Flutter中图片相关的LateInitializationError

Question

import 'dart:io';

import 'package:google_ml_kit/google_ml_kit.dart';
import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';
import 'package:image_picker/image_picker.dart';

class ImageNote extends StatefulWidget {
  static String id='image-note';

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

class _ImageNoteState extends State<ImageNote> {
  String result = "";
  late File image;
  ImagePicker imagePicker = ImagePicker();

  captureFromGallery() async {
    XFile? pickedFile =
    await imagePicker.pickImage(source: ImageSource.gallery);
    image = File(pickedFile!.path);

    setState(() {
      image;

      //Do the extract text from Image

      textFromImage();
    });
  }

  captureFromCamera() async {
    XFile? pickedFile =
    await imagePicker.pickImage(source: ImageSource.camera);
    image = File(pickedFile!.path);

    setState(() {
      image;

      textFromImage();
    });
  }

  textFromImage() async {
    // final FirebaseVisionImage firebaseVisionImage =
    // FirebaseVisionImage.fromFile(image);
    final InputImage inputImage = InputImage.fromFile(image);
    final TextDetector textDetector = GoogleMlKit.vision.textDetector();
    final RecognisedText recognisedText = await textDetector.processImage(inputImage);


    // final TextRecognizer recognizer = FirebaseVision.instance.textRecognizer();

    // VisionText visionText = await recognizer.processImage(firebaseVisionImage);

    result = "";

    setState(() {
      for (TextBlock block in recognisedText.blocks) {
        for (TextLine line in block.lines) {
          for (TextElement element in line.elements) {
            result += element.text + " ";
          }
        }

        result += "\n\n";
      }
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Container(
        decoration: BoxDecoration(
          image: DecorationImage(
              image: AssetImage('assets/background.png'),
              fit: BoxFit.cover),
        ),
        child: Column(
          children: [
            SizedBox(width: 100.0),

            //Result Container
            Container(
              height: 280.0,
              width: 250.0,
              margin: EdgeInsets.only(top: 70.0),
              padding: EdgeInsets.only(left: 28.0, bottom: 5.0, right: 18.0),
              child: SingleChildScrollView(
                child: Container(
                  margin: EdgeInsets.only(top: 50.0),
                  child: Padding(
                    padding: EdgeInsets.all(12.0),
                    child: Text(
                      result,
                      style: TextStyle(fontSize: 16.0),
                      textAlign: TextAlign.justify,
                    ),
                  ),
                ),
              ),
              decoration: BoxDecoration(
                image: DecorationImage(
                  image: AssetImage('assets/note.png'),
                  fit: BoxFit.cover,
                ),
              ),
            ),

            Container(
              margin: EdgeInsets.only(top: 20.0, right: 140.0),
              child: Stack(
                children: [
                  Stack(
                    children: [
                      Center(
                        child: Image.asset(
                          'assets/output.jpg',
                          height: 240.0,
                          width: 240.0,
                        ),
                      ),
                    ],
                  ),
                  Center(
                    child: TextButton(
                      onPressed: () {
                        captureFromGallery();
                      },
                      onLongPress: () {
                        captureFromCamera();
                      },
                      child: Container(
                        margin: EdgeInsets.only(top: 25.0),
                        child: image != null
                            ? Image.file(
                          image,
                          width: 140.0,
                          height: 192.0,
                          fit: BoxFit.fill,
                        )
                            : Container(
                          width: 240.0,
                          height: 200.0,
                          child: Icon(
                            Icons.camera_front,
                            size: 100.0,
                            color: Colors.grey,
                          ),
                        ),
                      ),
                    ),
                  ),
                ],
              ),
            ),
          ],
        ),
      ),
    );
  }
}

这是我的代码，我收到以下错误，我什至不确定这到底是关于哪张图片：

在构建 ImageNote（脏，状态：_ImageNoteState#8b383）时抛出了以下 LateError： LateInitializationError：字段 'image' 尚未初始化。

我已经到处找过了……所以，如果有人能帮忙的话！任何帮助都会很棒！

Answer 1

这里是错误所在

class _ImageNoteState extends State<ImageNote> {
String result = "";
late File image;// Here
ImagePicker imagePicker = ImagePicker();

发生这种情况是因为您告诉 flutter 您稍后将初始化文件，但它没有检测到它。

另一种方法是通过添加使其可为空？

像这样

class _ImageNoteState extends State<ImageNote> {
String result = "";
File? image;// this is better
ImagePicker imagePicker = ImagePicker();

Flutter中图片相关的LateInitializationError

LateInitializationError related to image in Flutter

android

dart

android-studio

flutter

google-mlkit