refactor: tweaks

android/app/build.gradle

@@ -1,10 +1,11 @@
 plugins {
     id "com.android.application"
     id "org.jetbrains.kotlin.android"
+
     // The Flutter Gradle Plugin must be applied after the Android and Kotlin Gradle plugins.
     id "dev.flutter.flutter-gradle-plugin"
 
-    // Apply React Native plugin
+    // React Native plugin
     // See: https://github.com/react-native-community/template/blob/main/template/android/app/build.gradle
 	id 'com.facebook.react'
 }
@@ -31,7 +32,11 @@ android {
     namespace = "com.example.flutter_brownfield_app"
 
     buildToolsVersion rootProject.ext.buildToolsVersion
+
+    // React Native and Flutter share the same compileSdkVersion = 34
     compileSdk rootProject.ext.compileSdkVersion // flutter.compileSdkVersion = 34
+
+    // Using React Native NDK version
     ndkVersion rootProject.ext.ndkVersion // flutter.ndkVersion = "23.1.7779620
 
     compileOptions {
@@ -67,12 +72,12 @@ flutter {
     source = "../.."
 }
 
-// React Native setup
+// React Native: dependencies
 // See: https://github.com/react-native-community/template/blob/main/template/android/app/build.gradle
 dependencies {
-	implementation 'com.facebook.react:react-android'
+    implementation 'com.facebook.react:react-android'
 	implementation 'com.facebook.react:hermes-android'
 }
 
-// Enable React Native autolinking
+// React Native: enable autolinking
 apply from: file("../../node_modules/@react-native-community/cli-platform-android/native_modules.gradle"); applyNativeModulesAppBuildGradle(project)

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

@@ -10,7 +10,9 @@ import io.flutter.embedding.engine.FlutterEngine
 import io.flutter.plugin.common.MethodChannel
 
 /**
- * Basic FlutterActivity extended with React Native lifecycle hooks/
+ * Basic FlutterActivity extended with React Native lifecycle hooks.
+ *
+ * This is hosting Flutter application as well as can draw React Native views using ReactView.
  *
  * See:
  * - https://reactnative.dev/docs/integration-with-existing-apps
@@ -39,7 +41,7 @@ class MainActivity: FlutterActivity(), DefaultHardwareBackBtnHandler {
             .registry
             .registerViewFactory("react_view", ReactViewFactory())
 
-        // Register MethodChannel, so we can call it from Flutter code.
+        // Register MethodChannel, so we can call it from Flutter code from native.
         MethodChannel(flutterEngine.dartExecutor.binaryMessenger, FLUTTER_CHANNEL).setMethodCallHandler {
                 call, result ->
             if (call.method == "navigateToReactNative") {
@@ -52,6 +54,8 @@ class MainActivity: FlutterActivity(), DefaultHardwareBackBtnHandler {
         }
     }
 
+    // This is used to start React Native component in a separate Activity for usage with React Navigation.
+    // Do not use this if you just want to embed ReactView in Flutter screen.
     private fun startReactNativeActivity(moduleName: String) {
         val intent = Intent(this, ReactActivity::class.java).apply {
             putExtra("moduleName", moduleName)

android/app/src/main/kotlin/com/example/flutter_brownfield_app/MainApplication.kt

@@ -8,6 +8,7 @@ import com.facebook.react.defaults.DefaultReactNativeHost
 import com.facebook.soloader.SoLoader
 
 class MainApplication: Application(), ReactApplication {
+    // React Native runtime
     override val reactNativeHost =
         object : DefaultReactNativeHost(this) {
             override fun getPackages(): List<ReactPackage> {

android/build.gradle

@@ -28,15 +28,15 @@ buildscript {
         ndkVersion = "26.1.10909125"
         kotlinVersion = "1.9.22"
     }
-	repositories {
-		google()
-		mavenCentral()
-	}
-	dependencies {
+    repositories {
+        google()
+        mavenCentral()
+    }
+    dependencies {
         classpath("com.android.tools.build:gradle")
         classpath("com.facebook.react:react-native-gradle-plugin")
         classpath("org.jetbrains.kotlin:kotlin-gradle-plugin")
-	}
+    }
 }
 
 apply plugin: "com.facebook.react.rootproject"

android/settings.gradle

@@ -20,13 +20,13 @@ plugins {
     id "dev.flutter.flutter-plugin-loader" version "1.0.0"
     id "com.android.application" version '8.2.2' apply false
 
-    // Plugin version matching React Native config:
+    // Kotlin plugin version needs to match React Native config:
     // https://github.com/react-native-community/template/blob/main/template/android/settings.gradle
     id "org.jetbrains.kotlin.android" version "1.9.22" apply false
 }
 
 include ":app"
 
-// Configure React Native auto-linking
+// React Native: configure autolinking
 includeBuild('../node_modules/@react-native/gradle-plugin')
 apply from: file("../node_modules/@react-native-community/cli-platform-android/native_modules.gradle"); applyNativeModulesSettingsGradle(settings)

ios/Runner/AppDelegate.swift

@@ -8,6 +8,7 @@ import UIKit
         _ application: UIApplication,
         didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?
     ) -> Bool {
+        // Register MethodChannel, so we can call it from Flutter code from native.
         let controller : FlutterViewController = window?.rootViewController as! FlutterViewController
         let channel = FlutterMethodChannel(
             name: "flutter-brownfield/native",
@@ -21,6 +22,7 @@ import UIKit
             }
 
             switch call.method {
+            // Trigger navigation to separate React Native ViewController for usage with React Navigation
             case "navigateToReactNative":
                 let args = call.arguments as! [String: Any];
                 let moduleName = args["moduleName"] as! String;
@@ -44,6 +46,7 @@ import UIKit
             withId: "react_view"
         )
 
+        // Load React Native to BridgeManager holder.
         BridgeManager.shared.loadReactNative(launchOptions: launchOptions)
         return super.application(application, didFinishLaunchingWithOptions: launchOptions)
     }
@@ -56,12 +59,14 @@ import UIKit
     func presentReactNativeViewController(
         moduleName: String
     ) {
-        let jsCodeLocation = URL(string: "http://localhost:8081/index.bundle?platform=ios")!
+        guard let bridge = BridgeManager.shared.bridge else {
+            fatalError("BridgeManager.shared.bridge is nil. Make sure to call BridgeManager.shared.loadReactNative() before calling presentReactNativeViewController.")
+        }
+
         let rootView = RCTRootView(
-            bundleURL: jsCodeLocation,
+            bridge: bridge,
             moduleName: moduleName,
-            initialProperties: [:] as [NSObject : AnyObject],
-            launchOptions: nil
+            initialProperties: [:]
         )
 
         let viewController = UIViewController()