Endless RecyclerView OnScrollListener for pagination

EndlessRecyclerOnScrollListener.java

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;

    private 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 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
                && view.getAdapter().getItemCount() > visibleThreshold) {// This condition will useful when recyclerview has less than visibleThreshold items
            currentPage++;
            onLoadMore(currentPage, totalItemCount, view);
            loading = true;
        }
    }

    // Call 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);

}

SampleActivity.java

public class SampleActivity extends AppCompatActivity {

    @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...
            }
        });
    }
}

thanks man! nice work, saved me tons of hours.

i tried this with the staggeredGridLayoutManager
it is not working with me it just load the first time
so any suggestions

i tried this with the staggeredGridLayoutManager
it is not working with me it just load the first time
so any suggestions

same here..

Same with GridLayoutManager

It works for all

import android.util.Log
import androidx.recyclerview.widget.GridLayoutManager
import androidx.recyclerview.widget.LinearLayoutManager
import androidx.recyclerview.widget.RecyclerView
import androidx.recyclerview.widget.StaggeredGridLayoutManager

abstract class PaginationScrollListener constructor() :
    RecyclerView.OnScrollListener() {

    private lateinit var mLayoutManager: RecyclerView.LayoutManager

    constructor(layoutManager: GridLayoutManager) : this() {
        this.mLayoutManager = layoutManager
    }

    constructor(layoutManager: StaggeredGridLayoutManager) : this() {
        this.mLayoutManager = layoutManager
    }

    constructor(layoutManager: LinearLayoutManager) : this() {
        this.mLayoutManager = layoutManager
    }


    /*
     Method gets callback when user scroll the search list
     */
    override fun onScrolled(recyclerView: RecyclerView, dx: Int, dy: Int) {
        super.onScrolled(recyclerView, dx, dy)

        val visibleItemCount = mLayoutManager.childCount
        val totalItemCount = mLayoutManager.itemCount
        var firstVisibleItemPosition = 0

        when (mLayoutManager) {
            is StaggeredGridLayoutManager -> {
                val firstVisibleItemPositions =
                    (mLayoutManager as StaggeredGridLayoutManager).findFirstVisibleItemPositions(null)
                // get maximum element within the list
                firstVisibleItemPosition = firstVisibleItemPositions[0]
            }
            is GridLayoutManager -> {
                firstVisibleItemPosition =
                    (mLayoutManager as GridLayoutManager).findFirstVisibleItemPosition()
            }
            is LinearLayoutManager -> {
                firstVisibleItemPosition =
                    (mLayoutManager as LinearLayoutManager).findFirstVisibleItemPosition()
            }
        }
        if (!isLoading && !isLastPage) {
            if (visibleItemCount + firstVisibleItemPosition >= totalItemCount
                && firstVisibleItemPosition >= 0
            ) {
                Log.i(TAG, "Loading more items")
                loadMoreItems()
            }
        }
    }

    protected abstract fun loadMoreItems()

    abstract val isLastPage: Boolean
    abstract val isLoading: Boolean

    companion object {
        private val TAG = PaginationScrollListener::class.java.simpleName
    }
}

Use it this way

        rvCategoryProducts.addOnScrollListener(object :
            PaginationScrollListener(layoutManager) {
            override fun loadMoreItems() {
                vm.isLoading = true
                vm.currentPage++

                GlobalScope.launch {
                    vm.getCategoryProductByCatId(vm.id, vm.currentPage)
                }
            }

            override val isLastPage: Boolean
                get() = vm.isLastPage
            override val isLoading: Boolean
                get() = vm.isLoading
        })

I have updated it. Try it

i tried this with the staggeredGridLayoutManager
it is not working with me it just load the first time
so any suggestions

Add one line more "mLayoutManager = view.getLayoutManager();"

@Override
public void onScrolled(RecyclerView view, int dx, int dy) {
    int lastVisibleItemPosition = 0;
    int totalItemCount = mLayoutManager.getItemCount();
    
    mLayoutManager = view.getLayoutManager();
    ...
}