qhd-prevention-flutter/ios/Runner/AppDelegate.swift

import UIKit
import Flutter

@main
@objc class AppDelegate: FlutterAppDelegate {
  // 动态方向掩码（默认竖屏）
  static var orientationMask: UIInterfaceOrientationMask = .portrait

  override func application(
    _ application: UIApplication,
    didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?
  ) -> Bool {

    let controller = window?.rootViewController as! FlutterViewController
    let channel = FlutterMethodChannel(name: "app.orientation",
                                       binaryMessenger: controller.binaryMessenger)

    channel.setMethodCallHandler { [weak self] call, result in
      guard let self = self else { return }

      if call.method == "setOrientation" {
        guard let arg = call.arguments as? String else {
          result(FlutterError(code: "BAD_ARGS", message: "need 'landscape' | 'portrait'", details: nil))
          return
        }

        // 先更新允许的方向掩码
        if arg == "landscape" {
          AppDelegate.orientationMask = .landscape
        } else if arg == "portrait" {
          AppDelegate.orientationMask = .portrait
        } else {
          result(FlutterError(code: "BAD_ARGS", message: "unknown arg", details: nil))
          return
        }


        // 再请求实际旋转
        if #available(iOS 16.0, *) {
            // 通知顶层 VC：其 supportedInterfaceOrientations 需要刷新
            self.window?.rootViewController?.setNeedsUpdateOfSupportedInterfaceOrientations()

          if let scene = self.window?.windowScene {
            let orientations: UIInterfaceOrientationMask =
              (arg == "landscape") ? .landscape : .portrait
            do {
              try scene.requestGeometryUpdate(.iOS(interfaceOrientations: orientations))
            } catch {
              result(FlutterError(code: "GEOMETRY_UPDATE_FAILED",
                                  message: error.localizedDescription, details: nil))
              return
            }
          }
        } else {
          let target: UIInterfaceOrientation =
            (arg == "landscape") ? .landscapeLeft : .portrait
          UIDevice.current.setValue(target.rawValue, forKey: "orientation")
          UIViewController.attemptRotationToDeviceOrientation()
        }

        result(true)
      } else {
        result(FlutterMethodNotImplemented)
      }
    }

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

  // 关键：把当前的掩码提供给系统
  override func application(_ application: UIApplication,
                            supportedInterfaceOrientationsFor window: UIWindow?)
    -> UIInterfaceOrientationMask {
    return AppDelegate.orientationMask
  }
}