FLUTTER → FULL DETAILED ARCHITECTURE → flutter_app_how_running_in_android_device_detailed_architecture (Check the github - interview prep docs )

Flutter App Architecture on Android

How a Flutter app runs on Android device:

Layer Architecture

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┌─────────────────────────────────┐
│   Flutter Framework (Dart)      │  ← User code, widgets, state
├─────────────────────────────────┤
│   Flutter Engine (C++)          │  ← Rendering, input handling
├─────────────────────────────────┤
│   Android Runtime (ART)         │  ← Java/Kotlin JVM
├─────────────────────────────────┤
│   Android Framework             │  ← Activity, Services, Sensors
├─────────────────────────────────┤
│   Linux Kernel                  │  ← Process management, I/O
└─────────────────────────────────┘

Startup Process

1. Android system launches MainActivity
2. FlutterActivity created
3. FlutterEngine initialized
4. Dart VM starts
5. main.dart executes
6. FlutterView renders UI on screen

Main Components

FlutterEngine: Hosts Dart VM and rendering engine FlutterView: Native view displaying rendered output Platform Channel: Bridges Dart and native code

dartCopy
// Platform channel example
static const methodChannel = MethodChannel('com.example.app/channel');

Future<void> callNativeCode() async {
  try {
    final result = await methodChannel.invokeMethod('getDeviceInfo');
    print(result);
  } catch (e) {
    print('Error: $e');
  }
}

App Lifecycle

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AppLifecycleState.resumed
  ↓
AppLifecycleState.inactive
  ↓
AppLifecycleState.paused
  ↓
AppLifecycleState.detached

Reference: Flutter Platform Architecture