横竖屏设置

  // 强制竖屏
  runApp(MyApp());
  SystemChrome.setPreferredOrientations([
    DeviceOrientation.portraitUp,
    DeviceOrientation.portraitDown
  ]);
}
void main() {
  // 强制横屏
  runApp(MyApp());
  SystemChrome.setPreferredOrientations([
    DeviceOrientation.landscapeLeft,
    DeviceOrientation.landscapeRight
  ]);
}