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Flutter教程——Dio的封装

程序员文章站 2024-02-28 11:45:10
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Dio是开源的Dart Http请求库,支持Restful API、FormData、拦截器、请求取消、Cookie管理、文件上传/下载、超时、自定义适配器等…

基础学习:https://book.flutterchina.club/chapter10/dio.html

 一,首先,添加依赖 https://github.com/flutterchina/dio 可以看这儿的版本,在pubspec.yaml文件下添加:

要注意对齐,否则报错“pubspec.yaml: A dependency may only have one source.”

dependencies:
  flutter:
    sdk: flutter
  cupertino_icons: ^0.1.2
  # 注意,这儿有个大坑,dio必须在dependencies下一级,别加空格或tab,否则加不进来
  dio: ^3.0.9

二,看下最简单的用法

Dio dio = new Dio();
//get请求
void getHttp() async {
  try{
    Response response = await dio.get("http://www.baidu.com");
    print("getHttp: $response");
  }catch(e){
    print("getHttp: Exception: $e");
  }
}
//post请求
void postHttp() async {
  try{
    Response response = await dio.post("https://www.csdn.net");
    print("postHttp: $response");
  }catch(e){
    print("postHttp: Exception: $e");
  }
}

三,封装

因为一个dio实例可以发起多个http请求,所以最好使用单例模式,节省资源;

直接贴代码:

import 'package:dio/dio.dart';
import 'package:dio_cookie_manager/dio_cookie_manager.dart';
import 'package:cookie_jar/cookie_jar.dart';

class HttpManager{
  //一个人工智能回答的免费API
  final String _BASEURL = 'http://api.qingyunke.com/api.php';
  final int _CONNECTTIMEOUT = 5000;
  final int _RECEIVETIMEOUT = 3000;

  //单例模式
  static HttpManager _instance;
  Dio _dio;
  BaseOptions _options;

  //单例模式,只创建一次实例
  static HttpManager getInstance(){
    if(null == _instance){
      _instance = new HttpManager();
      return _instance;
    }
  }

  //构造函数
  HttpManager(){
    _options =new BaseOptions(
      baseUrl: _BASEURL,
      //连接时间为5秒
      connectTimeout: _CONNECTTIMEOUT,
      //响应时间为3秒
      receiveTimeout: _RECEIVETIMEOUT,
      //设置请求头
      headers: {
        "resource":"android"
      },
      //默认值是"application/json; charset=utf-8",Headers.formUrlEncodedContentType会自动编码请求体.
      contentType: Headers.formUrlEncodedContentType,
      //共有三种方式json,bytes(响应字节),stream(响应流),plain
      responseType: ResponseType.json
    );
    _dio = new Dio(_options);
    //设置Cookie
    _dio.interceptors.add(CookieManager(CookieJar()));

    //添加拦截器
    _dio.interceptors.add(InterceptorsWrapper(
      onRequest: (RequestOptions options){
        print("在请求之前的拦截信息");
        return options;
      },
      onResponse: (Response response){
        print("在响应之前的拦截信息");
        return response;
      },
      onError: (DioError e){
        print("在错误之前的拦截信息");
        return e;
      }
    ));
  }

  //get请求方法
  get(url,{data,options,cancelToken}) async{
    Response response;
    try{
      response = await _dio.get(url,queryParameters: data,options: options,cancelToken: cancelToken);
      print('getHttp response: $response');
    }on DioError catch(e){
      print('getHttp exception: $e');
      formatError(e);
    }
    return response;
  }

  //post请求
  post(url,{params,options,cancelToken}) async{
    Response response;
    try{
      response = await _dio.post(url,queryParameters: params,options: options,cancelToken: cancelToken);
      print('postHttp response: $response');
    }on DioError catch(e){
      print('postHttp exception: $e');
      formatError(e);
    }
    return response;
  }

  //post Form请求
  postForm(url,{data,options,cancelToken}) async{
    Response response;
    try{
      response = await _dio.post(url,options: options,cancelToken: cancelToken,data: data);
      print('postHttp response: $response');
    }on DioError catch(e){
      print('postHttp exception: $e');
      formatError(e);
    }
    return response;
  }

  //下载文件
  downLoadFile(urlPath,savePath) async{
    Response response;
    try{
      response = await _dio.download(urlPath, savePath,onReceiveProgress: (int count,int total){
        print('$count $total');
      });
      print('downLoadFile response: $response');
    }on DioError catch(e){
      print('downLoadFile exception: $e');
      formatError(e);
    }
    return response;
  }


  //取消请求
  cancleRequests(CancelToken token){
    token.cancel("cancelled");
  }

  void formatError(DioError e) {
    if (e.type == DioErrorType.CONNECT_TIMEOUT) {
      print("连接超时");
    } else if (e.type == DioErrorType.SEND_TIMEOUT) {
      print("请求超时");
    } else if (e.type == DioErrorType.RECEIVE_TIMEOUT) {
      print("响应超时");
    } else if (e.type == DioErrorType.RESPONSE) {
      print("出现异常");
    } else if (e.type == DioErrorType.CANCEL) {
      print("请求取消");
    } else {
      print("未知错误");
    }
  }

}

调用时只需:

http.HttpManager.getInstance().get('',params:{'key': 'free','msg': '鹅鹅鹅'});

输出:

2020-04-17 14:42:30.252 25364-25460/com.example.flutter_module.host I/flutter: 在请求之前的拦截信息
2020-04-17 14:42:31.145 25364-25460/com.example.flutter_module.host I/flutter: 在响应之前的拦截信息
2020-04-17 14:42:31.148 25364-25460/com.example.flutter_module.host I/flutter: getHttp response: {"result":0,"content":"曲项向天歌"}

其实我觉得响应结果转为json就很好用了,如果喜欢转为实体类,自己再稍加封装就好。

相关标签: Flutter flutter