Question
Retrofit Already in run on background thread. Then why need another background task RxJava?
I think most importanly, avoid nested callbacks(callback hell
).
e.g) Callback hell (Retrofit)
public interface MyService
{
@GET("users")
Call<List<UserModel>> getUser();
@GET("userinfo")
Call<UserInfoModel> getUserInfoById(@Query("id") Integer id);
}
service.getUser().enqueue(new Callback<UserModel>() {
@Override
public void onResponse(Call<UserModel> call, Response<UserModel> response) {
//process UserModel
UserModel data = response.body();
//if you want user infomation from server
service.getUserInfo(data.getId()).enqueue(new Callback<UserInfoModel>(){
//... is callback hell!!
});
}
@Override
public void onFailure(Call<UserModel> call, Throwable t) {
//error handling
}
});
e.g) Avoid Callback hell(Retrofit + RxJava)
public interface MyService
{
@GET("users")
Observable<List<UserModel>> getUser();
@GET("userinfo")
Observable<UserInfoModel> getUserInfoById(@Query("id") Integer id);
}
service.getUser()
.flatMapIterable(list -> list)
.flatMap(user -> service.getUserInfoById(user.getId()))
.doOnNext(userinfo -> saveUserInfo(userinfo)).subscribe();
if you are using RxJava
you can use Observable
to avoid this situation.
Additional
The above code snippet is just an example.
In fact, RxJava
contains much more observe pattern
related features.
Additional – Benefit of Event-Driven Programming in Android (RxJava)
Most Android application
are built with the based on user or data interaction
. (e.g GUI updates when the interaction occurs). So we see these as a set of events
and designing and building an application based on this is a very intuitive and appropriate for internal and external events.