Question

这是我的LatestGradeAdapter

public class LatestGradeAdapter extends RecyclerView.Adapter<LatestGradeAdapter.RecyclerViewHolder> {

    private Context mCtx;
    private List<ListGradeData> sectionList;

    public LatestGradeAdapter(Context mCtx, List<ListGradeData> sectionList) {
        this.mCtx = mCtx;
        this.sectionList = sectionList;
    }

    @NonNull
    @Override
    public RecyclerViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        LayoutInflater inflater = LayoutInflater.from(mCtx);
        View view = inflater.inflate(R.layout.section_data_list, parent, false);
        return new LatestGradeAdapter.RecyclerViewHolder(view);
    }

    @Override
    public void onBindViewHolder(@NonNull RecyclerViewHolder holder, int position) {
        final ListGradeData sections = sectionList.get(position);
        //BIND DATA
        holder.textViewSection.setText(sections.getSection());
        holder.textViewLevel.setText(sections.getLevel());
        holder.textViewSchoolYear.setText(sections.getSchoolyear());
    }
    @Override
    public int getItemCount() {
        return sectionList.size();
    }

    public class RecyclerViewHolder extends RecyclerView.ViewHolder {

        //Variables for list
        TextView textViewSection, textViewLevel, textViewSchoolYear;

        //Variables for head section
        TextView textHeaderSection, textHeaderLevel, textHeaderSchoolYear;

        public RecyclerViewHolder(final View itemView) {
            super(itemView);

            textViewSection = (TextView) itemView.findViewById(R.id.textSection);
            textViewLevel = (TextView) itemView.findViewById(R.id.textLevel);
            textViewSchoolYear = (TextView) itemView.findViewById(R.id.textYear);



        }
    }
}`

This is my LatestGradeFragment
`public class LatestGradeFragment extends Fragment {
    List<ListGradeData> sectionList;
    RecyclerView recyclerView;

    public static LatestGradeFragment newInstance() {
        return new LatestGradeFragment();
    }

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

        //RecyclerView+CardView for section
        recyclerView = (RecyclerView) rootView.findViewById(R.id.display_recyclerView);
        recyclerView.setHasFixedSize(true);
        recyclerView.setLayoutManager(new LinearLayoutManager(getActivity()));

        sectionList = new ArrayList<>();

        loadSection();

        return rootView;
    }

    private void loadSection() {

        StringRequest stringRequest = new StringRequest(Request.Method.GET, Constants.USER_GRADE,
                new Response.Listener<String>() {
                    @Override
                    public void onResponse(String response) {
                        try {
                            //converting the string to json array object
                            JSONArray array = new JSONArray(response);

                            //traversing through all the object
                            for (int i = 0; i < array.length(); i++) {

                                //getting product object from json array
                                JSONObject sections = array.getJSONObject(i);

                                //adding the product to product list
                                sectionList.add(new ListGradeData(
                                        sections.getInt("id"),
                                        sections.getString("section"),
                                        sections.getString("level"),
                                        sections.getString("schoolyear")
                                ));
                            }

                            //creating adapter object and setting it to recyclerview
                            LatestGradeAdapter adapter = new LatestGradeAdapter(getActivity(), sectionList);
                            recyclerView.setAdapter(adapter);
                        } catch (JSONException e) {
                            e.printStackTrace();
                        }
                    }
                },
                new Response.ErrorListener() {
                    @Override
                    public void onErrorResponse(VolleyError error) {

                    }
                });

        //adding our stringrequest to queue
        Volley.newRequestQueue(getActivity().getApplicationContext()).add(stringRequest);
    }

    @Override
    public String toString() {
        return "HomeFragment";
    }
}`

我尝试了所有搜索内容，当我将其应用时，它不起作用。有人可以帮我吗？

Answer 1

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

recyclerView.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;
                   loadSection();
               }
           }
    }
  }
});

如何应用recyclerview +加载更多的上下滚动

1 个答案: