Develop Reference

Not able to display items properly in recycler view (pagination issue)

When I try to load more items when the user had scrolled to the end, a progress dialog is displayed and removed and then again displayed and then more items are displayed but progress dialog is still not removed from recycler view. And sometimes progress dialog is removed but still, it takes more time to display more items in recycler view. I'm using firestore addOnSuccessListener to retrieve items from cloud firestore and adding it to an arraylist and then adding native ads advanced to that arraylist and add the data to the recycler adapter.
Activity where recycler view items are displayed, MovieLists.java
public class MovieLists extends AppCompatActivity implements ItemInterface{
//nothing important just a comment
boolean runshowMovieOnce = true;
Query mQuery;
int loaderPosition;
DocumentSnapshot lastVisible;
String docId, catName, titleName;
ItemInterface itemInterface;
DatabaseReference listData;
String VideoId;
MovieListAdapter movieListAdapter;
RecyclerView movieLists;
// List of native ads that have been successfully loaded.
private List<UnifiedNativeAd> mNativeAds = new ArrayList<>();
List<Object> itemDatas = new ArrayList<>();
LinearLayoutManager layoutManager;
// The number of native ads to load.
public static final int NUMBER_OF_ADS = 2;
// The AdLoader used to load ads.
private AdLoader adLoader;
int index = 2;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_movie_lists);
MaterialToolbar mToolBar = (MaterialToolbar) findViewById(R.id.imagePreviewToolbar);
setSupportActionBar(mToolBar);
docId = getIntent().getStringExtra("documentId");
catName = getIntent().getStringExtra("catName");
titleName = getIntent().getStringExtra("titleName");
if (getSupportActionBar() != null) {
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
getSupportActionBar().setHomeAsUpIndicator(R.drawable.back_button);
getSupportActionBar().setTitle(titleName);
}
movieLists = (RecyclerView)findViewById(R.id.movie_lists);
layoutManager = new LinearLayoutManager(this,LinearLayoutManager.VERTICAL,false);
itemInterface = this;
loadMovies();
}
#Override
public void onFirebaseLoadSuccess(List<Object> itemDataList) {
loadNativeAds();
}
#Override
public void onFirebaseLoadFailed(String message) {
}
#SuppressLint("MissingPermission")
private void loadNativeAds() {
AdLoader.Builder builder = new AdLoader.Builder(this, "ca-app-pub-3940256099942544/8135179316");
adLoader = builder.forUnifiedNativeAd(
new UnifiedNativeAd.OnUnifiedNativeAdLoadedListener() {
#Override
public void onUnifiedNativeAdLoaded(UnifiedNativeAd unifiedNativeAd) {
// A native ad loaded successfully, check if the ad loader has finished loading
// and if so, insert the ads into the list.
mNativeAds.add(unifiedNativeAd);
if (!adLoader.isLoading()) {
insertAdsInMenuItems();
}
}
}).withAdListener(
new AdListener() {
#Override
public void onAdFailedToLoad(int errorCode) {
// A native ad failed to load, check if the ad loader has finished loading
// and if so, insert the ads into the list.
Log.e("MainActivity", "The previous native ad failed to load. Attempting to"
+ " load another.");
if (!adLoader.isLoading()) {
insertAdsInMenuItems();
}
}
}).build();
// Load the Native ads.
adLoader.loadAds(new AdRequest.Builder().build(), NUMBER_OF_ADS);
}
private void insertAdsInMenuItems() {
if (mNativeAds.size() <= 0) {
return;
}
int offset = 3;
for (UnifiedNativeAd ad : mNativeAds) {
if (index<itemDatas.size()) {
itemDatas.add(index, ad);
}
index = index + offset;
}
//index = itemDatas.size() - 3;
if (runshowMovieOnce){
showMoviesList();
}
runshowMovieOnce = false;
}
private void showMoviesList() {
movieLists.setLayoutManager(layoutManager);
movieListAdapter = new MovieListAdapter(movieLists,MovieLists.this,itemDatas);
movieLists.setHasFixedSize(true);
movieLists.setAdapter(movieListAdapter);
movieListAdapter.setLoadMore(new ILoadMore() {
#Override
public void onLoadMore() {
itemDatas.add(null);
movieLists.post(new Runnable() {
public void run() {
movieListAdapter.notifyItemInserted(itemDatas.size() - 1);
Log.d("load position insert", ""+(itemDatas.size()-1));
}
});
new Handler().postDelayed(new Runnable() {
#Override
public void run() {
itemDatas.remove(itemDatas.size()-1);
movieListAdapter.notifyItemRemoved(itemDatas.size() - 1);
Log.d("load position rem", ""+(itemDatas.size()-1));
int previousListSize = itemDatas.size();
Log.d("previousListSize",""+previousListSize);
loadMovies();
int newListSize = itemDatas.size();
Log.d("newListSize",""+newListSize);
movieListAdapter.notifyDataSetChanged();
movieListAdapter.setLoaded();
}
},5000);
}
});
}
private void loadMovies() {
FirebaseFirestore mFirestore = FirebaseFirestore.getInstance();
CollectionReference mPostsCollection = mFirestore.collection(catName).document(docId).collection("listItem");
//Defining Query cursors
if (lastVisible == null){
mQuery = mPostsCollection.orderBy("pr", Query.Direction.ASCENDING)
.limit(6);
}else {
mQuery = mPostsCollection.orderBy("pr", Query.Direction.ASCENDING)
.startAfter(lastVisible)
.limit(6);
}
mQuery.get().addOnSuccessListener(new OnSuccessListener<QuerySnapshot>() {
#Override
public void onSuccess(QuerySnapshot documentSnapshots) {
for (QueryDocumentSnapshot documentSnapshot : documentSnapshots){
ItemData itemData = documentSnapshot.toObject(ItemData.class);
itemDatas.add(itemData);
Log.d("movie name",itemData.getVn());
}
// Get the last visible document
if (documentSnapshots.size() > 0)
lastVisible = documentSnapshots.getDocuments()
.get(documentSnapshots.size() -1);
onFirebaseLoadSuccess(itemDatas);
}
});
}
}
MovieListAdapter.java
public class MovieListAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {
List<Object> itemDatas;
Context context;
String urlStart = "https://i1.ytimg.com/vi/";
String urlLast = "/mqdefault.jpg";
private static final int MOVIE_ITEM_VIEW_TYPE = 0;
private static final int UNIFIED_NATIVE_AD_VIEW_TYPE = 1;
private final int VIEW_TYPE_LOADING = 2;
boolean isLoading;
ILoadMore loadMore;
int visibleThreshold ;
int lastVisibleItem,totalItemCount;
View itemV;
public MovieListAdapter(RecyclerView recyclerView, Context context, #NonNull List<Object> itemData) {
this.itemDatas = itemData;
this.context = context;
final LinearLayoutManager linearLayoutManager = (LinearLayoutManager)recyclerView.getLayoutManager();
recyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
#Override
public void onScrolled(#NonNull RecyclerView recyclerView, int dx, int dy) {
super.onScrolled(recyclerView, dx, dy);
totalItemCount = linearLayoutManager.getItemCount();
visibleThreshold = linearLayoutManager.getChildCount();
lastVisibleItem = linearLayoutManager.findLastVisibleItemPosition();
if (!isLoading && (visibleThreshold + lastVisibleItem) >= totalItemCount){
if (loadMore != null){
loadMore.onLoadMore();
isLoading = true;
}
}
}
});
}
#NonNull
#Override
public RecyclerView.ViewHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
switch (viewType) {
case UNIFIED_NATIVE_AD_VIEW_TYPE:
View unifiedNativeLayoutView = LayoutInflater.from(
parent.getContext()).inflate(R.layout.ad_unified,
parent, false);
return new UnifiedNativeAdViewHolder(unifiedNativeLayoutView);
case VIEW_TYPE_LOADING:
View viewL = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_loading, parent, false);
return new LoadingViewHolder(viewL);
case MOVIE_ITEM_VIEW_TYPE:
// Fall through.
default: {
View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_movie_list, parent, false);
return new MovieListAdapter.MovieListsMyViewHolder(view);
}
}
}
#Override
public void onBindViewHolder(#NonNull RecyclerView.ViewHolder myViewHolder, int i) {
//int viewType = getItemViewType(i);
if (myViewHolder instanceof MovieListAdapter.MovieListsMyViewHolder){
MovieListsMyViewHolder movieListsMyViewHolder = (MovieListsMyViewHolder) myViewHolder;
ItemData model = (ItemData)itemDatas.get(i);
movieListsMyViewHolder.txt_item_title.setText(model.getVn());
String urlImage = urlStart + model.getVi() + urlLast;
Log.e("urlImage", urlImage);
Glide.with(context)
.load(urlImage)
.placeholder(R.drawable.placeholder)
.error(R.drawable.placeholder)
.centerCrop()
.diskCacheStrategy(DiskCacheStrategy.AUTOMATIC)
.into(movieListsMyViewHolder.img_title);
movieListsMyViewHolder.setiItemClickListener(new IItemClickListener() {
#Override
public void onItemclickListener(View view, int position) {
ItemData itemData = new ItemData(model.getVi(),model.getVn(),model.getVd(),model.getPr(),model.getTc(),model.getVvc());
Log.d("Tmdb ID",String.valueOf(model.getTc()));
MovieDetails.startActivity(context, ((MovieListsMyViewHolder) myViewHolder).transformationLayout, itemData);
}
});
}else if (myViewHolder instanceof UnifiedNativeAdViewHolder){
Object recyclerViewItems = itemDatas.get(i);
UnifiedNativeAd nativeAd = (UnifiedNativeAd) recyclerViewItems;
populateNativeAdView(nativeAd, ((UnifiedNativeAdViewHolder) myViewHolder).getAdView());
}else if (myViewHolder instanceof LoadingViewHolder){
LoadingViewHolder loadingViewHolder = (LoadingViewHolder)myViewHolder;
loadingViewHolder.progressBar.setIndeterminate(true);
}
}
#Override
public int getItemCount() {
return itemDatas.size();
}
public class MovieListsMyViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener{
AppCompatTextView txt_item_title;
ImageView img_title;
IItemClickListener iItemClickListener;
CardView itemCardView;
TransformationLayout transformationLayout;
public void setiItemClickListener(IItemClickListener iItemClickListener) {
this.iItemClickListener = iItemClickListener;
}
public MovieListsMyViewHolder(#NonNull View itemView) {
super(itemView);
itemV = itemView;
txt_item_title = (AppCompatTextView) itemView.findViewById(R.id.item_movie_Title);
img_title = (ImageView)itemView.findViewById(R.id.item_movie_Image);
//itemCardView = (CardView)itemView.findViewById(R.id.item_cardview);
//itemCardView.setOnClickListener(this);
transformationLayout = (TransformationLayout)itemView.findViewById(R.id.transformationMovieLayout);
transformationLayout.setOnClickListener(this);
}
#Override
public void onClick(View view){
iItemClickListener.onItemclickListener(view,getAdapterPosition());
}
}
private void populateNativeAdView(UnifiedNativeAd nativeAd,
UnifiedNativeAdView adView) {
// Some assets are guaranteed to be in every UnifiedNativeAd.
((TextView) adView.getHeadlineView()).setText(nativeAd.getHeadline());
((TextView) adView.getBodyView()).setText(nativeAd.getBody());
((Button) adView.getCallToActionView()).setText(nativeAd.getCallToAction());
// These assets aren't guaranteed to be in every UnifiedNativeAd, so it's important to
// check before trying to display them.
NativeAd.Image icon = nativeAd.getIcon();
if (icon == null) {
adView.getIconView().setVisibility(View.INVISIBLE);
} else {
((ImageView) adView.getIconView()).setImageDrawable(icon.getDrawable());
adView.getIconView().setVisibility(View.VISIBLE);
}
if (nativeAd.getPrice() == null) {
adView.getPriceView().setVisibility(View.INVISIBLE);
} else {
adView.getPriceView().setVisibility(View.VISIBLE);
((TextView) adView.getPriceView()).setText(nativeAd.getPrice());
}
if (nativeAd.getStore() == null) {
adView.getStoreView().setVisibility(View.INVISIBLE);
} else {
adView.getStoreView().setVisibility(View.VISIBLE);
((TextView) adView.getStoreView()).setText(nativeAd.getStore());
}
if (nativeAd.getStarRating() == null) {
adView.getStarRatingView().setVisibility(View.INVISIBLE);
} else {
((RatingBar) adView.getStarRatingView())
.setRating(nativeAd.getStarRating().floatValue());
adView.getStarRatingView().setVisibility(View.VISIBLE);
}
if (nativeAd.getAdvertiser() == null) {
adView.getAdvertiserView().setVisibility(View.INVISIBLE);
} else {
((TextView) adView.getAdvertiserView()).setText(nativeAd.getAdvertiser());
adView.getAdvertiserView().setVisibility(View.VISIBLE);
}
// Assign native ad object to the native view.
adView.setNativeAd(nativeAd);
}
#Override
public int getItemViewType(int position) {
//DocumentSnapshot itemData = getItem(position);
Object recyclerViewItem = itemDatas.get(position);
if (recyclerViewItem instanceof UnifiedNativeAd) {
return UNIFIED_NATIVE_AD_VIEW_TYPE;
}else if (itemDatas.get(position) == null){
return VIEW_TYPE_LOADING;
}else {
return MOVIE_ITEM_VIEW_TYPE;
}
}
public void setLoadMore(ILoadMore loadMore){
this.loadMore = loadMore;
}
private class LoadingViewHolder extends RecyclerView.ViewHolder {
ProgressBar progressBar;
public LoadingViewHolder(#NonNull View itemView) {
super(itemView);
progressBar = itemView.findViewById(R.id.progressBar);
}
}
public void setLoaded(){
isLoading = false;
}
}

The short term answer: There's a lot going on in your code. If you just want to remove the loadingProgress, add a void viewsLoaded() method inside your LoadingViewHolder with progressbar.setVisibility(View.GONE), and inside onBindViewHolder method, on the if(myViewHolder instanceof LoadingViewHolder), call the viewsLoaded() method if viewHolder is not positioned as the last one on the Adapter.
The long term answer: If you want to enhance the performance, read about how to use DiffUtil.ItemCallback<> instead of using notifydatasetchanged(), which is used for simple small datasets. You have a list of objectData on your activity and another one on your adapter, read about using LiveData, databinding and MVVM pattern.

i suggest first of all you should get The linearLayoutManager inside The Scroll View Listener.
another suggestion is to not call movieListAdapter.notifyItemInserted(itemDatas.size() - 1); Async inside the Runnable because after you add a null into list The Adapter should be notify:
itemsData.add(null);
movieListAdapter.notifyItemInserted(itemsData.size() - 1);
another is in the line: itemDatas.remove(itemDatas.size()-1)
after you remove the item from list, The List size will decrease by one.
so this would be correct:
movieListAdapter.notifyItemRemoved(itemDatas.size());
i Hope these would help.

How to reset recycler when recreate fragment

The problem is that in my tablayout when im switching between tabs my list duplicating. So i need to remove list on onStop() to recreate it then. Or might be other better solution.
I have tried the following solutions
https://code-examples.net/en/q/1c97047
How to reset recyclerView position item views to original state after refreshing adapter
Remove all items from RecyclerView
My code of adapter
public class OnlineUsersAdapter extends RecyclerView.Adapter<OnlineUsersAdapter.OnlineUserViewHolder> {
private List<OnlineUser> onlineUsers = new ArrayList<>();
private OnItemClickListener.OnItemClickCallback onItemClickCallback;
private OnItemClickListener.OnItemClickCallback onChatClickCallback;
private OnItemClickListener.OnItemClickCallback onLikeClickCallback;
private Context context;
public OnlineUsersAdapter(Context context) {
this.onlineUsers = new ArrayList<>();
this.context = context;
}
#NonNull
#Override
public OnlineUsersAdapter.OnlineUserViewHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
context = parent.getContext();
View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_user, parent, false);
return new OnlineUsersAdapter.OnlineUserViewHolder(v);
}
#Override
public void onBindViewHolder(#NonNull OnlineUsersAdapter.OnlineUserViewHolder holder, int position) {
OnlineUser user = onlineUsers.get(position);
Log.d("testList", "rating " + user.getRating() + " uid " + user.getUid());
holder.bind(user, position);
}
#Override
public int getItemCount() {
return onlineUsers.size();
}
class OnlineUserViewHolder extends RecyclerView.ViewHolder {
RelativeLayout container;
ImageView imageView, likeBtn, chatBtn;
TextView name, country;
private LottieAnimationView animationView;
OnlineUserViewHolder(View itemView) {
super(itemView);
context = itemView.getContext();
container = itemView.findViewById(R.id.item_user_container);
imageView = itemView.findViewById(R.id.user_img);
likeBtn = itemView.findViewById(R.id.search_btn_like);
chatBtn = itemView.findViewById(R.id.search_btn_chat);
name = itemView.findViewById(R.id.user_name);
country = itemView.findViewById(R.id.user_country);
animationView = itemView.findViewById(R.id.lottieAnimationView);
}
void bind(OnlineUser user, int position) {
ViewCompat.setTransitionName(imageView, user.getName());
if (FirebaseUtils.isUserExist() && user.getUid() != null) {
new FriendRepository().isLiked(user.getUid(), flag -> {
if (flag) {
likeBtn.setBackground(ContextCompat.getDrawable(context, R.drawable.ic_favorite));
animationView.setVisibility(View.VISIBLE);
} else {
likeBtn.setBackground(ContextCompat.getDrawable(context, R.drawable.heart_outline));
animationView.setVisibility(View.GONE);
}
});
}
if (user.getUid() != null) {
chatBtn.setOnClickListener(new OnItemClickListener(position, onChatClickCallback));
likeBtn.setOnClickListener(new OnItemClickListener(position, onLikeClickCallback));
}
imageView.setOnClickListener(new OnItemClickListener(position, onItemClickCallback));
imageView.setScaleType(ImageView.ScaleType.FIT_XY);
if (user.getImage().equals(Consts.DEFAULT)) {
Glide.with(context).load(context.getResources().getDrawable(R.drawable.default_avatar)).into(imageView);
} else {
Glide.with(context).load(user.getImage()).thumbnail(0.5f).into(imageView);
}
country.setText(user.getCountry());
ValueAnimator animator = ValueAnimator.ofFloat(0f, 1f).setDuration(500);
animator.addUpdateListener(valueAnimator ->
animationView.setProgress((Float) valueAnimator.getAnimatedValue()));
if (animationView.getProgress() == 0f) {
animator.start();
} else {
animationView.setProgress(0f);
}
}
}
public OnlineUsersAdapter(OnItemClickListener.OnItemClickCallback onItemClickCallback,
OnItemClickListener.OnItemClickCallback onChatClickCallback,
OnItemClickListener.OnItemClickCallback onLikeClickCallback) {
this.onItemClickCallback = onItemClickCallback;
this.onChatClickCallback = onChatClickCallback;
this.onLikeClickCallback = onLikeClickCallback;
}
public void addUsers(List<OnlineUser> userList) {
int initSize = userList.size();
onlineUsers.addAll(userList);
// notifyItemRangeInserted(onlineUsers.size() - userList.size(), onlineUsers.size());
}
public String getLastItemId() {
return onlineUsers.get(onlineUsers.size() - 1).getUid();
}
public void clearData() {
List<OnlineUser> data = new ArrayList<>();
addUsers(data);
notifyDataSetChanged();
}
My code in fragment
#Override
public void onStop() {
super.onStop();
firstUid = "";
stopDownloadList = false;
List<OnlineUser> list = new ArrayList<>();
mAdapter.addUsers(list);
mAdapter.notifyDataSetChanged();
}
`users are added after callback
#Override
public void addUsers(List<OnlineUser> onlineUsers) {
if (firstUid.equals("")){
firstUid = onlineUsers.get(0).getUid();
}
if (!firstUid.equals("") && onlineUsers.contains(firstUid)){
stopDownloadList = true;
}
if (!stopDownloadList){
mAdapter.addUsers(onlineUsers);
}
setRefreshProgress(false);
isLoading = false;
isMaxData = true;
}

The line mAdapter.addUsers(onlineUsers); from addUsers method gets called twice. Looks like your asynchronous operation gets triggered twice (e. g. from repeating lifecycle methods like onCreate/onCreateView/onViewCreated).
Solution #1: request users a single time
Move your user requesting machinery to onCreate or onAttach. This will save network traffic but could lead to showing outdated data.
Solution #2: replaceUsers
Your clearData calls mAdapter.addUsers(new ArrayList<>()); (btw, take a look at Collections.emptyList()). Looks like you're trying to replace adapter data but appending instead. Replacement method could look like
public void replaceUsers(List<OnlineUser> userList) {
int oldSize = userList.size();
onlineUsers = userList;
notifyItemRangeRemoved(0, oldSize);
notifyItemRangeInserted(0, userList.size);
}
This version still requeses users every time your fragment gets focused but shows fresher data.

how to update 1 recycler view adapter from 2 view models?

I have 2 view models observing 2 tables in room each emitting live data, they should update my recycler view when a value changes. My adapter is equipped to handle more than one model and view holder, but I'm not sure how to update the recycler views adapter with new data without overwriting the current data or duplicating any data any ideas?
So my adapter takes a list of Visitable (Visitable pattern)
I have 2 objects that implement this interface, the interface has a type so I can tell what view holder it wants and I update the recycler view using diff utils, it look like this
public class CardAdapter extends RecyclerView.Adapter<BaseViewHolder> {
private final List<Visitable> elements;
private final TypeFactory typeFactory;
private final ItemTouchListener onItemTouchListener;
private final Context context;
private String cardType;
private final String layoutIdentifier;
private static final String TAG = "Adptr-Card";
private String CARD_CLICK_UPDATE = "card_click_update";
private final String[] imageFilePathNames;
private RequestManager glide;
public CardAdapter(List<Visitable> elements, TypeFactory typeFactory, ItemTouchListener onItemTouchListener,
Context context,
String cardType, String layoutIdentifier, RequestManager glide) {
this.glide = glide;
this.elements = elements;
this.typeFactory = typeFactory;
this.onItemTouchListener = onItemTouchListener;
this.context = context;
this.cardType = cardType;
this.layoutIdentifier = layoutIdentifier;
this.imageFilePathNames = context.getResources().getStringArray(R.array.image_set_names);
}
#NonNull
#Override
public BaseViewHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
View contactView = LayoutInflater.from(context).inflate(viewType, parent, false);
return typeFactory.createViewHolder(contactView, viewType, onItemTouchListener, glide, cardType);
}
#Override
public void onBindViewHolder(#NonNull BaseViewHolder holder, int position) {
holder.bind(elements.get(position), position);
}
#Override
public int getItemViewType(int position) {
return elements.get(position).type(typeFactory);
}
public void setCardType(String cardType) {
this.cardType = cardType;
notifyDataSetChanged();
}
#Override
public int getItemCount() {
return elements.size();
}
public List<Visitable> getList() {
return elements;
}
public List<Sentence> getSentencesList() {
ArrayList<Sentence> sentences = new ArrayList<>();
for (Visitable visitable : elements) {
if (visitable.type(typeFactory) == CardViewHolder.LAYOUT) {
sentences.add((Sentence) visitable);
}
}
return sentences;
}
public Visitable getItem(int position) {
if (position > 0 && position < elements.size()) {
return elements.get(position);
}
return elements.get(0);
}
class CalculateDiffUtils extends AsyncTask<Void, Void, DiffResult> {
private final List<Visitable> oldCardList;
private final List<Visitable> newCardList;
CalculateDiffUtils(List<Visitable> oldCardList, List<Visitable> newCardList) {
this.oldCardList = oldCardList;
this.newCardList = newCardList;
}
#Override
protected DiffUtil.DiffResult doInBackground(Void... params) {
return DiffUtil.calculateDiff(new VisitableDiffUtils(oldCardList, newCardList, typeFactory));
}
#Override
protected void onPostExecute(DiffUtil.DiffResult diffResult) {
super.onPostExecute(diffResult);
dispatchUpdates(diffResult, newCardList);
}
}
private void dispatchUpdates(DiffUtil.DiffResult diffResult, List<Visitable> newCardList) {
this.elements.clear();
this.elements.addAll(newCardList);
diffResult.dispatchUpdatesTo(this);
}
public void refreshDiffUtilsList(List<Visitable> sentences) {
new CalculateDiffUtils(elements, sentences).execute();
}
public void removeItem(int position) {
elements.remove(position);
notifyItemRemoved(position);
}
public void addCard(Sentence sentence) {
elements.add(getItemCount(), sentence);
notifyItemInserted(getItemCount());
}
public void addGroup(GroupsWithSentences sentence) {
elements.add(getItemCount(), sentence);
notifyItemInserted(getItemCount());
}
public void updateCardClick(int position) {
notifyItemChanged(position, CARD_CLICK_UPDATE);
}
public void refreshList(List<Visitable> newElements) {
ArrayList<Visitable> elementArrayList = new ArrayList<>(newElements);
elements.clear();
elements.addAll(elementArrayList);
notifyDataSetChanged();
}
}
My 2 view models sit in a fragment, they observe some data from my Room database and are updated when changes happen, but this means I will only ever have the data from one of the view models, I guess I want a way to combine these view models maybe using some kind of mediator live data, here are my 2 view models (I've removed stuff for brevity, they are both initiated using factories)
GROUP VIEW MODEL
public class GroupViewModel extends ViewModel {
private final GroupRepository groupRepository;
private final LiveData<List<GroupsWithSentences>> groups;
public GroupViewModel(#NonNull Application application, String[] cardArgs) {
groupRepository = new GroupRepository(application);
groups = groupRepository.getGroupsByWordDescriptionAndWordType(cardArgs[0],cardArgs[1]);
}
public LiveData<List<GroupsWithSentences>> getGroups() {
return groups;
}
}
SENTENCE VIEW MODEL
public class CardViewModel extends ViewModel {
private final SentenceRepository sentenceRepository;
private final LiveData<List<Sentence>> cards;
private static final String TAG = "view_model";
public CardViewModel(#NonNull Application application , int clicks){
sentenceRepository = new SentenceRepository(application);
search = new MutableLiveData<>();
cardArgs = new MutableLiveData<>();
cards = Transformations.switchMap(search, mySearch -> sentenceRepository.searchLiveCardListByWordTypeAndWordDescriptionAndSearchWord(getCardArgs()[0],getCardArgs()[1],mySearch));
}
public LiveData<List<Sentence>> getLiveCardList(){
return cards;
}
}
CALLING ADAPTER IN MY FRAGMENT
private void setUpCardViewModelObserver(String[] args) {
cardViewModel.getLiveCardList().observe(getViewLifecycleOwner(), sentenceList -> {
if (sentenceList != null) {
ArrayList<Visitable> list = new ArrayList<>(sentenceList);
cardAdapter.refreshDiffUtilsList(list);
checkResults(list.size());
}
});
}
private void setUpGroupViewModelObserver() {
groupViewModel.getGroups().observe(getViewLifecycleOwner(), groupsWithSentencesList -> {
if (groupsWithSentencesList != null) {
ArrayList<Visitable> list = new ArrayList<>(groupsWithSentencesList);
cardAdapter.refreshDiffUtilsList(list);
checkResults(groupsWithSentencesList.size());
}
});
}
Any help is welcome, many thanks.

So the answer was to use Mediator Live data, i set the new mediator live data to respond to changes to my existing live data objects and then mediate those changes so i now only have one stream of data so my card view model now looks like this
public CardViewModel(#NonNull Application application , int clicks, String[] cardArgs){
sentenceRepository = new SentenceRepository(application);
search = new MutableLiveData<>();
cards = Transformations.switchMap(search, mySearch -> sentenceRepository.searchLiveCardListByWordTypeAndWordDescriptionAndSearchWord(cardArgs[0],cardArgs[1],mySearch));
groupRepository = new GroupRepository(application);
groups = groupRepository.getGroupsByWordDescriptionAndWordType(cardArgs[0],cardArgs[1]);
sentencesAndGroups = new MediatorLiveData<>();
sentencesAndGroups.addSource(cards, sentences -> {
sentencesAndGroups.setValue(combineLatest(sentences, groups.getValue()));
});
sentencesAndGroups.addSource(groups, groupsWithSentences -> {
sentencesAndGroups.setValue(combineLatest(cards.getValue(), groupsWithSentences));
});
}
and my new combine latest method looks like this
private List<Visitable> combineLatest(List<Sentence> sentenceList, List<GroupsWithSentences> groupsWithSentences) {
List<Visitable> visitableList = new ArrayList<>();
if (sentenceList != null){
visitableList.addAll(sentenceList);
}
if (groupsWithSentences != null){
visitableList.addAll(groupsWithSentences);
}
return visitableList;
}

Getting a RecyclerView to reload items

I am currently working on an app, that finds all MP3s on a users phone and then puts them into a list. This works very fine and is very quick, even with many songs. Now I populate a new list with an object for each item of the list to then display it inside my recyclerview. The problem is, that I have 700+ songs on my phone and this blocks the UI thread quite some time.
Now, I want to use the recyclerview to not load all items from the list into the objects all at once but rather only when they are about to be displayed - but I have NO clue over how to do this. Right now, all objects are build and then displayed in a very long scrollview from the recyclerview after the UI thread has been blocked for a good 30 seconds. Can please anyone help me? Here is my code:
namespace Media_Player
{
[Activity(Label = "Media_Player", MainLauncher = true)]
public class MainActivity : Activity
{
static public MediaPlayer mediaPlayer;
List<MP3object> mp3;
MediaMetadataRetriever reader;
public static Button btn_StartOrPause, btn_Stop;
public static TextView txt_CurrentSong;
public static bool stopIsActive = false, firstStart = true;
public static Android.Net.Uri CurrentActiveSongUri;
RecyclerView mRecyclerView;
RecyclerView.LayoutManager mLayoutManager;
PhotoAlbumAdapter mAdapter;
protected override void OnCreate(Bundle savedInstanceState)
{
base.OnCreate(savedInstanceState);
SetContentView(Resource.Layout.test);
reader = new MediaMetadataRetriever();
PopulateMP3List(ReturnPlayableMp3(true));
mediaPlayer = new MediaPlayer();
InitRecView();
}
private void InitRecView()
{
// Instantiate the adapter and pass in its data source:
mAdapter = new PhotoAlbumAdapter(mp3);
// Get our RecyclerView layout:
mRecyclerView = FindViewById<RecyclerView>(Resource.Id.recyclerView);
// Plug the adapter into the RecyclerView:
mRecyclerView.SetAdapter(mAdapter);
mLayoutManager = new LinearLayoutManager(this);
mRecyclerView.SetLayoutManager(mLayoutManager);
}
private void PopulateMP3List(List<string> content)
{
mp3 = new List<MP3object>();
foreach (string obj in content)
{
WriteMetaDataToFileList(obj);
}
}
void WriteMetaDataToFileList(string obj)
{
reader.SetDataSource(obj);
//Write Mp3 as object to global list
MP3object ob = new MP3object();
{
if(reader.ExtractMetadata(MediaMetadataRetriever.MetadataKeyTitle) != "" && reader.ExtractMetadata(MediaMetadataRetriever.MetadataKeyTitle) != null)
{
ob.SongName = reader.ExtractMetadata(MediaMetadataRetriever.MetadataKeyTitle);
}
else
{
ob.SongName = Resources.GetString(Resource.String.Unknown);
}
if (reader.ExtractMetadata(MediaMetadataRetriever.MetadataKeyArtist) != "" && reader.ExtractMetadata(MediaMetadataRetriever.MetadataKeyArtist) != null)
{
ob.ArtistName = reader.ExtractMetadata(MediaMetadataRetriever.MetadataKeyArtist);
}
else
{
ob.ArtistName = Resources.GetString(Resource.String.Unknown);
}
if (reader.ExtractMetadata(MediaMetadataRetriever.MetadataKeyAlbum) != "" && reader.ExtractMetadata(MediaMetadataRetriever.MetadataKeyAlbum) != null)
{
ob.AlbumName = reader.ExtractMetadata(MediaMetadataRetriever.MetadataKeyAlbum);
}
else
{
ob.AlbumName = Resources.GetString(Resource.String.Unknown);
}
if (reader.ExtractMetadata(MediaMetadataRetriever.MetadataKeyYear) != "" && reader.ExtractMetadata(MediaMetadataRetriever.MetadataKeyYear) != null)
{
ob.Year = reader.ExtractMetadata(MediaMetadataRetriever.MetadataKeyYear);
}
else
{
ob.Year = Resources.GetString(Resource.String.Unknown);
}
if (reader.ExtractMetadata(MediaMetadataRetriever.MetadataKeyYear) != "" && reader.ExtractMetadata(MediaMetadataRetriever.MetadataKeyYear) != null)
{
ob.Year = reader.ExtractMetadata(MediaMetadataRetriever.MetadataKeyYear);
}
else
{
ob.Year = Resources.GetString(Resource.String.Unknown);
}
ob.Mp3Uri = obj; // can never be unknown!
ob.DurationInSec = int.Parse(reader.ExtractMetadata(MediaMetadataRetriever.MetadataKeyDuration)) / 1000; // can never be unknown, div by 1000 to get sec not millis
}
mp3.Add(ob);
}
public List<string> ReturnPlayableMp3(bool sdCard)
{
List<string> res = new List<string>();
string phyle;
string path1 = null;
if(sdCard) // get mp3 from SD card
{
string baseFolderPath = "";
try
{
bool getSDPath = true;
Context context = Application.Context;
Java.IO.File[] dirs = context.GetExternalFilesDirs(null);
foreach (Java.IO.File folder in dirs)
{
bool IsRemovable = Android.OS.Environment.InvokeIsExternalStorageRemovable(folder);
bool IsEmulated = Android.OS.Environment.InvokeIsExternalStorageEmulated(folder);
if (getSDPath ? IsRemovable && !IsEmulated : !IsRemovable && IsEmulated)
baseFolderPath = folder.Path;
}
}
catch (Exception ex)
{
Console.WriteLine("GetBaseFolderPath caused the following exception: {0}", ex);
}
string xy = baseFolderPath.Remove(18); // This is result after this, but this hard coded solution could be a problem on different phones.: "/storage/05B6-2226/Android/data/Media_Player.Media_Player/files"
path1 = xy;
// path to SD card and MUSIC "/storage/05B6-2226/"
}
else // get Mp3 from internal storage
{
path1 = Android.OS.Environment.ExternalStorageDirectory.ToString();
}
var mp3Files = Directory.EnumerateFiles(path1, "*.mp3", SearchOption.AllDirectories);
foreach (string currentFile in mp3Files)
{
phyle = currentFile;
res.Add(phyle);
}
return res;
}
}
public class PhotoViewHolder : RecyclerView.ViewHolder
{
public ImageView Image { get; private set; }
public TextView Caption { get; private set; }
public PhotoViewHolder(View itemView) : base(itemView)
{
// Locate and cache view references:
Image = itemView.FindViewById<ImageView>(Resource.Id.imageView);
Caption = itemView.FindViewById<TextView>(Resource.Id.textView);
}
}
public class PhotoAlbumAdapter : RecyclerView.Adapter
{
public List<MP3object> mp3;
public PhotoAlbumAdapter(List<MP3object> mp3)
{
this.mp3 = mp3;
}
public override RecyclerView.ViewHolder OnCreateViewHolder(ViewGroup parent, int viewType)
{
View itemView = LayoutInflater.From(parent.Context).
Inflate(Resource.Layout.lay, parent, false);
PhotoViewHolder vh = new PhotoViewHolder(itemView);
return vh;
}
public override void OnBindViewHolder(RecyclerView.ViewHolder holder, int position)
{
PhotoViewHolder vh = holder as PhotoViewHolder;
vh.Caption.Text = mp3[position].SongName;
}
public override int ItemCount
{
get { return mp3.Count(); }
}
}
}
So getting the list of strings with the locations of the Mp3 works very quickly, but then "WriteMetaDataToFileList(obj)" kicks in, comming from "PopulateMP3List(List content)" and this is what takes so long. What I think I need is for the recyclerview to only build the first 20 objects, and when the user starts scrolling, builds the next 20 objects and attaches them to list for them to also be scrolled. Please help me out here :)

Here is an abstract class:
public abstract class PaginationScrollListener extends RecyclerView.OnScrollListener {
private LinearLayoutManager linearLayoutManager;
protected PaginationScrollListener(LinearLayoutManager linearLayoutManager) {
this.linearLayoutManager = linearLayoutManager;
}
#Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
super.onScrolled(recyclerView, dx, dy);
int visibleItemCount = linearLayoutManager.getChildCount();
int totalItemCount = linearLayoutManager.getItemCount();
int firstVisibleItemPosition = linearLayoutManager.findFirstVisibleItemPosition();
if (!isLoading() && !isLastPage()) {
if ((visibleItemCount + firstVisibleItemPosition) >= totalItemCount && firstVisibleItemPosition >= 0) {
loadMoreItems();
}
}
}
protected abstract void loadMoreItems();
public abstract boolean isLastPage();
public abstract boolean isLoading();
}
and In your adapter you must follow this pattern:
public class ConsultancyAdapter extends RecyclerView.Adapter<ConsultancyAdapter.ConsultancyVH> {
private static final int ITEM = 0;
private static final int LOADING = 1;
private boolean isLoadingAdded = false;
public ConsultancyAdapter(List<Consultancy> consultancies, ConsultancyAdapterListener listener) {
}
#NonNull
#Override
public ConsultancyVH onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
RecyclerView.ViewHolder viewHolder = null;
LayoutInflater layoutInflater = LayoutInflater.from(parent.getContext());
switch (viewType) {
case ITEM:
viewHolder = getViewHolder(parent, layoutInflater);
break;
case LOADING:
View v2 = layoutInflater.inflate(R.layout.item_progress, parent, false);
viewHolder = new ConsultancyVH(v2);
break;
}
return (ConsultancyVH) viewHolder;
}
#NonNull
private RecyclerView.ViewHolder getViewHolder(ViewGroup parent, LayoutInflater inflater) {
RecyclerView.ViewHolder viewHolder;
View v1 = inflater.inflate(R.layout.item_consultancy, parent, false);
viewHolder = new ConsultancyVH(v1);
return viewHolder;
}
#Override
public void onBindViewHolder(#NonNull ConsultancyVH holder, int position) {
Consultancy consultancy = consultancies.get(position);
switch (getItemViewType(position)) {
case ITEM:
ConsultancyVH mySingeCounseller = holder;
holder.title.setText(consultancy.getTitle()); // set cardTitle
holder.fieldArea.setText(consultancy.getField_filedoctorskills());
break;
case LOADING:
break;
}
}
#Override
public int getItemCount() {
return consultancies.size();
}
#Override
public int getItemViewType(int position) {
return (position == consultancies.size() - 1 && isLoadingAdded) ? LOADING : ITEM;
}
public void add(Consultancy mc) {
consultancies.add(mc);
notifyItemInserted(consultancies.size() - 1);
}
public void addAll(List<Consultancy> mcList) {
for (Consultancy mc : mcList) {
add(mc);
}
}
public void remove(Consultancy city) {
int position = consultancies.indexOf(city);
if (position > -1) {
consultancies.remove(position);
notifyItemRemoved(position);
}
}
public Consultancy getItem(int position) {
return consultancies.get(position);
}
public void clear() {
isLoadingAdded = false;
while (getItemCount() > 0) {
remove(getItem(0));
}
}
public boolean isEmpty() {
return getItemCount() == 0;
}
public void addLoadingFooter() {
isLoadingAdded = true;
add(new Consultancy());
}
public void removeLoadingFooter() {
isLoadingAdded = false;
int position = consultancies.size() - 1;
Consultancy item = getItem(position);
if (item != null) {
consultancies.remove(position);
notifyItemRemoved(position);
}
}
public interface ConsultancyAdapterListener {
void onCaseClicked(int position, String nid, String fieldArea, String title);
}
protected class ConsultancyVH extends RecyclerView.ViewHolder {
private TextView title, fieldArea;
private CircleImageView iconProfile;
private MaterialRippleLayout caseButtonRipple;
public ConsultancyVH(View itemView) {
super(itemView);
caseButtonRipple = itemView.findViewById(R.id.case_button_ripple);
this.title = itemView.findViewById(R.id.docName);
this.fieldArea = itemView.findViewById(R.id.fieldArea);
this.iconProfile = itemView.findViewById(R.id.icon_profile);
}
}
}
and in your activity:
private void setScrollListener() {
recyclerView.addOnScrollListener(new PaginationScrollListener(linearLayoutManager) {
#Override
protected void loadMoreItems() {
isLoading = true;
currentPage += 1;
loadNextPage();
}
#Override
public boolean isLastPage() {
return isLastPage;
}
#Override
public boolean isLoading() {
return isLoading;
}
});
loadFirstPage();
}
and in my loadFirstPage i talk to a API and you need some your code:
private void loadFirstPage() {
CallData().enqueue(new DefaultRetrofitCallback<List<Consultancy>>() {
#Override
protected void onFailure(Throwable t) {
super.onFailure(t);
}
#Override
protected void onSuccess(List<Consultancy> response) {
swipeRefreshLayout.setRefreshing(false);
dataList = response;
adapter.addAll(dataList);
recyclerView.setAdapter(adapter);
if (!checkLast(response)) adapter.addLoadingFooter();
else isLastPage = true;
}
#Override
protected void onOtherStatus(Response<List<Consultancy>> response) {
super.onOtherStatus(response);
}
#Override
protected void always() {
super.always();
}
});
}
and loadNextPage:
private void loadNextPage() {
CallData().enqueue(new DefaultRetrofitCallback<List<Consultancy>>() {
#Override
protected void onFailure(Throwable t) {
super.onFailure(t);
}
#Override
protected void onSuccess(List<Consultancy> response) {
swipeRefreshLayout.setRefreshing(false);
adapter.removeLoadingFooter();
isLoading = false;
swipeRefreshLayout.setRefreshing(false);
adapter.addAll(response);
if (!checkLast(response)) adapter.addLoadingFooter();
else isLastPage = true;
}
#Override
protected void onOtherStatus(Response<List<Consultancy>> response) {
super.onOtherStatus(response);
}
#Override
protected void always() {
super.always();
}
});
}

RecyclerView reload same data when refresh

I have a problem, when i swipe to refresh the data, the first swipe is ok but after that every swipe reload and add the same data over and over again, by the end i have a list with same items over and over... I'm using a loader.
I tried to clear before but i don't understand what's wrong with my code, if someone could explain it to me. Thank You.
Here my code :
public abstract class NewsFragment extends Fragment implements LoaderManager.LoaderCallbacks<ArrayList<Articles>> {
protected ItemAdapter mArticleAdapter;
protected RecyclerView mRecyclerView;
protected NewsFragment.OnNewSelectedInterface mListener;
protected RecyclerView.LayoutManager mManager;
protected SwipeRefreshLayout mSwipeRefreshLayout;
protected LoaderManager mLoaderManager;
private boolean mStateSaved;
private static final int NEWS_LOAD_ID = 1;
public static final String KEY_LIST = "key_list";
public interface OnNewSelectedInterface {
void onListNewSelected(int index, ArrayList<Articles> articles);
}
#Nullable
#Override
public View onCreateView(LayoutInflater inflater, #Nullable ViewGroup container, #Nullable Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.list_present_news, container, false);
mListener = (NewsFragment.OnNewSelectedInterface) getActivity();
mSwipeRefreshLayout = (SwipeRefreshLayout) view.findViewById(R.id.swipeContainer);
mRecyclerView = (RecyclerView) view.findViewById(R.id.recyclerview);
mManager = new LinearLayoutManager(getActivity());
mArticleAdapter = new ItemAdapter(getActivity(), new ArrayList<Articles>(), mListener);
mLoaderManager = getLoaderManager();
mStateSaved = mArticleAdapter.isStateSaved();
mRecyclerView.setAdapter(mArticleAdapter);
mRecyclerView.setLayoutManager(mManager);
getData();
refreshData();
if(!isNetworkAvailable())alertUserAboutError();
setDivider();
return view;
}
private void setDivider() {
DividerItemDecoration dividerItemDecoration = new DividerItemDecoration(mRecyclerView
.getContext(), DividerItemDecoration.VERTICAL);
mRecyclerView.addItemDecoration(dividerItemDecoration);
}
private void getData() {
getLoaderManager().initLoader(NEWS_LOAD_ID, null, this).forceLoad();
}
private void alertUserAboutError() {
AlertDialogFragment alertDialogFragment = new AlertDialogFragment();
alertDialogFragment.show(getActivity().getFragmentManager(), "error_dialog");
}
protected abstract String[] getUrl();
private boolean isNetworkAvailable() {
ConnectivityManager manager = (ConnectivityManager)
getActivity().getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo networkInfo = manager.getActiveNetworkInfo();
boolean isAvailable = false;
if (networkInfo != null && networkInfo.isConnected()) {
isAvailable = true;
}
return isAvailable;
}
private void refreshData() {
mSwipeRefreshLayout.setOnRefreshListener(new SwipeRefreshLayout.OnRefreshListener() {
#Override
public void onRefresh() {
mArticleAdapter.clear();
mSwipeRefreshLayout.setRefreshing(false);
}
});
mSwipeRefreshLayout.setColorSchemeResources(
android.R.color.holo_orange_light,
android.R.color.holo_red_light);
}
#Override
public Loader<ArrayList<Articles>> onCreateLoader(int id, Bundle args) {
return new NewsLoader(getActivity(), getUrl());
}
#Override
public void onLoadFinished(Loader<ArrayList<Articles>> loader, ArrayList<Articles> data) {
if (data != null && !data.isEmpty()) {
mArticleAdapter.addAll(data);
}
}
#Override
public void onLoaderReset(Loader<ArrayList<Articles>> loader) {
mArticleAdapter.clear();
}
}
My loader class :
public class NewsLoader extends AsyncTaskLoader<ArrayList<Articles>>{
private ArrayList<Articles> mArticlesArrayList;
private String[] mUrl;
public NewsLoader(Context context, String[] url) {
super(context);
mUrl = url;
}
#Override
public ArrayList<Articles> loadInBackground() {
OkHttpClient mClient = new OkHttpClient();
for (String aMUrl : mUrl) {
Request mRequest = new Request.Builder().url(aMUrl).build();
try {
Response response = mClient.newCall(mRequest).execute();
try {
if (response.isSuccessful()) {
String json = response.body().string();
getMultipleUrls(json);
}
} catch (IOException | JSONException e) {
e.printStackTrace();
}
} catch (IOException e) {
e.printStackTrace();
}
}
return mArticlesArrayList;
}
private void getMultipleUrls(String jsonData) throws JSONException {
if (mArticlesArrayList == null) {
mArticlesArrayList = getArticleForecast(jsonData);
} else {
mArticlesArrayList.addAll(getArticleForecast(jsonData));
}
}
private ArrayList<Articles> getArticleForecast(String jsonData) throws JSONException {
JSONObject forecast = new JSONObject(jsonData);
JSONArray articles = forecast.getJSONArray("articles");
ArrayList<Articles> listArticles = new ArrayList<>(articles.length());
for (int i = 0; i < articles.length(); i++) {
JSONObject jsonArticle = articles.getJSONObject(i);
Articles article = new Articles();
String urlImage = jsonArticle.getString("urlToImage");
article.setTitle(jsonArticle.getString("title"));
article.setDescription(jsonArticle.getString("description"));
article.setImageView(urlImage);
article.setArticleUrl(jsonArticle.getString("url"));
listArticles.add(i, article);
}
return listArticles;
}
}
My Adapter class :
public class ItemAdapter extends RecyclerView.Adapter<ItemAdapter.ArticleViewHolder> {
private static final String TAGO = ItemAdapter.class.getSimpleName();
private final NewsFragment.OnNewSelectedInterface mListener;
private ArrayList<Articles> mArticlesList;
private Context mContext;
private int lastPosition = -1;
private boolean mStateSaved = false;
public boolean isStateSaved() {
return mStateSaved;
}
public void setStateSaved(boolean stateSaved) {
mStateSaved = stateSaved;
}
public ItemAdapter(Context context, ArrayList<Articles> articles, NewsFragment.OnNewSelectedInterface listener){
mContext = context;
mArticlesList = articles;
mListener = listener;
}
#Override
public ArticleViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_card_view, parent, false);
ArticleViewHolder articleViewHolder = new ArticleViewHolder(view);
articleViewHolder.setIsRecyclable(false);
return articleViewHolder;
}
#Override
public void onBindViewHolder(ArticleViewHolder holder, int position) {
holder.bindArticle(mArticlesList.get(holder.getAdapterPosition()));
setAnimation(holder.itemView, holder.getAdapterPosition());
}
private void setAnimation(View viewToAnimate, int position) {
if (position > lastPosition) {
Animation animation = AnimationUtils.loadAnimation(viewToAnimate.getContext(), android.R.anim.slide_in_left);
viewToAnimate.startAnimation(animation);
lastPosition = position;
}
}
#Override
public int getItemCount() {
return mArticlesList.size();
}
public void clear() {
mArticlesList.clear();
notifyDataSetChanged();
}
public void addAll(ArrayList<Articles> articles) {
mArticlesList.addAll(articles);
notifyDataSetChanged();
}
protected class ArticleViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener{
private ImageView mImageView;
private TextView mTitleTextView, mDescriptionTextView;
private FloatingActionButton mSaveButton;
private ArticleViewHolder(View itemView) {
super(itemView);
mImageView = (ImageView) itemView.findViewById(R.id.photoImageView);
mTitleTextView = (TextView) itemView.findViewById(R.id.titleWithoutImage);
mDescriptionTextView = (TextView) itemView.findViewById(R.id.descriptionTextView);
mSaveButton = (FloatingActionButton) itemView.findViewById(R.id.floatingActionButton);
itemView.setOnClickListener(this);
}
private void bindArticle(final Articles article) {
Glide.with(mContext).load(article.getImageView()).into(mImageView);
mTitleTextView.setText(article.getTitle());
mDescriptionTextView.setText(article.getDescription());
if(mDescriptionTextView.getText().equals("")){
mDescriptionTextView.setVisibility(View.GONE);
}
mSaveButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
insertArticle(article);
article.setStateSaved(true);
}
});
Log.v(TAGO, "Item id : " + getItemId()
+ "Item count : " + getItemCount()
+ "Item position : " + getAdapterPosition()
+ String.valueOf(article.isStateSaved()));
}
private void insertArticle(Articles articles) {
String title = articles.getTitle();
String description = articles.getDescription();
String url = articles.getArticleUrl();
ContentValues contentValues = new ContentValues();
contentValues.put(ArticleContract.ArticleEntry.COLUMN_TITLE_ARTICLE, title);
contentValues.put(ArticleContract.ArticleEntry.COLUMN_DESCRIPTION_ARTICLE, description);
contentValues.put(ArticleContract.ArticleEntry.COLUMN_URL_ARTICLE, url);
Uri uri = mContext.getContentResolver().insert(ArticleContract.ArticleEntry.CONTENT_URI, contentValues);
if(uri == null) {
Log.v(TAGO, "Error");
} else Toast.makeText(mContext, "Article Saved", Toast.LENGTH_SHORT).show();
}
#Override
public void onClick(View view) {
mListener.onListNewSelected(getLayoutPosition(), mArticlesList);
}
}
}

You are using ViewHolder#setIsRecyclable incorrectly; this method is meant to be used to prevent a ViewHolder from being recycled only while changes are being made to it. According to the documentation:
Calls to setIsRecyclable() should always be paired (one call to
setIsRecyclabe(false) should always be matched with a later call to
setIsRecyclable(true)).
This means none of your ViewHolder objects will be recycled, effectively making the use of a RecyclerView worthless, and preventing it from reusing the views when you attempt to bind new objects to your RecyclerView.
So, in short, remove that line of code.
I noticed a few other small issues with your adapter code as well, which can cause a multitude headaches in the future; so I took the liberty of highlighting some of the changes I would make.
Just for my own sanity, I will refer to your Articles class as Article.
It is usually not a good idea to pass around your Context all over the place. The View passed to your ViewHolder already has a reference to a Context, so you can use that instead.
As for the insertArticle() code, the Activity should be handling this anyway. So you can pass the Article back to the Activity by passing a listener to your Adapter (and subsequently, each ViewHolder) instead of the Context.
You should also consider using the DiffUtil class instead of just calling notifyDataSetChanged(); it is much more efficient. Just make sure your Article class is implementing equals() and hashCode() or it will not work.
I didn't include the animation code (that can easily be added back in) or the saved state code (mostly because I don't know what you were trying to do).
public class ArticleAdapter extends RecyclerView.Adapter<Article> {
private List<Article> mData;
private ArticleViewHolder.OnSelectedListener mOnSelectedListener;
private ArticleViewHolder.OnSaveListener mOnSaveListener;
public ArticleAdapter(ArticleViewHolder.OnSelectedListener onSelectedListener, ArticleViewHolder.OnSaveListener onSaveListener) {
mOnSelectedListener = onSelectedListener;
mOnSaveListener = onSaveListener;
mData = new ArrayList<>();
}
public void replaceData(final List<Article> data) {
final List<Article> oldData = new ArrayList<>(mData);
mData.clear();
if (data != null) {
mData.addAll(data);
}
DiffUtil.calculateDiff(new DiffUtil.Callback() {
#Override
public int getOldListSize() {
return oldData.size();
}
#Override
public int getNewListSize() {
return mData.size();
}
#Override
public int areItemsTheSame(int oldItemPosition, int newItemPosition) {
return oldData.get(oldItemPosition).equals(mData.get(newItemPosition));
}
#Override
public boolean areContentsTheSame(int oldItemPosition, int newItemPosition) {
return oldData.get(oldItemPosition).equals(mData.get(newItemPosition));
}
}).dispatchUpdatesTo(this);
}
#Override
public ArticleViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_card_view, parent, false);
return new SelectLocationViewHolder(view, mOnSelectedListener, mOnSaveListener);
}
#Override
public void onBindViewHolder(ArticleViewHolder holder, int position) {
holder.bind(mData.get(position));
}
#Override
public int getItemCount() {
return mData.size();
}
}
public class ArticleViewHolder extends RecyclerView.ViewHolder {
public interface OnSelectedListener {
void onSelected(Article article);
}
public interface OnSaveListener {
void onSave(Article article);
}
private View mView;
private Article mArticle;
private OnSelectedListener mOnSelectedListener;
private OnSaveListener mOnSaveListener;
private ImageView mImageView;
private TextView mTitleTextView, mDescriptionTextView;
private FloatingActionButton mSaveButton;
public ArticleViewHolder(View itemView, final OnSelectedListener onSelectedListener, final OnSaveListener onSaveListener) {
super(itemView);
mImageView = (ImageView) itemView.findViewById(R.id.photoImageView);
mTitleTextView = (TextView) itemView.findViewById(R.id.titleWithoutImage);
mDescriptionTextView = (TextView) itemView.findViewById(R.id.descriptionTextView);
mSaveButton = (FloatingActionButton) itemView.findViewById(R.id.floatingActionButton);
mView = itemView;
mView.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
onSelectedListener.onSelected(mArticle);
}
});
mSaveButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
onSaveListener.onSave(mArticle);
}
});
}
public void bind(Article article) {
mArticle = article;
mTitleTextView.setText(article.getTitle());
mDescriptionTextView.setText(article.getDescription());
if(TextUtils.isEmpty(article.getDescription())) {
mDescriptionTextView.setVisibility(View.GONE);
}
Glide.with(mView.getContext()).load(article.getImage()).into(mImageView);
}
}
Edit
The actual issue is that your loader uses the same ArrayList every time, and keeps adding the new results to it.
public class NewsLoader extends AsyncTaskLoader<List<Article>> {
private final String[] mUrls;
private final OkHttpClient mClient;
public NewsLoader(Context context, OkHttpClient client, String... urls) {
super(context);
mClient = client;
mUrls = urls;
}
#Override
public List<Article> loadInBackground() {
List<Article> articles = new ArrayList<>();
for (String url : mUrls) {
Request request = new Request.Builder().url(url).build();
try {
Response response = mClient.newCall(request).execute();
if (response.isSuccessful()) {
parseData(response.body().string(), articles);
}
} catch (IOException | JSONException e) {
e.printStackTrace();
}
}
return articles;
}
private void parseData(List<Article> articles, String data) throws JSONException {
JSONObject forecast = new JSONObject(data);
JSONArray a = forecast.getJSONArray("articles");
for (int i = 0; i < a.length(); i++) {
JSONObject o = a.getJSONObject(i);
Article article = new Article(
o.getString("title"),
o.getString("description"),
o.getString("url"),
o.getString("urlToImage"));
articles.add(article);
}
}
}
Also, you may have noticed, I made a small change to your Article constructor. You should consider making the Article class immutable, as this will prevent you from making mistakes when dealing with multithreading. It should look something like this:
public class Article {
private final String mTitle;
private final String mDescription;
private final String mUrl;
private final String mImageUrl;
public Article(String title, String description, String url, String imageUrl) {
mTitle = title;
mDescription = description;
mUrl = url;
mImageUrl = imageUrl;
}
public String title() {
return mTitle;
}
public String description() {
return mDescription;
}
public String url() {
return mUrl;
}
public String imageUrl() {
return mImageUrl;
}
#Override
public boolean equals(Object o) {
if (this == o) return true;
if (o == null || getClass() != o.getClass()) return false;
Article other = (Article) o;
return mTitle != null && mTitle.equals(other.mTitle) &&
mDescription != null && mDescription.equals(other.mDescription) &&
mUrl != null && mUrl.equals(other.mUrl) &&
mImageUrl != null && mImageUrl.equals(other.mImageUrl);
}
#Override
public int hashCode() {
int result = mTitle != null ? mTitle.hashCode() : 0;
result = 31 * result + (mDescription != null ? mDescription.hashCode() : 0);
result = 31 * result + (mUrl != null ? mUrl.hashCode() : 0);
result = 31 * result + (mImageUrl != null ? mImageUrl.hashCode() : 0);
return result;
}
}

#Override
public void onBindViewHolder(ArticleViewHolder holder, int position) {
holder.bindArticle(mArticlesList.get(position));
setAnimation(holder.itemView, position);
}
public void addAll(ArrayList<Articles> articles) {
mArticlesList.clear();
mArticlesList.addAll(articles);
notifyDataSetChanged();
}
If this doesn't wrok then I think your api is giving you redundant data.
Why you are using articleViewHolder.setIsRecyclable(false);
One another place which might cause the problem is
private void getMultipleUrls(String jsonData) throws JSONException {
if (mArticlesArrayList == null) {
mArticlesArrayList = getArticleForecast(jsonData);
} else {
mArticlesArrayList.addAll(getArticleForecast(jsonData));
}
}
You are calling it from a loop add adding data to your arraylist. There somehow multiple data can be inserted in your ArrayList