🧱 Flutter 使用 Dio 封装网络请求（含完整代码）

dependencies:
  dio: ^5.4.0
  flutter:
    sdk: flutter

flutter pub get

import 'package:dio/dio.dart';

class HttpService {
  static final HttpService _instance = HttpService._internal();

  factory HttpService() => _instance;

  late Dio _dio;

  HttpService._internal() {
    BaseOptions options = BaseOptions(
      baseUrl: "https://api.example.com", // 替换为你的后端地址
      connectTimeout: const Duration(seconds: 10),
      receiveTimeout: const Duration(seconds: 10),
      headers: {
        'Content-Type': 'application/json',
      },
    );

    _dio = Dio(options);

    // 添加拦截器（可选）
    _dio.interceptors.add(InterceptorsWrapper(
      onRequest: (options, handler) {
        // 比如添加token
        // options.headers["Authorization"] = "Bearer xxx";
        return handler.next(options);
      },
      onResponse: (response, handler) {
        return handler.next(response);
      },
      onError: (DioException e, handler) {
        print("请求错误: ${e.message}");
        return handler.next(e);
      },
    ));
  }

  // GET请求
  Future<Response> get(String path, {Map<String, dynamic>? queryParameters}) async {
    try {
      return await _dio.get(path, queryParameters: queryParameters);
    } catch (e) {
      rethrow;
    }
  }

  // POST请求
  Future<Response> post(String path, {dynamic data, Map<String, dynamic>? queryParameters}) async {
    try {
      return await _dio.post(path, data: data, queryParameters: queryParameters);
    } catch (e) {
      rethrow;
    }
  }

  // 其他请求可按需添加（put、delete等）
}

import 'package:flutter/material.dart';
import 'package:dio/dio.dart';
import 'package:your_app/net/http_service.dart';

class TestApiPage extends StatefulWidget {
  const TestApiPage({Key? key}) : super(key: key);

  @override
  State<TestApiPage> createState() => _TestApiPageState();
}

class _TestApiPageState extends State<TestApiPage> {
  String result = "请求中...";

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

  void fetchData() async {
    try {
      Response response = await HttpService().get("/test");
      setState(() {
        result = response.data.toString();
      });
    } catch (e) {
      setState(() {
        result = "出错了：$e";
      });
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: const Text("API测试")),
      body: Center(child: Text(result)),
    );
  }
}