/// 切换全屏模式
  void _toggleFullScreen() async {
    if (_isFullscreen) {
      debugPrint('退出全屏模式');
      await SystemChrome.setPreferredOrientations([
        DeviceOrientation.portraitUp,
      ]);
      await SystemChrome.setEnabledSystemUIMode(SystemUiMode.edgeToEdge);
      setState(() {
        _isFullscreen = false;
      });
    } else {
      debugPrint('进入全屏模式');
      await SystemChrome.setPreferredOrientations([
        DeviceOrientation.landscapeLeft,
        DeviceOrientation.landscapeRight,
      ]);
      await SystemChrome.setEnabledSystemUIMode(SystemUiMode.immersiveSticky);
      setState(() {
        _isFullscreen = true;
      });
    }
  }