */,
+				2884022CCAE83A6EE2EB7D4F /* GoogleService-Info.plist in Resources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};

firebase_start_tutorial/lib/main.dart

@@ -1,12 +1,11 @@
 import 'package:firebase_core/firebase_core.dart';
 import 'package:firebase_database/firebase_database.dart';
+import 'package:firebase_start_tutorial/firebase_options.dart';
 import 'package:flutter/material.dart';
 
-
-
 void main() async {
   WidgetsFlutterBinding.ensureInitialized();
-  await Firebase.initializeApp();
+  await Firebase.initializeApp(options: DefaultFirebaseOptions.currentPlatform);
   runApp(MyApp());
 }
 
@@ -40,7 +39,7 @@ class _MyHomePageState extends State<MyHomePage> {
 
   @override
   Widget build(BuildContext context) {
-    final ref = fb.reference();
+    final ref = fb.ref();
     return Scaffold(
         appBar: AppBar(
           title: Text(widget.title!),
@@ -64,11 +63,11 @@ class _MyHomePageState extends State<MyHomePage> {
             ),
             ElevatedButton(
               onPressed: () {
-                ref.child("Name").once().then((DataSnapshot data){
-                  print(data.value);
-                  print(data.key);
+                ref.child("Name").once().then((DatabaseEvent data) {
+                  print(data.snapshot.key);
+                  print(data.snapshot.value);
                   setState(() {
-                    retrievedName = data.value;
+                    retrievedName = data.snapshot.value;
                   });
                 });
               },