I want to find out how to update a recyclerview with asychronous data.. I start the fragment out with an empty dataset and then go on to add values to it onSuccess of the Retrofit call then next I call notifyDatasetChanged if the adapter itemcount is 0, or notifyItemRangeInserted if it isnt..To my knowledge that shouldbe enough to make the ViewHolder be refreshed with the new dataset but it seems it's still referencing the empty one when binding and throws an NPE.. please help adapter
public class PlaceListRecyclerViewAdapter extends RecyclerView.Adapter<PlaceListRecyclerViewAdapter.PlaceObjectHolder>{
private static String LOG_TAG = "PlaceRVAdapter";
private ArrayList<Store> mDataSet;
private static MyClickListener myClickListener;
public static class PlaceObjectHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
protected ImageView placePicture;
protected TextView placeName;
public PlaceObjectHolder(View view){
super(view);
Log.i(LOG_TAG, "Object Holder constructor");
placePicture = (ImageView) view.findViewById(R.id.place_picture);
placeName = (TextView) view.findViewById(R.id.place_name);
itemView.setOnClickListener(this);
}
@Override
public void onClick(View v) {
myClickListener.onItemClick(getAdapterPosition(), v);
Log.d(LOG_TAG, "Listener has been called, returning control to calling class");
}
}
public void setOnItemClickListener (MyClickListener myClickListener){
PlaceListRecyclerViewAdapter.myClickListener = myClickListener;
}
public PlaceListRecyclerViewAdapter(ArrayList<Store> myDataSet){
mDataSet = myDataSet;
}
@Override
public PlaceObjectHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.product_item, parent, false);
PlaceObjectHolder productObjectHolder = new PlaceObjectHolder(view);
//return new PlaceObjectHolder(view);
return productObjectHolder;
}
@Override
public void onBindViewHolder(PlaceObjectHolder holder, int position) {
// TODO: Replace with proper, complete logic here
if (mDataSet != null) {
//FixMe: NPE on this;
holder.placeName.setText(mDataSet.get(position).getName());
}
// TODO: Image addition goes here
}
public void addItems(ArrayList<Store> stores, int index){
int cursize = mDataSet.size();
mDataSet.addAll(index, stores);
if (getItemCount() != 0) {
notifyItemRangeInserted(index, (mDataSet.size() - cursize));
} else {
notifyDataSetChanged();
}
}
public void deleteItem (int index){
mDataSet.remove(index);
notifyItemRemoved(index);
}
@Override
public int getItemCount() {
return mDataSet.size();
}
public interface MyClickListener {
void onItemClick(int position, View v);
}
}
place item
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:cardView="http://schemas.android.com/apk/res-auto"
android:layout_height="match_parent"
android:layout_width="match_parent">
<android.support.v7.widget.CardView
android:id="@+id/place_cardview"
android:layout_height="wrap_content"
android:layout_width="match_parent"
android:focusable="true"
android:layout_gravity="center"
cardView:cardPreventCornerOverlap="true"
cardView:cardElevation="15dp">
<ImageView
android:id="@+id/place_picture"
android:layout_width="fill_parent"
android:layout_height="wrap_content" />
<TextView
android:id="@+id/place_name"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:padding="10dp"
android:textStyle="bold"
android:textSize="16dp" />
</android.support.v7.widget.CardView>
Calling fragment
public class PlacesListFragment extends Fragment {
private static String LOG_TAG = "PlaceListFragment";
private RecyclerView mRecyclerView;
private PlaceListRecyclerViewAdapter mAdapter;
private RecyclerView.LayoutManager mLayoutManager;
private Context mContext = getContext();
private ArrayList<Store> storePlaces = new ArrayList<Store>();
private ArrayList<Store> viewDataSet = new ArrayList<Store>();
private String BASE_URL;
private String FORMAT_SPECIFIER;
private TextView storeName;
private TextView phoneNumber;
private TextView email;
private TextView website;
private TextView address;
private LayoutInflater supinf;
int statusCode;
int ressize;
public PlacesListFragment() {
// Required empty public constructor
}
public static PlacesListFragment newInstance() {
PlacesListFragment fragment = new PlacesListFragment();
return fragment;
}
@Override
public void onStart(){
super.onStart();
getDataSet(new com.urbanity.apps.shoplist.adapter.Callback<List<Store>>() {
@Override
public void next(List<Store> results, int requestCode) {
int cursize = mAdapter.getItemCount();
if (statusCode == 200) {
viewDataSet.addAll(results);
if (cursize != 0) {
mAdapter.addItems(viewDataSet, cursize);
Log.d(LOG_TAG, "Success, new data set is of size " + storePlaces.size() + " with status code: " + statusCode + " from source sized: " + ressize);
} else {
mAdapter.addItems(viewDataSet,cursize);
mAdapter.notifyDataSetChanged();
}
}
}
});
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
BASE_URL = getResources().getString(R.string.base_url);
FORMAT_SPECIFIER = getResources().getString(R.string.format_specifier);
Log.d(LOG_TAG, " Created");
}
@Override
public void onResume(){
super.onResume();
Log.d(LOG_TAG, " Resumed");
//set listener for this RV adapter instance
mAdapter.setOnItemClickListener(new PlaceListRecyclerViewAdapter.MyClickListener() {
@Override
public void onItemClick(int position, View v) {
Log.i(LOG_TAG, " Clicked on Item " + position);
Store store = (Store) storePlaces.get(position);
// TODO: place ALERT DIALOG here..
displayAlert(supinf);
}
});
}
public void displayAlert(LayoutInflater inflater){
View selectedPlaceDiag = inflater.inflate(R.layout.dialog_place_details, null);
AlertDialog.Builder alert = new AlertDialog.Builder(getContext());
alert.setTitle(R.string.alert_dialog_create_shlist);
alert.setView(selectedPlaceDiag);
alert.setCancelable(false);
alert.setNegativeButton(R.string.cancel, new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
Toast.makeText(getContext(), R.string.ok, Toast.LENGTH_SHORT).show();
}
});
alert.setPositiveButton(R.string.show_map, new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
// TODO: add logic here to display map
}
});
AlertDialog dialog = alert.create();
dialog.show();
}
public void getDataSet(final com.urbanity.apps.shoplist.adapter.Callback<List<Store>> callback) {
Gson gson = new GsonBuilder()
.setExclusionStrategies(new ExclusionStrategy() {
@Override
public boolean shouldSkipField(FieldAttributes f) {
return f.getDeclaringClass().equals(RealmObject.class);
}
@Override
public boolean shouldSkipClass(Class<?> clazz) {
return false;
}
})
.create();
Retrofit retrofitClient = new Retrofit.Builder()
.baseUrl(BASE_URL)
.addConverterFactory(GsonConverterFactory.create(gson))
.build();
// create a new service call variable from the interface with retrofitClient
ShoplistApiEndpointInterface apiService = retrofitClient.create(ShoplistApiEndpointInterface.class);
//create a new APICall variable of the api interface with its type being that of the call method you'll invoke from the interface
Call<List<Store>> storeListCall = apiService.getStoreList(FORMAT_SPECIFIER);
// make the call asynchronously by calling enqueue on the Call type
//FIXME: chane serverside encoding is option 1 (type:app/json, encoding: utf8)
storeListCall.enqueue(new Callback<List<Store>>() {
@Override
public void onResponse(Call<List<Store>> call, Response<List<Store>> response) {
if (response.isSuccessful()) {
// get status code from the HTTP response code
statusCode = response.code();
// add the parsed response body data (parsed pojo object list in this case)
// to the arrayList with the addAll(Collection<type>) method
List<Store> results = response.body();
ressize = response.body().size();
//int initialSize = storePlaces.size();
// FIXME: source of NPE?
storePlaces.addAll(results);//.addAll(initialSize, results);
callback.next(storePlaces, statusCode);
}
}
@Override
public void onFailure(Call<List<Store>> call, Throwable t) {
// log the error here
Log.e(LOG_TAG, "Failed to download Place list", t.getCause());
Toast.makeText(getActivity(), getResources().getString(R.string.failed_to_download_list) + t.getMessage() , Toast.LENGTH_SHORT).show();
}
});
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View v = inflater.inflate(R.layout.fragment_places_list, container, false);
// TODO: in event of an NPE, uncomment this
supinf = inflater;
Log.d(LOG_TAG, "setting RV");
mRecyclerView = (RecyclerView) v.findViewById(R.id.place_list_rv);
mRecyclerView.setHasFixedSize(true);
mLayoutManager = new GridLayoutManager(mContext, 2, GridLayoutManager.VERTICAL, false);
Log.d(LOG_TAG, "setting Layout Manager");
mRecyclerView.setLayoutManager(mLayoutManager);
Log.d(LOG_TAG, "setting dataset");
mAdapter = new PlaceListRecyclerViewAdapter(storePlaces);
Log.d(LOG_TAG, "setting adapter");
mRecyclerView.setAdapter(mAdapter);
Log.d(LOG_TAG, "Setting up endless scrolling listener");
mRecyclerView.addOnScrollListener(new EndlessRecyclerViewScrollListener((GridLayoutManager) mLayoutManager) {
@Override
public void onLoadMore(int page, int totalItemsCount) {
//Query server for more data
getDataSet(new com.urbanity.apps.shoplist.adapter.Callback<List<Store>>() {
@Override
public void next(List<Store> result, int requestCode) {
ArrayList<Store> stores = new ArrayList<Store>();
stores.addAll(result);
int cursize = mAdapter.getItemCount();
mAdapter.addItems(stores, cursize);
}
});
}
});
Log.d(LOG_TAG, " returning view");
AppCompatButton showMap = (AppCompatButton) v.findViewById(R.id.btn_show_map);
showMap.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
showOnMap();
}
});
getActivity().setTitle(R.string.store_locator);
return v;
}
public void showOnMap(){
// Insert the fragment by replacing any existing fragment
getActivity().setTitle(R.string.place_map_title);
SupportMapFragment mapFragment = PlacesListMapFragment.newInstance();
FragmentTransaction fragmentTransaction = getActivity().getSupportFragmentManager().beginTransaction();
fragmentTransaction.replace(R.id.flContent, mapFragment);
fragmentTransaction.addToBackStack(null);
fragmentTransaction.commit();
}
}
and finally the log starting from the point MainActivity begins the Fragment Transaction
MainActivity:: : fragment replaced with FragmentClass data
04-21 21:18:10.183 11953-11953/com.urbanity.apps.shoplist D/PlaceListFragment: Created
04-21 21:18:10.193 11953-11953/com.urbanity.apps.shoplist D/PlaceListFragment: setting RV
04-21 21:18:10.193 11953-11953/com.urbanity.apps.shoplist D/PlaceListFragment: setting Layout Manager
04-21 21:18:10.193 11953-11953/com.urbanity.apps.shoplist D/PlaceListFragment: setting dataset
04-21 21:18:10.193 11953-11953/com.urbanity.apps.shoplist D/PlaceListFragment: setting adapter
04-21 21:18:10.193 11953-11953/com.urbanity.apps.shoplist D/PlaceListFragment: Setting up endless scrolling listener
04-21 21:18:10.193 11953-11953/com.urbanity.apps.shoplist D/PlaceListFragment: returning view
04-21 21:18:10.253 11953-11953/com.urbanity.apps.shoplist D/PlaceListFragment: Resumed
04-21 21:18:10.463 11953-13554/com.urbanity.apps.shoplist W/dalvikvm: VFY: unable to find class referenced in signature (Ljava/nio/file/Path;)
04-21 21:18:10.463 11953-13554/com.urbanity.apps.shoplist W/dalvikvm: VFY: unable to find class referenced in signature ([Ljava/nio/file/OpenOption;)
04-21 21:18:10.463 11953-13554/com.urbanity.apps.shoplist I/dalvikvm: Could not find method java.nio.file.Files.newOutputStream, referenced from method okio.Okio.sink
04-21 21:18:10.463 11953-13554/com.urbanity.apps.shoplist W/dalvikvm: VFY: unable to resolve static method 61852: Ljava/nio/file/Files;.newOutputStream (Ljava/nio/file/Path;[Ljava/nio/file/OpenOption;)Ljava/io/OutputStream;
04-21 21:18:10.463 11953-13554/com.urbanity.apps.shoplist D/dalvikvm: VFY: replacing opcode 0x71 at 0x000a
04-21 21:18:10.463 11953-13554/com.urbanity.apps.shoplist W/dalvikvm: VFY: unable to find class referenced in signature (Ljava/nio/file/Path;)
04-21 21:18:10.463 11953-13554/com.urbanity.apps.shoplist W/dalvikvm: VFY: unable to find class referenced in signature ([Ljava/nio/file/OpenOption;)
04-21 21:18:10.463 11953-13554/com.urbanity.apps.shoplist I/dalvikvm: Could not find method java.nio.file.Files.newInputStream, referenced from method okio.Okio.source
04-21 21:18:10.463 11953-13554/com.urbanity.apps.shoplist W/dalvikvm: VFY: unable to resolve static method 61851: Ljava/nio/file/Files;.newInputStream (Ljava/nio/file/Path;[Ljava/nio/file/OpenOption;)Ljava/io/InputStream;
04-21 21:18:10.463 11953-13554/com.urbanity.apps.shoplist D/dalvikvm: VFY: replacing opcode 0x71 at 0x000a
04-21 21:18:10.763 11953-11953/com.urbanity.apps.shoplist D/PlaceListFragment: Success, new data set is of size 4 with status code: 200 from source sized: 2
04-21 21:18:10.803 11953-11953/com.urbanity.apps.shoplist I/PlaceRVAdapter: Object Holder constructor
04-21 21:18:10.803 11953-11953/com.urbanity.apps.shoplist D/AndroidRuntime: Shutting down VM
04-21 21:18:10.803 11953-11953/com.urbanity.apps.shoplist W/dalvikvm: threadid=1: thread exiting with uncaught exception (group=0x4162ae00)
04-21 21:18:10.813 11953-11953/com.urbanity.apps.shoplist E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.urbanity.apps.shoplist, PID: 11953
java.lang.NullPointerException
at com.urbanity.apps.shoplist.adapter.PlaceListRecyclerViewAdapter.onBindViewHolder(PlaceListRecyclerViewAdapter.java:69)
at com.urbanity.apps.shoplist.adapter.PlaceListRecyclerViewAdapter.onBindViewHolder(PlaceListRecyclerViewAdapter.java:20)
at android.support.v7.widget.RecyclerView$Adapter.onBindViewHolder(RecyclerView.java:5453)
at android.support.v7.widget.RecyclerView$Adapter.bindViewHolder(RecyclerView.java:5486)
at android.support.v7.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:4723)
at android.support.v7.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:4599)
at android.support.v7.widget.LinearLayoutManager$LayoutState.next(LinearLayoutManager.java:1988)
at android.support.v7.widget.GridLayoutManager.layoutChunk(GridLayoutManager.java:528)
at android.support.v7.widget.LinearLayoutManager.fill(LinearLayoutManager.java:1347)
at android.support.v7.widget.LinearLayoutManager.onLayoutChildren(LinearLayoutManager.java:574)
at android.support.v7.widget.GridLayoutManager.onLayoutChildren(GridLayoutManager.java:170)
at android.support.v7.widget.RecyclerView.dispatchLayoutStep2(RecyclerView.java:3003)
at android.support.v7.widget.RecyclerView.dispatchLayout(RecyclerView.java:2881)
at android.support.v7.widget.RecyclerView.consumePendingUpdateOperations(RecyclerView.java:1457)
at android.support.v7.widget.RecyclerView.access$400(RecyclerView.java:147)
at android.support.v7.widget.RecyclerView$1.run(RecyclerView.java:285)
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:768)
at android.view.Choreographer.doCallbacks(Choreographer.java:581)
at android.view.Choreographer.doFrame(Choreographer.java:550)
at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:754)
at android.os.Handler.handleCallback(Handler.java:733)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5333)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:895)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:711)
at dalvik.system.NativeStart.main(Native Method)
