我想将OnScrollListener实现到recyclerview，但代码中有错误，请参阅下面的dertails

Question

在滚动到底部后运行app时没有发生任何事情，下面没有加载数据的加载标志是endlessScroll代码扩展RecyclerView.OnScrollListener

public abstract class EndlessScroll extends RecyclerView.OnScrollListener {
public static String TAG = EndlessScroll.class.getSimpleName();

private int previousTotal = 0; // The total number of items in the dataset after the last load
private boolean loading = true; // True if we are still waiting for the last set of data to load.
private int visibleThreshold = 4; // The minimum amount of items to have below your current scroll position before loading more.
int firstVisibleItem, visibleItemCount, totalItemCount;

private int current_page = 1;

private LinearLayoutManager mLinearLayoutManager;

public EndlessScroll(LinearLayoutManager linearLayoutManager) {
    this.mLinearLayoutManager = linearLayoutManager;
}

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

    visibleItemCount = recyclerView.getChildCount();
    totalItemCount = mLinearLayoutManager.getItemCount();
    firstVisibleItem = mLinearLayoutManager.findFirstVisibleItemPosition();

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

        // Do something
        current_page++;

        onLoadMore(current_page);

        loading = true;
    }
}

public abstract void onLoadMore(int current_page);

}

现在下面是我的异步任务代码

public class RequestItems extends AsyncTask<Void, Void, Void> {
Context context;
ProgressDialog progressDialog;
List<ParseObject> parseObjects;
List<FeedItem> feedItems=new ArrayList<>();
EventsRecyclerView eventsRecyclerView;
RecyclerView recyclerView;





RequestItems(Context context,RecyclerView recyclerView) {
    this.context = context;
    this.recyclerView=recyclerView;

}

@Override
protected void onPreExecute() {
    progressDialog = new ProgressDialog(context);
    progressDialog.setMessage("Loading");
    progressDialog.show();
    progressDialog.setCancelable(false);
    super.onPreExecute();
}

@Override
protected Void doInBackground(Void... params) {
    Loadmore();
    return null;
}

@Override
protected void onPostExecute(Void aVoid) {
    super.onPostExecute(aVoid);
    progressDialog.dismiss();
    final EventsRecyclerView eventsRecyclerView=new EventsRecyclerView(context,feedItems);
    int spacingInPixels = context.getResources().getDimensionPixelSize(R.dimen.spacing);
    recyclerView.addItemDecoration(new SpacesItemDecoration(spacingInPixels));
    LinearLayoutManager manager=new LinearLayoutManager(context);
    recyclerView.setLayoutManager(manager);
    recyclerView.setOnScrollListener(new EndlessScroll(manager) {
        @Override
        public void onLoadMore(int current_page) {
           Loadmore();
        }
    });

    recyclerView.setAdapter(eventsRecyclerView);

}

private void Loadmore() {
    ParseQuery<ParseObject> query = ParseQuery.getQuery("Events");
    query.setLimit(5);
    query.orderByDescending("createdAt");
    try {
        parseObjects = query.find();
    } catch (ParseException e) {
        e.printStackTrace();
    }
    if (!parseObjects.isEmpty()) {
        for (int i = 0; i < parseObjects.size(); i++) {
            FeedItem item = new FeedItem();
            item.setTitle(parseObjects.get(i).getString("Title"));
            item.setDate(parseObjects.get(i).getString("Date"));
            item.setTime(parseObjects.get(i).getString("Time"));
            item.setVenue(parseObjects.get(i).getString("Venue"));
            item.setLike(parseObjects.get(i).getBoolean("Like"));
            ParseFile file = parseObjects.get(i).getParseFile("EventImage");
            try {
                byte bytes[] = file.getData();
                Bitmap bitmap = BitmapFactory.decodeByteArray(bytes, 0, bytes.length);
                Bitmap bitmap1 = Bitmap.createScaledBitmap(bitmap,150,200,true);
                item.setEventImage(bitmap1);
                feedItems.add(item);
            } catch (ParseException e) {
                e.printStackTrace();
            }
        }
    }


}

} 我无法在此代码中找到错误是否有遗漏或错误

Answer 1

请尝试以下方法

GroomViewAdapter groomViewPagerAdapter = new GroomViewAdapter(getBaseContext(), 
listGroom,R.layout.item_groom_viewpager);
    viewpagerGroom.setAdapter(groomViewPagerAdapter);
viewpagerGroom.clearOnScrollListeners();
    viewpagerGroom.addOnScrollListener(new RecyclerView.OnScrollListener(){

        @Override
        public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
            if(dy < 100){
                super.onScrolled(recyclerView, dx, 0);
            }else {
                super.onScrolled(recyclerView, dx, dy);
            }
        }


    });