retrofit2 使用教程 及 Android 網絡架構搭建

squareup 推出retrofit2 已經有一段時間了，現在的版本比較穩定，沒有什麼大坑了。網絡上的教程要麼太簡單，只是個Demo；要麼有些落時，要麼復用性比較差，所以自己寫個教程(alex9xu@hotmail.com)，供大家參考。

 

1. 首先在build.gradle引入依賴

compile 'com.squareup.retrofit2:retrofit:2.1.0'

compile 'com.squareup.retrofit2:converter-gson:2.1.0'

compile 'com.squareup.okhttp3:logging-interceptor:3.3.1'

注意，這裡的 logging 用於輸出網絡交互的Log，對於開發調試極其有用。之前retrofit2因為不能輸出Log被人嫌棄了很久，各高手實現了幾種打印Log的方式，現在總算有官方的了。

 

2. 這是工具類

import okhttp3.HttpUrl;

import okhttp3.Interceptor;

import okhttp3.OkHttpClient;

import okhttp3.Request;

import okhttp3.Response;

import okhttp3.logging.HttpLoggingInterceptor;

import retrofit2.Retrofit;

import retrofit2.converter.gson.GsonConverterFactory;
import com.alex9xu.test.config.AppConfigInterface;
import java.io.IOException;

/** * Created by Alex9Xu@hotmail.com on 2016/7/13 */public class RetrofitBase {
    private static Retrofit mRetrofit;
    public static Retrofit retrofit() {
        if (mRetrofit == null) {
            OkHttpClient client;
            // Notice: The only differ of debug is: HttpLoggingInterceptor

            if(!AppConfigInterface.isDebug) {
                client = new OkHttpClient.Builder()
                        .addInterceptor(new Interceptor() {
                            @Override

                            public Response intercept(Chain chain) throws IOException {
                                Request original = chain.request();

                                HttpUrl originalHttpUrl = original.url();

                                HttpUrl url = originalHttpUrl.newBuilder()
                                        .addQueryParameter("Id", "123456")
                                        .addQueryParameter("deviceType", "0")
                                        .build();

                                // Request customization: add request headers

                                Request.Builder requestBuilder = original.newBuilder()
                                        .url(url);

                                Request request = requestBuilder.build();

                                return chain.proceed(request);                            }
                        })
                        .build();

            } else {
                HttpLoggingInterceptor logging = new HttpLoggingInterceptor();

                logging.setLevel(HttpLoggingInterceptor.Level.BODY);

                client = new OkHttpClient.Builder()
                        .addInterceptor(logging)
                        .addInterceptor(new Interceptor() {
                            @Override

                            public Response intercept(Chain chain) throws IOException {
                                Request original = chain.request();

                                HttpUrl originalHttpUrl = original.url();

                                HttpUrl url = originalHttpUrl.newBuilder()
                                        .addQueryParameter("Id", "123456")
                                        .addQueryParameter("deviceType", "0")
                                        .build();

                                // Request customization: add request headers

                                Request.Builder requestBuilder = original.newBuilder()
                                        .url(url);

                                Request request = requestBuilder.build();

                                return chain.proceed(request);                            }
                        })
                        .build();

            }

            mRetrofit = new Retrofit.Builder()
                    .baseUrl(AppConfigInterface.BASE_COM_URL)
                    .addConverterFactory(GsonConverterFactory.create())
                    .client(client)
                    .build();        }
        return mRetrofit;    }

}

講解一下：

(1) 通過addInterceptor實現的打印日志及加入多個公共參數功能。

(2) 除了含有HttpLoggingInterceptor 外，測試的和正式的，沒有任何區別。通過全局變量控制是否為正式環境，如果是正式環境則不輸出網絡交互相關的Log。

(3) 可以通過addQueryParameter("deviceType", "0") 的形式加入多個公共參數，這樣所有的請求都會帶該參數。

(4) 這裡BASE_COM_URL是http://test.hello.com/的形式。

 

3. 使用方式:

 

(1) 先寫接口

import android.support.v4.util.ArrayMap;
import com.alex9xu.test.config.AppConfigInterface;
import com.alex9xu.test.model.ClassifyListResult;

import retrofit2.Call;

import retrofit2.http.GET;

import retrofit2.http.QueryMap;
/** * Created by Alex9Xu@hotmail.com on 2016/7/14 */

public interface ClassifyApi {
    @GET(AppConfigInterface.CLASSIFYLIST)
    Call getClassify(@QueryMap ArrayMap paramMap);}

這裡通過Post提交參數，參數存儲在Map裡，可以添加多組參數。注意，我使用了ArrayMap，這是Android裡特有的一種形式，內存占用只有HashMap的十分之一左右。

String CLASSIFYLIST = "query/classify.html";

 

(2) 再寫返回值結構

import com.alex9xu.test.base.BaseResponse;
import com.alex9xu.test.model.entity.ClassfiyBean;

import java.util.List;
/** * Created by Alex9Xu@hotmail.com on 2016/7/14
 */public class ClassifyListResult extends BaseResponse {
    private DataEntity data;
    public DataEntity getData() {
        return data;    }

    public static class DataEntity {
        private List classifyList;
        public List getClassifyList() {
            return classifyList;        }
    }
}

 

/** * Created by Alex9Xu@hotmail.com on 2016/7/14
 */public class ClassfiyBean {
    private String icon;    private String name;

    public String getIcon() {
        return icon;    }
    public String getName() {
        return name;    }

}

返回的數據寫成如上形式，以利於復用。

 

(3) 調用

import com.alex9xu.test.model.ClassifyListResult;
import com.alex9xu.test.model.entity.ClassfiyBean;
import com.alex9xu.test.net.ClassifyApi;
import com.alex9xu.test.net.RetrofitBase;

/** * Created by Alex9Xu@hotmail.com on 2016/7/14
 */

public class MainActivity extends AppCompatActivity{

  ...

private void getData() {
    ArrayMap paramMap = new ArrayMap<>();

    paramMap.put("version", "1.0");

    paramMap.put("uid", "654321");

    ClassifyApi classifyApi = RetrofitBase.retrofit().create(ClassifyApi.class);

    Call call = classifyApi.getClassify(paramMap);

    call.enqueue(new Callback() {
        @Override

        public void onResponse(Call call, Response response) {
            LogHelper.d(TAG, "getClassify, Suc");

            LogHelper.d(TAG, "getClassify = " + response.body());

            if(null != response.body() && null != response.body().getData()) {
                List list = response.body().getData().getClassifyList();

                if(null != list && list.size()>0) {
                    mTvwDisplay.setText(list.get(0).getName());

                }
            }
        }

        @Override

        public void onFailure(Call call, Throwable t) {
            LogHelper.e(TAG, "getClassify, Fail");

        }
    });

}

...

 

講解：會拼接成https://test.hello.com/query/classify.html?uid=654321&version=1.0&Id=123456&deviceType=0 ，注意，其中兩項是公共參數。

 

好了，這樣就可以正常運行了。