import UIKit import Flutter @UIApplicationMain @objc class AppDelegate: FlutterAppDelegate { override func application( _ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]? ) -> Bool { let flutterViewController = window.rootViewController as! FlutterViewController FlutterMethodChannel(name: "methodChannelDemo", binaryMessenger: flutterViewController.binaryMessenger).setMethodCallHandler({ (call: FlutterMethodCall, result: FlutterResult) -> Void in guard let count = (call.arguments as? NSDictionary)?["count"] as? Int else { result(FlutterError(code: "INVALID_ARGUMENT", message: "Value of count cannot be null", details: nil)) return } switch call.method { case "increment": result(count + 1) case "decrement": result(count - 1) default: result(FlutterMethodNotImplemented) } }) GeneratedPluginRegistrant.register(with: self) return super.application(application, didFinishLaunchingWithOptions: launchOptions) } }