Loading more data in recyclerview on scroll - android-recyclerview

Question

I am getting Json data in list which has like 100 of items. I am passing this list to the recyclerview adapter. But i want to pass only 10 items at first. after 10 items when user scrolls the list it should load more data from the list.I have Implemented the scroll listeners and other adapter.I am not sure how to pass 10 items from the json list to adapter.
ScrollListener
public abstract class PaginationScrollListener extends RecyclerView.OnScrollListener {
LinearLayoutManager layoutManager;
/**
* Supporting only LinearLayoutManager for now.
*
* #param layoutManager
*/
public PaginationScrollListener(LinearLayoutManager layoutManager) {
this.layoutManager = layoutManager;
}
#Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
super.onScrolled(recyclerView, dx, dy);
int visibleItemCount = layoutManager.getChildCount();
int totalItemCount = layoutManager.getItemCount();
int firstVisibleItemPosition = layoutManager.findFirstVisibleItemPosition();
if (!isLoading() && !isLastPage()) {
if ((visibleItemCount + firstVisibleItemPosition) >= totalItemCount
&& firstVisibleItemPosition >= 0
&& totalItemCount >= getTotalPageCount()) {
loadMoreItems();
}
}
}
protected abstract void loadMoreItems();
public abstract int getTotalPageCount();
public abstract boolean isLastPage();
public abstract boolean isLoading();
}
Adapter
public class PaginationAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {
private static final int ITEM = 0;
private static final int LOADING = 1;
private List<Movie> movies;
private Context context;
private boolean isLoadingAdded = false;
public PaginationAdapter(Context context) {
this.context = context;
movies = new ArrayList<>();
}
public List<Movie> getMovies() {
return movies;
}
public void setMovies(List<Movie> movies) {
this.movies = movies;
}
#Override
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
RecyclerView.ViewHolder viewHolder = null;
LayoutInflater inflater = LayoutInflater.from(parent.getContext());
switch (viewType) {
case ITEM:
viewHolder = getViewHolder(parent, inflater);
break;
case LOADING:
View v2 = inflater.inflate(R.layout.item_progress, parent, false);
viewHolder = new LoadingVH(v2);
break;
}
return viewHolder;
}
#NonNull
private RecyclerView.ViewHolder getViewHolder(ViewGroup parent, LayoutInflater inflater) {
RecyclerView.ViewHolder viewHolder;
View v1 = inflater.inflate(R.layout.item_list, parent, false);
viewHolder = new MovieVH(v1);
return viewHolder;
}
#Override
public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {
Movie movie = movies.get(position);
switch (getItemViewType(position)) {
case ITEM:
MovieVH movieVH = (MovieVH) holder;
movieVH.textView.setText(movie.getTitle());
break;
case LOADING:
break;
}
}
#Override
public int getItemCount() {
return movies == null ? 0 : movies.size();
}
#Override
public int getItemViewType(int position) {
return (position == movies.size() - 1 && isLoadingAdded) ? LOADING : ITEM;
}
public void add(Movie mc) {
movies.add(mc);
notifyItemInserted(movies.size() - 1);
}
public void addAll(List<Movie> mcList) {
for (Movie mc : mcList) {
add(mc);
}
}
public void remove(Movie city) {
int position = movies.indexOf(city);
if (position > -1) {
movies.remove(position);
notifyItemRemoved(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 Movie());
}
public void removeLoadingFooter() {
isLoadingAdded = false;
int position = movies.size() - 1;
Movie item = getItem(position);
if (item != null) {
movies.remove(position);
notifyItemRemoved(position);
}
}
public Movie getItem(int position) {
return movies.get(position);
}
public MovieVH(View itemView) {
super(itemView);
textView = (TextView) itemView.findViewById(R.id.item_text);
}
}
protected class LoadingVH extends RecyclerView.ViewHolder {
public LoadingVH(View itemView) {
super(itemView);
}
}
}
**Getting Api response **
private void callApi() {
apiInterfacePages = ApiClient.getRetrofit().create(APIInterface.class);
Call<CamerasItem> camerasCall = apiInterfacePages.getCameras();
camerasCall.enqueue(new Callback<CamerasItem>() {
#Override
public void onResponse(Call<CamerasItem> call, Response<CamerasItem> response) {
CamerasItem camerasItem = response.body();
itemList = new ArrayList<>();
itemList = camerasItem.getItems();
Log.i("Item", "" + getChannel().getName());
for (int i = 0; i < itemList.size(); i++) {
if (itemList.get(i).getCategory().equals(getChannel().getName())){
if (!itemList.get(i).getUrlMjpeg().endsWith("=mediaRedirect")) {
String videoUrl = itemList.get(i).getUrlMjpeg();
String imageUrl = itemList.get(i).getThumbnail();
String name = itemList.get(i).getName();
String city = itemList.get(i).getCity();
String flag = itemList.get(i).getFlag();
String country= itemList.get(i).getCountry();
modelList.add(new MyModel(videoUrl, imageUrl, name, city, flag,country));
}
}
}
#Override
public void onFailure(Call<CamerasItem> call, Throwable t) {
Log.i("Item", "" + t.getMessage());
}
});
}
So now how to pass to 10 items to recyclerview for the first time and 10 items at each scroll.

Answer 1

You have to set Progressbar inside the activity's xml where Recyclerview is defined.
and loadThumbnail is a function to download thumbnail. it just gives a little delay to scroll down. Now the complete code for the adapter class is as following
public class CamerasAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {
private List<MyModel> list;
private Activity mActivity;
private static final int TYPE_VIDEO = 0, TYPE_ADD = 1;
private static final int PAGE_LIMIT = 5;
private int mCurrentLimit = PAGE_LIMIT;
private boolean mIsLoading;
RelativeLayout mLoaderProgress;
public CamerasAdapter(FragmentActivity activity, RelativeLayout loaderLayout) {
mActivity = activity;
mLoaderProgress = loaderLayout;
}
#NonNull
#Override
public RecyclerView.ViewHolder onCreateViewHolder(#NonNull ViewGroup viewGroup, int i) {
View itemView = LayoutInflater.from(viewGroup.getContext()).inflate(R.layout.li_web_cam_view, viewGroup, false);
return new CamsViewHolder(itemView);
}
#Override
public void onBindViewHolder(#NonNull RecyclerView.ViewHolder viewHolder, int i) {
if (mCurrentLimit == (i + 1) && mCurrentLimit <= list.size() && !mIsLoading) {
mLoaderProgress.setVisibility(View.VISIBLE);
mIsLoading = true;
loadThumbnail(0, i + 1);
} else {
//do nothing
}
((CamsViewHolder) viewHolder).onBindData(mActivity, list.get(i), i);
((CamsViewHolder) viewHolder).emptyView.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
itemClickListner.onClick(i, ((CamsViewHolder) viewHolder).tvCamName, list.get(i));
}
});
}
private void loadThumbnail(final int count, int position) {
try {
if (count > 2 || position >= list.size()) {
new Handler().postDelayed(new Runnable() {
#Override
public void run() {
mIsLoading = false;
mCurrentLimit = mCurrentLimit + PAGE_LIMIT;
notifyItemChanged(position - count);
mLoaderProgress.setVisibility(View.GONE);
return;
}
}, 2000);
} else {
if (list.get(position) == null) {
loadThumbnail(count, position + 1);
} else {
Glide.with(mActivity).load(list.get(position).getImage_url()).downloadOnly(new SimpleTarget<File>() {
#Override
public void onResourceReady(File resource, GlideAnimation<? super File> glideAnimation) {
loadThumbnail((count + 1), (position + 1));
}
#Override
public void onLoadFailed(Exception e, Drawable errorDrawable) {
loadThumbnail((count + 1), (position + 1));
}
});
}
}
} catch (Exception e) {
e.printStackTrace();
mLoaderProgress.setVisibility(View.GONE);
mIsLoading = false;
}
}
#Override
public int getItemCount() {
return mCurrentLimit <= list.size() ? mCurrentLimit : list.size();
}
public void setData(List<MyModel> dataList) {
this.list = dataList;
notifyDataSetChanged();
}
ItemClickListner itemClickListner;
public void setListener(ItemClickListner listener) {
itemClickListner = listener;
}
ProgressLoadListener progressLoadListener;
public void setProgressLoadListener(ProgressLoadListener listener) {
progressLoadListener = listener;
}
}
code for xml file
<android.support.v7.widget.RecyclerView
android:id="#+id/recycler_view"
android:layout_width="match_parent"
android:visibility="gone"
android:layout_height="match_parent"
android:layout_above="#+id/loader_progress_bar_layout"
android:background="#f5f5f5"
android:layout_gravity="center" />
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:id="#+id/loader_progress_bar_layout"
android:visibility="gone"
android:background="#fff"
>
<ProgressBar
android:id="#+id/progress_bar_loader"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerHorizontal="true"
android:layout_gravity="center" />
</RelativeLayout>
initialize Recyclerview with adapter
public class Main2Activity extends AppCompatActivity {
RecyclerView recyclerView;
RelativeLayout layoutProgressBar;
CamerasAdapter adapter;
List<Item> itemList;
LinearLayoutManager mLayoutManager;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main2);
layoutProgressBar = findViewById(R.id.loader_progress_bar_layout);
recyclerView = findViewById(R.id.recycler_view);
adapter = new CamerasAdapter(getActivity(), loaderLayout);
mLayoutManager = new LinearLayoutManager(getActivity());
recyclerView.setLayoutManager(mLayoutManager);
recyclerView.setAdapter(adapter);
adapter.setProgressLoadListener(new ProgressLoadListener() {
#Override
public void loadProgressBar() {
layoutProgressBar.setVisibility(View.VISIBLE);
}
});
adapter.setData(setAdaperData());
}
public List<MyModel> setAdaperData(){
List<MyModel> modelList = new ArrayList<>();
/*addItemsto list*/
return modelList;
}
}