.dart

class ArScreen extends StatefulWidget {  
  const ArScreen({Key? key}) : super(key: key);  
  @override  
  _ArScreenState createState() => _ArScreenState();
}‍
  class _ArScreenState extends State<ArScreen> {  
  ARSessionManager? arSessionManager;  
  ARObjectManager? arObjectManager;  
  ARAnchorManager? arAnchorManager;‍  
    List<ARNode> nodes = [];  
  List<ARAnchor> anchors = [];‍  
    @override  
    void dispose() {    
    super.dispose();    
    arSessionManager!.dispose();  }‍  
    @override  
    Widget build(BuildContext context) {    
    return Scaffold(        
      appBar: AppBar(          
        title: const Text('Anchors & Objects on Planes'),        
      ),        
      body: Stack(children: [          
        ARView(        
          onARViewCreated: onARViewCreated,        
          planeDetectionConfig: PlaneDetectionConfig.horizontalAndVertical,          
        ),          
        Align(        
          alignment: FractionalOffset.bottomCenter,        
          child: Row(            
            mainAxisAlignment: MainAxisAlignment.spaceEvenly,            
            children: [              
              ElevatedButton(                  
                onPressed: onRemoveEverything,                  
                child: const Text("Remove Everything")),            
            ]),          
        )        
      ]));  
  }