public Object instantiateItem(ViewGroup container, int position) {
    Fragment fragment = (Fragment) super.instantiateItem(container, position);
    registeredFragments.put(position, fragment);
    return fragment;

}

@Override
public void destroyItem(ViewGroup container, int position, Object object) {
    super.destroyItem(container, position, object);
    registeredFragments.remove(position);
}
public Fragment getRegisteredFragment(int position) {
    return registeredFragments.get(position);
}

public class PageTabs extends Fragment {

public static TabLayout tabLayout;
public static ViewPager viewPager;
public static int int_items = 3;
private PagerAdapter MyAdapter;


public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {

    // Inflate the layout for this fragment
    return inflater.inflate(R.layout.activity_create_grups, container, false);

}

@Override
public void onActivityCreated(@Nullable Bundle savedInstanceState) {
    super.onActivityCreated(savedInstanceState);
    tabLayout = (TabLayout) getActivity().findViewById(R.id.tabs);
    viewPager = (ViewPager) getActivity().findViewById(R.id.viewpager);
    MyAdapter = new PagerAdapter(getChildFragmentManager());
    viewPager.setAdapter(MyAdapter);
    viewPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
        @Override
        public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
            ?
        }

        @Override
        public void onPageSelected(int position) {
            ?
        }

        @Override
        public void onPageScrollStateChanged(int state) {
            ??
        }
    });


}