我想把ListView改为RecyclerView。我想在RecyclerView中使用OnScrollListener的onScroll来确定用户是否滚动到列表的末尾。

我如何知道用户是否滚动到列表的末尾以便我可以从REST服务获取新数据?


当前回答

正如约翰·T所建议的。只需使用下面的代码块,真的很简短,美观简单:D

public void loadMoreOnRecyclerView() {
    mRecyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
        @Override
        public void onScrolled(@NonNull @NotNull RecyclerView recyclerView, int dx, int dy) {
            super.onScrolled(recyclerView, dx, dy);
            if (!recyclerView.canScrollVertically(1) && dy != 0) {
                //Load more items here
            }
        }
    });
}

你可以跟随我的回购来了解它的工作方式。

https://github.com/Nghien-Nghien/PokeAPI-Java/blob/0d8d69d348e068911b883f0ae7791d904cc75cb5/app/src/main/java/com/example/pokemonapi/MainActivity.java

关于应用程序的描述信息如下:https://github.com/skydoves/Pokedex#readme

其他回答

感谢@Kushal,这是我实现它的方式

private boolean loading = true;
int pastVisiblesItems, visibleItemCount, totalItemCount;

mRecyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
    @Override
    public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
        if (dy > 0) { //check for scroll down
            visibleItemCount = mLayoutManager.getChildCount();
            totalItemCount = mLayoutManager.getItemCount();
            pastVisiblesItems = mLayoutManager.findFirstVisibleItemPosition();

            if (loading) {
                if ((visibleItemCount + pastVisiblesItems) >= totalItemCount) {
                    loading = false;
                    Log.v("...", "Last Item Wow !");
                    // Do pagination.. i.e. fetch new data

                    loading = true;
                }
            }
        }
    }
});

别忘了加上

LinearLayoutManager mLayoutManager;
mLayoutManager = new LinearLayoutManager(this);
mRecyclerView.setLayoutManager(mLayoutManager);
if (layoutManager.findLastCompletelyVisibleItemPosition() == 
 recyclerAdapter.getItemCount() - 1) {
    //load more items.
 }

公平而简单。 这是可行的。

做这些变量。

private int previousTotal = 0;
private boolean loading = true;
private int visibleThreshold = 5;
int firstVisibleItem, visibleItemCount, totalItemCount;

设置为滚动回收视图。

mRecyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {

    @Override
    public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
        super.onScrolled(recyclerView, dx, dy);

        visibleItemCount = mRecyclerView.getChildCount();
        totalItemCount = mLayoutManager.getItemCount();
        firstVisibleItem = mLayoutManager.findFirstVisibleItemPosition();

        if (loading) {
            if (totalItemCount > previousTotal) {
                loading = false;
                previousTotal = totalItemCount;
            }
        }
        if (!loading && (totalItemCount - visibleItemCount) 
            <= (firstVisibleItem + visibleThreshold)) {
            // End has been reached

            Log.i("Yaeye!", "end called");

            // Do something

            loading = true;
        }
    }
});

注意:确保你使用LinearLayoutManager作为RecyclerView的布局管理器。

LinearLayoutManager mLayoutManager;
mLayoutManager = new LinearLayoutManager(this);
mRecyclerView.setLayoutManager(mLayoutManager);

对于网格来说

GridLayoutManager mLayoutManager;
mLayoutManager = new GridLayoutManager(getActivity(), spanCount);
mRecyclerView.setLayoutManager(mLayoutManager);

有乐趣与你无尽的卷轴!!^ ^。

更新:mRecyclerView.setOnScrollListener()已弃用,只需替换为mRecyclerView.addOnScrollListener(),警告将消失!你可以从这个SO问题中读到更多。

由于Android现在正式支持Kotlin,这里是相同的更新-

使OnScrollListener

class OnScrollListener(val layoutManager: LinearLayoutManager, val adapter: RecyclerView.Adapter<RecyclerAdapter.ViewHolder>, val dataList: MutableList<Int>) : RecyclerView.OnScrollListener() {
    var previousTotal = 0
    var loading = true
    val visibleThreshold = 10
    var firstVisibleItem = 0
    var visibleItemCount = 0
    var totalItemCount = 0

    override fun onScrolled(recyclerView: RecyclerView, dx: Int, dy: Int) {
        super.onScrolled(recyclerView, dx, dy)

        visibleItemCount = recyclerView.childCount
        totalItemCount = layoutManager.itemCount
        firstVisibleItem = layoutManager.findFirstVisibleItemPosition()

        if (loading) {
            if (totalItemCount > previousTotal) {
                loading = false
                previousTotal = totalItemCount
            }
        }

        if (!loading && (totalItemCount - visibleItemCount) <= (firstVisibleItem + visibleThreshold)) {
            val initialSize = dataList.size
            updateDataList(dataList)
            val updatedSize = dataList.size
            recyclerView.post { adapter.notifyItemRangeInserted(initialSize, updatedSize) }
            loading = true
        }
    }
}

然后像这样把它添加到你的RecyclerView中

recyclerView.addOnScrollListener(OnScrollListener(layoutManager, adapter, dataList))

要获得完整的代码示例,请参阅Github repo。

 recyclerList.setOnScrollListener(new RecyclerView.OnScrollListener() 
            {
                @Override
                public void onScrolled(RecyclerView recyclerView, int dx,int dy)
                {
                    super.onScrolled(recyclerView, dx, dy); 
                }

                @Override
                public void onScrollStateChanged(RecyclerView recyclerView,int newState) 
                {
                    int totalItemCount = layoutManager.getItemCount();
                    int lastVisibleItem = layoutManager.findLastVisibleItemPosition();

                    if (totalItemCount> 1) 
                    {
                        if (lastVisibleItem >= totalItemCount - 1) 
                        {
                            // End has been reached
                            // do something 
                        }
                    }          
                }
            });  

Create an abstract class and extends RecyclerView.OnScrollListener public abstract class EndlessRecyclerOnScrollListener extends RecyclerView.OnScrollListener { private int previousTotal = 0; private boolean loading = true; private int visibleThreshold; private int firstVisibleItem, visibleItemCount, totalItemCount; private RecyclerView.LayoutManager layoutManager; public EndlessRecyclerOnScrollListener(RecyclerView.LayoutManager layoutManager, int visibleThreshold) { this.layoutManager = layoutManager; this.visibleThreshold = visibleThreshold; } @Override public void onScrolled(RecyclerView recyclerView, int dx, int dy) { super.onScrolled(recyclerView, dx, dy); visibleItemCount = recyclerView.getChildCount(); totalItemCount = layoutManager.getItemCount(); firstVisibleItem = ((LinearLayoutManager)layoutManager).findFirstVisibleItemPosition(); if (loading) { if (totalItemCount > previousTotal) { loading = false; previousTotal = totalItemCount; } } if (!loading && (totalItemCount - visibleItemCount) <= (firstVisibleItem + visibleThreshold)) { onLoadMore(); loading = true; } } public abstract void onLoadMore();} in activity (or fragment) add addOnScrollListener to recyclerView LinearLayoutManager mLayoutManager = new LinearLayoutManager(this); recyclerView.setLayoutManager(mLayoutManager); recyclerView.addOnScrollListener(new EndlessRecyclerOnScrollListener(mLayoutManager, 3) { @Override public void onLoadMore() { //TODO ... } });