Consumindo API's Rest com Retrofit 2

Talk apresenta no Android Meetup BH - Droid Talks S02E03.
#retrofit #android

Transcript

1. Consumindo API's Rest com Retrofit 2
2. hello! Felipe Arimateia Software Engineer na CI&T e amante de séries.
3. 1. Retrofit Retrofit é uma biblioteca segura para consumir API's REST em Android ou Java desenvolvida pela Square.
4. “ Uma das principais funcionalidades do Retrofit é abstrair a complexidade de se criar e gerenciar conexões para API's.
5. 2. OKHTTP OkHttp é uma biblioteca desenvolvida pela Square para realizar requisições HTTP.
6. “ OkHttp foi construído por cima da biblioteca Okio, que tenta ser mais eficiente que as bibliotecas de I/O padrão do Java, criando um pool de memória compartilhada.
7. Exemplo https://github.com/androidbh/a ndroid_feedwrangler_example
8. Setup dependencies { compile 'com.squareup.retrofit2:retrofit:2.2.0' compile 'com.squareup.retrofit2:converter-gson:2.2.0' }
9. Converters Converter Library Gson com.squareup.retrofit2:converter-gson Jackson com.squareup.retrofit2:converter-jackson Moshi com.squareup.retrofit2:converter-moshi Protobuf com.squareup.retrofit2:converter-protobuf Wire com.squareup.retrofit2:converter-wire Simple XML com.squareup.retrofit2:converter-simplexml
10. Retrofit instance Retrofit retrofit = new Retrofit.Builder() .baseUrl("https://feedwrangler.net/") .build(); FeedWranglerApi api = retrofit.create(FeedWranglerApi.class);
11. Endpoints public interface FeedWranglerApi { @GET("api/v2/podcasts/categories") Call<ResponseApi<Category>> getCategories(); @GET("api/v2/podcasts/category/{id}") Call<ResponseApi<Podcast>>getCategory(@Path("id") int id); @GET("api/v2/podcasts/search") Call<ResponseApi<Podcast>>search(@Query("search_term") String term); }
12. Endpoints public interface FeedWranglerApi { @POST("api/v2/users/authorize") Call<ResponseApi<User>> authorize(@Body User user); }
13. Annotations Annotation Descrição @Path Adiciona paths no final do endpoint @Query Adiciona queries na requisição @Body Defini o payload para requisições POST @Header Adiciona cabeçalhos na requisição
14. Executando Call<ResponseApi<Category>> call = api.getCategories(); call.enqueue(new Callback<ResponseApi<Category>>() { @Override public void onResponse(Call<ResponseApi<Category>> call, Response<ResponseApi<Category>> response) { ResponseApi responseApi = response.body(); //... } @Override public void onFailure(Call<ResponseApi<Category>> call, Throwable t) {} });
15. Cancelando call.enqueue(new Callback<ResponseApi<Category>>() { @Override public void onResponse(Call<ResponseApi<Category>> call, Response<ResponseApi<Category>> response) { if (response.isSuccessful()) {//...} } @Override public void onFailure(Call<ResponseApi<Category>> call, Throwable t) { if (call.isCanceled()) { Log.d(TAG, "requisição cancelada");} } }); call.cancel();
16. Error Object { error = "Not authorized"; result = "error"; }
17. Simples Error Handler public static ResponseApi parseError(Response<?> response) { Converter<ResponseBody, ResponseApi> converter = RestAdpter.retrofit() .responseBodyConverter(ResponseApi.class, new Annotation[0]); ResponseApi error; try { error = converter.convert(response.errorBody()); } catch (IOException e) {return new ResponseApi();} return error; }
18. Tratando error call.enqueue(new Callback<ResponseApi<Podcast>>() { @Override public void onResponse(Call<ResponseApi<Podcast>> call, Response<ResponseApi<Podcast>> response) { if (response.isSuccessful()) {//...} else { ResponseApi responseApi = ErrorUtils.parseError(response); showMessage(responseApi.getError()); } } @Override public void onFailure(Call<ResponseApi<Podcast>> call, Throwable t) {} }
19. Interceptor OkHttpClient.Builder builder = new OkHttpClient.Builder(); HttpLoggingInterceptor httpLoggingInterceptor = new HttpLoggingInterceptor(); httpLoggingInterceptor.setLevel(HttpLoggingInterceptor.Level.BODY); builder.networkInterceptors().add(httpLoggingInterceptor); builder.build(); Retrofit retrofit = new Retrofit.Builder() .client(okHttpClient) https://github.com/square/okhttp/tree/master/okhttp-logging-interceptor
20. Interceptor return new Interceptor() { @Override public Response intercept(Chain chain) throws IOException { Request request = chain.request(); HttpUrl url = request.url().newBuilder() .addQueryParameter("client_key", BuildConfig.CLIENT_KEY) .build(); request = request.newBuilder().url(url).build(); return chain.proceed(request); } };
21. Logging (Stetho) OkHttpClient client = new OkHttpClient.Builder() .addNetworkInterceptor(new StethoInterceptor()) .build(); dependencies { compile 'com.facebook.stetho:stetho:1.4.2' compile 'com.facebook.stetho:stetho-okhttp3:1.4.2' }
22. Interceptor Sabe quando o desenvolvedor do backend fala que o problema de lentidão está no aplicativo? Prove para ele que não, criando um interceptor para calcular o tempo que cada requisção demora. Veja aqui um exemplo, de um interceptor que manda dados da requisição para o Answers do Fabric.
23. thanks! Any questions? You can find me at @twiterdoari