这是我的片段代码。
我使用此代码来查看无尽的回收器视图,即在滚动回收器视图项时从服务器获取数据。但密码不起作用。在这段代码中,recyclerview.setonScrollChangeListener()不起作用,这表明错误视图不能应用于android.content.context。
如何使用片段中的setonScrollChangeListener在滚动列表时从服务器加载数据。
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();
}
}
}
最佳答案
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();
}
}
});