check_folding.dart

import 'dart:ui' as ui;

// import 'package:flutter/services.dart';
import 'package:flutter/material.dart';

void main() {
  WidgetsFlutterBinding.ensureInitialized().addObserver(FoldObserver());
  runApp(const MaterialApp(home: Text('Hello!')));
}

class FoldObserver extends WidgetsBindingObserver {
  @override
  void didChangeMetrics() {
    super.didChangeMetrics();
    print(ui.window.displayFeatures);
    if (ui.window.displayFeatures.any((ui.DisplayFeature feature) =>
        feature.state == ui.DisplayFeatureState.postureHalfOpened)) {
      print('Unfolding!');
      // SystemChrome.setPreferredOrientations([]);
    } else {
      print('Not unfolding');
    }
  }
}