How to implement pagination in RecyclerView on scroll - android

Recyclerview comes with its own scroll listener which has the following methods :
void onScrollStateChanged(RecyclerView recyclerView, int newState)
Callback method to be invoked when RecyclerView's scroll state changes.
void onScrolled(RecyclerView recyclerView, int dx, int dy)
Callback method to be invoked when the RecyclerView has been scrolled.
Is there any way to trigger loader to load more data when scroll reaches end of the list?
I have implemented this way:
#Override
public void onBindViewHolder(ViewHolder viewHolder, int i) {
GenerItem generItem=generItems.get(i);
Log.d("TAG","position "+i);
if(i==generItems.size()-1)
((GenerSearchActivity)mContext).onScroll(i);
viewHolder.bindValues(generItem);
}
Here onScroll() in Activity, will trigger the loader to load more data. What is the best way please suggest.

Make Next Call at the end of scroll
There are essentially 3 steps.
Notify when the list is scrolled
Make REST call (for NEXT page)
Add the result in the old list + Notify DataSet change
CALLBACK
But first, we need a Callback which would work as a bridge between RecyclerView.Adapter and Activity
public interface PaginationCallBack{
public void oadNextPage();
}
Implement this callback in Your Activity
class YourActivity extends AppCompatActivity implements PaginationCallBack{
int pageNum = 1;
#Override
public void loadNextPage(){
// Your implementation
}
}
Initialize Callback in RecyclerView.Adapter
class YourAdapter extends RecyclerView.Adapter{
private PaginationCallBack paginationCallBack;
public YourAdapter(PaginationCallBack paginationCallBack) {
this.paginationCallBack = paginationCallBack;
}
}
STEP 1
Add a condition in onBindViewHolder method and notify with a Callback.
#Override
public void onBindViewHolder(#NonNull RecyclerView.ViewHolder viewholder, int position) {
if(position+1==images.size()){
paginationCallBack.loadNextPage(); // Callback
}
}
Step 2: Call NEXT Page
getImages(++pageNum) // YOUR REST method which page number
#Override
public void loadNextPage(){
getImages(++pageNumber) // REST call with next Page
}
Step 3 Add the result in old list and notify datasetChanged
public void getImages(int pageNum){
List<Images> newResults = //RESTCALL
imageList.addAll(newResults);
adapter.updateDataSet(imageList)
}
Where is updateDataSet(imageList) method?
Write this method inside RecyclerView.Adapter
public void updateDataSet(List<GalleryMedia> newImages){
if(newImages!=null){
images = newImages;
}
notifyDataSetChanged();
}
Full Code
RecyclerView Pagination
Result:

Here's a scroll listener which implements load more and quick return pattern:
public abstract class HidingScrollListener extends RecyclerView.OnScrollListener {
private static final float HIDE_THRESHOLD = 10;
private static final float SHOW_THRESHOLD = 70;
private int mToolbarOffset = 0;
private boolean mControlsVisible = true;
private int mToolbarHeight;
private int mTotalScrolledDistance;
private int previousTotal = 0;
private boolean loading = true;
private int visibleThreshold = 4;
int firstVisibleItem, visibleItemCount, totalItemCount;
private LinearLayoutManager layoutManager;
public HidingScrollListener(Context context, LinearLayoutManager layoutManager) {
mToolbarHeight = Tools.getFooterHeight(context);
this.layoutManager = layoutManager;
}
#Override
public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
super.onScrollStateChanged(recyclerView, newState);
if (newState == RecyclerView.SCROLL_STATE_IDLE) {
if (mTotalScrolledDistance < mToolbarHeight) {
setVisible();
}
else {
if (mControlsVisible) {
if (mToolbarOffset > HIDE_THRESHOLD) {
setInvisible();
}
else {
setVisible();
}
}
else {
if ((mToolbarHeight - mToolbarOffset) > SHOW_THRESHOLD) {
setVisible();
}
else {
setInvisible();
}
}
}
}
}
#Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
super.onScrolled(recyclerView, dx, dy);
clipToolbarOffset();
onMoved(mToolbarOffset);
if ((mToolbarOffset < mToolbarHeight && dy > 0) || (mToolbarOffset > 0 && dy < 0)) {
mToolbarOffset += dy;
}
if (mTotalScrolledDistance < 0) {
mTotalScrolledDistance = 0;
}
else {
mTotalScrolledDistance += dy;
}
// for load more
visibleItemCount = recyclerView.getChildCount();
totalItemCount = layoutManager.getItemCount();
firstVisibleItem = layoutManager.findFirstVisibleItemPosition();
if (loading) {
if (totalItemCount > previousTotal) {
loading = false;
previousTotal = totalItemCount;
}
}
if (!loading && (totalItemCount - visibleItemCount) <= (firstVisibleItem + visibleThreshold)) {
// End has been reached
// Do something
loading = true;
onLoadMore();
}
}
private void clipToolbarOffset() {
if (mToolbarOffset > mToolbarHeight) {
mToolbarOffset = mToolbarHeight;
}
else if (mToolbarOffset < 0) {
mToolbarOffset = 0;
}
}
private void setVisible() {
if (mToolbarOffset > 0) {
onShow();
mToolbarOffset = 0;
}
mControlsVisible = true;
}
private void setInvisible() {
if (mToolbarOffset < mToolbarHeight) {
onHide();
mToolbarOffset = mToolbarHeight;
}
mControlsVisible = false;
}
public abstract void onMoved(int distance);
public abstract void onShow();
public abstract void onHide();
public abstract void onLoadMore();
}
And it's implementation is below:
HidingScrollListener scrollListener = new HidingScrollListener(activity, manager) {
#Override
public void onMoved(int distance) {
}
#Override
public void onShow() {
}
#Override
public void onHide() {
}
#Override
public void onLoadMore() {
// you can do your pagination here.
}
};
mRecyclerView.addOnScrollListener(scrollListener);

Related

Recycler View - Show only minimum elements and expand recycler view if user clicks expand [duplicate]

I would like to change ListView to RecyclerView. I want to use the onScroll of the OnScrollListener in RecyclerView to determine if a user scrolled to the end of the list.
How do I know if a user scrolls to the end of the list so that I can fetch new data from a REST service?
Thanks to #Kushal and this is how I implemented it
private boolean loading = true;
int pastVisiblesItems, visibleItemCount, totalItemCount;
mRecyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
#Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
if (dy > 0) { //check for scroll down
visibleItemCount = mLayoutManager.getChildCount();
totalItemCount = mLayoutManager.getItemCount();
pastVisiblesItems = mLayoutManager.findFirstVisibleItemPosition();
if (loading) {
if ((visibleItemCount + pastVisiblesItems) >= totalItemCount) {
loading = false;
Log.v("...", "Last Item Wow !");
// Do pagination.. i.e. fetch new data
loading = true;
}
}
}
}
});
Don't forget to add
LinearLayoutManager mLayoutManager;
mLayoutManager = new LinearLayoutManager(this);
mRecyclerView.setLayoutManager(mLayoutManager);
Make these variables.
private int previousTotal = 0;
private boolean loading = true;
private int visibleThreshold = 5;
int firstVisibleItem, visibleItemCount, totalItemCount;
Set on Scroll for recycler view.
mRecyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
#Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
super.onScrolled(recyclerView, dx, dy);
visibleItemCount = mRecyclerView.getChildCount();
totalItemCount = mLayoutManager.getItemCount();
firstVisibleItem = mLayoutManager.findFirstVisibleItemPosition();
if (loading) {
if (totalItemCount > previousTotal) {
loading = false;
previousTotal = totalItemCount;
}
}
if (!loading && (totalItemCount - visibleItemCount)
<= (firstVisibleItem + visibleThreshold)) {
// End has been reached
Log.i("Yaeye!", "end called");
// Do something
loading = true;
}
}
});
Note : Make sure you are using LinearLayoutManager as layout manager for RecyclerView.
LinearLayoutManager mLayoutManager;
mLayoutManager = new LinearLayoutManager(this);
mRecyclerView.setLayoutManager(mLayoutManager);
and for a grid
GridLayoutManager mLayoutManager;
mLayoutManager = new GridLayoutManager(getActivity(), spanCount);
mRecyclerView.setLayoutManager(mLayoutManager);
Have fun with your endless scrolls !! ^.^
Update : mRecyclerView.setOnScrollListener() is deprecated just replace with mRecyclerView.addOnScrollListener() and the warning will be gone! You can read more from this SO question.
Since Android now officially support Kotlin, here is an update for the same -
Make OnScrollListener
class OnScrollListener(val layoutManager: LinearLayoutManager, val adapter: RecyclerView.Adapter<RecyclerAdapter.ViewHolder>, val dataList: MutableList<Int>) : RecyclerView.OnScrollListener() {
var previousTotal = 0
var loading = true
val visibleThreshold = 10
var firstVisibleItem = 0
var visibleItemCount = 0
var totalItemCount = 0
override fun onScrolled(recyclerView: RecyclerView, dx: Int, dy: Int) {
super.onScrolled(recyclerView, dx, dy)
visibleItemCount = recyclerView.childCount
totalItemCount = layoutManager.itemCount
firstVisibleItem = layoutManager.findFirstVisibleItemPosition()
if (loading) {
if (totalItemCount > previousTotal) {
loading = false
previousTotal = totalItemCount
}
}
if (!loading && (totalItemCount - visibleItemCount) <= (firstVisibleItem + visibleThreshold)) {
val initialSize = dataList.size
updateDataList(dataList)
val updatedSize = dataList.size
recyclerView.post { adapter.notifyItemRangeInserted(initialSize, updatedSize) }
loading = true
}
}
}
and add it to your RecyclerView like this
recyclerView.addOnScrollListener(OnScrollListener(layoutManager, adapter, dataList))
For a full code example, feel free to refer this Github repo.
For those who only want to get notified when the last item is totally shown, you can use View.canScrollVertically().
Here is my implementation:
public abstract class OnVerticalScrollListener
extends RecyclerView.OnScrollListener {
#Override
public final void onScrolled(RecyclerView recyclerView, int dx, int dy) {
if (!recyclerView.canScrollVertically(-1)) {
onScrolledToTop();
} else if (!recyclerView.canScrollVertically(1)) {
onScrolledToBottom();
} else if (dy < 0) {
onScrolledUp();
} else if (dy > 0) {
onScrolledDown();
}
}
public void onScrolledUp() {}
public void onScrolledDown() {}
public void onScrolledToTop() {}
public void onScrolledToBottom() {}
}
Note: You can use recyclerView.getLayoutManager().canScrollVertically() if you want to support API < 14.
Here is another approach. It will work with any layout manager.
Make Adapter class abstract
Then create an abstract method in adapter class (eg. load())
In onBindViewHolder check the position if last and call load()
Override the load() function while creating the adapter object in your activity or fragment.
In the overided load function implement your loadmore call
For a detail understanding I wrote a blog post and example project get it here
http://sab99r.com/blog/recyclerview-endless-load-more/
MyAdapter.java
public abstract class MyAdapter extends RecyclerView.Adapter<ViewHolder>{
#Override
public void onBindViewHolder(ViewHolder holder, int position) {
//check for last item
if ((position >= getItemCount() - 1))
load();
}
public abstract void load();
}
MyActivity.java
public class MainActivity extends AppCompatActivity {
List<Items> items;
MyAdapter adapter;
#Override
protected void onCreate(Bundle savedInstanceState) {
...
adapter=new MyAdapter(items){
#Override
public void load() {
//implement your load more here
Item lastItem=items.get(items.size()-1);
loadMore();
}
};
}
}
My answer is a modified version of Noor. I passed from a ListView where i had EndlessScrollListener (that you can find easily in many answers on SO) to a RecyclerView so i wanted a EndlessRecyclScrollListener to easily update my past listener.
So here is the code, hope it helps:
public abstract class EndlessScrollRecyclListener extends RecyclerView.OnScrollListener
{
// The total number of items in the dataset after the last load
private int previousTotalItemCount = 0;
private boolean loading = true;
private int visibleThreshold = 5;
int firstVisibleItem, visibleItemCount, totalItemCount;
private int startingPageIndex = 0;
private int currentPage = 0;
#Override
public void onScrolled(RecyclerView mRecyclerView, int dx, int dy)
{
super.onScrolled(mRecyclerView, dx, dy);
LinearLayoutManager mLayoutManager = (LinearLayoutManager) mRecyclerView
.getLayoutManager();
visibleItemCount = mRecyclerView.getChildCount();
totalItemCount = mLayoutManager.getItemCount();
firstVisibleItem = mLayoutManager.findFirstVisibleItemPosition();
onScroll(firstVisibleItem, visibleItemCount, totalItemCount);
}
public void onScroll(int firstVisibleItem, int visibleItemCount, int totalItemCount)
{
// If the total item count is zero and the previous isn't, assume the
// list is invalidated and should be reset back to initial state
if (totalItemCount < previousTotalItemCount)
{
this.currentPage = this.startingPageIndex;
this.previousTotalItemCount = totalItemCount;
if (totalItemCount == 0)
{
this.loading = true;
}
}
// If it’s still loading, we check to see if the dataset count has
// changed, if so we conclude it has finished loading and update the current page
// number and total item count.
if (loading && (totalItemCount > previousTotalItemCount))
{
loading = false;
previousTotalItemCount = totalItemCount;
currentPage++;
}
// If it isn’t currently loading, we check to see if we have breached
// the visibleThreshold and need to reload more data.
// If we do need to reload some more data, we execute onLoadMore to fetch the data.
if (!loading && (totalItemCount - visibleItemCount) <= (firstVisibleItem +
visibleThreshold))
{
onLoadMore(currentPage + 1, totalItemCount);
loading = true;
}
}
// Defines the process for actually loading more data based on page
public abstract void onLoadMore(int page, int totalItemsCount);
}
For me, it's very simple:
private boolean mLoading = false;
mList.setOnScrollListener(new RecyclerView.OnScrollListener() {
#Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
super.onScrolled(recyclerView, dx, dy);
int totalItem = mLinearLayoutManager.getItemCount();
int lastVisibleItem = mLinearLayoutManager.findLastVisibleItemPosition();
if (!mLoading && lastVisibleItem == totalItem - 1) {
mLoading = true;
// Scrolled to bottom. Do something here.
mLoading = false;
}
}
});
Be careful with asynchronous jobs: mLoading must be changed at the end of the asynchronous jobs. Hope it will be helpful!
With the power of Kotlin's extension functions, the code can look a lot more elegant. Put this anywhere you want (I have it inside an ExtensionFunctions.kt file):
/**
* WARNING: This assumes the layout manager is a LinearLayoutManager
*/
fun RecyclerView.addOnScrolledToEnd(onScrolledToEnd: () -> Unit){
this.addOnScrollListener(object: RecyclerView.OnScrollListener(){
private val VISIBLE_THRESHOLD = 5
private var loading = true
private var previousTotal = 0
override fun onScrollStateChanged(recyclerView: RecyclerView,
newState: Int) {
with(layoutManager as LinearLayoutManager){
val visibleItemCount = childCount
val totalItemCount = itemCount
val firstVisibleItem = findFirstVisibleItemPosition()
if (loading && totalItemCount > previousTotal){
loading = false
previousTotal = totalItemCount
}
if(!loading && (totalItemCount - visibleItemCount) <= (firstVisibleItem + visibleThreshold)){
onScrolledToEnd()
loading = true
}
}
}
})
}
And then use it like this:
youRecyclerView.addOnScrolledToEnd {
//What you want to do once the end is reached
}
This solution is based on Kushal Sharma's answer. However, this is a bit better because:
It uses onScrollStateChanged instead of onScroll. This is better because onScroll is called every time there is any sort of movement in the RecyclerView, whereas onScrollStateChanged is only called when the state of the RecyclerView is changed. Using onScrollStateChanged will save you CPU time and, as a consequence, battery.
Since this uses Extension Functions, this can be used in any RecyclerView you have. The client code is just 1 line.
Most answer are assuming the RecyclerView uses a LinearLayoutManager, or GridLayoutManager, or even StaggeredGridLayoutManager, or assuming that the scrolling is vertical or horyzontal, but no one has posted a completly generic answer.
Using the ViewHolder's adapter is clearly not a good solution. An adapter might have more than 1 RecyclerView using it. It "adapts" their contents. It should be the RecyclerView (which is the one class which is responsible of what is currently displayed to the user, and not the adapter which is responsible only to provide content to the RecyclerView) which must notify your system that more items are needed (to load).
Here is my solution, using nothing else than the abstracted classes of the RecyclerView (RecycerView.LayoutManager and RecycerView.Adapter):
/**
* Listener to callback when the last item of the adpater is visible to the user.
* It should then be the time to load more items.
**/
public abstract class LastItemListener extends RecyclerView.OnScrollListener {
#Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
super.onScrolled(recyclerView, dx, dy);
// init
RecyclerView.LayoutManager layoutManager = recyclerView.getLayoutManager();
RecyclerView.Adapter adapter = recyclerView.getAdapter();
if (layoutManager.getChildCount() > 0) {
// Calculations..
int indexOfLastItemViewVisible = layoutManager.getChildCount() -1;
View lastItemViewVisible = layoutManager.getChildAt(indexOfLastItemViewVisible);
int adapterPosition = layoutManager.getPosition(lastItemViewVisible);
boolean isLastItemVisible = (adapterPosition == adapter.getItemCount() -1);
// check
if (isLastItemVisible)
onLastItemVisible(); // callback
}
}
/**
* Here you should load more items because user is seeing the last item of the list.
* Advice: you should add a bollean value to the class
* so that the method {#link #onLastItemVisible()} will be triggered only once
* and not every time the user touch the screen ;)
**/
public abstract void onLastItemVisible();
}
// --- Exemple of use ---
myRecyclerView.setOnScrollListener(new LastItemListener() {
public void onLastItemVisible() {
// start to load more items here.
}
}
Although the accepted answer works perfectly, the solution below uses addOnScrollListener since setOnScrollListener is deprecated, and reduces number of variables, and if conditions.
final LinearLayoutManager layoutManager = new LinearLayoutManager(context);
feedsRecyclerView.setLayoutManager(layoutManager);
feedsRecyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
#Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
super.onScrolled(recyclerView, dx, dy);
if (dy > 0) {
if ((layoutManager.getChildCount() + layoutManager.findFirstVisibleItemPosition()) >= layoutManager.getItemCount()) {
Log.d("TAG", "End of list");
//loadMore();
}
}
}
});
This is how I do it, simple and short:
recyclerView.addOnScrollListener(new RecyclerView.OnScrollListener()
{
#Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy)
{
if(!recyclerView.canScrollVertically(1) && dy != 0)
{
// Load more results here
}
}
});
Although there are so many answers to the question, I would like to share our experience of creating the endless list view. We have recently implemented custom Carousel LayoutManager that can work in the cycle by scrolling the list infinitely as well as up to a certain point. Here is a detailed description on GitHub.
I suggest you take a look at this article with short but valuable recommendations on creating custom LayoutManagers: http://cases.azoft.com/create-custom-layoutmanager-android/
OK, I did it by using the onBindViewHolder method of RecyclerView.Adapter.
Adapter:
public interface OnViewHolderListener {
void onRequestedLastItem();
}
#Override
public void onBindViewHolder(ViewHolder holder, int position) {
...
if (position == getItemCount() - 1) onViewHolderListener.onRequestedLastItem();
}
Fragment (or Activity):
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
contentView = inflater.inflate(R.layout.comments_list, container, false);
recyclerView = (RecyclerView) mContentView.findViewById(R.id.my_recycler_view);
adapter = new Adapter();
recyclerView.setAdapter(adapter);
...
adapter.setOnViewHolderListener(new Adapter.OnViewHolderListener() {
#Override
public void onRequestedLastItem() {
//TODO fetch new data from webservice
}
});
return contentView;
}
recyclerList.setOnScrollListener(new RecyclerView.OnScrollListener()
{
#Override
public void onScrolled(RecyclerView recyclerView, int dx,int dy)
{
super.onScrolled(recyclerView, dx, dy);
}
#Override
public void onScrollStateChanged(RecyclerView recyclerView,int newState)
{
int totalItemCount = layoutManager.getItemCount();
int lastVisibleItem = layoutManager.findLastVisibleItemPosition();
if (totalItemCount> 1)
{
if (lastVisibleItem >= totalItemCount - 1)
{
// End has been reached
// do something
}
}
}
});
I would try to extend used LayoutManager (e.g. LinearLayoutManager) and override scrollVerticallyBy() method. Firstly, I would call super first and then check returned integer value. If the value equals to 0 then a bottom or a top border is reached. Then I would use findLastVisibleItemPosition() method to find out which border is reached and load more data if needed. Just an idea.
In addition, you can even return your value from that method allowing overscroll and showing "loading" indicator.
I achieved an infinite scrolling type implementation using this logic in the onBindViewHolder method of my RecyclerView.Adapter class.
if (position == mItems.size() - 1 && mCurrentPage <= mTotalPageCount) {
if (mCurrentPage == mTotalPageCount) {
mLoadImagesListener.noMorePages();
} else {
int newPage = mCurrentPage + 1;
mLoadImagesListener.loadPage(newPage);
}
}
With this code when the RecyclerView gets to the last item, it increments the current page and callbacks on an interface which is responsible for loading more data from the api and adding the new results to the adapter.
I can post more complete example if this isn't clear?
For people who use StaggeredGridLayoutManager here is my implementation, it works for me.
private class ScrollListener extends RecyclerView.OnScrollListener {
#Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
firstVivisibleItems = mLayoutManager.findFirstVisibleItemPositions(firstVivisibleItems);
if(!recyclerView.canScrollVertically(1) && firstVivisibleItems[0]!=0) {
loadMoreImages();
}
}
private boolean loadMoreImages(){
Log.d("myTag", "LAST-------HERE------");
return true;
}
}
There is an easy to use library for this named paginate . Supports both ListView and RecyclerView ( LinearLayout , GridLayout and StaggeredGridLayout).
Here is the link to the project on Github
My way to detect loading event is not to detect scrolling, but to listen whether the last view was attached. If the last view was attached, I regard it as timing to load more content.
class MyListener implements RecyclerView.OnChildAttachStateChangeListener {
RecyclerView mRecyclerView;
MyListener(RecyclerView view) {
mRecyclerView = view;
}
#Override
public void onChildViewAttachedToWindow(View view) {
RecyclerView.Adapter adapter = mRecyclerView.getAdapter();
RecyclerView.LayoutManager mgr = mRecyclerView.getLayoutManager();
int adapterPosition = mgr.getPosition(view);
if (adapterPosition == adapter.getItemCount() - 1) {
// last view was attached
loadMoreContent();
}
#Override
public void onChildViewDetachedFromWindow(View view) {}
}
Create an abstract class and extends RecyclerView.OnScrollListener
public abstract class EndlessRecyclerOnScrollListener extends RecyclerView.OnScrollListener {
private int previousTotal = 0;
private boolean loading = true;
private int visibleThreshold;
private int firstVisibleItem, visibleItemCount, totalItemCount;
private RecyclerView.LayoutManager layoutManager;
public EndlessRecyclerOnScrollListener(RecyclerView.LayoutManager layoutManager, int visibleThreshold) {
this.layoutManager = layoutManager; this.visibleThreshold = visibleThreshold;
}
#Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
super.onScrolled(recyclerView, dx, dy);
visibleItemCount = recyclerView.getChildCount();
totalItemCount = layoutManager.getItemCount();
firstVisibleItem = ((LinearLayoutManager)layoutManager).findFirstVisibleItemPosition();
if (loading) {
if (totalItemCount > previousTotal) {
loading = false;
previousTotal = totalItemCount;
}
}
if (!loading && (totalItemCount - visibleItemCount) <= (firstVisibleItem + visibleThreshold)) {
onLoadMore();
loading = true;
}
}
public abstract void onLoadMore();}
in activity (or fragment) add addOnScrollListener to recyclerView
LinearLayoutManager mLayoutManager = new LinearLayoutManager(this);
recyclerView.setLayoutManager(mLayoutManager);
recyclerView.addOnScrollListener(new EndlessRecyclerOnScrollListener(mLayoutManager, 3) {
#Override
public void onLoadMore() {
//TODO
...
}
});
I have a pretty detailed example of how to paginate with a RecyclerView. At a high level, I have a set PAGE_SIZE , lets say 30. So I request 30 items and if I get 30 back then I request the next page. If I get less than 30 items I flag a variable to indicate that the last page has been reached and then I stop requesting for more pages. Check it out and let me know what you think.
https://medium.com/#etiennelawlor/pagination-with-recyclerview-1cb7e66a502b
Here my solution using AsyncListUtil, in the web says:
Note that this class uses a single thread to load the data, so it suitable to load data from secondary storage such as disk, but not from network.
but i am using odata to read the data and work fine.
I miss in my example data entities and network methods.
I include only the example adapter.
public class AsyncPlatoAdapter extends RecyclerView.Adapter {
private final AsyncPlatoListUtil mAsyncListUtil;
private final MainActivity mActivity;
private final RecyclerView mRecyclerView;
private final String mFilter;
private final String mOrderby;
private final String mExpand;
public AsyncPlatoAdapter(String filter, String orderby, String expand, RecyclerView recyclerView, MainActivity activity) {
mFilter = filter;
mOrderby = orderby;
mExpand = expand;
mRecyclerView = recyclerView;
mActivity = activity;
mAsyncListUtil = new AsyncPlatoListUtil();
}
#Override
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View itemView = LayoutInflater.from(parent.getContext()).
inflate(R.layout.plato_cardview, parent, false);
// Create a ViewHolder to find and hold these view references, and
// register OnClick with the view holder:
return new PlatoViewHolderAsync(itemView, this);
}
#Override
public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {
final Plato item = mAsyncListUtil.getItem(position);
PlatoViewHolderAsync vh = (PlatoViewHolderAsync) holder;
if (item != null) {
Integer imagen_id = item.Imagen_Id.get();
vh.getBinding().setVariable(BR.plato, item);
vh.getBinding().executePendingBindings();
vh.getImage().setVisibility(View.VISIBLE);
vh.getProgress().setVisibility(View.GONE);
String cacheName = null;
String urlString = null;
if (imagen_id != null) {
cacheName = String.format("imagenes/imagen/%d", imagen_id);
urlString = String.format("%s/menusapi/%s", MainActivity.ROOTPATH, cacheName);
}
ImageHelper.downloadBitmap(mActivity, vh.getImage(), vh.getProgress(), urlString, cacheName, position);
} else {
vh.getBinding().setVariable(BR.plato, item);
vh.getBinding().executePendingBindings();
//show progress while loading.
vh.getImage().setVisibility(View.GONE);
vh.getProgress().setVisibility(View.VISIBLE);
}
}
#Override
public int getItemCount() {
return mAsyncListUtil.getItemCount();
}
public class AsyncPlatoListUtil extends AsyncListUtil<Plato> {
/**
* Creates an AsyncListUtil.
*/
public AsyncPlatoListUtil() {
super(Plato.class, //my data class
10, //page size
new DataCallback<Plato>() {
#Override
public int refreshData() {
//get count calling ../$count ... odata endpoint
return countPlatos(mFilter, mOrderby, mExpand, mActivity);
}
#Override
public void fillData(Plato[] data, int startPosition, int itemCount) {
//get items from odata endpoint using $skip and $top
Platos p = loadPlatos(mFilter, mOrderby, mExpand, startPosition, itemCount, mActivity);
for (int i = 0; i < Math.min(itemCount, p.value.size()); i++) {
data[i] = p.value.get(i);
}
}
}, new ViewCallback() {
#Override
public void getItemRangeInto(int[] outRange) {
//i use LinearLayoutManager in the RecyclerView
LinearLayoutManager layoutManager = (LinearLayoutManager) mRecyclerView.getLayoutManager();
outRange[0] = layoutManager.findFirstVisibleItemPosition();
outRange[1] = layoutManager.findLastVisibleItemPosition();
}
#Override
public void onDataRefresh() {
mRecyclerView.getAdapter().notifyDataSetChanged();
}
#Override
public void onItemLoaded(int position) {
mRecyclerView.getAdapter().notifyItemChanged(position);
}
});
mRecyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
#Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
onRangeChanged();
}
});
}
}
}
if (layoutManager.findLastCompletelyVisibleItemPosition() ==
recyclerAdapter.getItemCount() - 1) {
//load more items.
}
Fair and simple.
This will work.
As #John T suggest. Just use code block below, really short, beauty and simple :D
public void loadMoreOnRecyclerView() {
mRecyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
#Override
public void onScrolled(#NonNull #NotNull RecyclerView recyclerView, int dx, int dy) {
super.onScrolled(recyclerView, dx, dy);
if (!recyclerView.canScrollVertically(1) && dy != 0) {
//Load more items here
}
}
});
}
You can follow my Repo to understand the way that it work.
https://github.com/Nghien-Nghien/PokeAPI-Java/blob/0d8d69d348e068911b883f0ae7791d904cc75cb5/app/src/main/java/com/example/pokemonapi/MainActivity.java
Description info about app like this: https://github.com/skydoves/Pokedex#readme
There is a method public void setOnScrollListener (RecyclerView.OnScrollListener listener) in https://developer.android.com/reference/android/support/v7/widget/RecyclerView.html#setOnScrollListener%28android.support.v7.widget.RecyclerView.OnScrollListener%29. Use that
EDIT:
Override onScrollStateChanged method inside the onScrollListener and do this
boolean loadMore = firstVisibleItem + visibleItemCount >= totalItemCount;
//loading is used to see if its already loading, you have to manually manipulate this boolean variable
if (loadMore && !loading) {
//end of list reached
}
Check this every thing is explained in detail:
Pagination using RecyclerView From A to Z
mRecyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
#Override
public void onScrollStateChanged(RecyclerView recyclerView,
int newState) {
super.onScrollStateChanged(recyclerView, newState);
}
#Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
super.onScrolled(recyclerView, dx, dy);
int visibleItemCount = mLayoutManager.getChildCount();
int totalItemCount = mLayoutManager.getItemCount();
int firstVisibleItemPosition = mLayoutManager.findFirstVisibleItemPosition();
if (!mIsLoading && !mIsLastPage) {
if ((visibleItemCount + firstVisibleItemPosition) >= totalItemCount
&& firstVisibleItemPosition >= 0) {
loadMoreItems();
}
}
}
})
loadMoreItems():
private void loadMoreItems() {
mAdapter.removeLoading();
//load data here from the server
// in case of success
mAdapter.addData(data);
// if there might be more data
mAdapter.addLoading();
}
in MyAdapter :
private boolean mIsLoadingFooterAdded = false;
public void addLoading() {
if (!mIsLoadingFooterAdded) {
mIsLoadingFooterAdded = true;
mLineItemList.add(new LineItem());
notifyItemInserted(mLineItemList.size() - 1);
}
}
public void removeLoading() {
if (mIsLoadingFooterAdded) {
mIsLoadingFooterAdded = false;
int position = mLineItemList.size() - 1;
LineItem item = mLineItemList.get(position);
if (item != null) {
mLineItemList.remove(position);
notifyItemRemoved(position);
}
}
}
public void addData(List<YourDataClass> data) {
for (int i = 0; i < data.size(); i++) {
YourDataClass yourDataObject = data.get(i);
mLineItemList.add(new LineItem(yourDataObject));
notifyItemInserted(mLineItemList.size() - 1);
}
}
None of these answers take into account if the list is too small or not.
Here's a piece of code I've been using that works on RecycleViews in both directions.
#Override
public boolean onTouchEvent(MotionEvent motionEvent) {
if (recyclerViewListener == null) {
return super.onTouchEvent(motionEvent);
}
/**
* If the list is too small to scroll.
*/
if (motionEvent.getAction() == MotionEvent.ACTION_UP) {
if (!canScrollVertically(1)) {
recyclerViewListener.reachedBottom();
} else if (!canScrollVertically(-1)) {
recyclerViewListener.reachedTop();
}
}
return super.onTouchEvent(motionEvent);
}
public void setListener(RecyclerViewListener recycleViewListener) {
this.recyclerViewListener = recycleViewListener;
addOnScrollListener(new OnScrollListener() {
#Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
super.onScrolled(recyclerView, dx, dy);
if (recyclerViewListener == null) {
return;
}
recyclerViewListener.scrolling(dy);
if (!canScrollVertically(1)) {
recyclerViewListener.reachedBottom();
} else if (!canScrollVertically(-1)) {
recyclerViewListener.reachedTop();
}
}
});
}
I let you my aproximation. Works fine for me.
I hope it helps you.
/**
* Created by Daniel Pardo Ligorred on 03/03/2016.
*/
public abstract class BaseScrollListener extends RecyclerView.OnScrollListener {
protected RecyclerView.LayoutManager layoutManager;
public BaseScrollListener(RecyclerView.LayoutManager layoutManager) {
this.layoutManager = layoutManager;
this.init();
}
#Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
super.onScrolled(recyclerView, dx, dy);
this.onScroll(recyclerView, this.getFirstVisibleItem(), this.layoutManager.getChildCount(), this.layoutManager.getItemCount(), dx, dy);
}
private int getFirstVisibleItem(){
if(this.layoutManager instanceof LinearLayoutManager){
return ((LinearLayoutManager) this.layoutManager).findFirstVisibleItemPosition();
} else if (this.layoutManager instanceof StaggeredGridLayoutManager){
int[] spanPositions = null; //Should be null -> StaggeredGridLayoutManager.findFirstVisibleItemPositions makes the work.
try{
return ((StaggeredGridLayoutManager) this.layoutManager).findFirstVisibleItemPositions(spanPositions)[0];
}catch (Exception ex){
// Do stuff...
}
}
return 0;
}
public abstract void init();
protected abstract void onScroll(RecyclerView recyclerView, int firstVisibleItem, int visibleItemCount, int totalItemCount, int dx, int dy);
}
#kushal #abdulaziz
Why not use this logic instead?
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
int totalItemCount, lastVisibleItemPosition;
if (dy > 0) {
totalItemCount = _layoutManager.getItemCount();
lastVisibleItemPosition = _layoutManager.findLastVisibleItemPosition();
if (!_isLastItem) {
if ((totalItemCount - 1) == lastVisibleItemPosition) {
LogUtil.e("end_of_list");
_isLastItem = true;
}
}
}
}
Try below:
import android.support.v7.widget.GridLayoutManager;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.support.v7.widget.RecyclerView.LayoutManager;
/**
* Abstract Endless ScrollListener
*
*/
public abstract class EndlessScrollListener extends
RecyclerView.OnScrollListener {
// The minimum amount of items to have below your current scroll position
// before loading more.
private int visibleThreshold = 10;
// The current offset index of data you have loaded
private int currentPage = 1;
// True if we are still waiting for the last set of data to load.
private boolean loading = true;
// The total number of items in the data set after the last load
private int previousTotal = 0;
private int firstVisibleItem;
private int visibleItemCount;
private int totalItemCount;
private LayoutManager layoutManager;
public EndlessScrollListener(LayoutManager layoutManager) {
validateLayoutManager(layoutManager);
this.layoutManager = layoutManager;
}
public EndlessScrollListener(int visibleThreshold,
LayoutManager layoutManager, int startPage) {
validateLayoutManager(layoutManager);
this.visibleThreshold = visibleThreshold;
this.layoutManager = layoutManager;
this.currentPage = startPage;
}
private void validateLayoutManager(LayoutManager layoutManager)
throws IllegalArgumentException {
if (null == layoutManager
|| !(layoutManager instanceof GridLayoutManager)
|| !(layoutManager instanceof LinearLayoutManager)) {
throw new IllegalArgumentException(
"LayoutManager must be of type GridLayoutManager or LinearLayoutManager.");
}
}
#Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
super.onScrolled(recyclerView, dx, dy);
visibleItemCount = recyclerView.getChildCount();
totalItemCount = layoutManager.getItemCount();
if (layoutManager instanceof GridLayoutManager) {
firstVisibleItem = ((GridLayoutManager) layoutManager)
.findFirstVisibleItemPosition();
} else if (layoutManager instanceof LinearLayoutManager) {
firstVisibleItem = ((LinearLayoutManager) layoutManager)
.findFirstVisibleItemPosition();
}
if (loading) {
if (totalItemCount > previousTotal) {
loading = false;
previousTotal = totalItemCount;
}
}
if (!loading
&& (totalItemCount - visibleItemCount) <= (firstVisibleItem + visibleThreshold)) {
// End has been reached do something
currentPage++;
onLoadMore(currentPage);
loading = true;
}
}
// Defines the process for actually loading more data based on page
public abstract void onLoadMore(int page);
}
I have created LoadMoreRecyclerView using Abdulaziz Noor Answer
LoadMoreRecyclerView
public class LoadMoreRecyclerView extends RecyclerView {
private boolean loading = true;
int pastVisiblesItems, visibleItemCount, totalItemCount;
//WrapperLinearLayout is for handling crash in RecyclerView
private WrapperLinearLayout mLayoutManager;
private Context mContext;
private OnLoadMoreListener onLoadMoreListener;
public LoadMoreRecyclerView(Context context) {
super(context);
mContext = context;
init();
}
public LoadMoreRecyclerView(Context context, #Nullable AttributeSet attrs) {
super(context, attrs);
mContext = context;
init();
}
public LoadMoreRecyclerView(Context context, #Nullable AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
mContext = context;
init();
}
private void init(){
mLayoutManager = new WrapperLinearLayout(mContext,LinearLayoutManager.VERTICAL,false);
this.setLayoutManager(mLayoutManager);
this.setItemAnimator(new DefaultItemAnimator());
this.setHasFixedSize(true);
}
#Override
public void onScrolled(int dx, int dy) {
super.onScrolled(dx, dy);
if(dy > 0) //check for scroll down
{
visibleItemCount = mLayoutManager.getChildCount();
totalItemCount = mLayoutManager.getItemCount();
pastVisiblesItems = mLayoutManager.findFirstVisibleItemPosition();
if (loading)
{
if ( (visibleItemCount + pastVisiblesItems) >= totalItemCount)
{
loading = false;
Log.v("...", "Call Load More !");
if(onLoadMoreListener != null){
onLoadMoreListener.onLoadMore();
}
//Do pagination.. i.e. fetch new data
}
}
}
}
#Override
public void onScrollStateChanged(int state) {
super.onScrollStateChanged(state);
}
public void onLoadMoreCompleted(){
loading = true;
}
public void setMoreLoading(boolean moreLoading){
loading = moreLoading;
}
public void setOnLoadMoreListener(OnLoadMoreListener onLoadMoreListener) {
this.onLoadMoreListener = onLoadMoreListener;
}
}
WrapperLinearLayout
public class WrapperLinearLayout extends LinearLayoutManager
{
public WrapperLinearLayout(Context context, int orientation, boolean reverseLayout) {
super(context, orientation, reverseLayout);
}
#Override
public void onLayoutChildren(RecyclerView.Recycler recycler, RecyclerView.State state) {
try {
super.onLayoutChildren(recycler, state);
} catch (IndexOutOfBoundsException e) {
Log.e("probe", "meet a IOOBE in RecyclerView");
}
}
}
//Add it in xml like
<your.package.LoadMoreRecyclerView
android:id="#+id/recycler_view"
android:layout_width="match_parent"
android:layout_height="match_parent">
</your.package.LoadMoreRecyclerView>
OnCreate or onViewCreated
mLoadMoreRecyclerView = (LoadMoreRecyclerView) view.findViewById(R.id.recycler_view);
mLoadMoreRecyclerView.setOnLoadMoreListener(new OnLoadMoreListener() {
#Override
public void onLoadMore() {
callYourService(StartIndex);
}
});
callYourService
private void callYourService(){
//callyour Service and get response in any List
List<AnyModelClass> newDataFromServer = getDataFromServerService();
//Enable Load More
mLoadMoreRecyclerView.onLoadMoreCompleted();
if(newDataFromServer != null && newDataFromServer.size() > 0){
StartIndex += newDataFromServer.size();
if (newDataFromServer.size() < Integer.valueOf(MAX_ROWS)) {
//StopLoading..
mLoadMoreRecyclerView.setMoreLoading(false);
}
}
else{
mLoadMoreRecyclerView.setMoreLoading(false);
mAdapter.notifyDataSetChanged();
}
}

Pagination using retrofit to fetch next 10 items from API on scrolling in android

Pagination using retrofit to fetch next 10 items from API on scrolling in android
instead,
for pagination if you are using simple listview with BaseAdapter,
then you may follow below code.
Use 2 arrayList for paginataion.
one is to load all listview items(allDataList), and one is to set 10 items in adapter(paginationList).
first load all data in allDataList by using retrofit.
public static int itemsCount = 10;
//i need pagination of 10 records, so here i passed 10, you may increase this no. here as your requirement.
ArrayList<User_pojo> allDataList, paginationList;
Adapter_UserList adapter;
ListView listViewUser;
View footerView;
LayoutInflater layoutInflater;
int lastItem,preLast;
Context context;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
context = this;
listViewUser = (ListView) findViewById(R.id.listViewUser);
allDataList = new ArrayList<>();
paginationList = new ArrayList<>();
layoutInflater = LayoutInflater.from(context);
footerView = layoutInflater.inflate(R.layout.load_more_view, null);
listViewUser.addFooterView(footerView);
Call_api();
listViewUser.setOnScrollListener(new AbsListView.OnScrollListener() {
#Override
public void onScrollStateChanged(AbsListView view, int scrollState) {
}
#Override
public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) {
lastItem = (firstVisibleItem + visibleItemCount);
if (lastItem == totalItemCount) {
if (preLast != lastItem) {
//to avoid multiple calls for last item
preLast = lastItem;
footerView.findViewById(R.id.progress_bar).setVisibility(View.VISIBLE);
footerView.postDelayed(new Runnable() {
#Override
public void run() {
itemsCount += 10;
LoadMoreList();
listViewUser.setSelection(lastItem - 1); //to display more loaded records # current displayed position.
}
}, 1500);
}
}
}
});
}
#Override
public void onStart() {
super.onStart();
LoadMoreList();
}
public interface AppService{
#FormUrlEncoded
#POST("getUserList")
Call<User_pojo> getUserList(#FieldMap(encoded = true) Map<String, String> map);
}
void Call_api() {
Retrofit retrofit = new Retrofit.Builder()
.baseUrl("http://your_api_url_here.com/")
.addConverterFactory(GsonConverterFactory.create())
.build();
Call<User_pojo> call = retrofit.create(AppService.class).getUserList(getUserMap());
call.enqueue(new Callback<User_pojo>() {
#Override
public void onResponse(Call<User_pojo> call, Response<User_pojo> response) {
Log.e("Response", new Gson().toJson(response.body()));
if (response.body().getResponse().equalsIgnoreCase("true")) {
allDataList = response.body().getData();
Log.e("size", allDataList.size() + "");
LoadMoreList();
}
}
#Override
public void onFailure(Call<User_pojo> call, Throwable t) {
t.printStackTrace();
t.getMessage();
Log.e("Failed", t.getMessage());
}
});
}
private void LoadMoreList() {
try {
Log.e("size", String.valueOf(allDataList.size()));
if (allDataList.size() >= itemsCount) {
paginationList.clear();
for (int i = 0; i < itemsCount; i++) {
paginationList.add(allDataList.get(i));
}
Log.e("paginationList_Size", String.valueOf(paginationList.size()));
adapter = new Adapter_UserList(context, paginationList);
} else {
adapter = new Adapter_UserList(context, allDataList);
listViewUser.removeFooterView(footerView); // loaded all list then simply remove footerView.
}
if (footerView != null)
footerView.findViewById(R.id.progress_bar).setVisibility(View.INVISIBLE);
listViewUser.setAdapter(adapter);
} catch (Exception ignored) {
}
}
private Map<String, String> getUserMap() {
Map<String, String> map = new HashMap<>();
map.put("uid", "001");
map.put("token", "5526");
Log.e("logs", map.toString());
return map;
}
hope this help.
In your recycleview ScrollListener
private static final int PAGE_START = 0;
private boolean isLoading = false;
private boolean isLastPage = false;
private int TOTAL_PAGES = 3; //your total page
private int currentPage = PAGE_START;
rv.addOnScrollListener(new PaginationScrollListener(linearLayoutManager) {
#Override
protected void loadMoreItems() {
isLoading = true;
currentPage += 1;
loadApi(currentPage); //pass page number as parameter in your api calls
}
#Override
public int getTotalPageCount() {
return TOTAL_PAGES;
}
#Override
public boolean isLastPage() {
return isLastPage;
}
#Override
public boolean isLoading() {
return isLoading;
}
});
}
more details refer Pagination Android RecyclerView
Use below EndlessRecyclerViewScrollListener class.
public abstract class EndlessRecyclerViewScrollListener extends RecyclerView.OnScrollListener {
// The minimum amount of items to have below your current scroll position
// before loading more.
private int visibleThreshold = 5;
// The current offset index of data you have loaded
private int currentPage = 0;
// The total number of items in the dataset after the last load
private int previousTotalItemCount = 0;
// True if we are still waiting for the last set of data to load.
private boolean loading = true;
// Sets the starting page index
private int startingPageIndex = 0;
RecyclerView.LayoutManager mLayoutManager;
public EndlessRecyclerViewScrollListener(LinearLayoutManager layoutManager) {
this.mLayoutManager = layoutManager;
}
public EndlessRecyclerViewScrollListener(GridLayoutManager layoutManager) {
this.mLayoutManager = layoutManager;
visibleThreshold = visibleThreshold * layoutManager.getSpanCount();
}
public EndlessRecyclerViewScrollListener(StaggeredGridLayoutManager layoutManager) {
this.mLayoutManager = layoutManager;
visibleThreshold = visibleThreshold * layoutManager.getSpanCount();
}
public int getLastVisibleItem(int[] lastVisibleItemPositions) {
int maxSize = 0;
for (int i = 0; i < lastVisibleItemPositions.length; i++) {
if (i == 0) {
maxSize = lastVisibleItemPositions[i];
} else if (lastVisibleItemPositions[i] > maxSize) {
maxSize = lastVisibleItemPositions[i];
}
}
return maxSize;
}
// This happens many times a second during a scroll, so be wary of the code you place here.
// We are given a few useful parameters to help us work out if we need to load some more data,
// but first we check if we are waiting for the previous load to finish.
#Override
public void onScrolled(RecyclerView view, int dx, int dy) {
int lastVisibleItemPosition = 0;
int totalItemCount = mLayoutManager.getItemCount();
if (mLayoutManager instanceof StaggeredGridLayoutManager) {
int[] lastVisibleItemPositions = ((StaggeredGridLayoutManager) mLayoutManager).findLastVisibleItemPositions(null);
// get maximum element within the list
lastVisibleItemPosition = getLastVisibleItem(lastVisibleItemPositions);
} else if (mLayoutManager instanceof GridLayoutManager) {
lastVisibleItemPosition = ((GridLayoutManager) mLayoutManager).findLastVisibleItemPosition();
} else if (mLayoutManager instanceof LinearLayoutManager) {
lastVisibleItemPosition = ((LinearLayoutManager) mLayoutManager).findLastVisibleItemPosition();
if (((LinearLayoutManager) mLayoutManager).findFirstCompletelyVisibleItemPosition() == 0) {
doPullToRefresh();
}
}
// If the total item count is zero and the previous isn't, assume the
// list is invalidated and should be reset back to initial state
if (totalItemCount < previousTotalItemCount) {
this.currentPage = this.startingPageIndex;
this.previousTotalItemCount = totalItemCount;
if (totalItemCount == 0) {
this.loading = true;
}
}
// If it’s still loading, we check to see if the dataset count has
// changed, if so we conclude it has finished loading and update the current page
// number and total item count.
if (loading && (totalItemCount > previousTotalItemCount)) {
loading = false;
previousTotalItemCount = totalItemCount;
}
// If it isn’t currently loading, we check to see if we have breached
// the visibleThreshold and need to reload more data.
// If we do need to reload some more data, we execute onLoadMore to fetch the data.
// threshold should reflect how many total columns there are too
if (!loading && (lastVisibleItemPosition + visibleThreshold) > totalItemCount) {
currentPage++;
onLoadMore(currentPage, totalItemCount, view);
loading = true;
}
}
// Call this method whenever performing new searches
public void resetState() {
this.currentPage = this.startingPageIndex;
this.previousTotalItemCount = 0;
this.loading = true;
}
// Defines the process for actually loading more data based on page
public abstract void onLoadMore(int page, int totalItemsCount, RecyclerView view);
public abstract void doPullToRefresh();
}
Initialise recycler view and add scroll listener to the recycler view as:
scrollListener = new EndlessRecyclerViewScrollListener(llm) {
#Override
public void onLoadMore(int page, int totalItemsCount, RecyclerView view) {
fetchNextTenRecords(page);
}
#Override
public void doPullToRefresh() {
swipeRefreshLayout.setEnabled(true);
}
};
Using RecyclerView.OnScrollListener and RecyclerView.LayoutManager you can find index of the last visible item. If the index equals to the total items count - 1 you can consider it as the end of the list and load the next page.
recyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
#Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
if (dy > 0) //check for scroll down
{
int totalItemCount = layoutManager.getItemCount();
int lastVisibleItemPosition = layoutManager.findLastVisibleItemPosition();
if (!loading && lastVisibleItemPosition == totalItemCount - 1) {
loading = true;
currentPage = currentPage + 1;
if (!dynamicPages.equalsIgnoreCase("")) {
loadMoreData(currentPage);
}
}
}
}
});

GridLayoutManager with EndlessRecyclerOnScrollListener not working properly android

i wnat to integrate endlessrecyclerview with web seervice data in GridLayoutManager so below is my code
public class GridRecycle extends AppCompatActivity {
RecyclerView mRecyclerView;
private GridLayoutManager mLayoutManager;
ArrayList<GetProductListing.ListingBlock>rowListItem;
GetProductListing mGetProductListing;
PostParseGet mPostParseGet;
int pager=1;
RecyclerViewAdapter rcAdapter;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.layout_gird);
rowListItem=new ArrayList<>();
mPostParseGet=new PostParseGet(GridRecycle.this);
mGetProductListing=new GetProductListing();
mRecyclerView=(RecyclerView)findViewById(R.id.recycler_view);
mLayoutManager = new GridLayoutManager(GridRecycle.this, 2 );
mRecyclerView = (RecyclerView) findViewById(R.id.recycler_view);
mRecyclerView.setHasFixedSize(true);
mRecyclerView.setLayoutManager(mLayoutManager);
new getData().execute();
mRecyclerView.setOnScrollListener(new EndlessRecyclerOnScrollListener(
mLayoutManager) {
#Override
public void onLoadMore(int current_page) {
pager++;
new getData().execute();
}
});
}
public class getData extends AsyncTask<Void,Void,Void>
{
#Override
protected void onPreExecute() {
super.onPreExecute();
}
#Override
protected Void doInBackground(Void... voids) {
mGetProductListing=(GetProductListing)mPostParseGet.getProductDataWithSlug(mGetProductListing,pager);
return null;
}
#Override
protected void onPostExecute(Void aVoid) {
super.onPostExecute(aVoid);
if (mGetProductListing.getListing().getData().size()>0)
{
rowListItem=getProductBlock();
rcAdapter= new RecyclerViewAdapter(GridRecycle.this, Tags.mAllListingBlocks);
mRecyclerView.setAdapter(rcAdapter);
rcAdapter.notifyDataSetChanged();
}
}
}
public ArrayList<GetProductListing.ListingBlock> getProductBlock() {
ArrayList<GetProductListing.ListingBlock> mArrayListParserLog = new ArrayList<GetProductListing.ListingBlock>();
for (int i = 0; i < mGetProductListing.getListing().getData().size(); i++) {
GetProductListing.ListingBlock mParserLog = new GetProductListing.ListingBlock();
mParserLog.setId(mGetProductListing.getListing().getData().get(i).getId());
mParserLog.setTitle(mGetProductListing.getListing().getData().get(i).getTitle());
mParserLog.setDiscountSale(mGetProductListing.getListing().getData().get(i).getDiscountSale());
mParserLog.setDiscountSelling(mGetProductListing.getListing().getData().get(i).getDiscountSelling());
mParserLog.setPrice(mGetProductListing.getListing().getData().get(i).getPrice());
mParserLog.setSale_end(mGetProductListing.getListing().getData().get(i).getSale_end());
if (mGetProductListing.getListing().getData().get(i).getSale_price()!=null && !mGetProductListing.getListing().getData().get(i).getSale_price().isEmpty())
{
mParserLog.setSale_price(mGetProductListing.getListing().getData().get(i).getSale_price());
}
else
{
mParserLog.setSale_price("0");
}
mParserLog.setSale_start(mGetProductListing.getListing().getData().get(i).getSale_start());
mParserLog.setSelling_price(mGetProductListing.getListing().getData().get(i).getSelling_price());
mParserLog.setProduct_rating(mGetProductListing.getListing().getData().get(i).getProduct_rating());
mParserLog.setSlug(mGetProductListing.getListing().getData().get(i).getSlug());
mParserLog.setSold_out(mGetProductListing.getListing().getData().get(i).getSold_out());
mParserLog.setImage(mGetProductListing.getListing().getData().get(i).getImage());
mParserLog.setSku_id(mGetProductListing.getListing().getData().get(i).getSku_id());
mParserLog.setMedium_image(mGetProductListing.getListing().getData().get(i).getMedium_image());
mArrayListParserLog.add(mParserLog);
Tags.mAllListingBlocks.add(mParserLog);
}
return mArrayListParserLog;
}
public class RecyclerViewAdapter extends RecyclerView.Adapter<RecyclerViewHolders> {
private List<GetProductListing.ListingBlock> itemList;
private Context context;
public RecyclerViewAdapter(Context context, List<GetProductListing.ListingBlock> itemList) {
this.itemList = itemList;
this.context = context;
}
#Override
public RecyclerViewHolders onCreateViewHolder(ViewGroup parent, int viewType) {
View layoutView = LayoutInflater.from(parent.getContext()).inflate(R.layout.layout_reow, null);
RecyclerViewHolders rcv = new RecyclerViewHolders(layoutView);
return rcv;
}
#Override
public void onBindViewHolder(RecyclerViewHolders holder, final int position) {
holder.name.setText(itemList.get(position).getTitle());
holder.price.setText(itemList.get(position).getPrice());
}
#Override
public int getItemCount() {
return this.itemList.size();
}
}
}
EndlessRecyclerOnScrollListener.java
public abstract class EndlessRecyclerOnScrollListener extends
RecyclerView.OnScrollListener {
public static String TAG = EndlessRecyclerOnScrollListener.class
.getSimpleName();
private int previousTotal = 0;
private boolean loading = true;
private int visibleThreshold = 5;
int firstVisibleItem, visibleItemCount, totalItemCount;
private int current_page = 1;
private LinearLayoutManager mLinearLayoutManager;
public EndlessRecyclerOnScrollListener(
LinearLayoutManager linearLayoutManager) {
this.mLinearLayoutManager = linearLayoutManager;
}
#Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
super.onScrolled(recyclerView, dx, dy);
visibleItemCount = recyclerView.getChildCount();
totalItemCount = mLinearLayoutManager.getItemCount();
firstVisibleItem = mLinearLayoutManager.findFirstVisibleItemPosition();
if (loading) {
if (totalItemCount > previousTotal) {
loading = false;
previousTotal = totalItemCount;
}
}
if (!loading
&& (totalItemCount - visibleItemCount) <= (firstVisibleItem + visibleThreshold)) {
// End has been reached
// Do something
current_page++;
onLoadMore(current_page);
loading = true;
}
}
public abstract void onLoadMore(int current_page);
}
when i run above code and scroll down at that time my recycleview focus at top again and again not scrolling down continuously? so any idea how can i solve this problem ? your all suggestions are appreciable
Use addOnScrollListener() instead of setOnScrollListener()
listRecyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
#Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
super.onScrolled(recyclerView, dx, dy);
}
});
Remove following 2 lines from class getData->onPostExecute.
rcAdapter= new RecyclerViewAdapter(GridRecycle.this, Tags.mAllListingBlocks);
mRecyclerView.setAdapter(rcAdapter);
and add those lines(above 2 lines) in GridRecycle.java-> onCreate, below this line
mRecyclerView.setLayoutManager(mLayoutManager);
I Solve my problem
public abstract class EndlessRecyclerGridOnScrollListener extends
RecyclerView.OnScrollListener {
public static String TAG = EndlessRecyclerGridOnScrollListener.class
.getSimpleName();
private int previousTotal = 0;
private boolean loading = true;
private int visibleThreshold = 5;
int firstVisibleItem, visibleItemCount, totalItemCount;
private int current_page = 1;
private GridLayoutManager mLinearLayoutManager;
public EndlessRecyclerGridOnScrollListener(
GridLayoutManager linearLayoutManager) {
this.mLinearLayoutManager = linearLayoutManager;
}
#Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
super.onScrolled(recyclerView, dx, dy);
visibleItemCount = recyclerView.getChildCount();
totalItemCount = mLinearLayoutManager.getItemCount();
firstVisibleItem = mLinearLayoutManager.findFirstVisibleItemPosition();
if (loading) {
if (totalItemCount > previousTotal) {
loading = false;
previousTotal = totalItemCount;
}
}
if (!loading
&& (totalItemCount - visibleItemCount) <= (firstVisibleItem + visibleThreshold)) {
// End has been reached
// Do something
current_page++;
onLoadMore(current_page);
loading = true;
}
}
public abstract void onLoadMore(int current_page);
}
in GridRecycle.java file
mGridView.setOnScrollListener(new EndlessRecyclerGridOnScrollListener(
mLayoutManagerGrid) {
#Override
public void onLoadMore(int current_page) {
if (Tags.mArrayListingAllProductBlocks.size() < totalitem) {
page++;
new productList().execute();
}
}
});
And remove 2 line in onPost method
rcAdapter= new RecyclerViewAdapter(GridRecycle.this, Tags.mAllListingBlocks);
mRecyclerView.setAdapter(rcAdapter);

Hide/Show many views onScroll RecyclerView

I have layout like that:
I would like to implement that functionality: When user ScrollDown RecyclerView two things which he see are Toolbar and FilterPanel. The title and image is hidden, when he scroll up till to the beggining of the recyclerview the title and image appear.
There is my HiddingScrollListener:
public abstract class HidingScrollListener extends RecyclerView.OnScrollListener {
private static final float HIDE_THRESHOLD = 10;
private int scrolledDistance = 0;
private boolean controlsVisible = true;
public HidingScrollListener() {
}
#Override
public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
super.onScrollStateChanged(recyclerView, newState);
}
#Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
super.onScrolled(recyclerView, dx, dy);
if (scrolledDistance > HIDE_THRESHOLD && controlsVisible) {
onHide();
controlsVisible = false;
scrolledDistance = 0;
} else if (scrolledDistance < -HIDE_THRESHOLD && controlsVisible) {
onShow();
controlsVisible = true;
scrolledDistance = 0;
}
if((controlsVisible && dy>0) || (!controlsVisible && dy<0)) {
scrolledDistance += dy;
}
}
public abstract void onShow();
public abstract void onHide();
}
And my implementation of this listener in activity:
mRecyclerView.addOnScrollListener(new HidingScrollListener() {
#Override
public void onShow() {
}
#Override
public void onHide() {
mTitle.setVisibility(View.GONE);
mImageView.setVisibility(View.GONE);
}
});
I don't know how to catch when RecyclerView is in the beggining and how to show title and image in this case. And I have a problem: How to pin FilterPanel under the Toolbar when I scroll down?
Anyway, thank you!
You should use the CoordinatorLayout from the android design support library.
This layout coordinates between it's children events, most commonly scroll events. Here is a tutorial: https://guides.codepath.com/android/Handling-Scrolls-with-CoordinatorLayout

How to implement endless list with RecyclerView?

I would like to change ListView to RecyclerView. I want to use the onScroll of the OnScrollListener in RecyclerView to determine if a user scrolled to the end of the list.
How do I know if a user scrolls to the end of the list so that I can fetch new data from a REST service?
Thanks to #Kushal and this is how I implemented it
private boolean loading = true;
int pastVisiblesItems, visibleItemCount, totalItemCount;
mRecyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
#Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
if (dy > 0) { //check for scroll down
visibleItemCount = mLayoutManager.getChildCount();
totalItemCount = mLayoutManager.getItemCount();
pastVisiblesItems = mLayoutManager.findFirstVisibleItemPosition();
if (loading) {
if ((visibleItemCount + pastVisiblesItems) >= totalItemCount) {
loading = false;
Log.v("...", "Last Item Wow !");
// Do pagination.. i.e. fetch new data
loading = true;
}
}
}
}
});
Don't forget to add
LinearLayoutManager mLayoutManager;
mLayoutManager = new LinearLayoutManager(this);
mRecyclerView.setLayoutManager(mLayoutManager);
Make these variables.
private int previousTotal = 0;
private boolean loading = true;
private int visibleThreshold = 5;
int firstVisibleItem, visibleItemCount, totalItemCount;
Set on Scroll for recycler view.
mRecyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
#Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
super.onScrolled(recyclerView, dx, dy);
visibleItemCount = mRecyclerView.getChildCount();
totalItemCount = mLayoutManager.getItemCount();
firstVisibleItem = mLayoutManager.findFirstVisibleItemPosition();
if (loading) {
if (totalItemCount > previousTotal) {
loading = false;
previousTotal = totalItemCount;
}
}
if (!loading && (totalItemCount - visibleItemCount)
<= (firstVisibleItem + visibleThreshold)) {
// End has been reached
Log.i("Yaeye!", "end called");
// Do something
loading = true;
}
}
});
Note : Make sure you are using LinearLayoutManager as layout manager for RecyclerView.
LinearLayoutManager mLayoutManager;
mLayoutManager = new LinearLayoutManager(this);
mRecyclerView.setLayoutManager(mLayoutManager);
and for a grid
GridLayoutManager mLayoutManager;
mLayoutManager = new GridLayoutManager(getActivity(), spanCount);
mRecyclerView.setLayoutManager(mLayoutManager);
Have fun with your endless scrolls !! ^.^
Update : mRecyclerView.setOnScrollListener() is deprecated just replace with mRecyclerView.addOnScrollListener() and the warning will be gone! You can read more from this SO question.
Since Android now officially support Kotlin, here is an update for the same -
Make OnScrollListener
class OnScrollListener(val layoutManager: LinearLayoutManager, val adapter: RecyclerView.Adapter<RecyclerAdapter.ViewHolder>, val dataList: MutableList<Int>) : RecyclerView.OnScrollListener() {
var previousTotal = 0
var loading = true
val visibleThreshold = 10
var firstVisibleItem = 0
var visibleItemCount = 0
var totalItemCount = 0
override fun onScrolled(recyclerView: RecyclerView, dx: Int, dy: Int) {
super.onScrolled(recyclerView, dx, dy)
visibleItemCount = recyclerView.childCount
totalItemCount = layoutManager.itemCount
firstVisibleItem = layoutManager.findFirstVisibleItemPosition()
if (loading) {
if (totalItemCount > previousTotal) {
loading = false
previousTotal = totalItemCount
}
}
if (!loading && (totalItemCount - visibleItemCount) <= (firstVisibleItem + visibleThreshold)) {
val initialSize = dataList.size
updateDataList(dataList)
val updatedSize = dataList.size
recyclerView.post { adapter.notifyItemRangeInserted(initialSize, updatedSize) }
loading = true
}
}
}
and add it to your RecyclerView like this
recyclerView.addOnScrollListener(OnScrollListener(layoutManager, adapter, dataList))
For a full code example, feel free to refer this Github repo.
For those who only want to get notified when the last item is totally shown, you can use View.canScrollVertically().
Here is my implementation:
public abstract class OnVerticalScrollListener
extends RecyclerView.OnScrollListener {
#Override
public final void onScrolled(RecyclerView recyclerView, int dx, int dy) {
if (!recyclerView.canScrollVertically(-1)) {
onScrolledToTop();
} else if (!recyclerView.canScrollVertically(1)) {
onScrolledToBottom();
} else if (dy < 0) {
onScrolledUp();
} else if (dy > 0) {
onScrolledDown();
}
}
public void onScrolledUp() {}
public void onScrolledDown() {}
public void onScrolledToTop() {}
public void onScrolledToBottom() {}
}
Note: You can use recyclerView.getLayoutManager().canScrollVertically() if you want to support API < 14.
Here is another approach. It will work with any layout manager.
Make Adapter class abstract
Then create an abstract method in adapter class (eg. load())
In onBindViewHolder check the position if last and call load()
Override the load() function while creating the adapter object in your activity or fragment.
In the overided load function implement your loadmore call
For a detail understanding I wrote a blog post and example project get it here
http://sab99r.com/blog/recyclerview-endless-load-more/
MyAdapter.java
public abstract class MyAdapter extends RecyclerView.Adapter<ViewHolder>{
#Override
public void onBindViewHolder(ViewHolder holder, int position) {
//check for last item
if ((position >= getItemCount() - 1))
load();
}
public abstract void load();
}
MyActivity.java
public class MainActivity extends AppCompatActivity {
List<Items> items;
MyAdapter adapter;
#Override
protected void onCreate(Bundle savedInstanceState) {
...
adapter=new MyAdapter(items){
#Override
public void load() {
//implement your load more here
Item lastItem=items.get(items.size()-1);
loadMore();
}
};
}
}
My answer is a modified version of Noor. I passed from a ListView where i had EndlessScrollListener (that you can find easily in many answers on SO) to a RecyclerView so i wanted a EndlessRecyclScrollListener to easily update my past listener.
So here is the code, hope it helps:
public abstract class EndlessScrollRecyclListener extends RecyclerView.OnScrollListener
{
// The total number of items in the dataset after the last load
private int previousTotalItemCount = 0;
private boolean loading = true;
private int visibleThreshold = 5;
int firstVisibleItem, visibleItemCount, totalItemCount;
private int startingPageIndex = 0;
private int currentPage = 0;
#Override
public void onScrolled(RecyclerView mRecyclerView, int dx, int dy)
{
super.onScrolled(mRecyclerView, dx, dy);
LinearLayoutManager mLayoutManager = (LinearLayoutManager) mRecyclerView
.getLayoutManager();
visibleItemCount = mRecyclerView.getChildCount();
totalItemCount = mLayoutManager.getItemCount();
firstVisibleItem = mLayoutManager.findFirstVisibleItemPosition();
onScroll(firstVisibleItem, visibleItemCount, totalItemCount);
}
public void onScroll(int firstVisibleItem, int visibleItemCount, int totalItemCount)
{
// If the total item count is zero and the previous isn't, assume the
// list is invalidated and should be reset back to initial state
if (totalItemCount < previousTotalItemCount)
{
this.currentPage = this.startingPageIndex;
this.previousTotalItemCount = totalItemCount;
if (totalItemCount == 0)
{
this.loading = true;
}
}
// If it’s still loading, we check to see if the dataset count has
// changed, if so we conclude it has finished loading and update the current page
// number and total item count.
if (loading && (totalItemCount > previousTotalItemCount))
{
loading = false;
previousTotalItemCount = totalItemCount;
currentPage++;
}
// If it isn’t currently loading, we check to see if we have breached
// the visibleThreshold and need to reload more data.
// If we do need to reload some more data, we execute onLoadMore to fetch the data.
if (!loading && (totalItemCount - visibleItemCount) <= (firstVisibleItem +
visibleThreshold))
{
onLoadMore(currentPage + 1, totalItemCount);
loading = true;
}
}
// Defines the process for actually loading more data based on page
public abstract void onLoadMore(int page, int totalItemsCount);
}
For me, it's very simple:
private boolean mLoading = false;
mList.setOnScrollListener(new RecyclerView.OnScrollListener() {
#Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
super.onScrolled(recyclerView, dx, dy);
int totalItem = mLinearLayoutManager.getItemCount();
int lastVisibleItem = mLinearLayoutManager.findLastVisibleItemPosition();
if (!mLoading && lastVisibleItem == totalItem - 1) {
mLoading = true;
// Scrolled to bottom. Do something here.
mLoading = false;
}
}
});
Be careful with asynchronous jobs: mLoading must be changed at the end of the asynchronous jobs. Hope it will be helpful!
With the power of Kotlin's extension functions, the code can look a lot more elegant. Put this anywhere you want (I have it inside an ExtensionFunctions.kt file):
/**
* WARNING: This assumes the layout manager is a LinearLayoutManager
*/
fun RecyclerView.addOnScrolledToEnd(onScrolledToEnd: () -> Unit){
this.addOnScrollListener(object: RecyclerView.OnScrollListener(){
private val VISIBLE_THRESHOLD = 5
private var loading = true
private var previousTotal = 0
override fun onScrollStateChanged(recyclerView: RecyclerView,
newState: Int) {
with(layoutManager as LinearLayoutManager){
val visibleItemCount = childCount
val totalItemCount = itemCount
val firstVisibleItem = findFirstVisibleItemPosition()
if (loading && totalItemCount > previousTotal){
loading = false
previousTotal = totalItemCount
}
if(!loading && (totalItemCount - visibleItemCount) <= (firstVisibleItem + visibleThreshold)){
onScrolledToEnd()
loading = true
}
}
}
})
}
And then use it like this:
youRecyclerView.addOnScrolledToEnd {
//What you want to do once the end is reached
}
This solution is based on Kushal Sharma's answer. However, this is a bit better because:
It uses onScrollStateChanged instead of onScroll. This is better because onScroll is called every time there is any sort of movement in the RecyclerView, whereas onScrollStateChanged is only called when the state of the RecyclerView is changed. Using onScrollStateChanged will save you CPU time and, as a consequence, battery.
Since this uses Extension Functions, this can be used in any RecyclerView you have. The client code is just 1 line.
Most answer are assuming the RecyclerView uses a LinearLayoutManager, or GridLayoutManager, or even StaggeredGridLayoutManager, or assuming that the scrolling is vertical or horyzontal, but no one has posted a completly generic answer.
Using the ViewHolder's adapter is clearly not a good solution. An adapter might have more than 1 RecyclerView using it. It "adapts" their contents. It should be the RecyclerView (which is the one class which is responsible of what is currently displayed to the user, and not the adapter which is responsible only to provide content to the RecyclerView) which must notify your system that more items are needed (to load).
Here is my solution, using nothing else than the abstracted classes of the RecyclerView (RecycerView.LayoutManager and RecycerView.Adapter):
/**
* Listener to callback when the last item of the adpater is visible to the user.
* It should then be the time to load more items.
**/
public abstract class LastItemListener extends RecyclerView.OnScrollListener {
#Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
super.onScrolled(recyclerView, dx, dy);
// init
RecyclerView.LayoutManager layoutManager = recyclerView.getLayoutManager();
RecyclerView.Adapter adapter = recyclerView.getAdapter();
if (layoutManager.getChildCount() > 0) {
// Calculations..
int indexOfLastItemViewVisible = layoutManager.getChildCount() -1;
View lastItemViewVisible = layoutManager.getChildAt(indexOfLastItemViewVisible);
int adapterPosition = layoutManager.getPosition(lastItemViewVisible);
boolean isLastItemVisible = (adapterPosition == adapter.getItemCount() -1);
// check
if (isLastItemVisible)
onLastItemVisible(); // callback
}
}
/**
* Here you should load more items because user is seeing the last item of the list.
* Advice: you should add a bollean value to the class
* so that the method {#link #onLastItemVisible()} will be triggered only once
* and not every time the user touch the screen ;)
**/
public abstract void onLastItemVisible();
}
// --- Exemple of use ---
myRecyclerView.setOnScrollListener(new LastItemListener() {
public void onLastItemVisible() {
// start to load more items here.
}
}
Although the accepted answer works perfectly, the solution below uses addOnScrollListener since setOnScrollListener is deprecated, and reduces number of variables, and if conditions.
final LinearLayoutManager layoutManager = new LinearLayoutManager(context);
feedsRecyclerView.setLayoutManager(layoutManager);
feedsRecyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
#Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
super.onScrolled(recyclerView, dx, dy);
if (dy > 0) {
if ((layoutManager.getChildCount() + layoutManager.findFirstVisibleItemPosition()) >= layoutManager.getItemCount()) {
Log.d("TAG", "End of list");
//loadMore();
}
}
}
});
This is how I do it, simple and short:
recyclerView.addOnScrollListener(new RecyclerView.OnScrollListener()
{
#Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy)
{
if(!recyclerView.canScrollVertically(1) && dy != 0)
{
// Load more results here
}
}
});
Although there are so many answers to the question, I would like to share our experience of creating the endless list view. We have recently implemented custom Carousel LayoutManager that can work in the cycle by scrolling the list infinitely as well as up to a certain point. Here is a detailed description on GitHub.
I suggest you take a look at this article with short but valuable recommendations on creating custom LayoutManagers: http://cases.azoft.com/create-custom-layoutmanager-android/
OK, I did it by using the onBindViewHolder method of RecyclerView.Adapter.
Adapter:
public interface OnViewHolderListener {
void onRequestedLastItem();
}
#Override
public void onBindViewHolder(ViewHolder holder, int position) {
...
if (position == getItemCount() - 1) onViewHolderListener.onRequestedLastItem();
}
Fragment (or Activity):
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
contentView = inflater.inflate(R.layout.comments_list, container, false);
recyclerView = (RecyclerView) mContentView.findViewById(R.id.my_recycler_view);
adapter = new Adapter();
recyclerView.setAdapter(adapter);
...
adapter.setOnViewHolderListener(new Adapter.OnViewHolderListener() {
#Override
public void onRequestedLastItem() {
//TODO fetch new data from webservice
}
});
return contentView;
}
recyclerList.setOnScrollListener(new RecyclerView.OnScrollListener()
{
#Override
public void onScrolled(RecyclerView recyclerView, int dx,int dy)
{
super.onScrolled(recyclerView, dx, dy);
}
#Override
public void onScrollStateChanged(RecyclerView recyclerView,int newState)
{
int totalItemCount = layoutManager.getItemCount();
int lastVisibleItem = layoutManager.findLastVisibleItemPosition();
if (totalItemCount> 1)
{
if (lastVisibleItem >= totalItemCount - 1)
{
// End has been reached
// do something
}
}
}
});
I would try to extend used LayoutManager (e.g. LinearLayoutManager) and override scrollVerticallyBy() method. Firstly, I would call super first and then check returned integer value. If the value equals to 0 then a bottom or a top border is reached. Then I would use findLastVisibleItemPosition() method to find out which border is reached and load more data if needed. Just an idea.
In addition, you can even return your value from that method allowing overscroll and showing "loading" indicator.
I achieved an infinite scrolling type implementation using this logic in the onBindViewHolder method of my RecyclerView.Adapter class.
if (position == mItems.size() - 1 && mCurrentPage <= mTotalPageCount) {
if (mCurrentPage == mTotalPageCount) {
mLoadImagesListener.noMorePages();
} else {
int newPage = mCurrentPage + 1;
mLoadImagesListener.loadPage(newPage);
}
}
With this code when the RecyclerView gets to the last item, it increments the current page and callbacks on an interface which is responsible for loading more data from the api and adding the new results to the adapter.
I can post more complete example if this isn't clear?
For people who use StaggeredGridLayoutManager here is my implementation, it works for me.
private class ScrollListener extends RecyclerView.OnScrollListener {
#Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
firstVivisibleItems = mLayoutManager.findFirstVisibleItemPositions(firstVivisibleItems);
if(!recyclerView.canScrollVertically(1) && firstVivisibleItems[0]!=0) {
loadMoreImages();
}
}
private boolean loadMoreImages(){
Log.d("myTag", "LAST-------HERE------");
return true;
}
}
There is an easy to use library for this named paginate . Supports both ListView and RecyclerView ( LinearLayout , GridLayout and StaggeredGridLayout).
Here is the link to the project on Github
My way to detect loading event is not to detect scrolling, but to listen whether the last view was attached. If the last view was attached, I regard it as timing to load more content.
class MyListener implements RecyclerView.OnChildAttachStateChangeListener {
RecyclerView mRecyclerView;
MyListener(RecyclerView view) {
mRecyclerView = view;
}
#Override
public void onChildViewAttachedToWindow(View view) {
RecyclerView.Adapter adapter = mRecyclerView.getAdapter();
RecyclerView.LayoutManager mgr = mRecyclerView.getLayoutManager();
int adapterPosition = mgr.getPosition(view);
if (adapterPosition == adapter.getItemCount() - 1) {
// last view was attached
loadMoreContent();
}
#Override
public void onChildViewDetachedFromWindow(View view) {}
}
Create an abstract class and extends RecyclerView.OnScrollListener
public abstract class EndlessRecyclerOnScrollListener extends RecyclerView.OnScrollListener {
private int previousTotal = 0;
private boolean loading = true;
private int visibleThreshold;
private int firstVisibleItem, visibleItemCount, totalItemCount;
private RecyclerView.LayoutManager layoutManager;
public EndlessRecyclerOnScrollListener(RecyclerView.LayoutManager layoutManager, int visibleThreshold) {
this.layoutManager = layoutManager; this.visibleThreshold = visibleThreshold;
}
#Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
super.onScrolled(recyclerView, dx, dy);
visibleItemCount = recyclerView.getChildCount();
totalItemCount = layoutManager.getItemCount();
firstVisibleItem = ((LinearLayoutManager)layoutManager).findFirstVisibleItemPosition();
if (loading) {
if (totalItemCount > previousTotal) {
loading = false;
previousTotal = totalItemCount;
}
}
if (!loading && (totalItemCount - visibleItemCount) <= (firstVisibleItem + visibleThreshold)) {
onLoadMore();
loading = true;
}
}
public abstract void onLoadMore();}
in activity (or fragment) add addOnScrollListener to recyclerView
LinearLayoutManager mLayoutManager = new LinearLayoutManager(this);
recyclerView.setLayoutManager(mLayoutManager);
recyclerView.addOnScrollListener(new EndlessRecyclerOnScrollListener(mLayoutManager, 3) {
#Override
public void onLoadMore() {
//TODO
...
}
});
I have a pretty detailed example of how to paginate with a RecyclerView. At a high level, I have a set PAGE_SIZE , lets say 30. So I request 30 items and if I get 30 back then I request the next page. If I get less than 30 items I flag a variable to indicate that the last page has been reached and then I stop requesting for more pages. Check it out and let me know what you think.
https://medium.com/#etiennelawlor/pagination-with-recyclerview-1cb7e66a502b
Here my solution using AsyncListUtil, in the web says:
Note that this class uses a single thread to load the data, so it suitable to load data from secondary storage such as disk, but not from network.
but i am using odata to read the data and work fine.
I miss in my example data entities and network methods.
I include only the example adapter.
public class AsyncPlatoAdapter extends RecyclerView.Adapter {
private final AsyncPlatoListUtil mAsyncListUtil;
private final MainActivity mActivity;
private final RecyclerView mRecyclerView;
private final String mFilter;
private final String mOrderby;
private final String mExpand;
public AsyncPlatoAdapter(String filter, String orderby, String expand, RecyclerView recyclerView, MainActivity activity) {
mFilter = filter;
mOrderby = orderby;
mExpand = expand;
mRecyclerView = recyclerView;
mActivity = activity;
mAsyncListUtil = new AsyncPlatoListUtil();
}
#Override
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View itemView = LayoutInflater.from(parent.getContext()).
inflate(R.layout.plato_cardview, parent, false);
// Create a ViewHolder to find and hold these view references, and
// register OnClick with the view holder:
return new PlatoViewHolderAsync(itemView, this);
}
#Override
public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {
final Plato item = mAsyncListUtil.getItem(position);
PlatoViewHolderAsync vh = (PlatoViewHolderAsync) holder;
if (item != null) {
Integer imagen_id = item.Imagen_Id.get();
vh.getBinding().setVariable(BR.plato, item);
vh.getBinding().executePendingBindings();
vh.getImage().setVisibility(View.VISIBLE);
vh.getProgress().setVisibility(View.GONE);
String cacheName = null;
String urlString = null;
if (imagen_id != null) {
cacheName = String.format("imagenes/imagen/%d", imagen_id);
urlString = String.format("%s/menusapi/%s", MainActivity.ROOTPATH, cacheName);
}
ImageHelper.downloadBitmap(mActivity, vh.getImage(), vh.getProgress(), urlString, cacheName, position);
} else {
vh.getBinding().setVariable(BR.plato, item);
vh.getBinding().executePendingBindings();
//show progress while loading.
vh.getImage().setVisibility(View.GONE);
vh.getProgress().setVisibility(View.VISIBLE);
}
}
#Override
public int getItemCount() {
return mAsyncListUtil.getItemCount();
}
public class AsyncPlatoListUtil extends AsyncListUtil<Plato> {
/**
* Creates an AsyncListUtil.
*/
public AsyncPlatoListUtil() {
super(Plato.class, //my data class
10, //page size
new DataCallback<Plato>() {
#Override
public int refreshData() {
//get count calling ../$count ... odata endpoint
return countPlatos(mFilter, mOrderby, mExpand, mActivity);
}
#Override
public void fillData(Plato[] data, int startPosition, int itemCount) {
//get items from odata endpoint using $skip and $top
Platos p = loadPlatos(mFilter, mOrderby, mExpand, startPosition, itemCount, mActivity);
for (int i = 0; i < Math.min(itemCount, p.value.size()); i++) {
data[i] = p.value.get(i);
}
}
}, new ViewCallback() {
#Override
public void getItemRangeInto(int[] outRange) {
//i use LinearLayoutManager in the RecyclerView
LinearLayoutManager layoutManager = (LinearLayoutManager) mRecyclerView.getLayoutManager();
outRange[0] = layoutManager.findFirstVisibleItemPosition();
outRange[1] = layoutManager.findLastVisibleItemPosition();
}
#Override
public void onDataRefresh() {
mRecyclerView.getAdapter().notifyDataSetChanged();
}
#Override
public void onItemLoaded(int position) {
mRecyclerView.getAdapter().notifyItemChanged(position);
}
});
mRecyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
#Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
onRangeChanged();
}
});
}
}
}
if (layoutManager.findLastCompletelyVisibleItemPosition() ==
recyclerAdapter.getItemCount() - 1) {
//load more items.
}
Fair and simple.
This will work.
As #John T suggest. Just use code block below, really short, beauty and simple :D
public void loadMoreOnRecyclerView() {
mRecyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
#Override
public void onScrolled(#NonNull #NotNull RecyclerView recyclerView, int dx, int dy) {
super.onScrolled(recyclerView, dx, dy);
if (!recyclerView.canScrollVertically(1) && dy != 0) {
//Load more items here
}
}
});
}
You can follow my Repo to understand the way that it work.
https://github.com/Nghien-Nghien/PokeAPI-Java/blob/0d8d69d348e068911b883f0ae7791d904cc75cb5/app/src/main/java/com/example/pokemonapi/MainActivity.java
Description info about app like this: https://github.com/skydoves/Pokedex#readme
There is a method public void setOnScrollListener (RecyclerView.OnScrollListener listener) in https://developer.android.com/reference/android/support/v7/widget/RecyclerView.html#setOnScrollListener%28android.support.v7.widget.RecyclerView.OnScrollListener%29. Use that
EDIT:
Override onScrollStateChanged method inside the onScrollListener and do this
boolean loadMore = firstVisibleItem + visibleItemCount >= totalItemCount;
//loading is used to see if its already loading, you have to manually manipulate this boolean variable
if (loadMore && !loading) {
//end of list reached
}
Check this every thing is explained in detail:
Pagination using RecyclerView From A to Z
mRecyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
#Override
public void onScrollStateChanged(RecyclerView recyclerView,
int newState) {
super.onScrollStateChanged(recyclerView, newState);
}
#Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
super.onScrolled(recyclerView, dx, dy);
int visibleItemCount = mLayoutManager.getChildCount();
int totalItemCount = mLayoutManager.getItemCount();
int firstVisibleItemPosition = mLayoutManager.findFirstVisibleItemPosition();
if (!mIsLoading && !mIsLastPage) {
if ((visibleItemCount + firstVisibleItemPosition) >= totalItemCount
&& firstVisibleItemPosition >= 0) {
loadMoreItems();
}
}
}
})
loadMoreItems():
private void loadMoreItems() {
mAdapter.removeLoading();
//load data here from the server
// in case of success
mAdapter.addData(data);
// if there might be more data
mAdapter.addLoading();
}
in MyAdapter :
private boolean mIsLoadingFooterAdded = false;
public void addLoading() {
if (!mIsLoadingFooterAdded) {
mIsLoadingFooterAdded = true;
mLineItemList.add(new LineItem());
notifyItemInserted(mLineItemList.size() - 1);
}
}
public void removeLoading() {
if (mIsLoadingFooterAdded) {
mIsLoadingFooterAdded = false;
int position = mLineItemList.size() - 1;
LineItem item = mLineItemList.get(position);
if (item != null) {
mLineItemList.remove(position);
notifyItemRemoved(position);
}
}
}
public void addData(List<YourDataClass> data) {
for (int i = 0; i < data.size(); i++) {
YourDataClass yourDataObject = data.get(i);
mLineItemList.add(new LineItem(yourDataObject));
notifyItemInserted(mLineItemList.size() - 1);
}
}
None of these answers take into account if the list is too small or not.
Here's a piece of code I've been using that works on RecycleViews in both directions.
#Override
public boolean onTouchEvent(MotionEvent motionEvent) {
if (recyclerViewListener == null) {
return super.onTouchEvent(motionEvent);
}
/**
* If the list is too small to scroll.
*/
if (motionEvent.getAction() == MotionEvent.ACTION_UP) {
if (!canScrollVertically(1)) {
recyclerViewListener.reachedBottom();
} else if (!canScrollVertically(-1)) {
recyclerViewListener.reachedTop();
}
}
return super.onTouchEvent(motionEvent);
}
public void setListener(RecyclerViewListener recycleViewListener) {
this.recyclerViewListener = recycleViewListener;
addOnScrollListener(new OnScrollListener() {
#Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
super.onScrolled(recyclerView, dx, dy);
if (recyclerViewListener == null) {
return;
}
recyclerViewListener.scrolling(dy);
if (!canScrollVertically(1)) {
recyclerViewListener.reachedBottom();
} else if (!canScrollVertically(-1)) {
recyclerViewListener.reachedTop();
}
}
});
}
I let you my aproximation. Works fine for me.
I hope it helps you.
/**
* Created by Daniel Pardo Ligorred on 03/03/2016.
*/
public abstract class BaseScrollListener extends RecyclerView.OnScrollListener {
protected RecyclerView.LayoutManager layoutManager;
public BaseScrollListener(RecyclerView.LayoutManager layoutManager) {
this.layoutManager = layoutManager;
this.init();
}
#Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
super.onScrolled(recyclerView, dx, dy);
this.onScroll(recyclerView, this.getFirstVisibleItem(), this.layoutManager.getChildCount(), this.layoutManager.getItemCount(), dx, dy);
}
private int getFirstVisibleItem(){
if(this.layoutManager instanceof LinearLayoutManager){
return ((LinearLayoutManager) this.layoutManager).findFirstVisibleItemPosition();
} else if (this.layoutManager instanceof StaggeredGridLayoutManager){
int[] spanPositions = null; //Should be null -> StaggeredGridLayoutManager.findFirstVisibleItemPositions makes the work.
try{
return ((StaggeredGridLayoutManager) this.layoutManager).findFirstVisibleItemPositions(spanPositions)[0];
}catch (Exception ex){
// Do stuff...
}
}
return 0;
}
public abstract void init();
protected abstract void onScroll(RecyclerView recyclerView, int firstVisibleItem, int visibleItemCount, int totalItemCount, int dx, int dy);
}
#kushal #abdulaziz
Why not use this logic instead?
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
int totalItemCount, lastVisibleItemPosition;
if (dy > 0) {
totalItemCount = _layoutManager.getItemCount();
lastVisibleItemPosition = _layoutManager.findLastVisibleItemPosition();
if (!_isLastItem) {
if ((totalItemCount - 1) == lastVisibleItemPosition) {
LogUtil.e("end_of_list");
_isLastItem = true;
}
}
}
}
Try below:
import android.support.v7.widget.GridLayoutManager;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.support.v7.widget.RecyclerView.LayoutManager;
/**
* Abstract Endless ScrollListener
*
*/
public abstract class EndlessScrollListener extends
RecyclerView.OnScrollListener {
// The minimum amount of items to have below your current scroll position
// before loading more.
private int visibleThreshold = 10;
// The current offset index of data you have loaded
private int currentPage = 1;
// True if we are still waiting for the last set of data to load.
private boolean loading = true;
// The total number of items in the data set after the last load
private int previousTotal = 0;
private int firstVisibleItem;
private int visibleItemCount;
private int totalItemCount;
private LayoutManager layoutManager;
public EndlessScrollListener(LayoutManager layoutManager) {
validateLayoutManager(layoutManager);
this.layoutManager = layoutManager;
}
public EndlessScrollListener(int visibleThreshold,
LayoutManager layoutManager, int startPage) {
validateLayoutManager(layoutManager);
this.visibleThreshold = visibleThreshold;
this.layoutManager = layoutManager;
this.currentPage = startPage;
}
private void validateLayoutManager(LayoutManager layoutManager)
throws IllegalArgumentException {
if (null == layoutManager
|| !(layoutManager instanceof GridLayoutManager)
|| !(layoutManager instanceof LinearLayoutManager)) {
throw new IllegalArgumentException(
"LayoutManager must be of type GridLayoutManager or LinearLayoutManager.");
}
}
#Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
super.onScrolled(recyclerView, dx, dy);
visibleItemCount = recyclerView.getChildCount();
totalItemCount = layoutManager.getItemCount();
if (layoutManager instanceof GridLayoutManager) {
firstVisibleItem = ((GridLayoutManager) layoutManager)
.findFirstVisibleItemPosition();
} else if (layoutManager instanceof LinearLayoutManager) {
firstVisibleItem = ((LinearLayoutManager) layoutManager)
.findFirstVisibleItemPosition();
}
if (loading) {
if (totalItemCount > previousTotal) {
loading = false;
previousTotal = totalItemCount;
}
}
if (!loading
&& (totalItemCount - visibleItemCount) <= (firstVisibleItem + visibleThreshold)) {
// End has been reached do something
currentPage++;
onLoadMore(currentPage);
loading = true;
}
}
// Defines the process for actually loading more data based on page
public abstract void onLoadMore(int page);
}
I have created LoadMoreRecyclerView using Abdulaziz Noor Answer
LoadMoreRecyclerView
public class LoadMoreRecyclerView extends RecyclerView {
private boolean loading = true;
int pastVisiblesItems, visibleItemCount, totalItemCount;
//WrapperLinearLayout is for handling crash in RecyclerView
private WrapperLinearLayout mLayoutManager;
private Context mContext;
private OnLoadMoreListener onLoadMoreListener;
public LoadMoreRecyclerView(Context context) {
super(context);
mContext = context;
init();
}
public LoadMoreRecyclerView(Context context, #Nullable AttributeSet attrs) {
super(context, attrs);
mContext = context;
init();
}
public LoadMoreRecyclerView(Context context, #Nullable AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
mContext = context;
init();
}
private void init(){
mLayoutManager = new WrapperLinearLayout(mContext,LinearLayoutManager.VERTICAL,false);
this.setLayoutManager(mLayoutManager);
this.setItemAnimator(new DefaultItemAnimator());
this.setHasFixedSize(true);
}
#Override
public void onScrolled(int dx, int dy) {
super.onScrolled(dx, dy);
if(dy > 0) //check for scroll down
{
visibleItemCount = mLayoutManager.getChildCount();
totalItemCount = mLayoutManager.getItemCount();
pastVisiblesItems = mLayoutManager.findFirstVisibleItemPosition();
if (loading)
{
if ( (visibleItemCount + pastVisiblesItems) >= totalItemCount)
{
loading = false;
Log.v("...", "Call Load More !");
if(onLoadMoreListener != null){
onLoadMoreListener.onLoadMore();
}
//Do pagination.. i.e. fetch new data
}
}
}
}
#Override
public void onScrollStateChanged(int state) {
super.onScrollStateChanged(state);
}
public void onLoadMoreCompleted(){
loading = true;
}
public void setMoreLoading(boolean moreLoading){
loading = moreLoading;
}
public void setOnLoadMoreListener(OnLoadMoreListener onLoadMoreListener) {
this.onLoadMoreListener = onLoadMoreListener;
}
}
WrapperLinearLayout
public class WrapperLinearLayout extends LinearLayoutManager
{
public WrapperLinearLayout(Context context, int orientation, boolean reverseLayout) {
super(context, orientation, reverseLayout);
}
#Override
public void onLayoutChildren(RecyclerView.Recycler recycler, RecyclerView.State state) {
try {
super.onLayoutChildren(recycler, state);
} catch (IndexOutOfBoundsException e) {
Log.e("probe", "meet a IOOBE in RecyclerView");
}
}
}
//Add it in xml like
<your.package.LoadMoreRecyclerView
android:id="#+id/recycler_view"
android:layout_width="match_parent"
android:layout_height="match_parent">
</your.package.LoadMoreRecyclerView>
OnCreate or onViewCreated
mLoadMoreRecyclerView = (LoadMoreRecyclerView) view.findViewById(R.id.recycler_view);
mLoadMoreRecyclerView.setOnLoadMoreListener(new OnLoadMoreListener() {
#Override
public void onLoadMore() {
callYourService(StartIndex);
}
});
callYourService
private void callYourService(){
//callyour Service and get response in any List
List<AnyModelClass> newDataFromServer = getDataFromServerService();
//Enable Load More
mLoadMoreRecyclerView.onLoadMoreCompleted();
if(newDataFromServer != null && newDataFromServer.size() > 0){
StartIndex += newDataFromServer.size();
if (newDataFromServer.size() < Integer.valueOf(MAX_ROWS)) {
//StopLoading..
mLoadMoreRecyclerView.setMoreLoading(false);
}
}
else{
mLoadMoreRecyclerView.setMoreLoading(false);
mAdapter.notifyDataSetChanged();
}
}

Categories

Resources