java - What should be done in Activity/Fragment and ViewModel in MVVM -

our company has been developing android application using mvp pattern while. mvp, put business logic inside presenter , activity/fragment responsible view update when receiving event callback presenter.

now, decided try mvvm using android databinding. seems mvvm, can put business logic in viewmodel (just presenter in mvp) , notify view(s) of changes data model, in 1 object.

but then, raise question in our mind, should left handle activity/fragment? since adopted mvp pattern avoid fat-activity/fragment. don't want have slim-activity/fragment , fat-viewmodel.

what think can left handle activity/fragment far

• request/check permission
• access context
• access resources

every correction, comment or suggestion welcome since i'm new mvvm, if seems similar mvp.

thank you.

a bit more question

is possible , practice combine mvvm listener (like mvp)? example

public class mainactivityviewmodel extends baseobservable {      mainactivityviewmodellistener listener;     user user;      public void setmainactivityviewmodellistener(mainactivityviewmodellistener listener) {         this.listener = listener;     }      public void refreshuser(view v) {         // user update via internet         notifypropertychanged(br.useralias);          if (listener != null) {             listener.onuserrefreshed(user);         }     }      @bindable     public void getuseralias() {         return user.getalias();     } }  public interface mainactivityviewmodellistener {     void onuserrefreshed(user user); }  public class mainactivity implements mainactivityviewmodellistener {      mainactivitybinding binding;      @override     public void oncreate(bundle savedinstancestate) {         binding = databindingutil.setcontentview(r.layout.main_activity);           mainactivityviewmodel viewmodel = new mainactivityviewmodel();         viewmodel.setmainactivityviewmodellistener(this);         binding.setmainactivityviewmodel(viewmodel);     }      @override     public void onuserrefreshed(user user) {         // update     } } 

yes can have business logic in viewmodel, here links personaly follows learn mvvm

approaching android mvvm
https://github.com/ivacf/archi
mvvm on android: need know

you can mention listeners in viewmodel data model consist.

viewmodel alters content , notifies binding framework content has changed.

model - data model containing business , validation logic
view - defines structure, layout , appearance of view on screen
viewmodel - acts link between view , model, dealing view logic

reference