Is there a way wait for code to take effect before a "notify" method is called (E.G. notifyItemRangeInserted) on a Recycler view? - android-recyclerview

Question

I want to show a progress dialog screen in my app whenever a recycler view begins to load more items. The problem is: I can't get to show the dialog screen because the notify method is ALWAYS executed (and freezes the screen) before the loading screen shows up. Happens even if the "show()" method for it is called in the very first line of my "addContacts()" method.
I've already tried:
getActivity().runOnUiThread();
creating a Thread, starting it, calling join()
starting it with executors
public void addContactsToScreen() {
((BaseActivity) lcf.getActivity()).showProgressDialog();
try {
int currentSize = contactsLoaded.size();
int inserted;
for (inserted = 0;
inserted < DEFAULT_ITEM_INSERTION
&& inserted < lcf.getController().getContacts().size()
&& contactsLoaded.size() < lcf.getController().getContacts().size()
; inserted++) {
contactsLoaded.add(lcf.getController().getContacts().get(currentSize + inserted));
}
if (inserted > 0) {
notifyItemRangeInserted(contactsLoaded.size() - 1, inserted);
}
lcf.getContactsRecycler().getViewTreeObserver()
.addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
#Override
public void onGlobalLayout() {
lcf.isLoading=false;
lcf.getContactsRecycler().post(new Runnable() {
#Override
public void run() {
((BaseActivity) lcf.getActivity()).hideProgressDialog();
}
});
lcf.getContactsRecycler().getViewTreeObserver().removeOnGlobalLayoutListener(this);
}
});
} catch (Exception e) {
e.printStackTrace();
}
}
That is the original code (no threads or failed attempts). The void is called everytime I initialize the adapter or the view reaches a threshold limit. It loads a list that ends up being shown on screen after "notifyItemRangeInserted()" is called. As you can see the VERY FIRST LINE tries to show the loading screen but for some reason, in the debugger itself I find with breakpoints that the method calls the show method, but the loading screen never appears, fills the list in the "for" loop, calls the notify event, the screen freezes, THEN the loading screen finally shows up but then immediately the hide method is called (rendering teh loading screen useless)

Answer 1

Did you try post runnable method?
progressbar.setvisibility(view.visible);
progressbar.post(new Runnable() {
#Override
public void run() {
fetchMoreDataInTheRecyclerView();
}
});
*Now do the fetching inside fetchMoreDataInTheRecyclerView(); and once done simply make progressbar invisible.
Let me know if this helps.