Native (Swift/Kotlin) vs Cross-Platform (Flutter/RN) Comparison

// Swift (iOS) - HealthKit integration (only possible on native)
import HealthKit
import SwiftUI

@Observable
class HealthViewModel {
    var stepCount: Int = 0
    var heartRate: Double = 0
    var activeCalories: Double = 0
    private let healthStore = HKHealthStore()

    func requestPermission() async throws {
        let readTypes: Set<HKObjectType> = [
            HKObjectType.quantityType(forIdentifier: .stepCount)!,
            HKObjectType.quantityType(forIdentifier: .heartRate)!,
            HKObjectType.quantityType(forIdentifier: .activeEnergyBurned)!
        ]
        try await healthStore.requestAuthorization(toShare: [], read: readTypes)
    }

    func fetchTodayStats() async throws {
        let now = Date()
        let startOfDay = Calendar.current.startOfDay(for: now)
        let predicate = HKQuery.predicateForSamples(
            withStart: startOfDay, end: now, options: .strictStartDate
        )

        // Step count
        let stepType = HKQuantityType(.stepCount)
        let stepQuery = HKStatisticsQuery(
            quantityType: stepType,
            quantitySamplePredicate: predicate,
            options: .cumulativeSum
        ) { [weak self] _, result, _ in
            Task { @MainActor in
                self?.stepCount = Int(result?.sumQuantity()?.doubleValue(for: .count()) ?? 0)
            }
        }
        healthStore.execute(stepQuery)
    }
}

// ARKit integration — native exclusive
import ARKit
import RealityKit

struct ARViewContainer: UIViewRepresentable {
    func makeUIView(context: Context) -> ARView {
        let arView = ARView(frame: .zero)
        let config = ARWorldTrackingConfiguration()
        config.planeDetection = [.horizontal, .vertical]
        arView.session.run(config)

        // Load and place a 3D model
        let anchor = AnchorEntity(plane: .horizontal)
        let box = ModelEntity(mesh: .generateBox(size: 0.1))
        anchor.addChild(box)
        arView.scene.addAnchor(anchor)
        return arView
    }

    func updateUIView(_ uiView: ARView, context: Context) {}
}

// Flutter - Accessing platform features (Method Channel)
import 'package:flutter/services.dart';
import 'package:flutter/material.dart';

// Platform channel definition
const platform = MethodChannel('com.myapp/native');

class NativeFeatureService {
  // HealthKit on iOS, Health Connect on Android
  static Future<Map<String, dynamic>> getHealthData() async {
    try {
      final result = await platform.invokeMethod<Map>('getHealthData');
      return Map<String, dynamic>.from(result ?? {});
    } on PlatformException catch (e) {
      debugPrint('HealthKit/Health Connect error: \${e.message}');
      return {};
    }
  }

  // Device-specific biometric authentication
  static Future<bool> authenticateWithBiometrics() async {
    try {
      return await platform.invokeMethod<bool>('biometricAuth') ?? false;
    } on PlatformException catch (e) {
      debugPrint('Biometric error: \${e.message}');
      return false;
    }
  }
}

// Flutter UI (same on both platforms)
class HealthDashboard extends StatefulWidget {
  const HealthDashboard({super.key});

  @override
  State<HealthDashboard> createState() => _HealthDashboardState();
}

class _HealthDashboardState extends State<HealthDashboard> {
  Map<String, dynamic> healthData = {};

  @override
  void initState() {
    super.initState();
    loadHealthData();
  }

  Future<void> loadHealthData() async {
    final data = await NativeFeatureService.getHealthData();
    setState(() => healthData = data);
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: const Text('Health Summary')),
      body: ListView(
        children: [
          _StatCard(label: 'Step Count', value: '\${healthData["steps"] ?? 0}'),
          _StatCard(label: 'Calories', value: '\${healthData["calories"] ?? 0} kcal'),
        ],
      ),
    );
  }
}