Android - smoothScrollToPosition inside a child Fragment in a ViewPager -

i'm having difficulty in setting smooth scroll fragments inside viewpager, nested in fragment acts parent.

i set method :

public void scrolltotop()     {         this.recyclerview.smoothscrolltoposition(0);     } 

for fragments not in viewpager, don't know how reference of fragments inside viewpager.

i did

bottomlobifragment activelobi = (bottomlobifragment)getsupportfragmentmanager().findfragmentbytag(utilities.lobbytag); 

to parent fragment.

code viewpager (the rest identical, difference @ number of item, , constructor)

public class lobbypageradapter extends fragmentstatepageradapter {          public lobbypageradapter (fragmentmanager fm) {             super(fm);         }          @override         public fragment getitem(int pos) {             switch(pos) {                 case 0: return friends.newinstance("friends, instance 1"); //                case 1: return photo.newinstance("photo, instance 1"); //                case 2: return activities.newinstance("activities, instance 1");                 default: return friends.newinstance("friends, default");             }         }          @override         public charsequence getpagetitle(int position) {             return content[position % content.length];         }          @override         public int getcount() {             //return 3;             return content.length;         }          private class setadaptertask extends asynctask<void,void,void> {             protected void doinbackground(void... params) {                 return null;             }              @override             protected void onpostexecute(void result) {             }         }     } 

note : every adapter located inside parent fragment

first modify adapter this

public class lobbypageradapter extends fragmentstatepageradapter {          private arraylist<fragment> mfragments = new arraylist<>();          public lobbypageradapter (fragmentmanager fm) {             super(fm);             mfragments.add(friends.newinstance("friends, instance 1"));              mfragments.add(photo.newinstance("photo, instance 1"));              mfragments.add(activities.newinstance("activities, instance 1"));          }          @override         public fragment getitem(int pos) {             return mfragments.get(pos);         }          @override         public charsequence getpagetitle(int position) {             return content[position % content.length];         }          @override         public int getcount() {             //return 3;             return content.length;         }          private class setadaptertask extends asynctask<void,void,void> {             protected void doinbackground(void... params) {                 return null;             }              @override             protected void onpostexecute(void result) {             }         }     } 

now in fragment or activity holding viewpager & adapter instance, can adapter.getitem(1); example :

//suppose lobbypageradapter instance looks in code  lobbypageradapter adapter = new lobbypageradapter(getfragmentmanager());  // , want fragment @ second position in tab  photo photofragmentobject = (photo)adapter.getitem(1);  // , want fragment @ first position in tab  friends friendsfragmentobject = (friends)adapter.getitem(0);