Agfdhyk

I created Application module called AppRetroServiceModule to provide retrofit.

@Module(includes = NetworkModule.class)

public class AppRetroServiceModule {



    @Provides

    @AppScope

    public RetroService retroService(Retrofit retrofit) {

        return retrofit.create(RetroService.class);

    }



    @Provides

    @AppScope

    public Retrofit retrofit(OkHttpClient okHttpClient, Gson gson) {

        return new Retrofit.Builder()

                .addConverterFactory(GsonConverterFactory.create(gson))

                .client(okHttpClient)

                .baseUrl("http://webservise/Srv1.svc/json/")

                .build();

    }

}

As you can see baseUrl is hardcoded and fixed. In application component I created getter to get retrofit and other provider, when application component is dependency for other component :

@AppScope

@Component(modules = {NetworkModule.class, AppRetroServiceModule.class})

public interface IApplicationComponent {

    RetroService getRetroService();



    Gson getGsonBuilder();



    Context getAppContext();

}  

I initialized dagger in application class:

public class App extends Application {

    private IApplicationComponent component;

    ...

    @Override

    public void onCreate() {

        super.onCreate();



        Timber.plant(new Timber.DebugTree());

        component = DaggerIApplicationComponent.builder()

                .networkModule(new NetworkModule(this))

                .build();



    }...



    public IApplicationComponent getAppComponent() {

        return component;

    }

}

Now in main activity i need to use other baseurl to fetching data from server :

public class MainActivity extends AppCompatActivity implements IMain.IMainView {



    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_m);

        ButterKnife.bind(this);

        setSupportActionBar(toolbar);



        DaggerIMainComponent.builder()

                .iApplicationComponent(((App) getApplication()).getAppComponent())

                .build()

                .inject(this);

    ...

Because retrofit is initialized when application is started, how can i change anytime retrofit baseurl when i need to fetch data from servers in other activity or fragment ?
Sometimes i need to connect to number of servers and fetch data from these server and use in one activity then i need to change baseurl every i needed.

If your base url is dynamic then you can use @Url. This will help you to pass dynamic base url to your requests.

public interface RetrofitClient {



    // Simple call with dynamic url

    @GET

    public Call<YouModelClass> doSomeRequest(@Url String url);



    // Call with dynamic url and request parameter

    @GET

    public Call<YouModelClass> doSomeRequest(@Url String url, @Query("id") String id);



    // Call with dynamic url and more request parameters

    @GET

    public Call<YouModelClass> doSomeRequest(@Url String url, @Query("id") String id, @Query("key") String key, @Query("part") String part);

}

And calling code would be

RetrofitClient service = retrofit.create(RetrofitClient.class);

Call<YouModelClass> call = service.doSomeRequest("your_dynamic_url_with_base_url");

// and so on

Read more at Retrofit 2 — How to Use Dynamic Urls for Requests