android - Lost reference of Fragments in FragmentPagerAdapter -

i have simple fragmentpageradapter :

public class sectionspageradapter extends fragmentpageradapter {  public sectionspageradapter(fragmentmanager fm) {     pageradapterlist = new arraylist<>();     super(fm); }  @override public fragment getitem(int position) {     pageradapter fragment;     if (position > pageradapterlist.size() - 1) {                 fragment = new pageradapter(followrequests.get(position));                 pageradapterlist.add(fragment);              } else                 return pageradapterlist.get(position);      return fragment; }          public int removeview (viewpager pager, int position)     {         pager.setadapter (null);         pageradapterlist.remove (position);         data.remove (position);         pager.setadapter (this);          return position;     }          @override     public object instantiateitem(viewgroup container, int position) {         getitem(position);         return super.instantiateitem(container, position);     }  @override public int getcount() { return data.size(); }  } 

and pageradapter class:

public class pageradapter extends fragment {  data data; private view overlayview;  public pageradapter() { }  public pageradapter(data data) {     this.data= data; }  @nullable @override public view oncreateview(layoutinflater inflater, @nullable viewgroup container, @nullable bundle savedinstancestate) {     view rootview = inflater.inflate(r.layout.notification_header_fragment_pager, container, false);     textview id_txtview = (textview)      overlayview = (view) rootview.findviewbyid(r.id.viewoverlay);      //bind data example id_txtview.settext(data.gettext());      return rootview; }  public void showoverlayview() {     if(overlayview != null)     overlayview.setvisibility(view.visible); } } 

first call

removeview(mviewpager, position);

then new data, , call

adapter.notifydatasetchanged();

all things work fine , can bind new data in pageradapter , show on view pager.

but when call

((pageradapter) adapter.getitem(mviewpager.getcurrentitem())).showoverlayview();

i current fragment without reference ui components(like overlayview) , null !!

what's wrong? please me, thanks.