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<Business> mBusinesses = new ArrayList<Business>();  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<BusinessAdapter.ViewHolder> {      private List<Business> mBusinesses = new ArrayList<Business>();      // 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<Business> myBusinesses) {          Log.d(Const.DEBUG, "BusinessAdapter -> 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 -> 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 -> 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 -> 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 -> constructor 

I don't get any logs after this. Shouldn't getItemCount() in adapter should be called again?

Answer 1

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().