检测RecyclerView在滚动时何时到达最底部位置

Question

我有一个RecyclerView的代码.

    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);

我需要知道RecyclerView在滚动时何时到达最底部位置.可能吗 ？如果有,怎么样？

Answer 1

还有一种简单的方法可以做到这一点

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();

        }
    }
});

方向整数:-1表示向上,1表示向下,0表示总是返回false.

Answer 2

只需在recyclerview上实现addOnScrollListener()即可.然后在滚动侦听器内部实现下面的代码.

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
            }
        }
    };

Answer 3

答案在Kotlin中,它将在Java中运行.如果您复制和粘贴,IntelliJ应该为您转换它.

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)
    }
})

这也适用,LinearLayoutManager因为它具有上面使用的相同方法.即findLastVisibleItemPosition()和getItemCount()(itemCount在科特林).

Answer 4

使用此代码避免重复调用

        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");

            }
        }
    });

Answer 5

我没有通过上述答案得到完美的解决方案，因为它甚至在 onScrolled

override fun onScrolled(recyclerView: RecyclerView, dx: Int, dy: Int) {
            super.onScrolled(recyclerView, dx, dy)
           if( !recyclerView.canScrollVertically(RecyclerView.FOCUS_DOWN))
               context?.toast("Scroll end reached")
        }

Answer 6

在对这个线程中的大多数其他答案不满意之后，我发现了一些我认为更好的东西，而且这里没有任何地方。

recyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
    @Override
    public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
        if (!recyclerView.canScrollVertically(1) && dy > 0)
        {
             //scrolled to BOTTOM
        }else if (!recyclerView.canScrollVertically(-1) && dy < 0)
        {
            //scrolled to TOP
        }
    }
});

这很简单，当您滚动到顶部或底部时，在所有条件下都会命中一次。

Answer 7

尝试这个

我已经使用了上面的答案，当你在回收站视图结束时它总是运行，

如果您只想检查一次是否在底部？ 示例：-如果我每次进入底部时都有 10 个项目的列表，它会再次显示我，如果我从上到下滚动，它不会再次打印，如果您添加更多列表并转到那里，它会再次显示。

注意：-在处理命中 API 中的偏移量时使用此方法

1. 创建一个名为 EndlessRecyclerViewScrollListener 的类

       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. 像这样使用这个类

        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();
               }
           });
   

它在我的最后运行完美，如果您遇到任何问题，请评论我

Answer 8

科特林答案

您可以使用此 Kotlin 函数作为底部滚动跟随的最佳实践，以创建无限或无限滚动。

// Scroll listener.
private fun setupListenerPostListScroll() {
    val scrollDirectionDown = 1 // Scroll down is +1, up is -1.
    var currentListSize = 0

    mRecyclerView.addOnScrollListener(
        object : RecyclerView.OnScrollListener() {

            override fun onScrollStateChanged(recyclerView: RecyclerView, newState: Int) {
                super.onScrollStateChanged(recyclerView, newState)

                if (!recyclerView.canScrollVertically(scrollDirectionDown)
                    && newState == RecyclerView.SCROLL_STATE_IDLE
                ) {
                    val listSizeAfterLoading = recyclerView.layoutManager!!.itemCount

                    // List has more item.
                    if (currentListSize != listSizeAfterLoading) {
                        currentListSize = listSizeAfterLoading

                        // Get more posts.
                        postListScrollUpAction(listSizeAfterLoading)
                    }
                    else { // List comes limit.
                        showToastMessageShort("No more items.")
                    }
                }
            }
        })
}