android - “总”变量未更新

Question

所以我制作了一个检测纸币价值的应用程序，每次检测到货币时，它的值都应该在“total”变量中更新。例如：假设我拍了一张 200 卢比钞票的照片，“总”变量应该增加 200。现在，如果我给一张 500 卢比的钞票拍照，总数应该是 700（200+500），但它显示的是 500，这意味着它没有存储之前的 200，并且又回到了 0。请有人帮忙，这似乎是一个非常小的错误，我尝试了很多，但徒劳无功。

    import 'dart:io';

import 'package:flutter/material.dart';
import 'package:camera/camera.dart';
import 'package:path/path.dart';
import 'package:path_provider/path_provider.dart';
import 'package:torch_compat/torch_compat.dart';
import 'package:flutter_tts/flutter_tts.dart';
import 'package:tflite/tflite.dart';

int total = 0;

Future<void> main() async {
  WidgetsFlutterBinding.ensureInitialized();
  final cameras = await availableCameras();
  final firstCamera = cameras.first;


  runApp(
    MaterialApp(
      theme: ThemeData.dark(),
      home: TakePictureScreen(
        // Pass the appropriate camera to the TakePictureScreen widget.
        camera: firstCamera,
      ),
    ),
  );
}

class TakePictureScreen extends StatefulWidget {
  final CameraDescription camera;
  const TakePictureScreen({
    Key key,
    @required this.camera,
  }) : super(key: key);

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

class _TakePictureScreenState extends State<TakePictureScreen> {
  CameraController _controller;
  Future<void> _initializeControllerFuture;

  @override
  void initState() {
    super.initState();
    // To display the current output from the Camera,
    // create a CameraController.
    _controller = CameraController(
      // Get a specific camera from the list of available cameras.
      widget.camera,
      // Define the resolution to use.
      ResolutionPreset.high,
    );

    // Next, initialize the controller. This returns a Future.
    _initializeControllerFuture = _controller.initialize();
  }

  @override
  void dispose() {
    // Dispose of the controller when the widget is disposed.
    _controller.dispose();
    TorchCompat.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: Center(child: Text('Noteify'))),
      // Wait until the controller is initialized before displaying the
      // camera preview. Use a FutureBuilder to display a loading spinner
      // until the controller has finished initializing.
      body: FutureBuilder<void>(
        future: _initializeControllerFuture,
        builder: (context, snapshot) {
          if (snapshot.connectionState == ConnectionState.done) {
            // If the Future is complete, display the preview.
            return CameraPreview(_controller);
          } else {
            // Otherwise, display a loading indicator.
            return Center(child: CircularProgressIndicator());
          }
        },
      ),
      floatingActionButton: Column(
        mainAxisAlignment: MainAxisAlignment.end,
        children: <Widget>[
          Center(
            child: Container(
              height: 100.0,
              width: 100.0,
              child: FittedBox(
                child: FloatingActionButton(
                  child: Icon(Icons.camera_alt),
                  // Provide an onPressed callback.
                  onPressed: () async {
                    // Take the Picture in a try / catch block. If anything goes wrong,
                    // catch the error.
                    try {
                      TorchCompat.turnOn();
                      // Ensure that the camera is initialized.
                      await _initializeControllerFuture;

                      // Construct the path where the image should be saved using the
                      // pattern package.
                      final path = join(
                        // Store the picture in the temp directory.
                        // Find the temp directory using the `path_provider` plugin.
                        (await getTemporaryDirectory()).path,
                        '${DateTime.now()}.png',
                      );

                      // Attempt to take a picture and log where it's been saved.
                      await _controller.takePicture(path);
                      TorchCompat.turnOff();

                      // If the picture was taken, display it on a new screen.
                      Navigator.push(
                        context,
                        MaterialPageRoute(
                          builder: (context) => DisplayPictureScreen(path),
                        ),
                      );
                    } catch (e) {
                      // If an error occurs, log the error to the console.
                      print(e);
                    }
                  },
                ),
              ),
            ),
          ),
        ],
      ),
    );
  }
}

// A widget that displays the picture taken by the user.
class DisplayPictureScreen extends StatefulWidget {
  final String imagePath;
  DisplayPictureScreen(this.imagePath);
  @override
  _DisplayPictureScreenState createState() => _DisplayPictureScreenState();
}

class _DisplayPictureScreenState extends State<DisplayPictureScreen> {
  List op;
  Image img;

  @override
  void initState() {
    super.initState();
    loadModel().then((value) {
      setState(() {});
    });
    img = Image.file(File(widget.imagePath));
    classifyImage(widget.imagePath, total);
  }

  @override
  Widget build(BuildContext context) {
//    Image img = Image.file(File(widget.imagePath));
//    classifyImage(widget.imagePath, total);

    return Scaffold(
      appBar: AppBar(title: Text('Display the Picture')),
      // The image is stored as a file on the device. Use the `Image.file`
      // constructor with the given path to display the image.
      body: Container(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            Expanded(child: Center(child: img)),
            SizedBox(
              height: 20,
            )
          ],
        ),
      ),
    );
  }

  Future<void> runTextToSpeech(String outputMoney, int totalMoney) async {
    FlutterTts flutterTts;
    flutterTts = new FlutterTts();

    if (outputMoney == "50 rupees") {
      String tot = totalMoney.toString();
      print(tot);
      String speakString = "Fifty rupees, Your total is now rupees, $tot";
      await flutterTts.setSpeechRate(0.3);
      await flutterTts.awaitSpeakCompletion(true);
      await flutterTts.speak(speakString);
    }
    if (outputMoney == "100 rupees") {
      String tot = totalMoney.toString();
      print(tot);
      String speakString = "One Hundred rupees, Your total is now rupees, $tot";
      await flutterTts.setSpeechRate(0.3);
      await flutterTts.awaitSpeakCompletion(true);
      await flutterTts.speak(speakString);
    }
    if (outputMoney == "200 rupees") {
      String tot = totalMoney.toString();
      print(tot);
      String speakString = "Two Hundred rupees, Your total is now rupees, $tot";
      await flutterTts.setSpeechRate(0.3);
      await flutterTts.awaitSpeakCompletion(true);
      await flutterTts.speak(speakString);
    }
    if (outputMoney == "500 rupees") {
      String tot = totalMoney.toString();
      print(tot);
      String speakString =
          "Five Hundred rupees, Your total is now rupees, $tot";
      await flutterTts.setSpeechRate(0.3);
      await flutterTts.awaitSpeakCompletion(true);
      await flutterTts.speak(speakString);
    }
    if (outputMoney == "2000 rupees") {
      String tot = totalMoney.toString();
      print(tot);
      String speakString =
          "Two thousand rupees, Your total is now rupees, $tot";
      await flutterTts.setSpeechRate(0.3);
      await flutterTts.awaitSpeakCompletion(true);
      await flutterTts.speak(speakString);
    }
  }

  classifyImage(String image, int total) async {
    var output = await Tflite.runModelOnImage(
      path: image,
      numResults: 5,
      threshold: 0.5,
      imageMean: 127.5,
      imageStd: 127.5,
    );

      op = output;

      if (op != null) {
        if (op[0]["label"] == "50 rupees") {
          total += 50;
          runTextToSpeech("50 rupees", total);
        }
        if (op[0]["label"] == "100 rupees") {
          total += 100;
          runTextToSpeech("100 rupees", total);
        }
        if (op[0]["label"] == "200 rupees") {
          total += 200;
          runTextToSpeech("200 rupees", total);
        }
        if (op[0]["label"] == "500 rupees") {
          total += 500;
          runTextToSpeech("500 rupees", total);
        }

        if (op[0]["label"] == "2000 rupees") {
          total += 2000;
          runTextToSpeech("2000 rupees", total);
        }
      } else
        runTextToSpeech("No note found", total);
  }

  loadModel() async {
    await Tflite.loadModel(
      model: "assets/model_unquant.tflite",
      labels: "assets/labels.txt",
    );
  }

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

标签： androidiosflutter

Answer 1

您有一个名为的全局变量total和一个局部classifyImage函数变量total作为参数。当你这样做时total += 50;，它默认引用局部变量。classifyImage出于某种原因，您在完全没有必要时将全局变量传递给您的函数。

total从函数定义中删除参数。

classifyImage(String image, int total) async {

至

classifyImage(String image) async {