Détecter quand RecyclerView atteint la position la plus basse en faisant défiler

j'ai ce code pour RecyclerView.

    recyclerView = (RecyclerView)rootview.findViewById(R.id.fabric_recyclerView);
    recyclerView.setLayoutManager(layoutManager);
    recyclerView.addItemDecoration(new RV_Item_Spacing(5));
    FabricAdapter fabricAdapter=new FabricAdapter(ViewAdsCollection.getFabricAdsDetailsAsArray());
    recyclerView.setAdapter(fabricAdapter);

j'ai besoin de savoir quand le RecyclerView atteint la position la plus basse pendant le scrolling. Est-il possible ? Si oui, comment ?

28
demandé sur Adrian 2016-03-21 12:53:06

7 réponses

il y a aussi une façon simple de le faire

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

        if (!recyclerView.canScrollVertically(1)) {
            Toast.makeText(YourActivity.this, "Last", Toast.LENGTH_LONG).show();

        }
    }
});

entiers de direction: -1 pour up, 1 pour down, 0 retournera toujours false.

61
répondu Kaustubh Bhagwat 2018-08-17 15:21:30

il suffit d'implémenter un addonscrollllistener() sur votre recyclerview. Puis à l'intérieur de l'écouteur scroll mettre en œuvre le code ci-dessous.

RecyclerView.OnScrollListener mScrollListener = new RecyclerView.OnScrollListener() {
        @Override
        public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
            if (mIsLoading)
                return;
            int visibleItemCount = mLayoutManager.getChildCount();
            int totalItemCount = mLayoutManager.getItemCount();
            int pastVisibleItems = mLayoutManager.findFirstVisibleItemPosition();
            if (pastVisibleItems + visibleItemCount >= totalItemCount) {
                //End of list
            }
        }
    };
31
répondu Febi M Felix 2016-10-13 19:42:30

Il y a ma place, il est très utile pour StaggeredGridLayout.

Utilisation :

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

rvMain.addOnScrollListener(scrollListener);

mise en œuvre de L'écoute :

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);
}  }
3
répondu Aleksey Timoshchenko 2018-01-16 22:11:41

la réponse est en Kotlin, ça marchera en Java. L'ide doit convertir il pour vous si vous copiez et collez.

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)
    }
})

Cela fonctionnera aussi pour les LinearLayoutManager parce qu'il a les mêmes méthodes utilisées ci-dessus. findLastVisibleItemPosition() et getItemCount() (itemCount à Kotlin).

2
répondu daka 2018-09-19 15:10:09

Essayez Ceci

j'ai utilisé les réponses ci-dessus, il s'exécute toujours lorsque vous allez à la fin de recycleur de vue,

Si vous voulez vérifier une seule fois si c'est sur un fond ou pas? Exemple: - si j'ai la liste des 10 articles chaque fois que je vais en bas, il m'affichera et à nouveau si je fais défiler haut en bas, il ne sera pas imprimer à nouveau, et si vous ajoutez plus de listes et vous allez là-bas, il s'affichera à nouveau.

Remarque: utilisez cette méthode lorsque vous traitez avec décalage frapper API

  1. créer une classe nommée Endlessrecyclerviewscrollistener

        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. utilisez cette classe comme ceci

         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();
                }
            });
    

Son fonctionnement parfait sur ma fin, commnent moi si vous obtenez toute question

1
répondu Sunil 2018-05-18 08:14:55

j'étais aussi à la recherche de cette question mais je n'ai pas trouvé la réponse qui me satisfait, donc je crée sa propre réalisation de recyclerView.

ma solution résoudre ce problème.

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)
}

puis dans votre activité/fragment:

override fun onCreate() {
    customRecyclerView.layoutManager = LinearLayoutManager(context)
}

override fun onResume() {
    super.onResume()
    customRecyclerView.setTopAndBottomListener(this)
}

override fun onStop() {
    super.onStop()
    customRecyclerView.setTopAndBottomListener(null)
}

j'espère qu'il va hepl quelqu'un ;-)

1
répondu Andriy Antonov 2018-08-29 10:03:30

C'est ma solution:

    val onScrollListener = object : RecyclerView.OnScrollListener() {

    override fun onScrolled(recyclerView: RecyclerView?, dx: Int, dy: Int) {
        directionDown = dy > 0
    }

    override fun onScrollStateChanged(recyclerView: RecyclerView, newState: Int) {
        if (recyclerView.canScrollVertically(1).not()
                && state != State.UPDATING
                && newState == RecyclerView.SCROLL_STATE_IDLE
                && directionDown) {
               state = State.UPDATING
            // TODO do what you want  when you reach bottom, direction
            // is down and flag for non-duplicate execution
        }
    }
}
0
répondu Alex Zezekalo 2018-08-15 14:07:03