因无限滚动而无法向上滚动 - setOnScrollListener

Question

我正在使用向下滑动来刷新功能。它工作正常。

这里是我使用的代码：

swipeRefreshLayout = (SwipeRefreshLayout) v.findViewById(R.id.swipe_container);
        swipeRefreshLayout.setOnRefreshListener(this);
        swipeRefreshLayout.setColorSchemeColors(Color.CYAN, Color.MAGENTA, Color.YELLOW, Color.BLUE, Color.CYAN);

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

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

                int topRowVerticalPostion = (mRecyclerView == null || mRecyclerView.getChildCount() == 0) ? 0 : mRecyclerView.getChildAt(0).getTop();
                swipeRefreshLayout.setEnabled(dx == 0 && topRowVerticalPostion >= 0);
            }
        });

然后我添加了向上滑动以加载更多功能。但之后我注意到，在我向下滚动到第N个项目之前，我无法向上滚动到上一个项目。当我尝试向上滚动时，它会调用RefreshLayout。

我使用的代码（https://gist.github.com/ssinss/e06f12ef66c51252563e）：

mRecyclerView.setOnScrollListener(new EndlessRecyclerOnScrollListener(mLayoutManager) {
            @Override
            public void onLoadMore(int current_page) {
                Log.d("SCROLL PAST UPDATE", "You hit me");

                //maintain scroll position
                int lastFirstVisiblePosition = ((LinearLayoutManager) mRecyclerView.getLayoutManager()).findFirstCompletelyVisibleItemPosition();
                ((LinearLayoutManager) mRecyclerView.getLayoutManager()).scrollToPosition(lastFirstVisiblePosition);

                loadMore(articles);
            }
        });

完整代码：

public class Tab3 extends Fragment implements SwipeRefreshLayout.OnRefreshListener {

    private boolean isLoading = true;
    int currentFirstVisibleItem, currentVisibleItemCount, currentScrollState, SCROLL_STATE_IDLE = 0;

    public static final String TAG = "MyRecyclerList";
    private List<ListItems> listItemsList = new ArrayList<ListItems>();

    private RecyclerView mRecyclerView;
    private MyRecyclerViewAdapter2 mAdapter;
    protected LinearLayoutManager mLayoutManager;

    private int page = 1;
    private int post_count;
    private String count;
    private String jsonCategory;
    private static final String url = "http://example.com/api/get_category_posts/?slug=";
    private static final String articles = "article/";

    private ProgressDialog progressDialog;
    SwipeRefreshLayout swipeRefreshLayout;

    @Override
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        View v = inflater.inflate(R.layout.tab_3,container,false);

        mRecyclerView = (RecyclerView) v.findViewById(R.id.my_recycler_view);
        mRecyclerView.setHasFixedSize(true);
        mLayoutManager = new LinearLayoutManager(getActivity());
        mRecyclerView.setLayoutManager(mLayoutManager);

        updateList(articles);


        swipeRefreshLayout = (SwipeRefreshLayout) v.findViewById(R.id.swipe_container);
        swipeRefreshLayout.setOnRefreshListener(this);
        swipeRefreshLayout.setColorSchemeColors(Color.CYAN, Color.MAGENTA, Color.YELLOW, Color.BLUE, Color.CYAN);

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

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


                int topRowVerticalPostion = (mRecyclerView == null || mRecyclerView.getChildCount() == 0) ? 0 : mRecyclerView.getChildAt(0).getTop();
                swipeRefreshLayout.setEnabled(dx == 0 && topRowVerticalPostion >= 0);
            }
        });


        mRecyclerView.setOnScrollListener(new EndlessRecyclerOnScrollListener(mLayoutManager) {
            @Override
            public void onLoadMore(int current_page) {
                Log.d("SCROLL PAST UPDATE", "You hit me");

                //maintain scroll position
                int lastFirstVisiblePosition = ((LinearLayoutManager) mRecyclerView.getLayoutManager()).findFirstCompletelyVisibleItemPosition();
                ((LinearLayoutManager) mRecyclerView.getLayoutManager()).scrollToPosition(lastFirstVisiblePosition);

                loadMore(articles);
            }
        });

        return v;
    }

    public void updateList (String category) {
        page = 1;
        category  = url + category;

        mAdapter = new MyRecyclerViewAdapter2(getActivity(), listItemsList);
        mRecyclerView.setAdapter(mAdapter);

        RequestQueue queue = Volley.newRequestQueue(getActivity().getApplicationContext());

        mAdapter.clearAdapter();

        JsonObjectRequest jsonObjectRequest = new JsonObjectRequest(Request.Method.GET, category, null, new Response.Listener<JSONObject>() {
            @Override
            public void onResponse(JSONObject response) {

                Log.d(TAG, response.toString());
                swipeRefreshLayout.setRefreshing(false);

                try {
                    JSONArray posts = response.getJSONArray("posts");
                    post_count = response.getInt("count");

                    for (int i = 0; i < post_count; i++) {
                        JSONObject singlePost = posts.getJSONObject(i);

                        ListItems item = new ListItems();

                        try {
                            item.setTitle(singlePost.getString("title_plain"));
                            item.setSlug(singlePost.getString("slug"));
                            item.setUrl(singlePost.getString("url"));
                            item.setContent(singlePost.getString("content"));
                            item.setDate(singlePost.getString("date"));
                            item.setThumbnail(singlePost.getString("thumbnail"));
                        }catch (JSONException e){
                            //item.setThumbnail("drawable://" +  R.drawable.website_placeholder);
                            e.printStackTrace();
                        }

                        //jsonCategory = singlePost.getString()
                        listItemsList.add(item);
                    }
                } catch (JSONException e) {
                    e.printStackTrace();
                }
                mAdapter.notifyDataSetChanged();
            }
        }, new Response.ErrorListener() {
            @Override
            public void onErrorResponse (VolleyError error) {
                VolleyLog.d(TAG, "Помилка" + error.getMessage());
                swipeRefreshLayout.setRefreshing(false);
            }
        });

        queue.add(jsonObjectRequest);
    }

    public void loadMore (String category) {
        page = page + 1;
        category  = url + category + "&page=" + page;

        mAdapter = new MyRecyclerViewAdapter2(getActivity(), listItemsList);
        mRecyclerView.setAdapter(mAdapter);

        RequestQueue queue = Volley.newRequestQueue(getActivity().getApplicationContext());

        showProgressDialog();

        JsonObjectRequest jsonObjectRequest = new JsonObjectRequest(Request.Method.GET, category, null, new Response.Listener<JSONObject>() {
            @Override
            public void onResponse(JSONObject response) {

                Log.d(TAG, response.toString());
                hideProgressDialog();

                try {
                    JSONArray posts = response.getJSONArray("posts");
                    post_count = response.getInt("count");

                    for (int i = 0; i < post_count; i++) {
                        JSONObject singlePost = posts.getJSONObject(i); 
                        //JSONArray singlePost = response.getJSONArray("posts").getJSONObject(i);

                        ListItems item = new ListItems();

                        try {
                            item.setTitle(singlePost.getString("title_plain"));
                            item.setSlug(singlePost.getString("slug"));
                            item.setUrl(singlePost.getString("url"));
                            item.setContent(singlePost.getString("content"));
                            item.setDate(singlePost.getString("date"));
                            item.setThumbnail(singlePost.getString("thumbnail"));
                        }catch (JSONException e){
                            //item.setThumbnail("drawable://" +  R.drawable.website_placeholder);
                            e.printStackTrace();
                        }

                        //jsonCategory = singlePost.getString()
                        listItemsList.add(item);
                    }
                } catch (JSONException e) {
                    e.printStackTrace();
                }
                mAdapter.notifyDataSetChanged();
            }
        }, new Response.ErrorListener() {
            @Override
            public void onErrorResponse (VolleyError error) {
                VolleyLog.d (TAG, "Помилка" + error.getMessage());
                hideProgressDialog();
            }
        });

        queue.add(jsonObjectRequest);
    }

    public void showProgressDialog () {
        if(progressDialog == null){
            progressDialog = new ProgressDialog(this.getActivity());
            progressDialog.setMessage("Будь ласка, зачекайте...");
            progressDialog.setCancelable(false);
            progressDialog.setCanceledOnTouchOutside(false);
            progressDialog.show();
        }
    }

    public void hideProgressDialog () {
        if(progressDialog != null){
            progressDialog.dismiss();
            progressDialog = null;
        }
    }


    @Override
    public void onRefresh(){
        new Handler().postDelayed(new Runnable() {
            @Override
            public void run() {
                updateList(articles);
                mAdapter.notifyDataSetChanged();
            }
        }, 1000);
    }

}

Answer 1

通过删除以下内容解决：

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

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

                int topRowVerticalPostion = (mRecyclerView == null || mRecyclerView.getChildCount() == 0) ? 0 : mRecyclerView.getChildAt(0).getTop();
                swipeRefreshLayout.setEnabled(dx == 0 && topRowVerticalPostion >= 0);
            }
        });

并将其添加到mRecyclerView.setOnScrollListener(new EndlessRecyclerOnScrollListener(mLayoutManager) {

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

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

            int topRowVerticalPostion = (mRecyclerView == null || mRecyclerView.getChildCount() == 0) ? 0 : mRecyclerView.getChildAt(0).getTop();
            swipeRefreshLayout.setEnabled(dx == 0 && topRowVerticalPostion >= 0);
        }

Answer 2

如果您使用此库'com.lzy.widget:view-core:0.2.1'并与SwipeRefresh集成添加此代码，请为我工作。

scrollableLayout.setOnScrollListener(new HeaderViewPager.OnScrollListener() {
        @Override
        public void onScroll(int currentY, int maxY) {
            pagerHeader.setTranslationY(currentY / 2);
            int topRowVerticalPostion = (rvRestaurant == null || rvRestaurant.getChildCount() == 0) ? 0 : rvRestaurant.getChildAt(0).getTop();
            mSwipeRefreshLayout.setEnabled(currentY == 0 && topRowVerticalPostion >= 0);
        }
    });