Android网络请求--Retrofit2使用方法

Retrofit 是Square开发的网络请求库, 简化了网络请求的使用, 这个库太知名了, 好处我就不多说了. 让我们看看如何使用吧?

Github 下载地址

1. 基本请求

使用接口, 区分 Get 和 Post 方法.

/** * 网络请求 * <p> * Created by wangchenlong on 16/1/21. */  public interface MarvelService {      String END_POINT = "http://gateway.marvel.com/";      String PARAM_API_KEY = "apikey";      String PARAM_HASH = "hash";      String PARAM_TIMESTAMP = "ts";        @GET("/v1/public/characters")      Observable<List<AvengersCharacter>> getCharacters(@Query("offset") int offset);  }

使用Retrofit类创建接口服务, 指定Gson为转换器, RxJava为适配器.

public class RestDataSource implements Repository {        private final MarvelService mMarvelService;        @Inject      public RestDataSource() {          // Log信息          HttpLoggingInterceptor loggingInterceptor = new HttpLoggingInterceptor();          loggingInterceptor.setLevel(HttpLoggingInterceptor.Level.BASIC);            // 公私密匙          MarvelSigningInterceptor signingInterceptor = new MarvelSigningInterceptor(                  BuildConfig.MARVEL_PUBLIC_KEY, BuildConfig.MARVEL_PRIVATE_KEY);            // OkHttp3.0的使用方式          OkHttpClient client = new OkHttpClient.Builder()                  .addInterceptor(signingInterceptor)                  .addInterceptor(loggingInterceptor)                  .build();            // 选择人物信息          Gson customGsonInstance = new GsonBuilder()                  .registerTypeAdapter(new TypeToken<List<AvengersCharacter>>() {                          }.getType(),                          new MarvelResultsDeserializer<AvengersCharacter>())                  .create();            // 适配器          Retrofit marvelApiAdapter = new Retrofit.Builder()                  .baseUrl(MarvelService.END_POINT)                  .addConverterFactory(GsonConverterFactory.create(customGsonInstance))                  .addCallAdapterFactory(RxJavaCallAdapterFactory.create())                  .client(client)                  .build();            // 服务          mMarvelService = marvelApiAdapter.create(MarvelService.class);      }        // 返回人物信息      @Override      public Observable<List<AvengersCharacter>> getCharacters(int currentOffset) {          return mMarvelService.getCharacters(currentOffset);      }  }

2. Interceptor

Interceptor是拦截器, 在发送之前, 添加一些参数, 或者获取一些信息.如MarvelSigningInterceptor是添加参数, loggingInterceptor是打印参数.

/** * 添加Key和密码 * <p> * Created by wangchenlong on 16/1/21. */  public class MarvelSigningInterceptor implements Interceptor {      private final String mApiKey;      private final String mApiSecret;        public MarvelSigningInterceptor(String apiKey, String apiSecret) {          mApiKey = apiKey;          mApiSecret = apiSecret;      }        @Override public Response intercept(Interceptor.Chain chain) throws IOException {          String marvelHash = MarvelApiUtils.generateMarvelHash(mApiKey, mApiSecret);          Request oldRequest = chain.request();            // 添加新的参数          HttpUrl.Builder authorizedUrlBuilder = oldRequest.url()                  .newBuilder()                  .scheme(oldRequest.url().scheme())                  .host(oldRequest.url().host())                  .addQueryParameter(MarvelService.PARAM_API_KEY, mApiKey)                  .addQueryParameter(MarvelService.PARAM_TIMESTAMP, MarvelApiUtils.getUnixTimeStamp())                  .addQueryParameter(MarvelService.PARAM_HASH, marvelHash);            // 新的请求          Request newRequest = oldRequest.newBuilder()                  .method(oldRequest.method(), oldRequest.body())                  .url(authorizedUrlBuilder.build())                  .build();            return chain.proceed(newRequest);      }  }

Okhttp3使用了装饰者模式, 使用Builder添加Interceptor.

        // OkHttp3.0的使用方式          OkHttpClient client = new OkHttpClient.Builder()                  .addInterceptor(signingInterceptor)                  .addInterceptor(loggingInterceptor)                  .build();

3. Deserializer

Deserializer是反序列化, Gson使用, 去除不使用的参数.

public class MarvelResultsDeserializer<T> implements JsonDeserializer<List<T>> {      @Override      public List<T> deserialize(JsonElement je, Type typeOfT,                                 JsonDeserializationContext context) throws JsonParseException {          // 转换Json的数据, 获取内部有用的信息          JsonElement results = je.getAsJsonObject().get("data")                  .getAsJsonObject().get("results");          return new Gson().fromJson(results, typeOfT);      }  }

Gson使用Deserializer, 过滤不用的参数.

        // 选择人物信息          Gson customGsonInstance = new GsonBuilder()                  .registerTypeAdapter(new TypeToken<List<AvengersCharacter>>() {                          }.getType(),                          new MarvelResultsDeserializer<AvengersCharacter>())                  .create();

4. 获取数据

Rx选择执行线程和返回线程.

    private void loadData() {          mCharactersSubscription = mRepository.getCharacters(0)                  .subscribeOn(Schedulers.io())                  .observeOn(AndroidSchedulers.mainThread())                  .subscribe(avengersCharacters -> {                      mMainView.setListData(avengersCharacters);                  });      }

Rxjava + Dagger + Retrofit , 三个编程库, 都已经写完了, 基本都是在一起使用. 文章里面都含有独立Demo, 大家可以配合使用, 感谢Square给我们带来, 的优雅代码.

OK, that’s all! Enjoy it.

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来自： http://blog.csdn.net/caroline_wendy/article/details/50557470