Unimplemented error caused by widgets in Android studio using Flutter for home page?

Question

I am trying to build and install the app created in android studio using flutter, but while installing I am getting this error and the app is not running. on the mobile phone I'm getting the error " Unimplemented error" How to resolve this error?

import 'package:flutter/material.dart';
import 'package:camera/camera.dart';
import 'package:flutter/services.dart';
import 'package:tflite/tflite.dart';
import 'dart:async';
//import 'lib.dart';

import 'main.dart';

class HomePage extends StatefulWidget {
  const HomePage({Key? key}) : super(key: key);

  @override
  _HomePageState createState() => _HomePageState();
}

class _HomePageState extends State<HomePage>
{
  late CameraController cameraController;
  //defining variables
  late CameraImage imgCamera;
  bool isWorking=false;
  late double imgHeight;
  late double imgWidth;
  late List recognitionsList;

  initCamera()
  {
    cameraController=CameraController(cameras[0],ResolutionPreset.medium);
    cameraController.initialize().then((value)
    {
      if(!mounted)
        {
          return;
        }
      setState(()
      {
         cameraController.startImageStream((imageFromStream)=>
         {
           if(!isWorking)
             {
               isWorking=true,
               imgCamera= imageFromStream,
               runModelOnStreamFrame(),
             }
         });
      });
    });
  }
  runModelOnStreamFrame() async {
    imgHeight = imgCamera.height + 0.0;
    imgWidth=imgCamera.width + 0.0;
    recognitionsList= (await Tflite.detectObjectOnFrame(bytesList:imgCamera.planes.map((plane){
      return  plane.bytes;
    }).toList() ,

    model:"SSDMobileNet", //change it to other name assets/ssd_mobilenet.tflite
    imageHeight: imgCamera.height,
    imageWidth: imgCamera.width,
    imageMean:  127.5,
    imageStd: 127.5,
    numResultsPerClass: 1,

    threshold: 0.4,
    ))!;
    isWorking=false;
    setState(()
    {
      imgCamera;

    });

  Future <dynamic> loadModel() async
  {
    Tflite.close();
    try{
      late String response;
      response = (await Tflite.loadModel(
        model:"assets/ssd_mobilenet.tflite",
        labels: "assets/ssd_mobilenet.txt"

      ))!;
      print(response);
    }
   // catch{}
    on PlatformException
    {
      print("unable to load model");
    }
  }

  @override
  void dispose()
    {
     super.dispose();
     cameraController.stopImageStream();
     Tflite.close();
    }


  @override
  void initState()
  {
    super.initState();
    initCamera();
  }

  List<Widget> displayBoxesAroundRecognizedObjects(Size screen)
    {
        if(recognitionsList == null) return[];

        if(imgHeight == null || imgWidth == null) return[];


        double factorX = screen.width;
        double factorY = imgHeight;
        Color colorPick = Colors.lightGreenAccent;

        return recognitionsList.map((result)
        {
          return Positioned(
            left:result["rect"]["x"] * factorX,
            top:result["rect"]["y"] * factorY,
            width:result["rect"]["w"] * factorX,
            height:result["rect"]["h"] * factorY,
          child: Container(
            decoration: BoxDecoration(
              borderRadius: BorderRadius.all(Radius.circular(10.0)),
              border: Border.all(color:Colors.lightGreenAccent,width:2.0),
            ),

            child:Text(
              "${result['detectedClass']} ${(result['confidenceInClass'] * 100).toStringAsFixed(0)}%",
              style:TextStyle(
                background:Paint()..color= colorPick,
                color:Colors.black,
                fontSize:16.0,
              ),
            ),
          ),

          );
        }).toList();
    }
  @override
  Widget build(BuildContext context)
  {
    Size size = MediaQuery.of(context).size;
    List<Widget> stackChildrenWidgets =[];
    stackChildrenWidgets.add(
      Positioned(
        top: 0.0,
        left : 0.0,
        width:size.width,height:size.height-100,
        child:Container(
          height:size.height-100,
          child:(!cameraController.value.isInitialized)
              ? new Container()
              : AspectRatio(
            aspectRatio: cameraController.value.aspectRatio,
            child: CameraPreview(cameraController),

          ),
        ),

      ),
    );
      if(imgCamera != null)
        {
       stackChildrenWidgets.addAll(displayBoxesAroundRecognizedObjects(size));
        }


    return SafeArea(
        child: Scaffold
          (
          backgroundColor: Colors.black,
          body: Container(
            margin : EdgeInsets.only(top:50),
            color:Colors.black,
            child:Stack(
              children:stackChildrenWidgets,
            ),

          ),
        ),
    );
  }
}

  @override
  Widget build(BuildContext context) {
    // TODO: implement build
    throw UnimplementedError();
  }}

======== Exception caught by widgets library ======== The following UnimplementedError was thrown building HomePage(dirty, state: _HomePageState#f3ad6): UnimplementedError

The relevant error-causing widget was: HomePage file:///C:/Users/Vedika/AndroidStudioProjects/object_detection_app/lib/main.dart:20:13 When the exception was thrown, this was the stack: #0 _HomePageState.build (package:object_detection_app/HomePage.dart:195:5) #1 StatefulElement.build (package:flutter/src/widgets/framework.dart:4691:27) #2 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4574:15) #3 StatefulElement.performRebuild (package:flutter/src/widgets/framework.dart:4746:11) #4 Element.rebuild (package:flutter/src/widgets/framework.dart:4267:5)

Answer 1

you just having Unimplemented Error because you throw it in the last peace of code

@override
Widget build(BuildContext context) {
  // TODO: implement build
  throw UnimplementedError();
}}

please check the code above