android - recyclerView.setOnScrollChangeListener 不工作

Question

这是我的 fragment 代码。我正在使用这段代码用于无尽的回收器 View ，它是在滚动回收器 View 项时从服务器获取数据的。但代码不工作。在此代码中，recyclerView.setOnScrollChangeListener() 不起作用，它显示错误 View 无法应用于 android.content .context。滚动列表时，如何使用fragment中的setOnScrollChangeListener从服务器加载数据。

    public class Fragment1 extends Fragment implements 
    RecyclerView.OnScrollChangeListener{
    //Creating a List of superheroes
     private List<SuperHero> listSuperHeroes;

     //Creating Views
     private RecyclerView recyclerView;
     private RecyclerView.LayoutManager layoutManager;
     private RecyclerView.Adapter adapter;
     public ProgressBar progressBar;

     //Volley Request Queue
      private RequestQueue requestQueue;

       //The request counter to send ?page=1, ?page=2  requests
       private int requestCount = 1;

       public Fragment1() {}

       @Override
        public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        }

      @Override
        public View onCreateView(LayoutInflater inflater, ViewGroup 
        container, Bundle savedInstanceState) {
         // Inflate the layout for this fragment
         View view= inflater.inflate(R.layout.activity_main, container, 
       false);
       //Initializing Views
       recyclerView.setLayoutManager(layoutManager);

    //Initializing our superheroes list
    listSuperHeroes = new ArrayList<>();
    requestQueue = Volley.newRequestQueue(getContext());

    //Calling method to get data to fetch data
    getData();

    //Adding an scroll change listener to recyclerview
    recyclerView.setOnScrollChangeListener(getActivity());

    //initializing our adapter
    adapter = new CardAdapter(listSuperHeroes, getActivity());

    //Adding adapter to recyclerview
    recyclerView.setAdapter(adapter);
 progressBar = (ProgressBar) view.findViewById(R.id.progressBar1);
    return view;
}

//Request to get json from server we are passing an integer here
//This integer will used to specify the page number for the request ?page = requestcount
//This method would return a JsonArrayRequest that will be added to the request queue
private JsonArrayRequest getDataFromServer(int requestCount) {
    //Initializing ProgressBar


    //Displaying Progressbar
   // progressBar.setVisibility(View.VISIBLE);
    //setProgressBarIndeterminateVisibility(true);

    //JsonArrayRequest of volley
    JsonArrayRequest jsonArrayRequest = new JsonArrayRequest(Config.DATA_URL + String.valueOf(requestCount),
            new Response.Listener<JSONArray>() {
                @Override
                public void onResponse(JSONArray response) {
                    //Calling method parseData to parse the json response

                    Log.e("response",response.toString());
                    parseData(response);
                    //Hiding the progressbar
                    progressBar.setVisibility(View.GONE);
                }
            },
            new Response.ErrorListener() {
                @Override
                public void onErrorResponse(VolleyError error) {
                    progressBar.setVisibility(View.GONE);
                    //If an error occurs that means end of the list has reached
                    Toast.makeText(getActivity(), "No More Items Available", Toast.LENGTH_SHORT).show();
                }
            });

    //Returning the request
    return jsonArrayRequest;
}

//This method will get data from the web api
private void getData() {
    //Adding the method to the queue by calling the method getDataFromServer
    requestQueue.add(getDataFromServer(requestCount));
    //Incrementing the request counter
    requestCount++;
}

//This method will parse json data
private void parseData(JSONArray array) {
    for (int i = 0; i < array.length(); i++) {
        //Creating the superhero object
        //int a= array.length();
        //String s=String.valueOf(a);
        //Log.e("array",s);
        SuperHero superHero = new SuperHero();
        JSONObject json = null;
        try {
            //Getting json
            json = array.getJSONObject(i);

            //Adding data to the superhero object
            superHero.setImageUrl(json.getString(Config.TAG_IMAGE_URL));
            //superHero.setName(json.getString(Config.TAG_NAME));
            //superHero.setPublisher(json.getString(Config.TAG_PUBLISHER));
            superHero.setMglId(json.getString(Config.TAG_MGLID));
            superHero.setAgeHeight(json.getString(Config.TAG_AGEHEIGHT));
            superHero.setCommunity(json.getString(Config.TAG_COMMUNITY));
            superHero.setOccupation(json.getString(Config.TAG_OCCUPATION));
            superHero.setIncome(json.getString(Config.TAG_INCOME));
        } catch (JSONException e) {
            e.printStackTrace();
        }
        //Adding the superhero object to the list
        listSuperHeroes.add(superHero);
    }

    //Notifying the adapter that data has been added or changed
    adapter.notifyDataSetChanged();
}

//This method would check that the recyclerview scroll has reached the bottom or not
private boolean isLastItemDisplaying(RecyclerView recyclerView) {
    if (recyclerView.getAdapter().getItemCount() != 0) {
        int lastVisibleItemPosition = ((LinearLayoutManager) recyclerView.getLayoutManager()).findLastCompletelyVisibleItemPosition();
        if (lastVisibleItemPosition != RecyclerView.NO_POSITION && lastVisibleItemPosition == recyclerView.getAdapter().getItemCount() - 1)
            return true;
    }
    return false;
}

//Overriden method to detect scrolling
@Override
public void onScrollChange(View v, int scrollX, int scrollY, int oldScrollX, int oldScrollY) {
    //Ifscrolled at last then
    if (isLastItemDisplaying(recyclerView)) {
        //Calling the method getdata again
        getData();
    }
}

Answer 1

使用这个

recyclerView.setOnScrollChangeListener(Fragment1.this);

而不是这个

recyclerView.setOnScrollChangeListener(getActivity());

编辑

recyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
            @Override
            public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
                super.onScrolled(recyclerView, dx, dy);
                if (isLastItemDisplaying(recyclerView)) {
                  //Calling the method getdata again
                   getData();
                }
            }
        });