Support RecyclerView doesn't show anything until touched

I'm using the support RecyclerView in my app, and I see the most bizarre thing. It doesn't display any items until I touch to scroll. Then, all of a sudden, the RecyclerView populates itself. I have verified that the list backing the adapter is populated, and that onCreatViewHolder and onBindViewHolder are never called until a touch event.

Here's how I set up the recyclerview:

    @Override
    public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
        Drawable divider = new ColorDrawable(ProfileInfo.getCurrentProfileColor());
        mInboxList.addItemDecoration(new DividerItemDecoration(getActivity(), divider, false));
        mInboxList.setLayoutManager(new LinearLayoutManager(getActivity(), LinearLayoutManager.VERTICAL, false));
        mInboxList.setAdapter(new InboxAdapter(getActivity(), new ArrayList<Conversation>()));
        new AsyncTask<Void, Void, List<Conversation>{

              public List<Conversation> doInBackground(...){
                   //load the conversations
                   return conversations;
              }

              public void onPostExecute(List<Conversation> conversations){
                   ((InboxAdapter) mInboxList.getAdapter()).clear(false);
                   ((InboxAdapter) mInboxList.getAdapter()).addAll(conversations);

              }

        }.executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR);
     }

Here's a gist of my adapter:

public class InboxAdapter extends RecyclerView.Adapter<InboxAdapter.ViewHolder> {
    List<Conversation> mConversations; //initialized in contructor

    @Override
    public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View v = mInflater.inflate(R.layout.inbox_item, parent, false);
        ViewHolder holder = new ViewHolder(v);
        Log.d(LOG_TAG, "oncreateviewholder : " + viewType); //never called when I first bind the adapter
        return holder;
    }

    @Override
    public void onBindViewHolder(final ViewHolder holder, int position) {
        final Conversation item = mConversations.get(position);
        Log.d(LOG_TAG, "binding " + position);
        ...
    }

    @Override
    public int getItemCount() {
        Log.d(LOG_TAG, "item count: " + mConversations.size());
        return mConversations.size();
    }

    /**
     * Empties out the whole and optionally notifies
     */
    public void clear(boolean notify) {
        mConversations.clear();
        if (notify) {
            notifyDataSetChanged();
        }
    }

    public void addAll(List<Conversation> conversations) {
        mConversations.addAll(conversations);
        notifyDataSetChanged();
    }


}

Here's the layout file:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
                xmlns:app="http://schemas.android.com/apk/res-auto"
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:paddingTop="?attr/actionBarSize">


    <android.support.v7.widget.RecyclerView
        android:id="@+id/lv_inbox"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        ></android.support.v7.widget.RecyclerView>
</RelativeLayout>

I'm using recyclerview-v7:21.0.3 running on a Moto X with version 4.4.4.

EDIT: Smooth scrolling at the end of the onPostExecute seems to resolve the issue:

if (mInboxList.getAdapter().getItemCount() > 0) {
    mInboxList.smoothScrollToPosition(0);
}

If anyone else is having this issue using RxJava and Retrofit, I solved this issue by adding the .observeOn(AndroidSchedulers.mainThread()) operator into my method chain before subscribing. I had read this was taken care of by default, and thus not explicitly necessary, but I guess not. Hope this helps.

Example:

public void loadPhotos() {
    mTestPhotoService.mServiceAPI.getPhotos()
                                 .subscribeOn(Schedulers.io())
                                 .observeOn(AndroidSchedulers.mainThread())
                                 .subscribe(photoList -> mRecyclerActivity.OnPhotosLoaded(photoList));
}

In my case only this worked:

recyclerView.smoothScrollToPosition(arrayModel.size-1); // I am passing last position here you can pass any existing position

RecyclerView was showing data only when I scroll it. So instead of user to manually scroll I have added above line which will scroll the recyclerView programmatically .

So at first, just like everybody else I just added:

recyclerView.smoothScrollToPosition(0)

and it worked pretty much good enough, however it wasn't nice and you had to remember to add it every time. and I then I followed @SudoPlz comment and answer on another question and it also worked too, you have to extend RecyclerView and override requestLayout:

private boolean mRequestedLayout = false;

@SuppressLint("WrongCall")
@Override
public void requestLayout() {
    super.requestLayout();
    // We need to intercept this method because if we don't our children will never update
    // Check https://stackoverflow.com/questions/49371866/recyclerview-wont-update-child-until-i-scroll
    if (!mRequestedLayout) {
        mRequestedLayout = true;
        this.post(() -> {
            mRequestedLayout = false;
            layout(getLeft(), getTop(), getRight(), getBottom());
            onLayout(false, getLeft(), getTop(), getRight(), getBottom());
        });
    }
}

while still, I would have preferred this to fixed after 4, 5 years, however, this was a good workaround, and you won't forget about them in your view.