Set dynamic base url using Retrofit 2.0 and Dagger 2

Question

I'm trying to perform a login action using Retrofit 2.0 using Dagger 2

Here's how I set up Retrofit dependency

@Provides
@Singleton
Retrofit provideRetrofit(Gson gson, OkHttpClient client) {
    Retrofit retrofit = new Retrofit.Builder()
                            .addConverterFactory(GsonConverterFactory.create(gson)
                            .client(client)
                            .baseUrl(application.getUrl())
                            .build();
    return retrofit;     
}

Here's the API interface.

interface LoginAPI {
   @GET(relative_path)
   Call<Boolean> logMe();
}

I have three different base urls users can log into. So I can't set a static url while setting up Retrofit dependency. I created a setUrl() and getUrl() methods on Application class. Upon user login, I set the url onto Application before invoking the API call.

I use lazy injection for retrofit like this

Lazy<Retrofit> retrofit

That way, Dagger injects dependency only when I can call

retrofit.get()

This part works well. I got the url set to retrofit dependency. However, the problem arises when the user types in a wrong base url (say, mywifi.domain.com), understands it's the wrong one and changes it(say to mydata.domain.com). Since Dagger already created the dependency for retrofit, it won't do again. So I have to reopen the app and type in the correct url.

I read different posts for setting up dynamic urls on Retrofit using Dagger. Nothing really worked out well in my case. Do I miss anything?

Answer 1

Retrofit2 library comes with a @Url annotation. You can override baseUrl like this:

API interface:

public interface UserService {  
    @GET
    public Call<ResponseBody> profilePicture(@Url String url);
}

And call the API like this:

Retrofit retrofit = Retrofit.Builder()  
    .baseUrl("https://your.api.url/");
    .build();

UserService service = retrofit.create(UserService.class);  
service.profilePicture("https://s3.amazon.com/profile-picture/path");

For more details refer to this link: https://futurestud.io/tutorials/retrofit-2-how-to-use-dynamic-urls-for-requests