Flutter 错误 : Type 'File' not found. 这是怎么回事？

Question

我正在尝试将 firebase_ml_vision 与 image_picker 一起使用。

代码如下:

import 'package:flutter/material.dart';

import 'package:image_picker/image_picker.dart';
import 'package:firebase_ml_vision/firebase_ml_vision.dart';

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

class MyHomePage extends StatefulWidget {
  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
    FirebaseVisionImage visionImage;

    final BarcodeDetector barcodeDetector = FirebaseVision.instance.barcodeDetector();
    final TextRecognizer textRecognizer = FirebaseVision.instance.textRecognizer();
    final ImageLabeler labeler = FirebaseVision.instance.imageLabeler(
          ImageLabelerOptions(confidenceThreshold: 0.75),
    );
    final FaceDetector faceDetector = FirebaseVision.instance.faceDetector();

    void detections() async {
        final VisionText visionText = await textRecognizer.processImage(visionImage);
    }

  File _image;

  Future getImage() async {
    var image = await ImagePicker.pickImage(source: ImageSource.camera);
    var something = await ImagePicker.pickImage(source: ImageSource.camera);

    setState(() {
      this.visionImage = FirebaseVisionImage.fromFile(something);
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Image Picker Example'),
      ),
      body: Center(
        child: _image == null
            ? Text('No image selected.')
            : Image.file(_image),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: getImage,
        tooltip: 'Pick Image',
        child: Icon(Icons.add_a_photo),
      ),
    );
  }
}

但我无法使用 File 数据类型，这是我得到的错误: Error

这是我在运行 flutter doctor 时得到的结果: Doctor

这是我运行 flutter --version 时得到的结果: Version

我是 Flutter 的新手，所以如果您需要其他任何东西，请告诉我。

谢谢!

Answer 1

文件类型在 dart:io ，你错过了。将 import 'dart:io'; 添加到文件顶部。