我无法将图像文件上传到服务器(Flutter-API)

import 'dart:io';
import 'package:flutter/material.dart';
import 'package:image_picker/image_picker.dart';

Future<File> pickImage() async {
  final pickedFile = await ImagePicker().pickImage(source: ImageSource.gallery);
  if (pickedFile != null) {
    return File(pickedFile.path);
  } else {
    throw Exception('Failed to pick image');
  }
}

import 'package:http/http.dart' as http;
import 'dart:convert';

Future<void> uploadImage(File file) async {
  var request = http.MultipartRequest(
      'POST', Uri.parse('YOUR_SERVER_ENDPOINT'));
  request.files.add(await http.MultipartFile.fromPath('file', file.path));

  try {
    var response = await request.send();
    if (response.statusCode == 200) {
      print('Image uploaded successfully');
    } else {
      print('Failed to upload image, status code: ${response.statusCode}');
    }
  } catch (e) {
    print('Error uploading image: $e');
  }
}

<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>

import 'package:permission_handler/permission_handler.dart';

Future<void> requestPermissions() async {
  await Permission.storage.request();
}