Communicate Between Flutter and Native iOS Code Using Platform Channel

AppDelegate.swift

// iOS Native

import Flutter
import UIKit

@UIApplicationMain
@objc class AppDelegate: FlutterAppDelegate {

    override func application(
        _ application: UIApplication,
        didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?
    ) -> Bool {
      
        registerMethodChannel()
        GeneratedPluginRegistrant.register(with: self)
        return super.application(application, didFinishLaunchingWithOptions: launchOptions)
    }

    // MARK: - Flutter way to call native iOS function
    private func registerMethodChannel() {
        let controller: FlutterViewController = window?.rootViewController as! FlutterViewController
        let methodChannel = FlutterMethodChannel(name: "flutter_call",
                                                 binaryMessenger: controller.binaryMessenger)

        methodChannel.setMethodCallHandler {
            [weak self] (call: FlutterMethodCall, result: @escaping FlutterResult) in
            if let weakSelf = self {
                weakSelf.handle(call, result: result)
            }
        }
    }

    private func handle(_ call: FlutterMethodCall, result: @escaping FlutterResult) {
        if call.method == "getDeviceModel" {
            result("iPhone 14")
        } else {
            result(FlutterMethodNotImplemented)
        }
    }
}

main.dart

// Flutter

import 'package:flutter/material.dart';
import 'package:flutter/services.dart';

void main() {
  runApp(const MyApp());
}

class MyApp extends StatelessWidget {
  const MyApp({super.key});

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        colorScheme: ColorScheme.fromSeed(seedColor: Colors.deepPurple),
        useMaterial3: true,
      ),
      home: const MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  const MyHomePage({super.key, required this.title});
  final String title;

  @override
  State<MyHomePage> createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  String _deviceModel = 'Unknown Model.';
  static const platformChannel = MethodChannel('flutter_call');

  Future<void> _getDeviceModel() async {
    String model;
    try {
      final String result =
          await platformChannel.invokeMethod('getDeviceModel');
      model = result;
    } catch (e) {
      model = "Can't fetch the method: '$e'.";
    }
    setState(() {
      _deviceModel = model;
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        backgroundColor: Theme.of(context).colorScheme.inversePrimary,
        title: Text(widget.title),
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            Text(
              _deviceModel,
            ),
            ElevatedButton(
              onPressed: _getDeviceModel,
              child: const Text('Get Device Model'),
            )
          ],
        ),
      ),
    );
  }
}