android fragments - ViewPager inside RecyclerView -

i have recyclerview 20 viewpagers (viewpager fragment) want display different pictures inside viewpagers hel of fragments. have problems viewpagers. first viewpager ok!, next 19 clear, without pics. after scroll down , up, pictures appears in viewpager, after swipe on viewpager disappear.

here viewpager adapter:

public class viewpageradapter extends fragmentpageradapter { arraylist<string> mpics; public viewpageradapter(fragmentmanager fm, arraylist<string> pics) {     super(fm);     mpics = pics;     (string pic: mpics) {         log.d("!!!!!!!->",pic);     } } @override public fragment getitem(int position) {      return viewpagerfragment.newinstance(mpics,position); }  @override public int getcount() {     return mpics.size(); }} 

and recyclerview onbindviewholder

 @override public void onbindviewholder(final flatviewholder flatviewholder, int position) {      flat flat = mflat.get(position);      if (flat.getadv_pics().size()>0){          viewpageradapter viewpageradapter = new viewpageradapter( fragmentmanager,(arraylist) flat.getadv_pics()  );         flatviewholder.viewpager.setadapter(viewpageradapter);      }else{      } }