rog_app/ios/Runner/AppDelegate.swift

import Flutter
import UIKit
import CoreMotion

@main
@objc class AppDelegate: FlutterAppDelegate {
  private let motionManager = CMMotionManager()

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

    let controller : FlutterViewController = window?.rootViewController as! FlutterViewController
    let motionChannel = FlutterMethodChannel(name: "net.sumasen.gifunavi/motion",
                                              binaryMessenger: controller.binaryMessenger)
    motionChannel.setMethodCallHandler({
      [weak self] (call: FlutterMethodCall, result: @escaping FlutterResult) -> Void in
      guard let self = self else { return }

      switch call.method {
      case "startMotionUpdates":
        self.startMotionUpdates(result: result)
      case "stopMotionUpdates":
        self.stopMotionUpdates(result: result)
      default:
        result(FlutterMethodNotImplemented)
      }
    })

    GeneratedPluginRegistrant.register(with: self)
    return super.application(application, didFinishLaunchingWithOptions: launchOptions)
  }

// この実装では以下のことを行っています：
//   デバイスのモーションデータ（姿勢、重力、ユーザー加速度）を取得します。
//   取得したデータを辞書形式にまとめます。
//   sendMotionDataメソッドを使って、Flutterアプリにデータを送信します。

    private func startMotionUpdates(result: @escaping FlutterResult) {
      if motionManager.isDeviceMotionAvailable {
        motionManager.deviceMotionUpdateInterval = 0.1
        motionManager.startDeviceMotionUpdates(to: .main) { [weak self] (motion, error) in
            guard let self = self else { return }

            if let error = error {
                DispatchQueue.main.async {
                    result(FlutterError(code: "MOTION_ERROR",
                        message: error.localizedDescription,
                        details: nil))
                }
                return
            }

            guard let motion = motion else {
                DispatchQueue.main.async {
                    result(FlutterError(code: "NO_MOTION_DATA",
                                        message: "No motion data available",
                                        details: nil))
                }
                return
            }

            DispatchQueue.main.async {
                let motionData: [String: Any] = [
                    "attitude": [
                        "roll": motion.attitude.roll,
                        "pitch": motion.attitude.pitch,
                        "yaw": motion.attitude.yaw
                    ],
                    "gravity": [
                        "x": motion.gravity.x,
                        "y": motion.gravity.y,
                        "z": motion.gravity.z
                    ],
                    "userAcceleration": [
                        "x": motion.userAcceleration.x,
                        "y": motion.userAcceleration.y,
                        "z": motion.userAcceleration.z
                    ]
                ]

                self.sendMotionData(motionData)
            }
        }
        result(nil)     // 初期化成功を示す
      } else {
        result(FlutterError(code: "UNAVAILABLE",
                            message: "Device motion is not available.",
                            details: nil))
      }
    }

    private func sendMotionData(_ data: [String: Any]) {
        let motionChannel = FlutterMethodChannel(name: "net.sumasen.gifunavi/motion",
                                                 binaryMessenger: (window?.rootViewController as! FlutterViewController).binaryMessenger)
        motionChannel.invokeMethod("onMotionData", arguments: data)
    }

    private func stopMotionUpdates(result: @escaping FlutterResult) {
      motionManager.stopDeviceMotionUpdates()
      result(nil)
    }
}