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

User · Answer

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

User · Answer

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 behaviour 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

User · Answer

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

User · Answer

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  quot first visible child is   firstChild quot   println  quot last visible child is   lastChild quot

User · Answer

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

User · Answer

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

User · Answer

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

User · Answer

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

User · Answer

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  amp  amp  getItemCount    gt  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  gt  -1                                View v   llm findViewByPosition visiblePosition                                 do something                             v setBackgroundColor Color parseColor   777777

[android] Get visible items in RecyclerView

Examples related to android

Examples related to android-recyclerview