Get visible items in RecyclerView

Question

I need to know which elements are currently displayed in my RecyclerView. There is no equivalent to the OnScrollListener.onScroll(...) method on ListViews. I tried to work with View.getGlobalVisibleRect(...), but that hack is too ugly and does not always work too.

Someone any ideas?

Answer 1

First / last visible child depends on the LayoutManager. If you are using LinearLayoutManager or GridLayoutManager, you can use

int findFirstVisibleItemPosition();
int findFirstCompletelyVisibleItemPosition();
int findLastVisibleItemPosition();
int findLastCompletelyVisibleItemPosition();

For example:

GridLayoutManager layoutManager = ((GridLayoutManager)mRecyclerView.getLayoutManager());
int firstVisiblePosition = layoutManager.findFirstVisibleItemPosition();

For LinearLayoutManager, first/last depends on the adapter ordering. Don't query children from RecyclerView; LayoutManager may prefer to layout more items than visible for caching.

Answer 2

for those who have a logic to be implemented inside the RecyclerView adapter you can still use @ernesto approach combined with an on scrollListener to get what you want as the RecyclerView is consulted. Inside the adapter you will have something like this:

@Override
    public void onAttachedToRecyclerView(@NonNull RecyclerView recyclerView) {
        super.onAttachedToRecyclerView(recyclerView);
        RecyclerView.LayoutManager manager = recyclerView.getLayoutManager();
        if(manager instanceof LinearLayoutManager && getItemCount() > 0) {
            LinearLayoutManager llm = (LinearLayoutManager) manager;
            recyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
                @Override
                public void onScrollStateChanged(@NonNull RecyclerView recyclerView, int newState) {
                    super.onScrollStateChanged(recyclerView, newState);
                }

                @Override
                public void onScrolled(@NonNull RecyclerView recyclerView, int dx, int dy) {
                    super.onScrolled(recyclerView, dx, dy);
                        int visiblePosition = llm.findFirstCompletelyVisibleItemPosition();
                        if(visiblePosition > -1) {
                            View v = llm.findViewByPosition(visiblePosition);
                            //do something
                            v.setBackgroundColor(Color.parseColor("#777777"));
                        }
                }
            });
        }
    }

Answer 3

Finally, I found a solution to know if the current item is visible, from the onBindViewHolder event in the adapter.

The key is the method isViewPartiallyVisible from LayoutManager.

In your adapter, you can get the LayoutManager from the RecyclerView, which you get as parameter from the onAttachedToRecyclerView event.

Answer 4

You can use recyclerView.getChildAt() to get each visible child, and setting some tag convertview.setTag(index) on these view in adapter code will help you to relate it with adapter data.

Answer 5

Addendum:

The proposed functions findLast...Position() do not work correctly in a scenario with a collapsing toolbar while the toolbar is expanded.

It seems that the recycler view has a fixed height, and while the toolbar is expanded, the recycler is moved down, partially out of the screen. As a consequence, the results of the proposed functions are too high. Example: The last visible item is told to be #9, but in fact item #7 is the last one that is on screen.

This behavior is also the reason why my view often failed to scroll to the correct position, i.e. scrollToPosition() did not work correctly (I finally collapsed the toolbar programmatically).

Answer 6

Following Linear / Grid LayoutManager methods can be used to check which items are visible

int findFirstVisibleItemPosition();
int findLastVisibleItemPosition();
int findFirstCompletelyVisibleItemPosition();
int findLastCompletelyVisibleItemPosition();

and if you want to track is item visible on screen for some threshold then you can refer to the following blog.

https://proandroiddev.com/detecting-list-items-perceived-by-user-8f164dfb1d05

Answer 7

For StaggeredGridLayoutManager do this:

RecyclerView rv = findViewById(...);
StaggeredGridLayoutManager lm = new StaggeredGridLayoutManager(...);
rv.setLayoutManager(lm);

And to get visible item views:

int[] viewsIds = lm.findFirstCompletelyVisibleItemPositions(null);
ViewHolder firstViewHolder = rvPlantios.findViewHolderForLayoutPosition(viewsIds[0]);
View itemView = viewHolder.itemView;

Remember to check if it is empty.

Answer 8

Every answer above is correct and I would like to add also a snapshot from my working codes.

recycler.addOnScrollListener(new RecyclerView.OnScrollListener() {
        @Override
        public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
            super.onScrollStateChanged(recyclerView, newState);
           //some code when initially scrollState changes
        }

        @Override
        public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
            super.onScrolled(recyclerView, dx, dy);
            //Some code while the list is scrolling
            LinearLayoutManager lManager = (LinearLayoutManager) recycler.getLayoutManager();
            int firstElementPosition = lManager.findFirstVisibleItemPosition();
            
        }
    });

Answer 9

You can find the first and last visible children of the recycle view and check if the view you're looking for is in the range:

var visibleChild: View = rv.getChildAt(0)
val firstChild: Int = rv.getChildAdapterPosition(visibleChild)
visibleChild = rv.getChildAt(rv.childCount - 1)
val lastChild: Int = rv.getChildAdapterPosition(visibleChild)
println("first visible child is: $firstChild")
println("last visible child is: $lastChild")

Answer 10

I hope below code helps someone define int a above methods. if visibile item position different before item position toast message will show on screen

myRecyclerview.addOnScrollListener(new RecyclerView.OnScrollListener() {
        @Override
        public void onScrollStateChanged(@NonNull RecyclerView recyclerView, int newState) {
            super.onScrollStateChanged(recyclerView, newState);

            LinearLayoutManager manager= (LinearLayoutManager) myRecyclerview.getLayoutManager();
            assert manager != null;
            int visiblePosition = manager.findLastCompletelyVisibleItemPosition();


            if(visiblePosition > -1&&a!=visiblePosition) {
                Toast.makeText(context,String.valueOf(visiblePosition),Toast.LENGTH_SHORT).show();
                //do something
                a=visiblePosition;

            }
        }

        @Override
        public void onScrolled(@NonNull RecyclerView recyclerView, int dx, int dy) {
            super.onScrolled(recyclerView, dx, dy);
            //Some code while the list is scrolling


        }
    });