android-retrofit-2-0.md

title: Android and Retrofit 2.0 tags:android,android-retrofit

Now Retrofit is at 2.0, there are a few basic changes to the usual approach. Here's the interface which is as before:

public interface GitHubService {
  @GET("users/{user}")
  Call<User> listRepos(@Path("user") String user);
}

And here's the basic builder to create the service:

final GitHubService service = new Retrofit.Builder()
        .baseUrl("https://api.github.com")
        .addConverterFactory(GsonConverterFactory.create())
        .build()
        .create(GitHubService.class);

But to get this we must now explictly include our Gson dependency in our gradle file:

compile 'com.squareup.retrofit2:retrofit:2.0.0-beta4'
compile 'com.squareup.retrofit2:converter-gson:2.0.0-beta4'

And finally we call the repo and it returns a Call, and we call the enqueue method on that to get the data asynchronously.

Call<User> repos = service.listRepos("octocat");

repos.enqueue(new Callback<User>() {
  @Override
  public void onResponse(Call<User> call, Response<User> response) {
    User body = response.body(); // Body could be null if parse error
    Log.d("HIYA", "good " + body.avatar_url);
  }

  @Override
  public void onFailure(Call<User> call, Throwable t) {
    Log.d("HIYA", "error " + t.getMessage());
  }
});

The good thing about the new Call architecture if that we can check the headers and such on a valid response.

Our data object is as simple as ever:

private static class User {
  public String avatar_url;
}