Retrofit 2.0 — Just a Tip – The Blog of Tássio Auad

by Philip Barlow / from beautifuldecay.com

Yes, I’m late to post about Retrofit, but this post is in my drafts box there is a long time! =D It will not be a big post explaining each detail of this framework even because I’m late (again) and there is already lot of posts doing this job . I will try to do something diferente, resuming the use of Retrofit in a easy way to see how it works.

Step 1 – Implement the Resource

Firstly, we must to create a interface that will represent each resources from the API that will be consumed.

	public interface UserResource {

	@GET("user/list")
	Call listAll();

	}

view raw

UserResource.java

hosted with ❤ by GitHub

Step 2 – Retrofit Instance

So, we gonna need a Retrofit instance to call this UserResource

	Retrofit retrofit = new Retrofit.Builder()
	.baseUrl("http://api.myapi.com/")
	.build(); retrofit = new Retrofit.Builder()
	.baseUrl("http://api.myapi.com/")
	.build();

view raw

RetrofitInstance.java

hosted with ❤ by GitHub

Step 3 – Instanciate the Resource

And, we gonna instanciate our UserResource like that:

UserResource userResource = retrofit.create(UserResource.class)

view raw

UserResourceInstance.java

hosted with ❤ by GitHub

Easy, isn’t it?

Step 4 – Call

Let’s execute UserResource method listAll() synchronously:

	Call callUser = userResource.listAll();
	Response response = callUser.execute();
	Integer HttpResponseCode = response.code(); //202 HTTP_OK
	List userList = response.body();

view raw

ListAll.java

hosted with ❤ by GitHub

Or we can do it assynchronously:

	Call callUser = userResource.listAll();
	call.enqueue(new Callback() {
	@Override
	public void onResponse(Response response) {
	Integer HttpResponseCode = response.code(); //202 HTTP_OK
	List userList = response.body();
	}

	@Override
	public void onFailure(Throwable t) {
	//Ops! Failed!
	}
	});