Reputation: 3962
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?
Upvotes: 381
Views: 293426
Reputation: 297
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.
Description info about app like this: https://github.com/skydoves/Pokedex#readme
Upvotes: 3
Reputation: 6423
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);
Upvotes: 473
Reputation: 1602
No repetition calls however you scroll. fetchData will be called only when you are at the end of the list and there is more data to be fetched
Regarding my code:
1.fetchData() fetches 10 items on each call.
2.isScrolling is a class member variable
3.previousTotalCount is also a class member. It stores previously visited last item
recyclerView.addOnScrollListener(object : RecyclerView.OnScrollListener() {
override fun onScrollStateChanged(recyclerView: RecyclerView, newState: Int) {
super.onScrollStateChanged(recyclerView, newState)
if (newState == AbsListView.OnScrollListener.SCROLL_STATE_TOUCH_SCROLL) {
isScrolling = true
}
}
override fun onScrolled(recyclerView: RecyclerView, dx: Int, dy: Int) {
super.onScrolled(recyclerView, dx, dy)
val visibleItemCount = layoutManager.childCount
val totalItemCount = layoutManager.itemCount
val scrolledOutItems = layoutManager.findFirstVisibleItemPosition()
if (isScrolling && (visibleItemCount + scrolledOutItems == totalItemCount)
&& (visibleItemCount + scrolledOutItems != previousTotalCount)) {
previousTotalCount = totalItemCount
isScrolling = false
fetchData() //fetches 10 new items from Firestore
pagingProgressBar.visibility = View.VISIBLE
}
}
})
Upvotes: 0
Reputation: 716
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
...
}
});
Upvotes: 3
Reputation: 479
Here is example for Simple Implementation of Endless Scrolling RecyclerView using a Simple Library compiled from the various sources.
Add this line in build.gradle
implementation 'com.hereshem.lib:awesomelib:2.0.1'
Create RecyclerView Layout in Activity with
<com.hereshem.lib.recycler.MyRecyclerView
android:id="@+id/recycler"
app:layoutManager="LinearLayoutManager"
android:layout_width="match_parent"
android:layout_height="match_parent"/>
Create a ViewHolder by passing the class it supports
public static class EVHolder extends MyViewHolder<Events> {
TextView date, title, summary;
public EVHolder(View v) {
super(v);
date = v.findViewById(R.id.date);
title = v.findViewById(R.id.title);
summary = v.findViewById(R.id.summary);
}
@Override
public void bindView(Events c) {
date.setText(c.date);
title.setText(c.title);
summary.setText(c.summary);
}
}
Create Items List variable and adapters with very few lines by passing items, class and layout in the adapter
List<Events> items = new ArrayList<>();
MyRecyclerView recycler = findViewById(R.id.recycler);
RecyclerViewAdapter adapter = new RecyclerViewAdapter(this, items, EVHolder.class, R.layout.row_event);
recycler.setAdapter(adapter);
ClickListener and LoadMore Listener can be added with following lines
recycler.setOnItemClickListener(new MyRecyclerView.OnItemClickListener() {
@Override
public void onItemClick(int position) {
Toast.makeText(MainActivity.this, "Recycler Item Clicked " + position, Toast.LENGTH_SHORT).show();
}
});
recycler.setOnLoadMoreListener(new MyRecyclerView.OnLoadMoreListener() {
@Override
public void onLoadMore() {
loadData();
}
});
loadData();
After the data is loaded this must be called
recycler.loadComplete();
When no LoadMore is required LoadMore layout can be hidden by calling
recycler.hideLoadMore();
More example can be found here
Hope this helps :)
Upvotes: -1
Reputation: 1082
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
}
}
});
Upvotes: 8
Reputation: 1328
I just tried this:
final LinearLayoutManager rvLayoutManager = new LinearLayoutManager(this);
rvMovieList = (RecyclerView) findViewById(R.id.rvMovieList);
rvMovieList.setLayoutManager(rvLayoutManager);
adapter = new MovieRecyclerAdapter(this, movies);
rvMovieList.setAdapter(adapter);
adapter.notifyDataSetChanged();
rvMovieList.addOnScrollListener(new OnScrollListener() {
boolean loading = true;
int pastVisiblesItems, visibleItemCount, totalItemCount;
@Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
super.onScrolled(recyclerView, dx, dy);
visibleItemCount = rvLayoutManager.getChildCount();
totalItemCount = rvLayoutManager.getItemCount();
pastVisiblesItems = rvLayoutManager.findFirstVisibleItemPosition();
int lastitem = visibleItemCount + pastVisiblesItems;
if ( lastitem == totalItemCount
&& page < total_pages
&& !keyword.equals("") ) {
// hit bottom ..
String strnext;
if (page == total_pages - 1) {
int last = total_results - (page * 20);
strnext = String.format(getResources().getString(R.string.next), last);
} else {
strnext = String.format(getResources().getString(R.string.next), 20);
}
btNext.setText(strnext);
btNext.setVisibility(View.VISIBLE);
} else {
btNext.setVisibility(View.INVISIBLE);
}
if(pastVisiblesItems == 0 && page > 1){
// hit top
btPrev.setVisibility(View.VISIBLE);
} else {
btPrev.setVisibility(View.INVISIBLE);
}
}
});
I've got confused where to put loading
with true
or false
, so I try to remove it, and this code works as I expected.
Upvotes: -1
Reputation: 2670
if (layoutManager.findLastCompletelyVisibleItemPosition() ==
recyclerAdapter.getItemCount() - 1) {
//load more items.
}
Fair and simple. This will work.
Upvotes: 2
Reputation: 11731
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:
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.Upvotes: 11
Reputation: 573
@erdna Please refer my below code.May be it will become helpful to you.
int firstVisibleItem, visibleItemCount, totalItemCount;
recyclerView.setOnScrollListener(new RecyclerView.OnScrollListener() {
@Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
super.onScrolled(recyclerView, dx, dy);
visibleItemCount = layoutManager.getChildCount();
totalItemCount = layoutManager.getItemCount();
firstVisibleItem = layoutManager.findFirstVisibleItemPosition();
Log.e("firstVisibleItem", firstVisibleItem + "");
Log.e("visibleItemCount", visibleItemCount + "");
Log.e("totalItemCount", totalItemCount + "");
if (page != total_page_index) {
if (loading) {
if ((visibleItemCount + firstVisibleItem) >= totalItemCount) {
Log.e("page", String.valueOf(page));
page=page+1;
new GetSummary().execute(String.valueOf(page), "");
loading = false;
}
}
}
}
});
Upvotes: 0
Reputation: 1201
This solution works perfectly for me.
//Listener
public abstract class InfiniteScrollListener extendsRecyclerView.OnScrollListener {
public static String TAG = InfiniteScrollListener.class.getSimpleName();
int firstVisibleItem, visibleItemCount, totalItemCount;
private int previousTotal = 0;
private boolean loading = true;
private int visibleThreshold = 1;
private int current_page = 1;
private LinearLayoutManager mLinearLayoutManager;
public InfiniteScrollListener(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)) {
current_page++;
onLoadMore(current_page);
loading = true;
}
}
public void resetState() {
loading = true;
previousTotal = 0;
current_page = 1;
}
public abstract void onLoadMore(int current_page);
}
//Implementation into fragment
private InfiniteScrollListener scrollListener;
scrollListener = new InfiniteScrollListener(manager) {
@Override
public void onLoadMore(int current_page) {
//Load data
}
};
rv.setLayoutManager(manager);
rv.addOnScrollListener(scrollListener);
Upvotes: 1
Reputation: 21728
It is also possible to implement without the scroll listener, using the pure logic of the data model alone. The scroll view requires to get items by position as well as the maximal item count. The model can have the background logic to fetch the needed items in chunks, rather than one by one, and do this in the background thread, notifying the view when the data are ready.
This approach allows to have the fetching queue which prefers most recently requested (so currently visible) items over older (most likely already scrolled away) submissions, control the number of parallel threads to use and things the like. The complete source code for this approach (demo app and reusable library) are available here.
Upvotes: 1
Reputation: 5973
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 forRecyclerView
.
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 withmRecyclerView.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.
Upvotes: 177
Reputation: 4110
Here is another approach. It will work with any layout manager.
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();
}
};
}
}
Upvotes: 75
Reputation: 34360
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();
}
}
Upvotes: 1
Reputation: 10324
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.
}
}
Upvotes: 9
Reputation: 2775
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);
}
Upvotes: 21
Reputation: 111
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) {}
}
Upvotes: 3
Reputation: 7394
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);
}
Upvotes: 1
Reputation: 244
@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;
}
}
}
}
Upvotes: 1
Reputation: 9581
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
Upvotes: 3
Reputation: 371
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/
Upvotes: 6
Reputation: 31
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();
}
});
}
}
}
Upvotes: 2
Reputation: 10651
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();
}
}
}
});
Upvotes: 7
Reputation: 4111
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);
}
Upvotes: 1
Reputation: 7405
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();
}
}
});
}
Upvotes: 1
Reputation: 1909
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);
}
}
Upvotes: 1
Reputation: 5842
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.
Upvotes: 79
Reputation: 6687
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
Upvotes: 2
Reputation: 1851
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;
}
}
Upvotes: 3