在Flutter中通过表单将图像上传到服务器？

import 'dart:io';
import 'package:flutter/material.dart';
import 'package:http/http.dart' as http;
import 'package:dio/dio.dart';

class ImageUploadForm extends StatefulWidget {
  @override
  _ImageUploadFormState createState() => _ImageUploadFormState();
}

class _ImageUploadFormState extends State<ImageUploadForm> {
  File _imageFile;

  Future<void> _uploadImage() async {
    if (_imageFile == null) {
      // 图像文件为空，进行错误处理
      return;
    }

    String url = 'http://your-server-url.com/upload'; // 替换为服务器的上传接口地址

    try {
      Dio dio = Dio();
      FormData formData = FormData.fromMap({
        'image': await MultipartFile.fromFile(_imageFile.path),
      });

      Response response = await dio.post(url, data: formData);

      // 处理服务器返回的响应数据
      if (response.statusCode == 200) {
        // 上传成功
        print('Image uploaded successfully');
        print('Response: ${response.data}');
      } else {
        // 上传失败
        print('Image upload failed');
        print('Response: ${response.data}');
      }
    } catch (error) {
      // 异常处理
      print('Error uploading image: $error');
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Image Upload'),
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            _imageFile != null
                ? Image.file(
                    _imageFile,
                    height: 200,
                  )
                : Text('No image selected'),
            RaisedButton(
              onPressed: () async {
                // 选择图像文件
                File imageFile = await ImagePicker.pickImage(
                  source: ImageSource.gallery,
                );
                setState(() {
                  _imageFile = imageFile;
                });
              },
              child: Text('Select Image'),
            ),
            RaisedButton(
              onPressed: _uploadImage,
              child: Text('Upload Image'),
            ),
          ],
        ),
      ),
    );
  }
}