Retrofit

How to rest right

Transcript

1. Retrofit How to rest right Vlad Vysotsky Android, iOs developer eKreative wolltone@gmail.com
2. Android Boilerplate Code - Databases (ORM, DAO) - Networking (JSON, data transferring) - UI templates - UI binding (view, saving states etc)
3. REST Client POST PUT DELETE Server GET
4. Using JSON to Exchange Data
5. Retrofit: Creators Type-safe HTTP client for Android and Java by Square, Inc Jake Wharton @JakeWharton http://jakewharton.com Bob Lee @crazybob http://crazybob.org http://square.github.io/
6. Retrofit: MetaLibrary Retrofit API Json Converters (e.g.GSON) OkHttp OkIO
7. Retrofit: MetaLibrary Retrofit API Json Converters (e.g.GSON) OkHttp OkIO
8. OkHttp OkHttp is an HTTP client that’s efficient by default: • HTTP/2 support allows all requests to the same host to share a socket. • Connection pooling reduces request latency (if HTTP/2 isn’t available). • Transparent GZIP shrinks download sizes. • Response caching avoids the network completely for repeat requests. • OkHttp initiates new connections with modern TLS features (SNI, ALPN), and falls back to TLS 1.0 if the handshake fails.
9. GSON Gson is a Java library that can be used to convert Java Objects into their JSON representation. It can also be used to convert a JSON string to an equivalent Java object. Gson can work with arbitrary Java objects including pre-existing objects that you do not have source-code of.
10. GSON: From Java to Json (and vice-versa) public class Country { private String name; private int population; @SerializableName(“cities”) private List<String> listOfCities; private Government government; //getter and setter methods } class Government { @SerializableName(“president”) private String nameOfPresident; } { "name":"Ukraine", "population":46000000, "cities":[ "Kyiv", "Lviv", "Cherkasy" ], "government":{ "president":"Poroshenko P." } }
11. RetroFit: Gradle Dependencies compile 'com.squareup.retrofit2:retrofit:2.0.0-beta4' compile 'com.squareup.retrofit2:converter-gson:2.0.0-beta4' compile 'com.squareup.okhttp3:okhttp:3.1.0'
12. RetroFit: Creating an Instance Retrofit retrofit = new Retrofit.Builder() .baseUrl(API_ROOT) .addConverterFactory(GsonConverterFactory.create()) //or something else you need .client(new OkHttpClient()) //or already configured instance of the client .build();
13. RetroFit: Services public interface GithubService { @GET("group/{id}/users") Call<List<User>> groupList( @Path("id") int groupId, @Query("sort") String sort ); } GithubService githubService = retrofit.create(GithubService.class)
14. RetroFit: Using a Service Async githubService.groupList(1, “desc”).enqueue(new Callback<List<User>>() { @Override public void onResponse(Call<List<User>> call, Response<List<User>> response) { if (response.isSuccess()) { // 2** // do what you need } else { int statusCode = response.code(); // handle an error } } @Override public void onFailure(Call<List<User>> call, Throwable error) { // handle an exception } });
15. RetroFit: Blocking Call try { List<User> users = githubService.groupList(1, “desc”).execute(); } catch (IOException e) { // handle an exception } NOTE: Use it only if you’re not in main thread!
16. What About LifeCycle? 1. Use Retrofit in loaders 2. Use it with RxJava 3. Use it with EventBus 4. Use it in another way created by your own imagination (but don’t forget about GC)
17. RetroFit: Using with EventBus LINK: https://www.ekreative.com/blog /how-to-use-retrofit-and-otto-for -android-networking EXAMPLE: https://github.com/vysotsky/Peo pleApp
18. RetroFit: Using with Loaders Actually, it would be great if you’re going to explore it by yourself like it’s your home task
19. QA Merry Retrofit!
20. Useful Resources 1. http://square.github.io/retrofit/ 2. http://inthecheesefactory.com/blog/retrofit-2.0/en 3. https://github.com/square/retrofit/tree/master/samples 4. https://www.ekreative.com/blog/how-to-use-retrofit-and-otto-for-android-n etworking 5. https://futurestud.io/blog/retrofit-getting-started-and-android-client