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Ich habe ein Problem mit der endlosen Scroll. Jedes Mal, wenn es mehr Daten lädt, kehrt es in die Draufsicht zurück. Ich möchte, dass der RecyclerView beim Laden neuer Daten an der letzten Position bleibt. Ich versuche, diesen CodeEndlos Scroll RecyclerView immer nach oben
public abstract class EndlessRecyclerViewScrollListener extends RecyclerView.OnScrollListener{
// The minimum amount of items to have below your current scroll position
// before loading more.
private int visibleThreshold = 30;
// The current offset index of data you have loaded
private int currentPage = 0;
// The total number of items in the dataset after the last load
private int previousTotalItemCount = 0;
// True if we are still waiting for the last set of data to load.
private boolean loading = true;
// Sets the starting page index
private int startingPageIndex = 0;
RecyclerView.LayoutManager mLayoutManager;
public EndlessRecyclerViewScrollListener(LinearLayoutManager layoutManager) {
this.mLayoutManager = layoutManager;
}
public int getLastVisibleItem(int[] lastVisibleItemPositions) {
int maxSize = 0;
for (int i = 0; i < lastVisibleItemPositions.length; i++) {
if (i == 0) {
maxSize = lastVisibleItemPositions[i];
}
else if (lastVisibleItemPositions[i] > maxSize) {
maxSize = lastVisibleItemPositions[i];
}
}
return maxSize;
}
// This happens many times a second during a scroll, so be wary of the code you place here.
// We are given a few useful parameters to help us work out if we need to load some more data,
// but first we check if we are waiting for the previous load to finish.
@Override
public void onScrolled(RecyclerView view, int dx, int dy) {
int lastVisibleItemPosition = 0;
int totalItemCount = mLayoutManager.getItemCount();
if (mLayoutManager instanceof LinearLayoutManager) {
lastVisibleItemPosition = ((LinearLayoutManager) mLayoutManager).findLastVisibleItemPosition();
}
// If the total item count is zero and the previous isn't, assume the
// list is invalidated and should be reset back to initial state
if (totalItemCount < previousTotalItemCount) {
this.currentPage = this.startingPageIndex;
this.previousTotalItemCount = totalItemCount;
if (totalItemCount == 0) {
this.loading = true;
}
}
// If it’s still loading, we check to see if the dataset count has
// changed, if so we conclude it has finished loading and update the current page
// number and total item count.
if (loading && (totalItemCount > previousTotalItemCount)) {
loading = false;
previousTotalItemCount = totalItemCount;
}
// If it isn’t currently loading, we check to see if we have breached
// the visibleThreshold and need to reload more data.
// If we do need to reload some more data, we execute onLoadMore to fetch the data.
// threshold should reflect how many total columns there are too
if (!loading && (lastVisibleItemPosition + visibleThreshold) > totalItemCount) {
currentPage++;
onLoadMore(currentPage, totalItemCount, view);
loading = true;
}
}
// Call this method whenever performing new searches
public void resetState() {
this.currentPage = this.startingPageIndex;
this.previousTotalItemCount = 0;
this.loading = true;
}
// Defines the process for actually loading more data based on page
public abstract void onLoadMore(int page, int totalItemsCount, RecyclerView view);
}
OnCreateView
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState){
View view = inflater.inflate(R.layout.booking_fragment, container, false);
recyclerView = (RecyclerView) view.findViewById(R.id.bookingRecyclerView);
linearLayoutManager = new LinearLayoutManager(getActivity());
recyclerView.setLayoutManager(linearLayoutManager);
recyclerView.setHasFixedSize(true);
scrollListener = new EndlessRecyclerViewScrollListener(linearLayoutManager) {
@Override
public void onLoadMore(int page, int totalItemsCount, RecyclerView view) {
// Triggered only when new data needs to be appended to the list
// Add whatever code is needed to append new items to the bottom of the list
if(CurrentStatus.equals("notSearch")){
if (current < Integer.parseInt(TP)) {
current++;
loadMoreBookings(sort);
}
else if(current == Integer.parseInt(TP)){
Toast.makeText(getActivity(),"No More Data to Load", Toast.LENGTH_SHORT).show();
}
}else{
if (current < Integer.parseInt(TP)) {
current++;
searchMoreBookings(search, sort);
}
else if(current == Integer.parseInt(TP)){
Toast.makeText(getActivity(),"No More Data to Be Load", Toast.LENGTH_SHORT).show();
}
}
}
LoadMoreBookings
private void loadMoreBookings(final String sort){
CurrentStatus = "notSearch";
final ProgressDialog progressDialog = new ProgressDialog(getActivity());
progressDialog.setMessage("Please Wait While Retrieving Data");
progressDialog.setCancelable(false);
progressDialog.show();
StringRequest requesting = new StringRequest(Request.Method.POST, URL,
new Response.Listener<String>() {
@Override
public void onResponse(String JSONString) {
progressDialog.dismiss();
try{
JSONObject jsonTP = new JSONObject(JSONString);
JSONArray jsonArrayB = jsonTP.getJSONArray("Data");
for(int i = 0; i < jsonArrayB.length(); i++){
JSONObject o = jsonArrayB.getJSONObject(i);
Booking list = new Booking(
o.getString("bookID"),
o.getString("userEmail"),
o.getString("paymentMethod"),
o.getString("paymentStatus"),
o.getString("totalPrice"),
o.getString(String.valueOf("securityCode")),
o.getString(String.valueOf("travelDate")),
o.getString("paymentID"),
o.getString("userFN"),
o.getString("userLN"),
o.getString(String.valueOf("createdAt")),
o.getString("tTM"),
o.getString("messageToCustomer"),
o.getString("messageFromMerchant"),
o.getString("wCN"),
o.getString("wLocation"),
o.getString("wWebsite")
);
listBooking.add(list);
count++;
}
Toast.makeText(getActivity(), "Data : "+count, Toast.LENGTH_SHORT).show();
adapter = new BookingAdapter(listBooking,getActivity());
recyclerView.setAdapter(adapter);
} catch (JSONException e) {
loadMoreBookings(sort);
}
}
},
new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
progressDialog.dismiss();
Toast.makeText(getActivity().getApplicationContext(), "Failed To Retrieve Data. Please Try Again.",Toast.LENGTH_LONG).show();
}
}
){
@Override
protected Map<String, String> getParams() throws AuthFailureError {
Map<String,String> params = new HashMap<String, String>();
String user = getActivity().getIntent().getStringExtra("username");
params.put("username", user);
params.put("currentpage", String.valueOf(current));
params.put("sorting", sort);
return params;
}
};
RequestQueue requestQueue = Volley.newRequestQueue(getActivity().getApplicationContext());
requestQueue.add(requesting);
}
hier ist der Endlos-Scroll-Code zu implementieren
Ich versuche es so zu machen, aber der RecyclerView ist immer leer – wizzone
können Sie mir bitte Adaptercode zeigen? –
ok, es funktioniert jetzt, ich habe es einfach falsch beim ersten Aufruf der Methode zum Laden der Daten angegeben. – wizzone