Detect when RecyclerView reaches the bottom most position while scrolling

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没有蜡笔的小新
没有蜡笔的小新 2020-11-29 19:56

I have this code for a RecyclerView.

    recyclerView = (RecyclerView)rootview.findViewById(R.id.fabric_recyclerView);
    recyclerView.setLayoutManager(layo         


        
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  • 2020-11-29 20:29

    I was also searching for this question but I didn't find the answer that satisfied me, so I create own realization of recyclerView.

    other solutions is less precise then mine. for example: if the last item is pretty big (lot of text) then callback of other solutions will come much earlier then recyclerView realy reached bottom.

    my sollution fix this issue.

    class CustomRecyclerView: RecyclerView{
    
        abstract class TopAndBottomListener{
            open fun onBottomNow(onBottomNow:Boolean){}
            open fun onTopNow(onTopNow:Boolean){}
        }
    
    
        constructor(c:Context):this(c, null)
        constructor(c:Context, attr:AttributeSet?):super(c, attr, 0)
        constructor(c:Context, attr:AttributeSet?, defStyle:Int):super(c, attr, defStyle)
    
    
        private var linearLayoutManager:LinearLayoutManager? = null
        private var topAndBottomListener:TopAndBottomListener? = null
        private var onBottomNow = false
        private var onTopNow = false
        private var onBottomTopScrollListener:RecyclerView.OnScrollListener? = null
    
    
        fun setTopAndBottomListener(l:TopAndBottomListener?){
            if (l != null){
                checkLayoutManager()
    
                onBottomTopScrollListener = createBottomAndTopScrollListener()
                addOnScrollListener(onBottomTopScrollListener)
                topAndBottomListener = l
            } else {
                removeOnScrollListener(onBottomTopScrollListener)
                topAndBottomListener = null
            }
        }
    
        private fun createBottomAndTopScrollListener() = object :RecyclerView.OnScrollListener(){
            override fun onScrolled(recyclerView: RecyclerView, dx: Int, dy: Int) {
                checkOnTop()
                checkOnBottom()
            }
        }
    
        private fun checkOnTop(){
            val firstVisible = linearLayoutManager!!.findFirstCompletelyVisibleItemPosition()
            if(firstVisible == 0 || firstVisible == -1 && !canScrollToTop()){
                if (!onTopNow) {
                    onTopNow = true
                    topAndBottomListener?.onTopNow(true)
                }
            } else if (onTopNow){
                onTopNow = false
                topAndBottomListener?.onTopNow(false)
            }
        }
    
        private fun checkOnBottom(){
            var lastVisible = linearLayoutManager!!.findLastCompletelyVisibleItemPosition()
            val size = linearLayoutManager!!.itemCount - 1
            if(lastVisible == size || lastVisible == -1 && !canScrollToBottom()){
                if (!onBottomNow){
                    onBottomNow = true
                    topAndBottomListener?.onBottomNow(true)
                }
            } else if(onBottomNow){
                onBottomNow = false
                topAndBottomListener?.onBottomNow(false)
            }
        }
    
    
        private fun checkLayoutManager(){
            if (layoutManager is LinearLayoutManager)
                linearLayoutManager = layoutManager as LinearLayoutManager
            else
                throw Exception("for using this listener, please set LinearLayoutManager")
        }
    
        private fun canScrollToTop():Boolean = canScrollVertically(-1)
        private fun canScrollToBottom():Boolean = canScrollVertically(1)
    }
    

    then in your activity/fragment:

    override fun onCreate() {
        customRecyclerView.layoutManager = LinearLayoutManager(context)
    }
    
    override fun onResume() {
        super.onResume()
        customRecyclerView.setTopAndBottomListener(this)
    }
    
    override fun onStop() {
        super.onStop()
        customRecyclerView.setTopAndBottomListener(null)
    }
    

    hope it will hepl someone ;-)

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  • 2020-11-29 20:35

    Try This

    I have used above answers it runs always when you will go at the end of recycler view,

    If you want to check only one time whether it is on a bottom or not? Example:- If I have the list of 10 items whenever I go on the bottom it will display me and again if I scroll top to bottom it will not print again, and if you add more lists and you go there it will again display.

    Note:- Use this method when you deal with offset in hitting API

    1. Create a class named as EndlessRecyclerViewScrollListener

          import android.support.v7.widget.GridLayoutManager;
          import android.support.v7.widget.LinearLayoutManager;
          import android.support.v7.widget.RecyclerView;
          import android.support.v7.widget.StaggeredGridLayoutManager;
      
          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;
      
              RecyclerView.LayoutManager mLayoutManager;
      
              public EndlessRecyclerViewScrollListener(LinearLayoutManager layoutManager) {
                  this.mLayoutManager = layoutManager;
              }
      
          //    public EndlessRecyclerViewScrollListener() {
          //        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 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;
                  }
      
                  // 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) {
                      currentPage++;
                      onLoadMore(currentPage, totalItemCount, view);
                      loading = true;
                  }
              }
      
              // Call this method 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);
      
          }
      
    2. use this class like this

           LinearLayoutManager linearLayoutManager = new LinearLayoutManager(getActivity());
              recyclerView.setLayoutManager(linearLayoutManager);
              recyclerView.addOnScrollListener(new EndlessRecyclerViewScrollListener( linearLayoutManager) {
                  @Override
                  public void onLoadMore(int page, int totalItemsCount, RecyclerView view) {
                      Toast.makeText(getActivity(),"LAst",Toast.LENGTH_LONG).show();
                  }
              });
      

    Its running perfect at my end, commnent me if you are getting any issue

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  • 2020-11-29 20:38

    Use this code for avoiding repeated calls

        recyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
            @Override
            public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
                super.onScrollStateChanged(recyclerView, newState);
    
                if (!recyclerView.canScrollVertically(1) && newState==RecyclerView.SCROLL_STATE_IDLE) {
                    Log.d("-----","end");
                    
                }
            }
        });
    
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  • 2020-11-29 20:38

    Answer is in Kotlin, it will work in Java. IntelliJ should convert it for you if you copy and paste.

    recyclerView.addOnScrollListener(object : RecyclerView.OnScrollListener(){
    
        override fun onScrolled(recyclerView: RecyclerView, dx: Int, dy: Int) {
    
            // 3 lines below are not needed.
            Log.d("TAG","Last visible item is: ${gridLayoutManager.findLastVisibleItemPosition()}")
            Log.d("TAG","Item count is: ${gridLayoutManager.itemCount}")
            Log.d("TAG","end? : ${gridLayoutManager.findLastVisibleItemPosition() == gridLayoutManager.itemCount-1}")
    
            if(gridLayoutManager.findLastVisibleItemPosition() == gridLayoutManager.itemCount-1){
                // We have reached the end of the recycler view.
            }
    
            super.onScrolled(recyclerView, dx, dy)
        }
    })
    

    This will also work for LinearLayoutManager because it has the same methods used above. Namely findLastVisibleItemPosition() and getItemCount() (itemCount in Kotlin).

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  • 2020-11-29 20:39

    We can use Interface for get the position

    Interface : Create an Interface for listener

    public interface OnTopReachListener { void onTopReached(int position);}
    

    Activity :

    mediaRecycleAdapter = new MediaRecycleAdapter(Class.this, taskList); recycle.setAdapter(mediaRecycleAdapter); mediaRecycleAdapter.setOnSchrollPostionListener(new OnTopReachListener() {
    @Override
    public void onTopReached(int position) {
        Log.i("Position","onTopReached "+position);  
    }
    });
    

    Adapter :

    public void setOnSchrollPostionListener(OnTopReachListener topReachListener) {
        this.topReachListener = topReachListener;}@Override public void onBindViewHolder(MyViewHolder holder, int position) {if(position == 0) {
      topReachListener.onTopReached(position);}}
    
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  • 2020-11-29 20:41

    There is my implementation, it is very useful for StaggeredGridLayout.

    Usage :

    private EndlessScrollListener scrollListener =
            new EndlessScrollListener(new EndlessScrollListener.RefreshList() {
                @Override public void onRefresh(int pageNumber) {
                    //end of the list
                }
            });
    
    rvMain.addOnScrollListener(scrollListener);
    

    Listener implementation :

    class EndlessScrollListener extends RecyclerView.OnScrollListener {
    private boolean isLoading;
    private boolean hasMorePages;
    private int pageNumber = 0;
    private RefreshList refreshList;
    private boolean isRefreshing;
    private int pastVisibleItems;
    
    EndlessScrollListener(RefreshList refreshList) {
        this.isLoading = false;
        this.hasMorePages = true;
        this.refreshList = refreshList;
    }
    
    @Override public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
        super.onScrolled(recyclerView, dx, dy);
        StaggeredGridLayoutManager manager =
                (StaggeredGridLayoutManager) recyclerView.getLayoutManager();
    
        int visibleItemCount = manager.getChildCount();
        int totalItemCount = manager.getItemCount();
        int[] firstVisibleItems = manager.findFirstVisibleItemPositions(null);
        if (firstVisibleItems != null && firstVisibleItems.length > 0) {
            pastVisibleItems = firstVisibleItems[0];
        }
    
        if (visibleItemCount + pastVisibleItems >= totalItemCount && !isLoading) {
            isLoading = true;
            if (hasMorePages && !isRefreshing) {
                isRefreshing = true;
                new Handler().postDelayed(new Runnable() {
                    @Override public void run() {
                        refreshList.onRefresh(pageNumber);
                    }
                }, 200);
            }
        } else {
            isLoading = false;
        }
    }
    
    public void noMorePages() {
        this.hasMorePages = false;
    }
    
    void notifyMorePages() {
        isRefreshing = false;
        pageNumber = pageNumber + 1;
    }
    
    interface RefreshList {
        void onRefresh(int pageNumber);
    }  }
    
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