Retrofit网络请求框架基础操作

Retrofit网络请求框架基础操作

Retrofit

Retrofit 是一套 RESTful 架构的 Android（Java) 客户端实现，基于注解，提供 JSON to POJO（Plain Ordinary Java Object ，简单 Java 对象），POJO to JSON，网络请求（POST，GET， PUT，DELETE 等）封装。

优点：Retrofit 是一套注解形的网络请求封装库，让我们的代码结构更给为清晰。它可以直接解析JSON数据变成JAVA对象，甚至支持回调操作，处理不同的结果。

基础操作

- Demo中使用的接口地址 :http://apis.baidu.com/heweather/weather/free

- 添加依赖

compile 'com.squareup.okhttp3: okhttp:3.2.0'
compile 'com.squareup.retrofit2: retrofit:2.0.0-beta4'
compile 'com.squareup.retrofit2: converter-gson:2.0.0-beta3'

建议：如果API返回的是JSON数据，可以利用AndroidStudio的插件GsonFormat,将JSON数据转换为Java对象。

创建请求接口

public interface NetRequest {
@GET("/heweather/weather/free?/")
Call<WeatherInfo> getWeather(@Header("apiKey")String apiKey,     @Query("city")String city);
}

讲解：

1. @GET()用来填写需要访问的接口

2. @Header用来添加Header

3. @Query用来添加输入请求的标识

创建网络接口服务封装类

public class RetrofitWrapper {

private static RetrofitWrapper instance;

private Context mContext;

private Retrofit retrofit;

private RetrofitWrapper() {

Gson gson = new Gson();

//创建Retrofit对象

retrofit = new Retrofit.Builder().baseUrl(Constant.BASE_URL)

.addConverterFactory(GsonConverterFactory.create(gson))

.build();

}

public static RetrofitWrapper getInstance() {

if (instance == null) {

synchronized (RetrofitWrapper.class){

if (instance==null){

instance = new RetrofitWrapper();

}

}

}

return instance;

}

//创建请求接口的对象

public T create(final Class service) {

return retrofit.create(service);

}

}

讲解：

1. BASE_URL:接口的API主机地址

创建功能模块类

public class WeatherInfoModel {

private static WeatherInfoModel weatherInfoModel;

private NetRequest netRequest;

public WeatherInfoModel(Context context) {
netRequest = (NetRequest) RetrofitWrapper.getInstance().create(NetRequest.class);
}

public static WeatherInfoModel getInstance(Context context) {
if (weatherInfoModel == null) {
weatherInfoModel = new WeatherInfoModel(context);
}
return weatherInfoModel;
}

/**
* 查询天气
*
* @param weatherInfoReq
* @return
*/
public Call<WeatherInfo> queryWeather(WeatherInfoReq weatherInfoReq) {
Call<WeatherInfo> infoCall = netRequest.getWeather(weatherInfoReq.apiKey, weatherInfoReq.city);
return infoCall;
}

}

Activity类

public class MainActivity extends Activity {

private Button request;

private TextView tv;

private WeatherInfoModel weatherInfoModel;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
weatherInfoModel = WeatherInfoModel.getInstance(getApplicationContext());
initViews();
initParams();
initEvent();
}

private void initEvent() {
request.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
//创建访问的API请求
Call<WeatherInfo> callWeather= weatherInfoModel.queryWeather(initParams());
final Gson gson = new Gson();
//发送请求
callWeather.enqueue(new Callback<WeatherInfo>() {
@Override
public void onResponse(Call<WeatherInfo> call, Response<WeatherInfo> response) {
if(response.isSuccessful()){
WeatherInfo result = response.body();
if(result!=null){
tv.setText(gson.toJson(result));
}
}
}
@Override
public void onFailure(Call<WeatherInfo> call, Throwable t) {

}
});
}
});
}

/*

*初始化请求参数

*/

private WeatherInfoReq initParams() {

WeatherInfoReq weatherInfoReq = new WeatherInfoReq();

weatherInfoReq.apiKey = Constant.API_KEY;

weatherInfoReq.city = Constant.CITY;

return weatherInfoReq;

}

/*

*初始化控件

*/

private void initViews() {

request = (Button) this.findViewById(R.id.request);

tv = (TextView) this.findViewById(R.id.tv);

}

}

PS:

1.本文并未贴上所用到的Bean类和一些用到的常量，如需请到个人的github上下载源码

2.本文参考http://blog.csdn.net/u011974987/article/details/50895633