Flutter工具学习与拓展1--网络请求封装(dio)

学习flutter已有一段时间了, 想找个项目练练手, 准备项目框架:

1. 网络请求封装--dio+json_serializable
2. 路由--flutter-ARoute
3. 状态机管理--flutter_redux=>fish_redux

第一章---简易常用网络请求封装

导入库

  dio: ^2.1.7
  json_serializable: ^3.0.0
  build_runner: ^1.6.0
  fluttertoast: ^3.1.0

封装网络请求 单例 netUtil类

import 'package:dio/dio.dart';
import 'dart:convert';
import 'package:fluttertoast/fluttertoast.dart';

class NetworkUtil {
  static const String k_GET = "get";
  static const String k_POST = "post";
  static const String k_DELETE = "delete";
  static const String k_PUT = "put";

  /* 
  warning: 下面两个参数是根据封装的格式进行调整的, 如下面数据格式是:{s(就是常见的status):1, m:ok, d(数据, data):{}}, 具体可参考下方实例get请求返回的数据格式
  */
  static const String k_DATA = "d";//数据, 类似data
  static const String k_CODE = "s";//状态码, 类似status
  static const String k_MSG  = "m";//提示语, 类似msg

 /* 
  封装单例, 类似于iOS和Android
  */
  Dio dio;
  static NetworkUtil _instance;
  static NetworkUtil getInstance() {
    if (_instance == null) {
      _instance = NetworkUtil();
    }
    return _instance;
  }

  NetworkUtil() {
    dio = new Dio(BaseOptions(
      headers: {},
      connectTimeout: 5000,
      receiveTimeout: 100000,
      //baseUrl: "http://baidu.com"
    ));
  }

  get(String url, Function successCallBack,
      {params, Function errorCallBack}) async {
    _requestHttp(url, successCallBack, k_GET, params, errorCallBack);
  }

  post(String url, Function successCallBack,
      {params, Function errorCallBack}) async {
    _requestHttp(url, successCallBack, k_POST, params, errorCallBack);
  }

  put(String url, Function successCallBack,
      {params, Function errorCallBack}) async {
    _requestHttp(url, successCallBack, k_PUT, params, errorCallBack);
  }

  delete(String url, Function successCallBack,
      {params, Function errorCallBack}) async {
    _requestHttp(url, successCallBack, k_PUT, params, errorCallBack);
  }

  _requestHttp(String url, Function successCallBack,
      [String method, FormData params, Function errorCallBack]) async {
    String errorMsg = "";
    int code;

    try {
      Response response;
      _addStartHttpInterceptor(dio);
      if (method == k_GET) {
        if (params != null && params.isNotEmpty) {
          response = await dio.get(url, queryParameters: params);
        } else {
          response = await dio.get(url);
        }
      } else if (method == k_POST) {
        if (params != null && params.isNotEmpty) {
          response = await dio.post(url, queryParameters: params);
        } else {
          response = await dio.post(url);
        }
      } else if (method == k_PUT) {
        if (params != null && params.isNotEmpty) {
          response = await dio.put(url, queryParameters: params);
        } else {
          response = await dio.put(url);
        }
      } else if (method == k_DELETE) {
        if (params != null && params.isNotEmpty) {
          response = await dio.delete(url, queryParameters: params);
        } else {
          response = await dio.delete(url);
        }
      }
      code = response.statusCode;
      if (code != 200) {
        errorMsg = '错误码: ' + code.toString() + ', ' + response.data.toString();
        _error(errorCallBack, errorMsg);
        return;
      }

      String dataStr = json.encode(response.data);
      Map dataMap = json.decode(dataStr);
      //此处判断弹出错误信息的条件, 注意k_Code对应异常的值
      if (dataMap != null && dataMap[k_CODE] != 1) {
        errorMsg = dataMap[k_MSG].toString();
        _error(errorCallBack, errorMsg);
        return;
      }

      if (successCallBack != null) {
        //此处需要注意, 该方法现在传递的是整体的数据, 如需要可根据返回数据的样式, 回调调整
        successCallBack(dataMap);
      }
    } catch (e) {
      _error(errorCallBack, e.toString());
    }
  }

/*
  错误处理的地方
*/
  _error(Function errorCallBack, String error) {
    Fluttertoast.showToast(
        msg: error.toString(),
        toastLength: Toast.LENGTH_SHORT,
        gravity: ToastGravity.CENTER);
    if (errorCallBack != null) {
      errorCallBack(error);
    }
  }

/*
  对参数数据进行二次处理, 加密算法
*/
  _addStartHttpInterceptor(Dio dio) {
    dio.interceptors
        .add(InterceptorsWrapper(onRequest: (RequestOptions options) {
      //请求前的操作, 通常会在这里进行参数的处理, 比如加密, 添加参数等
      Map headers = options.headers;
      Map body = options.data;
      /*
      body['addParam'] = 'aaaaaaaa';
      */
      print('''$headers
      $body''');
      return options;
    }));
  }
}

上面根据数据格式进行封装, 使用者请根据自身项目网络请求返回的常规格式进行调整
此文对应demo结构

F0A92536-0BC6-416E-B7D1-2FF0B01E284B.png

var url =
        'https://timeline-merger-ms.juejin.im/v1/get_entry_by_rank?src=web&before=26.723845333467&limit=20&category=all';
    NetworkUtil.getInstance().get(url, (data) {
      print(data);
      setState(() {
//将在第二章记录json_serializable的使用
     //   _indexCell = IndexCell.fromJson(data);
      });
    });