Flutter platform-specific code

import 'package:flutter/services.dart';

// Define channel
class PlatformChannel {
  static const MethodChannel _channel = MethodChannel('my_app/channel');

  // Call native method - get battery level
  static Future<int> getBatteryLevel() async {
    try {
      final int batteryLevel = await _channel.invokeMethod('getBatteryLevel');
      return batteryLevel;
    } on PlatformException catch (e) {
      print('Failed to get battery level: ${e.message}');
      return -1;
    }
  }

  // Call native method - show Toast
  static Future<void> showToast(String message) async {
    try {
      await _channel.invokeMethod('showToast', {'message': message});
    } on PlatformException catch (e) {
      print('Failed to show Toast: ${e.message}');
    }
  }

  // Call native method - get device information
  static Future<Map<String, dynamic>> getDeviceInfo() async {
    try {
      final result = await _channel.invokeMapMethod('getDeviceInfo');
      return result ?? {};
    } on PlatformException catch (e) {
      print(Failed to get device information: ${e.message});
      return {};
    }
  }
}

// Usage example
class MyWidget extends StatelessWidget {
  const MyWidget({super.key});

  @override
  Widget build(BuildContext context) {
    return ElevatedButton(
      onPressed: () async {
        final battery = await PlatformChannel.getBatteryLevel();
        print(Battery level: $battery%);
      },
      child: const Text(Get battery level),
    );
  }
}

// MainActivity.kt
package com.example.my_app

import android.os.Bundle
import io.flutter.embedding.android.FlutterActivity
import io.flutter.embedding.engine.FlutterEngine
import io.flutter.plugin.common.MethodChannel

class MainActivity : FlutterActivity() {
    private val CHANNEL = "my_app/channel"

    override fun configureFlutterEngine(flutterEngine: FlutterEngine) {
        super.configureFlutterEngine(flutterEngine)

        MethodChannel(flutterEngine.dartExecutor.binaryMessenger, CHANNEL)
            .setMethodCallHandler { call, result ->
                when (call.method) {
                    "getBatteryLevel" -> {
                        val batteryLevel = getBatteryLevel()
                        if (batteryLevel != -1) {
                            result.success(batteryLevel)
                        } else {
result.error("UNAVAILABLE", "Unable to get battery level", null)
                        }
                    }
                    "showToast" -> {
                        val message = call.argument<String>("message")
                        showToast(message!!)
                        result.success(null)
                    }
                    else -> {
                        result.notImplemented()
                    }
                }
            }
    }

    private fun getBatteryLevel(): Int {
        return try {
            val batteryManager = getSystemService(BATTERY_SERVICE) as BatteryManager
            batteryManager.getIntProperty(BatteryManager.BATTERY_PROPERTY_CAPACITY)
        } catch (e: Exception) {
            -1
        }
    }

    private fun showToast(message: String) {
        android.widget.Toast.makeText(this, message, android.widget.Toast.LENGTH_SHORT).show()
    }
}

// AppDelegate.swift
import Flutter
import UIKit

@UIApplicationMain
@objc class AppDelegate: FlutterAppDelegate {
    private let CHANNEL = "my_app/channel"

    override func application(
        _ application: UIApplication,
        didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?
    ) -> Bool {
        let controller = window?.rootViewController as! FlutterViewController

        let channel = FlutterMethodChannel(
            name: CHANNEL,
            binaryMessenger: controller.binaryMessenger
        )

        channel.setMethodCallHandler { (call: FlutterMethodCall, result: @escaping FlutterResult) in
            switch call.method {
            case "getBatteryLevel":
                self.getBatteryLevel(result: result)
            case "showToast":
                if let args = call.arguments as? [String: Any],
                   let message = args["message"] as? String {
                    self.showToast(message: message)
                    result(nil)
                }
            default:
                result(FlutterMethodNotImplemented)
            }
        }

        return super.application(application, didFinishLaunchingWithOptions: launchOptions)
    }

    private func getBatteryLevel(result: @escaping FlutterResult) {
        UIDevice.current.isBatteryMonitoringEnabled = true
        let batteryLevel = UIDevice.current.batteryLevel

        if batteryLevel < 0 {
result(FlutterError(code: "UNAVAILABLE", message: "Unable to get battery level", details: nil))
        } else {
            result(Int(batteryLevel * 100))
        }
    }

    private func showToast(message: String) {
        let alert = UIAlertController(title: nil, message: message, preferredStyle: .alert)
        present(alert, animated: true)
        DispatchQueue.main.asyncAfter(deadline: .now() + 1.5) {
            alert.dismiss(animated: true)
        }
    }
}