Support RecyclerView doesn't show anything until touched

Question

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); } 

Answer 1

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)); } 

Answer 2

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 .