notifyDataSetChanged not working on RecyclerView

Question

I am getting data from server and then parsing it and storing it in a List  I am using this list for the RecyclerView s adapter  I am using Fragments    I am using a Nexus 5 with KitKat  I am using support library for this  Will this make a difference   Here is my code   Using dummy data for the question   Member Variables   List lt Business gt  mBusinesses   new ArrayList lt Business gt      RecyclerView recyclerView  RecyclerView LayoutManager mLayoutManager  BusinessAdapter mBusinessAdapter    My onCreateView      Override public View onCreateView LayoutInflater inflater  ViewGroup container          Bundle savedInstanceState            Getting data from server     getBusinessesDataFromServer         View view   inflater inflate R layout fragment business list              container  false       recyclerView    RecyclerView  view              findViewById R id business recycler view       recyclerView setHasFixedSize true        mLayoutManager   new LinearLayoutManager getActivity         recyclerView setLayoutManager mLayoutManager        mBusinessAdapter   new BusinessAdapter mBusinesses       recyclerView setAdapter mBusinessAdapter        return view      After getting data from server  parseResponse   is called   protected void parseResponse JSONArray response  String url           insert dummy data for demo      mBusinesses clear         Business business       business   new Business        business setName  Google        business setDescription  Google HeadQuaters        mBusinesses add business        business   new Business        business setName  Yahoo        business setDescription  Yahoo HeadQuaters        mBusinesses add business        business   new Business        business setName  Microsoft        business setDescription  Microsoft HeadQuaters        mBusinesses add business        Log d Const DEBUG   Dummy Data Inserted nBusinesses Length                  mBusinesses size          mBusinessAdapter   new BusinessAdapter mBusinesses       mBusinessAdapter notifyDataSetChanged        My BusinessAdapter   public class BusinessAdapter extends     RecyclerView Adapter lt BusinessAdapter ViewHolder gt         private List lt Business gt  mBusinesses   new ArrayList lt Business gt             Provide a reference to the type of views that you are using         custom viewholder      public static class ViewHolder extends RecyclerView ViewHolder           public TextView mTextViewName          public TextView mTextViewDescription          public ImageView mImageViewLogo           public ViewHolder View v                super v               mTextViewName    TextView  v                      findViewById R id textView company name               mTextViewDescription    TextView  v                      findViewById R id textView company description               mImageViewLogo    ImageView  v                      findViewById R id imageView company logo                           Provide a suitable constructor  depends on the kind of dataset      public BusinessAdapter List lt Business gt  myBusinesses             Log d Const DEBUG   BusinessAdapter - gt  constructor             mBusinesses   myBusinesses                Create new views  invoked by the layout manager       Override     public BusinessAdapter ViewHolder onCreateViewHolder ViewGroup parent              int viewType             Log d Const DEBUG   BusinessAdapter - gt  onCreateViewHolder                  create a new view         View v   LayoutInflater from parent getContext    inflate                  R layout item business list  parent  false            ViewHolder vh   new ViewHolder v           return vh                Replace the contents of a view  invoked by the layout manager       Override     public void onBindViewHolder ViewHolder holder  int position               - get element from your dataset at this position            - replace the contents of the view with that element          Log d Const DEBUG   BusinessAdapter - gt  onBindViewHolder               Business item   mBusinesses get position           holder mTextViewName setText item getName             holder mTextViewDescription setText item getDescription             holder mImageViewLogo setImageResource R drawable ic launcher                  Return the size of your dataset  invoked by the layout manager       Override     public int getItemCount              Log d Const DEBUG   BusinessAdapter - gt  getItemCount               if  mBusinesses    null                Log d Const DEBUG   mBusinesses Count      mBusinesses size                 return mBusinesses size                      return 0            But I don t get the data displayed in the view  What am I doing wrong   Here is my log   07-14 21 15 35 669  D xxx 2259   Dummy Data Inserted 07-14 21 15 35 669  D xxx 2259   Businesses Length  3 07-14 21 26 26 969  D xxx 2732   BusinessAdapter - gt  constructor   I don t get any logs after this  Shouldn t getItemCount   in adapter should be called again

User · Answer

Although it is a bit strange  but the notifyDataSetChanged does not really work without setting new values to adapter  So  you should do   array   getNewItems                          MyAdapter  mAdapter  setValues array       pass the new list to adapter     mAdapter notifyDataSetChanged             This has worked for me

User · Answer

Just to complement the other answers as I don t think anyone mentioned this here   notifyDataSetChanged   should be executed on the main thread  other notify lt Something gt  methods of RecyclerView Adapter as well  of course   From what I gather  since you have the parsing procedures and the call to  notifyDataSetChanged   in the same block  either you re calling it from a worker thread  or you re doing JSON parsing on main thread  which is also a no-no as I m sure you know   So the proper way would be   protected void parseResponse JSONArray response  String url           insert dummy data for demo         lt yadda yadda yadda gt      mBusinessAdapter   new BusinessAdapter mBusinesses          or just use recyclerView post   or  Fragment getView   post          instead  but make sure views haven t been destroyed while you were        parsing     new Handler Looper getMainLooper    post new Runnable             public void run                 mBusinessAdapter notifyDataSetChanged                           PS Weird thing is  I don t think you get any indications about the main thread thing from either IDE or run-time logs  This is just from my personal observations  if I do call notifyDataSetChanged   from a worker thread  I don t get the obligatory Only the original thread that created a view hierarchy can touch its views message or anything like that - it just fails silently  and in my case one off-main-thread call can even prevent succeeding main-thread calls from functioning properly  probably because of some kind of race condition   Moreover  neither the RecyclerView Adapter api reference nor the relevant official dev guide explicitly mention the main thread requirement at the moment  the moment is 2017  and none of the Android Studio lint inspection rules seem to concern this issue either   But  here is an explanation of this by the author himself

User · Answer

In my case  force run  notifyDataSetChanged in main ui thread will fix public void refresh             clearSelection               notifyDataSetChanged must run in main ui thread  if run in not ui thread  it will not update until manually scroll recyclerview           Activity  ctx  runOnUiThread new Runnable                  Override             public void run                     adapter notifyDataSetChanged

User · Answer

I had same problem  I just solved it with declaring adapter public before onCreate of class   PostAdapter postAdapter    after that  postAdapter   new PostAdapter getActivity    posts   recList setAdapter postAdapter     at last I have called    Override protected void onPostExecute Void aVoid        super onPostExecute aVoid          Display the size of your ArrayList     Log i  TAG    Size       posts size         progressBar setVisibility View GONE       postAdapter notifyDataSetChanged        May this will helps you

User · Answer

Try this method   List lt Business gt  mBusinesses2   mBusinesses  mBusinesses clear    mBusinesses addAll mBusinesses2     and do the notification   a little time consuming  but it should work

User · Answer

Clear your old viewmodel and set the new data to the adapter and call notifyDataSetChanged

User · Answer

In your parseResponse   you are creating a new instance of the BusinessAdapter class  but you aren t actually using it anywhere  so your RecyclerView doesn t know the new instance exists   You either need to    Call recyclerView setAdapter mBusinessAdapter  again to update the RecyclerView s adapter reference to point to your new one Or just remove mBusinessAdapter   new BusinessAdapter mBusinesses   to continue using the existing adapter  Since you haven t changed the mBusinesses reference  the adapter will still use that array list and should update correctly when you call notifyDataSetChanged

[android] notifyDataSetChanged not working on RecyclerView

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