Flutter 断言失败，但资产可以使用

Question

我一直在尝试使用 Tesseract ocr 库执行 ocr。但是，使用 TesseractOcr.extractText() 方法，它执行断言以检查图像是否存在，但总是失败。为了确认我已经正确添加了图像，我添加了一个效果很好的图像小部件。我在这里错过了什么吗？

屏幕截图

main.dart


import 'package:flutter/services.dart';
import 'package:flutter/material.dart';
import 'dart:async';
import 'package:tesseract_ocr/tesseract_ocr.dart';

void main() => runApp(MyApp());

class MyApp extends StatefulWidget {
 @override
 _MyAppState createState() => _MyAppState();
}

class _MyAppState extends State<MyApp> {
 String _extractText = 'Unknown';

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

 // Platform messages are asynchronous, so we initialize in an async method.
 Future<void> initPlatformState() async {
   String extractText;
   try {
     
     extractText = await TesseractOcr.extractText('assests/images/test.jpeg', language: "eng");
   } on PlatformException {
     extractText = 'Failed to extract text';
   }

   if (!mounted) return;

   setState(() {
     _extractText = extractText;
   });
 }

 @override
 Widget build(BuildContext context) {
   return MaterialApp(
     home: Scaffold(
         appBar: AppBar(
           title: const Text('Tesseract OCR'),
         ),
         body: Column(
           children: <Widget>[
             Center(
               child: Text('Detected Texts: $_extractText\n'),
             ),
             Image.asset('assests/images/test.jpeg', width:300,height:100)
           ],
         )),
   );
 }
}

pubspec.yaml

name: hello_world
description: A new Flutter project.

# The following line prevents the package from being accidentally published to
# pub.dev using `pub publish`. This is preferred for private packages.
publish_to: "none" # Remove this line if you wish to publish to pub.dev

# The following defines the version and build number for your application.
# A version number is three numbers separated by dots, like 1.2.43
# followed by an optional build number separated by a +.
# Both the version and the builder number may be overridden in flutter
# build by specifying --build-name and --build-number, respectively.
# In Android, build-name is used as versionName while build-number used as versionCode.
# Read more about Android versioning at https://developer.android.com/studio/publish/versioning
# In iOS, build-name is used as CFBundleShortVersionString while build-number used as CFBundleVersion.
# Read more about iOS versioning at
# https://developer.apple.com/library/archive/documentation/General/Reference/InfoPlistKeyReference/Articles/CoreFoundationKeys.html
version: 1.0.0+1

environment:
  sdk: ">=2.7.0 <3.0.0"

dependencies:
  flutter:
    sdk: flutter
  tesseract_ocr: ^0.3.0

  # The following adds the Cupertino Icons font to your application.
  # Use with the CupertinoIcons class for iOS style icons.
  cupertino_icons: ^0.1.3

dev_dependencies:
  flutter_test:
    sdk: flutter

  # For information on the generic Dart part of this file, see the
  # following page: https://dart.dev/tools/pub/pubspec
  cupertino_icons: ^0.1.2
  flutter_spinkit: ^4.1.2+1
  file_picker: ^1.9.0+1
# The following section is specific to Flutter.
flutter:
  assets:
    - assests/images/
    - assests/tessdata/
    - assests/
  # The following line ensures that the Material Icons font is
  # included with your application, so that you can use the icons in
  # the material Icons class.
  uses-material-design: true
  # To add assets to your application, add an assets section, like this:
  # assets:
  #   - images/a_dot_burr.jpeg
  #   - images/a_dot_ham.jpeg
  # An image asset can refer to one or more resolution-specific "variants", see
  # https://flutter.dev/assets-and-images/#resolution-aware.
  # For details regarding adding assets from package dependencies, see
  # https://flutter.dev/assets-and-images/#from-packages
  # To add custom fonts to your application, add a fonts section here,
  # in this "flutter" section. Each entry in this list should have a
  # "family" key with the font family name, and a "fonts" key with a
  # list giving the asset and other descriptors for the font. For
  # example:
  # fonts:
  #   - family: Schyler
  #     fonts:
  #       - asset: fonts/Schyler-Regular.ttf
  #       - asset: fonts/Schyler-Italic.ttf
  #         style: italic
  #   - family: Trajan Pro
  #     fonts:
  #       - asset: fonts/TrajanPro.ttf
  #       - asset: fonts/TrajanPro_Bold.ttf
  #         weight: 700
  #
  # For details regarding fonts from package dependencies,
  # see https://flutter.dev/custom-fonts/#from-packages

TesseractOcr.extractText() 方法

  static Future<String> extractText(String imagePath, {String language}) async {
    assert(await File(imagePath).exists(), true);
    final String tessData = await _loadTessData();
    final String extractText = await _channel.invokeMethod('extractText', <String, dynamic>{
      'imagePath': imagePath,
      'tessData': tessData,
      'language': language,
    });
    return extractText;
  }

Answer 1

您的 'assets' 文件夹拼写错误。

不是：

assests/images/
assests/tessdata/
资产/

应该是：

assets/images/
assets/tessdata/
资产/

Flutter 断言失败，但资产可以使用

Flutter assertion fails while assets can be utilized

flutter

ocr

tesseract

assert