android - RecyclerView scroll to top after back navigation if adapter's data set through RxAndroid -

when set adapter's data directly scroll position of list correct after come detial fragment, if i'm using rxandroid handle data scroll jump top. here example problem:

public class listfragment extends fragment {  private myadapter adapter; private list<string> data = new arraylist<>();  @override public void oncreate(@nullable bundle savedinstancestate) {     super.oncreate(savedinstancestate);     (int = 1; < 30; i++) {         data.add("pos: " + i);     } }  @nullable @override public view oncreateview(layoutinflater inflater, @nullable viewgroup container, @nullable bundle savedinstancestate) {     view root = inflater.inflate(r.layout.fragment_list, container, false);     adapter = new myadapter();     ((recyclerview) root.findviewbyid(r.id.bone_list)).setadapter(adapter);     return root; }  @override public void onresume() {     super.onresume();     data.add("pos: " + (data.size() + 1));      // working     //adapter.setdata(data);      // not working     observable.just(data)             .subscribeon(schedulers.io())             .observeon(androidschedulers.mainthread())             .subscribe(new consumer<list<string>>() {                 @override                 public void accept(list<string> strings) throws exception {                     adapter.setdata(strings);                 }             }); }  class myadapter extends recyclerview.adapter<myadapter.viewholder> {      private list<string> values = new arraylist<>();      public void setdata(list<string> items) {         values = items;         notifydatasetchanged();     }      @override     public viewholder oncreateviewholder(viewgroup parent, int viewtype) {         return new viewholder(layoutinflater.from(parent.getcontext()).inflate(r.layout.item_list_content, parent, false));     }      @override     public void onbindviewholder(final viewholder holder, int position) {         holder.content.settext(values.get(position));         holder.root.setonclicklistener(new view.onclicklistener() {             @override             public void onclick(view v) {                 getfragmentmanager().begintransaction()                         .replace(r.id.container, fragment.instantiate(getcontext(), detialfragment.class.getname()))                         .addtobackstack(null)                         .commit();             }         });     }      @override     public int getitemcount() {         return values.size();     }      class viewholder extends recyclerview.viewholder {         final view root;         final textview content;          viewholder(view view) {             super(view);             root = view;             content = (textview) view.findviewbyid(r.id.content);         }     } } 

}

working (simple set data):

not working (rx):

thanks, robert