移步Retrofit--网络通讯框架

使用前准备

• 免费的公共接口:查询天气
  https://www.apiopen.top/weatherApi?city=临沂

依赖框架

    /** 添加网络框架Retrofit*/
    implementation 'com.squareup.retrofit2:retrofit:2.4.0'
    implementation 'com.squareup.retrofit2:converter-gson:2.4.0'
    implementation "com.google.code.gson:gson:2.8.0"

接口返回数据的内容，并做Gson类解析

1. 返回内容

{
    "code":200,
    "msg":"成功!",
    "data":{
        "yesterday":{
            "date":"3日星期日",
            "high":"高温 10℃",
            "fx":"北风",
            "low":"低温 1℃",
            "fl":"<![CDATA[<3级]]>",
            "type":"小雨"
        },
        "city":"临沂",
        "aqi":null,
        "forecast":[
            {
                "date":"4日星期一",
                "high":"高温 9℃",
                "fengli":"<![CDATA[<3级]]>",
                "low":"低温 0℃",
                "fengxiang":"东南风",
                "type":"阴"
            },
            {
                "date":"5日星期二",
                "high":"高温 14℃",
                "fengli":"<![CDATA[<3级]]>",
                "low":"低温 1℃",
                "fengxiang":"北风",
                "type":"阴"
            },
            {
                "date":"6日星期三",
                "high":"高温 12℃",
                "fengli":"<![CDATA[3-4级]]>",
                "low":"低温 3℃",
                "fengxiang":"东北风",
                "type":"晴"
            },
            {
                "date":"7日星期四",
                "high":"高温 11℃",
                "fengli":"<![CDATA[<3级]]>",
                "low":"低温 0℃",
                "fengxiang":"东南风",
                "type":"晴"
            },
            {
                "date":"8日星期五",
                "high":"高温 11℃",
                "fengli":"<![CDATA[<3级]]>",
                "low":"低温 0℃",
                "fengxiang":"东北风",
                "type":"阴"
            }
        ],
        "ganmao":"天凉，昼夜温差较大，较易发生感冒，请适当增减衣服，体质较弱的朋友请注意适当防护。",
        "wendu":"8"
    }
}

2. Gson数据解析

public class WeatherInfoModel {
    public String code;
    @SerializedName("message")
    public String message;
    @SerializedName("data")
    public WeatherInfo weatherInfo;

    public class WeatherInfo{
        @SerializedName("yesterday")
        public DayWeatherInfo yesterdayWeatherInfo;
        public String city;
        public String aqi;
        @SerializedName("forecast")
        public List<DayWeatherInfo> forecastWeatherInfo;
        @SerializedName("ganmao")
        public String hint;
        public String wendu;
    }

    public class DayWeatherInfo{
        public String date;
        public String high;
        public String fx;
        public String low;
        public String fl;
        public String type;
    }

    @Override
    public String toString(){
        return "城市: " + weatherInfo.city+", 天气:"+weatherInfo.forecastWeatherInfo.get(0).type+", "+ weatherInfo.forecastWeatherInfo.get(0).high+", "
                + weatherInfo.forecastWeatherInfo.get(0).low+", 提醒:"+weatherInfo.hint;
    }

Gson的分析移步Json数据解析-Gson库

创建请求接口

public interface HttpService {
    /**
     * 动态指定查询条件
     * @Query("字段")
     * */
    @GET("weatherApi")
    Call<WeatherInfoModel> getWeatherInfo(@Query("city") String city);
}

创建Retrofit并实例化HttpService

        Retrofit retrofit = new Retrofit.Builder().
                baseUrl(URL).
                addConverterFactory(GsonConverterFactory.create()).
                build();
        mHttpService = retrofit.create(HttpService.class);

通过接口获取Call并做网络请求

        Call<WeatherInfoModel> call = mHttpService.getWeatherInfo("临沂");
        call.enqueue(new Callback<WeatherInfoModel>() {
            @Override
            public void onResponse(Call<WeatherInfoModel> call, Response<WeatherInfoModel> response) {
                if (response.body().code.equals("200")){
                    LogShowUtil.addLog("Retrofit",response.body().toString(),true);
                }else {
                    LogShowUtil.addLog("Retrofit", "请求失败: " + response.body().message,true);
                }
            }
            @Override
            public void onFailure(Call<WeatherInfoModel> call, Throwable t) {

            }
        });

注解分类

1. 请求方法注解
   GET、POST、PUT、DELETE、HEAD、PATCH、OPTIONS、HTTP
   对应HTTP的七种请求方法，HTTP可替换前面的七种
2. 标记类注解
   ForMUrlEncoded、Multipart、Streaming

• @ForMUrlEncoded 注解来标明这是一个表单请求
• @Streaming 代表响应的数据以流的形式返回，如果不使用他则默认会把全部数据加载到内存，所以下周大文件时需要加上这个注解
• @Multipart 上传文件

3. 参数类注解
   Header、Headers、Body、Path、Field、FieldMap、Part、PartMap、Query、QueryMap等

• @Path 动态的配置URL地址
• @Query 动态指定查询条件
• @QueryMap 动态指定查询条件组
• @Field 传输数据类型键值对
• @Body 传输数据类型JSON字符串
• @Part 单个文件上传
• @PartMap 多个文件上传
• @Header 消息报头

实例

    @GET("weatherApi")
    Call<WeatherInfoModel> getWeatherInfo(@Query("city") String city);

GET请求
动态指定查询条件

    @GET("weatherApi")
    Call<WeatherInfoModel> getWeatherInfo(@QueryMap Map<String,String> params);

GET请求
动态指定查询条件组

    @GET("{path}")
    Call<WeatherInfoModel> getWeatherInfo(@Path ("path") String path, @Query("city") String city);

GET请求
动态的配置URL地址
动态指定查询条件

    @FormUrlEncoded
    @POST("weatherApi")
    Call<WeatherInfoModel> postWeatherInfo(@Field("city") String city);

POST请求
传输数据类型为键值对
注解来标明这是一个表单请求

    @POST("weatherApi")
    Call<WeatherInfoModel> postWeatherInfo(@Body CityBody body);

POST请求
传输数据类型为JSON字符串