Endless RecyclerView OnScrollListener

EndlessRecyclerOnScrollListener.java

import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;

public abstract class EndlessRecyclerOnScrollListener extends RecyclerView.OnScrollListener {
    public static String TAG = EndlessRecyclerOnScrollListener.class.getSimpleName();

    private int previousTotal = 0; // The total number of items in the dataset after the last load
    private boolean loading = true; // True if we are still waiting for the last set of data to load.
    private int visibleThreshold = 5; // The minimum amount of items to have below your current scroll position before loading more.
    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);
}

SampleActivity.java

import android.os.Bundle;
import android.support.v7.app.ActionBarActivity;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;

public class SampleActivity extends ActionBarActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_sample);

        RecyclerView recyclerView = (RecyclerView) findViewById(R.id.list);
        LinearLayoutManager linearLayoutManager = new LinearLayoutManager(this);
        recyclerView.setLayoutManager(linearLayoutManager);
        recyclerView.setOnScrollListener(new EndlessRecyclerOnScrollListener(linearLayoutManager) {
            @Override
            public void onLoadMore(int current_page) {
                // do something...
            }
        });
    }
}

References
http://stackoverflow.com/a/26561717/500714
https://github.com/codepath/android_guides/wiki/Endless-Scrolling-with-AdapterViews

Thanks

private int visibleThreshold = 5; means the number of items remain to the recycler before reaching the end?

@panagorn I added comments. You can find details here.

Nice, i was looking for something like this. Thank you.

You should add a reset method:

public void reset(int previousTotal, boolean loading) {
  this.previousTotal = previousTotal;
  this.loading = loading;
}

And call it on onResume() in SampleActivity:

@Override
  public void onResume() {
    super.onResume();
    endlessScrollListener.reset(0, true);
}

Because after you pause the activity and resume again, the condition !loading && (totalItemCount - visibleItemCount) <= (firstVisibleItem + visibleThreshold) is always false, thus onLoadMore is never called.

totalItemCount = mLinearLayoutManager.getItemCount();

which gets the fixed count the first loading, may be wrong, I think should be adater.getItemCount(), get from adapter.

Great, this is a very clean solution. Thank you.

How can i add progress bar at the footer, while loading data ?

I created a Helper class to get position for any LayoutManager based on Android implementation in LinearLayoutManager.

https://gist.github.com/mipreamble/b6d4b3d65b0b4775a22e#file-recyclerviewpositionhelper-java

@mipreamble
Thank you! I just looking for something that can be implemented to GridLayoutManager .

How can i add a loading spinner as last item while i am fetching the data?

My list of item is retrieved via JSON, how do I know what has been clicked?

1. Attach custom value to the item on list
2. Retrieve position and check Array data

Kindly advice >.<

any updates on adding loading spinner while fetching data?

@cielantropi, you can use an android.support.v4.widget.SwipeRefreshLayout:

    <android.support.v4.widget.SwipeRefreshLayout
        android:id="@+id/swipe_refresh"
        android:layout_width="match_parent"
        android:layout_height="match_parent">

        <android.support.v7.widget.RecyclerView
            android:id="@+id/recycler_view"
            android:layout_width="match_parent"
            android:layout_height="match_parent" />

    </android.support.v4.widget.SwipeRefreshLayout>

public class MainActivity implements LoaderManager.LoaderCallbacks<List<...>>, SwipeRefreshLayout.OnRefreshListener {

    private ...Adapter adapter;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        adapter = new ...Adapter(...);
        getSupportLoaderManager().initLoader(1, null, this);

        setContentView(R.layout.activity_main);

        swipeRefreshLayout = (SwipeRefreshLayout) findViewById(R.id.swipe_refresh);
        swipeRefreshLayout.setOnRefreshListener(this);

        final RecyclerView recyclerView = (RecyclerView) findViewById(R.id.recycler_view);
        recyclerView.setLayoutManager(new LinearLayoutManager(recyclerView.getContext()));
        recyclerView.setAdapter(adapter);
    }

    @Override
    protected void onDestroy() {
        getSupportLoaderManager().destroyLoader(1);
        super.onDestroy();
    }

    @Override
    public void onRefresh() {
        if (!getSupportLoaderManager().hasRunningLoaders()) {
            getSupportLoaderManager().restartLoader(1, null, this);
        }
    }

    @Override
    public Loader<List<FilterableAdapter.Item>> onCreateLoader(int id, Bundle args) {
        if (swipeRefreshLayout != null && !swipeRefreshLayout.isRefreshing()) {
            swipeRefreshLayout.setRefreshing(true);  // This show the spinner on top of activity
        }
        return new OverviewLoader(this);
    }

    @Override
    public void onLoadFinished(Loader<List<...>> loader, List<...> data) {
        if (swipeRefreshLayout != null && swipeRefreshLayout.isRefreshing()) {
            swipeRefreshLayout.setRefreshing(false);  // This hides the spinner
        }
        adapter.addAll(data);  // Custom method on adapter, of course
    }

    @Override
    public void onLoaderReset(Loader<List<...>> loader) {
    }

}

if (layoutManager.findLastCompletelyVisibleItemPosition() == recyclerAdapter.getItemCount() - 1) {
//load more
} its over 😄

My Scroller always come on top on load more why? it should be smooth scroll from last position.

@pushpendra-spartan: you could try out this https://github.com/rockerhieu/rv-adapter-endless/

RecyclerView.setOnScrollListener(listener) is deprecated now. Please update it to addOnScrollListener(new listener);

@pushpendra-spartan u found any solution ? i also look at the code and did not find code for recyclerview selection position ?

Implemented this together w/ List/Endless List Adapter w/ code sample.
View it here: https://gist.github.com/polbins/b6830d392e5c687c8e77

This doesn't seem to work well in a fragment - since during paging (in a viewpager for multiple lists) or rotation the recyclerview adapter retains all its items, but the listener must get recreated onCreateView (meaning it thinks its loading and on page 1).

I worked around it by making a no parameter constructor (that I can call in onCreate or I can make the listener as a member variable) and then a setLayoutManager (that I can call in onCreateView) but it feels like a hack.

@jt-gilkeson i'm in the same situation as you.

Just found out another solution. You don't have to call setLayoutManager.

Just use mAdapter.notifyDataSetChanged();.

mRecyclerView.addOnScrollListener(new EndlessRecyclerOnScrollListener((LinearLayoutManager) mLayoutManager) {
            @Override
            public void onLoadMore(int current_page) {
                // Do somthing with the list

                // Notify the adapter that the data has changed
                mAdapter.notifyDataSetChanged();
            }
        });

Working with recyclerview inside a viewpager fragment.
When the list begun to load endlessly, it wont be at the TOP of the list and it will behave as intended.

How do you handle rotation changes? some pages are reloading on rotation changes and duplicate entries are shown on the list. Did anyone faced this issue?

@akuafi My situation seemed to be the same as yours. I ended up handling the page number in the activty / fragment itself rather than relying on the listener. Use savedinstancestate as appropriate. This way, you don't need to call mAdapter.notifyDatasetChanged() which is processor heavy if you have 1000+ records :)

how do i add progress bar at the bottom and show when scroll at the end??

OnScrollListener is deprecated… we should use OnScrollChangedListener instead

@LouisCAD
Use addOnScrollListener .

How does this scale when data gets huge, like a very loooong list?

If I use you file in my app project, should I include a license or declaration in some place?

Does this work with staggeredGridlLayoutManager??

https://gist.github.com/cyberrob/41a95de42498839d428b Add reset method and pageIndex to 1.

change if (totalItemCount > previousTotal) to if (totalItemCount != previousTotal) will be better for dataset changing.

why the onScroll() method is getting called twice? Even its getting called initially.

this is for my
https://gist.github.com/esantiago1/b3261365491372ba1473

Thanks a lot for this, much appreciated.

when I tried to use the above code, I found one problem: onLoadMore() might be called multiple times! So I have to make modification to this implementation to make sure only one onLoadMore is triggered. here are the changes:

`package com.zfdang.zsmth_android.listeners;

import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;

public abstract class EndlessRecyclerOnScrollListener extends RecyclerView.OnScrollListener {
public static String TAG = EndlessRecyclerOnScrollListener.class.getSimpleName();

private int previousTotal = 0; // The total number of items in the dataset after the last load
private boolean loading = false; // True if we are still waiting for the last set of data to load.
private int visibleThreshold = 2; // The minimum amount of items to have below your current scroll position before loading more.
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);

    if(dy < 0) return;
    // check for scroll down
    visibleItemCount = recyclerView.getChildCount();
    totalItemCount = mLinearLayoutManager.getItemCount();
    firstVisibleItem = mLinearLayoutManager.findFirstVisibleItemPosition();

    synchronized (this) {
        if (!loading && (totalItemCount - visibleItemCount) <= (firstVisibleItem + visibleThreshold)) {
            // End has been reached, Do something
            current_page++;
            onLoadMore(current_page);
            loading = true;
        }
    }
}


public void setLoading(boolean loading) {
    this.loading = loading;
}

public abstract void onLoadMore(int current_page);

}`

when I'm using this listener, I will call listener.setLoading(false) explicitly to re-enable onLoadMore after loading is finished.

it works pretty well for me.

Will it work when stackFromEnd is set to true ?

                int lastVisibleItem = ((LinearLayoutManager) mLayoutManager).findLastVisibleItemPosition();
                int totalItem = mAdapter.getItemCount();

                if (lastVisibleItem > totalItem - 2 && dy > 0 && notLoading) {
                    curPage++;
                    onLoadMore(curPage);
                }

@zfdang Why is there a synchronized block in onScrolled()?

i faced an issue like this : "cannot call this method while RecyclerView is computing a layout or scrolling Load More". How should i do?

other questions, do i put

list.clear();
list.addAll(list);
adapter.notifySetDataChanged()

inside loadMore() ?

that error comes, because i put these code inside loadMore()

Thanks so much! excellent

Will it work with orientation changes?

Please note that using this view with a SwipeRefreshLayout can cause some issues... You are going to have to reset the EndlessRecyclerViewScrollListener when you refresh, or else it gets confused and may not work when you continue to try to scroll again. There needs to be a basic reset() method added...

public void reset()
{
    previousTotalItemCount = 0;
    currentPage = 1;
}

If you call this in the onRefresh() of your SwipeRefreshLayout.OnRefreshListener(), it should work properly. It does for me.

@Dooskington your solutions works well for me. Thanks

Its calling two times when RecyclerView not have enough (2 or 3 row) data as height of screen.

I have Updated this file as per my usage. I got problem like its calling two times when RecyclerView not have enough (2 or 3 row) data as height of screen.

This thing is all the way bugged.
It stuck when I use SwipeOnRefresh even with proposet reset.
Eventually employed https://gist.github.com/nesquena/d09dc68ff07e845cc622 this

if (layoutManager.findLastCompletelyVisibleItemPosition() == recyclerAdapter.getItemCount() - 1) {
//load more
}

it works good with activity but I am facing problem with fragment onLoadMore not calling.

how can be resolved this ?

How to use it to scroll a "Horizontal" linearLayoutManager ?

Cool. Useful !
How to use it in horizontal Recyclerview ?

Not working when "visibleThreshold" set to 1 & current_page = 0;. Setting "visibleThreshold" as 2 and current_page = 0, cause an unnecessary "onLoadMore" call. Which is result in bad experience to user if there in not data on 2nd page.

It works. Thanks!
It was not working for me because I was wrapping the recycler view in a scroll view in my layout file. I spent days to find that it was the root cause of the issue and that I should remove the scroll view.

Great work!
I'm using kotlin and i was stuck on this one.
Thank

You should add a reset method:

public void reset(int previousTotal, boolean loading) {
  this.previousTotal = previousTotal;
  this.loading = loading;
}

And call it on onResume() in SampleActivity:

@Override
  public void onResume() {
    super.onResume();
    endlessScrollListener.reset(0, true);
}

Because after you pause the activity and resume again, the condition !loading && (totalItemCount - visibleItemCount) <= (firstVisibleItem + visibleThreshold) is always false, thus onLoadMore is never called.

Thanks...Worked like a pro

change if (totalItemCount > previousTotal) to if (totalItemCount != previousTotal) will be better for dataset changing.

Thanks, you saved my time