欢迎Follow我的GitHub, 关注我的CSDN.

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, 优点我就不多说了. 让我们看看怎样使用吧?

注意: Retrofit2的beta3版本号, 使用Okhttp3, Interceptor使用方式发生改变.

主要

(1) Retrofit2(beta3)的请求方式.

(2) Okhttp3的Interceptor.

(3) Okhttp3的Deserializer.

(4) Retrofit2使用Gson转换器(Converter)和RxJava适配器(Adapter).

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, 加入一些參数, 或者获取一些信息.

如MarvelSigningInterceptor是加入參数, loggingInterceptor是打印參数.

/**

 * 加入Key和password

 * <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();

        // 加入新的參数

        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);

    }

}

addQueryParameter加入网络參数.

Okhttp3使用了装饰者模式, 使用Builder加入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, 去除不使用的參数.

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, 获取内部实用的信息

        JsonElement results = je.getAsJsonObject().get("data")

                .getAsJsonObject().get("results");

        return new Gson().fromJson(results, typeOfT);

    }

}

Gson使用Deserializer, 过滤不用的參数.

        // 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选择运行线程和返回线程.

    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, 大家能够配合使用, 感谢Square给我们带来, 的优雅代码.

OK, that’s all! Enjoy it.