static const platform = MethodChannel('com.example.native/channel');

Future<void> _getBatteryLevel() async {
  try {
    final int result = await platform.invokeMethod('getBatteryLevel');
    print('Battery level: \$result%');
  } catch (e) {
    print('Failed to get battery level: \$e');
  }
}

class MainActivity: FlutterActivity() {
  private val CHANNEL = "com.example.native/channel"

  override fun configureFlutterEngine(flutterEngine: FlutterEngine) {
    super.configureFlutterEngine(flutterEngine)
    MethodChannel(flutterEngine.dartExecutor.binaryMessenger, CHANNEL).setMethodCallHandler {
      call, result ->
      if (call.method == "getBatteryLevel") {
        val batteryLevel = getBatteryLevel()
        result.success(batteryLevel)
      } else {
        result.notImplemented()
      }
    }
  }

  private fun getBatteryLevel(): Int {
    val batteryManager = getSystemService(BATTERY_SERVICE) as BatteryManager
    return batteryManager.getIntProperty(BatteryManager.BATTERY_PROPERTY_CAPACITY)
  }
}

let controller = window.rootViewController as! FlutterViewController
let channel = FlutterMethodChannel(name: "com.example.native/channel", binaryMessenger: controller.binaryMessenger)

channel.setMethodCallHandler { (call, result) in
  if call.method == "getBatteryLevel" {
    let device = UIDevice.current
    device.isBatteryMonitoringEnabled = true
    result(device.batteryLevel * 100)
  } else {
    result(FlutterMethodNotImplemented)
  }
}