Develop Reference

scroll pagination with Laravel API

I am using Laravel API with paginated data in Android...
I want to get auto paginated data.
e.g. data on first page load first and when I scroll down, next pages load continously!

You can use laravel default pagination method instate of get rows.
For example i want show users list:
//instate of :
$users = User::get();
//Use :
$users = User::paginate();
more info at : laravel site
https://laravel.com/docs/5.5/pagination

You can do so easily using the LengthAwarePaginator
protected function paginate(Collection $collection)
{
$rules = [
'per_page' => 'integer|min:2|max:50',
];
Validator::validate(request()->all(), $rules);
$page = LengthAwarePaginator::resolveCurrentPage();
$perPage = 15;
if (request()->has('per_page')) {
$perPage = (int) request()->per_page;
}
$results = $collection->slice(($page - 1) * $perPage, $perPage)->values();
$paginated = new LengthAwarePaginator($results, $collection->count(), $perPage, $page, [
'path' => LengthAwarePaginator::resolveCurrentPath(),
]);
$paginated->appends(request()->all());
return $paginated;
}
Make sure you import all the namespaces needed,
You can go ahead and paginate the collection thus
$collection = $this->paginate($collection);
Hope this helps

On Laravel Side
// Get Collection
$query = SomeModel::where('some_thing', "5")
->paginate(10);
return Response::json(array(
'some_result' => $query,
));
On Android Side (Retrofit Call)
#FormUrlEncoded
#POST
Call<JsonObject> getActions(
#Url String url);
On Android Side (Activity/Fragment)
public class NewTemplateActivity
extends AppCompatActivity {
// Recycler View
private SomeActionListAdapter someActionsAdapter;
private List<SomesomeActionListModel> listSomeActionModel;
private RecyclerView rv;
private Boolean isScrolling = false;
private int currentItems, totalItems, scrollOutItems;
private int pageNumber = 1;
private Boolean firstLoad = true;
private Boolean firstSearch = false;
private LinearLayoutManager manager;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_list);
// Init Recycler View
rv = findViewById(R.id.f_list_rv_list);
rv.setHasFixedSize(true);
listSomeActionModel = new ArrayList<>();
someActionsAdapter = new SomeActionListAdapter(
mContext,
listSomeActionModel);
manager = new LinearLayoutManager(mContext);
rv.setLayoutManager(manager);
rv.setAdapter(someActionsAdapter);
}
private void getSomeAction(
String url) {
if (firstLoad || firstSearch) {
listSomeActionModel.clear();
}
// Retrofit Call
Call<JsonObject> call = RetrofitClientLaravel.getInstance(mContext)
.discussGetApi()
.getSomeAction(url);
call.enqueue(new Callback<JsonObject>() {
#Override
public void onResponse(
Call<JsonObject> call,
Response<JsonObject> response) {
JSONObject jsonObject;
try {
jsonObject = new JSONObject(new Gson().toJson(response.body()));
// Get The Relevant Array
JSONObject jsonObject2 = jsonObject.getJSONObject("some_result");
JSONArray returnArray = jsonObject2.getJSONArray("data");
onScrolled();
if (!returnArray.isNull(0)) {
for (int l = 0; l < returnArray.length(); l++) {
if (returnArray.length() > 0) {
// Get The Json Object
JSONObject returnJSONObject = returnArray.getJSONObject(l);
// Get Details
String id = returnJSONObject.optString("SomesomeAction_id");
// Populate The Array List
listSomeActionModel.add(new SomesomeActionListModel(id));
}
}
}
if (firstLoad || firstSearch) {
someActionsAdapter = new SomeActionListAdapter(
mContext,
listSomeActionModel);
rv.setAdapter(someActionsAdapter);
}
someActionsAdapter.notifyDataSetChanged();
} catch (JSONException e) {
e.printStackTrace();
}
}
#Override
public void onFailure(
Call<JsonObject> call,
Throwable t) {
}
});
}
public void onScrolled() {
rv.addOnScrollListener(new RecyclerView.OnScrollListener() {
#Override
public void onScrollStateChanged(
RecyclerView recyclerView,
int newState) {
super.onScrollStateChanged(
recyclerView,
newState);
if (newState == AbsListView.OnScrollListener.SCROLL_STATE_TOUCH_SCROLL) {
isScrolling = true;
}
}
#Override
public void onScrolled(
RecyclerView recyclerView,
int dx,
int dy) {
super.onScrolled(
recyclerView,
dx,
dy);
currentItems = manager.getChildCount();
totalItems = manager.getItemCount();
scrollOutItems = manager.findFirstVisibleItemPosition();
if (isScrolling && (currentItems + scrollOutItems == totalItems)) {
isScrolling = false;
firstLoad = false;
firstSearch = false;
Toast.makeText(
mContext,
"Loading More...",
Toast.LENGTH_SHORT)
.show();
pageNumber++;
getSomeAction(Env.LARAVEL_MAIN_URL +
"/api/get_SomesomeActions" +
"?page=" +
pageNumber);
}
}
});
}
}

Recyclerview Inconsistency detected. Invalid view holder adapter positionViewHolder

In my app right now I am working with two lists. One is a List of an Object and the other the a List of Lists of the same object. I have a method in my Activity that transforms a list of Object into a List of Lists of object. And to my adapter I am passing the list of lists through this call:
mAdapter.swap(transformList(pipe.mList));
The method swap is responsible for passing the transformed list to my Adapter:
public void swap(List<List<Feed>> feedList) {
if (finallist == null) {
finallist = new ArrayList<>();
}
finallist.clear();
finallist.addAll(feedList);
}
The transformation checks if there are images in a row and puts all of them inside a single list (I am trying to implement something similar to WhatsApp image grouping). So I have a bunch of messages, they can be text messages, files, images, etc. In case of the last one, I group them in a single list.
Let me give a scenario as an example:
I have four images and 1 text message in my original array. The transformation puts all the four images into a single List of objects and de text message in another list of objects (both of them are inserted in my list of lists).
I thought about two ways to handle this transformation: 1 - do it inside the Adapter and 2 - do it in my Activity and pass the modified list to the Adapter. Each one of this solutions generated a different problem.
By following the steps in 1, I was able to display all of the content almost in the way I wanted. The grouping was working just fine! The problem is that if the original array had a length equals to 30, and the transformed array's length was decreased to 12. The RecyclerView would show all of the remaining 18 items as empty states (so after the transformation it wasn't handling the removing items properly).
By following the steps in 2, I was not able to display all of the content. Just the first element of my array. And I would get a IndexOutOfBoundsException in RecyclerView happens java.lang.IndexOutOfBoundsException: Inconsistency detected. Invalid view holder adapter positionViewHolder error message. But I was not able to identify the problem. I checked many questions here and none of them helped me.
This is my Adapter class:
public class FeedAdapter extends BaseSkeletonAdapter<Feed> implements FeedHolder.FeedHolderListener{
private static final int HOLDER_COMMENT = 1;
private static final int HOLDER_IMAGE = 2;
private static final int HOLDER_FILE = 3;
private static final int HOLDER_AUDIO = 4;
private static final int HOLDER_MARKER = 5;
private static final int HOLDER_EMPTY = 6;
private static final int HOLDER_GROUP = 7;
private final FeedItemListener mListener;
private final int mAvatarSize;
private final String mUserId;
private final int mPictureSize;
private final int mSkeletonColor;
public static List<List<Feed>> finallist;
public FeedAdapter(FeedItemListener listener, String userId, int avatarSize, int pictureSize, int skeletonColor) {
super(2);
mListener = listener;
mUserId = userId;
mAvatarSize = avatarSize;
mPictureSize = pictureSize;
mSkeletonColor = skeletonColor;
}
#Override
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
switch (viewType){
case HOLDER_COMMENT:
case HOLDER_IMAGE:
case HOLDER_FILE:
case HOLDER_MARKER:
case HOLDER_AUDIO:
View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.adapter_feed, parent, false);
return new FeedHolder(view, this, mPictureSize);
case HOLDER_GROUP:
System.out.println("É um grupo!!!");
View viewGroup = LayoutInflater.from(parent.getContext()).inflate(R.layout.adapter_feed_group,parent,false);
return new FeedHolder(viewGroup, this, mPictureSize);
case HOLDER_EMPTY:
default:
View empty = LayoutInflater.from(parent.getContext()).inflate(R.layout.adapter_empty, parent, false);
return new EmptyPlaceholderViewHolder(empty, R.string.placeholder_feed_empty_title, R.string.placeholder_feed_empty_description, R.drawable.ic_feed_placeholder);
}
}
#Override
protected void onBind(RecyclerView.ViewHolder holder, int position) {
if(!(holder instanceof EmptyPlaceholderViewHolder)){
//Feed feed = finallist.get(position).get(0);
if (holder instanceof FeedHolder) {
if (position < finallist.size()) {
if (mUserId.equals(finallist.get(position).get(0).getCreatedById())) {
((FeedHolder) holder).onBind(finallist.get(position), mUserId, mAvatarSize);
} else {
((FeedHolder) holder).onBind(finallist.get(position), mUserId, mAvatarSize);
}
}
}
}
}
#Override
protected void onBind(RecyclerView.ViewHolder holder, int position, List<Object> payloads) {
if (payloads.isEmpty()) {
onBindViewHolder(holder, position);
}else {
if (holder instanceof FeedHolder) {
((FeedHolder) holder).onBind(finallist.get(position), payloads, mUserId, mAvatarSize);
}
}
}
#Override
protected void setHolderSkeleton(RecyclerView.ViewHolder holder) {
if (holder instanceof FeedHolder) {
((FeedHolder) holder).setHolderSkeleton(R.drawable.rounded_skeleton, mSkeletonColor);
}
}
#Override
protected void clearHolderSkeleton(RecyclerView.ViewHolder holder) {
if (holder instanceof FeedHolder) {
((FeedHolder) holder).clearHolderSkeleton();
}
}
#Override
public int getItemViewType(int position) {
if(mSkeletonMode){
return HOLDER_COMMENT;
} if (finallist != null && finallist.size() > 0 && position >= 0 && position < finallist.size()) {
System.out.println("Tamanho total: " + finallist.size());
if (finallist.get(position).size() > 1) {
System.out.println("Tamanho do grupo: " + finallist.get(position).size());
return HOLDER_GROUP;
} else {
Feed feed = finallist.get(position).get(0);
if (feed != null) {
String type = feed.getFeedType();
if (type != null) {
switch (type) {
case FEED_IMAGE:
return HOLDER_IMAGE;
case FEED_AUDIO:
return HOLDER_AUDIO;
case FEED_FILE:
return HOLDER_FILE;
case FEED_MARKER:
return HOLDER_MARKER;
case FEED_COMMENT:
default:
return HOLDER_COMMENT;
}
}
}
}
return HOLDER_COMMENT;
}else {
System.out.println("Tá vazia!");
return HOLDER_EMPTY;
}
}
public List<Feed> getItems() {
return returnList(finallist);
}
public List<List<Feed>> getListItems() {
return finallist;
}
public void swap(List<List<Feed>> feedList) {
if (finallist == null) {
finallist = new ArrayList<>();
}
finallist.clear();
finallist.addAll(feedList);
}
#Override
public void toggleLike(final int pos){
if(mListener != null && pos >= 0 && pos < finallist.size()){
mListener.toggleLike(finallist.get(pos).get(0));
}
}
#Override
public void onLongClick(final int pos, final View v) {
if (mListener != null && pos >= 0 && pos < finallist.size()) {
mListener.onLongClick(finallist.get(pos).get(0), v);
}
}
#Override
public int onAudioActionClicked(final int pos, final int progress) {
if (mListener != null) {
return mListener.onAudioActionClicked(pos, finallist.get(pos).get(0), progress);
}else {
return 0;
}
}
#Override
public void onClick(int pos) {
if (finallist!=null && pos >= 0 && pos<finallist.size()) {
Feed feed = finallist.get(pos).get(0);
if (feed != null && mListener != null) {
mListener.onClick(feed);
}
}
}
public interface FeedItemListener {
void toggleLike(#NonNull Feed feed);
void onLongClick(#NonNull Feed feed, #NonNull View v);
void onClick(#NonNull Feed feed);
int onAudioActionClicked(int pos, #NonNull Feed feed, final int progress);
}
private void transformList(List<Feed> mItems) {
finallist = new ArrayList<>();
for (int i = 0; i< mItems.size();i++) {
List<Feed> feed = new ArrayList<>();
feed.add(mItems.get(i));
finallist.add(feed);
}
int j = 0;
List<String> list = new ArrayList<>();
List<Integer> indexList = new ArrayList<>();
//System.out.println("Tamanho: " + mItems.size());
for (int i = 0; i < mItems.size(); i++) {
if (!mItems.get(i).getFeedType().equals("filePicture")) {
if (j >= 4) {
String temp = "";
for (int k = 0; k < j; k++) {
temp = temp + "->" + Integer.toString(i - (k+1));
if (k != 0) {
finallist.get(i - 1).add(finallist.get(i - (k + 1)).get(0));
indexList.add(i - (k+1));
}
}
list.add(temp);
}
j = 0;
} else {
j = j + 1;
}
if (i == mItems.size()-1) {
//System.out.println("Imagem por ultimo!");
if (j >= 4) {
//System.out.println("Grupo vem por ultimo!");
String temp = "";
for (int k = 0; k < j; k++) {
temp = temp + "->" + Integer.toString(i - (k));
if (k != 0) {
finallist.get(i).add(finallist.get(i - (k)).get(0));
indexList.add(i - (k));
}
}
list.add(temp);
}
}
}
Collections.sort(indexList);
int aux = 0;
for (int i = 0; i < indexList.size();i++) {
//System.out.println("Valor da posição: " + indexList.get(i)+ "\nTipo: "+ finallist.get((indexList.get(i).intValue())+aux).get(0).getFeedType()
// +"\nValor da posição + i: " + (indexList.get(i)+aux) + "\nAux: " + aux);
finallist.remove((indexList.get(i).intValue())+aux);
//notifyItemRangeRemoved(0, finallist.size());
//notifyDataSetChanged();
aux = aux - 1;
}
/*for (int i = 0; i< finallist.size(); i++){
if (finallist.get(i).size() > 1) {
System.out.println("groupImage: " + finallist.get(i).size());
} else {
System.out.println(finallist.get(i).get(0).getFeedType());
}
}*/
//returnList(finallist);
notifyItemRangeRemoved(0, returnList(finallist).size() - finallist.size() - 1);
//notifyItemRangeInserted(0, finallist.size());
}
public List<Feed> returnList(List<List<Feed>> lists) {
List<Feed> list = new ArrayList<>();
if (lists != null) {
for (int i = 0; i < lists.size(); i++) {
if (lists.get(i).size() > 1) {
for (int j = 0; j < lists.get(i).size(); j++) {
list.add(lists.get(i).get(j));
}
} else {
list.add(lists.get(i).get(0));
}
}
System.out.println("Tamanho de list: " + list.size());
}
return list;
}
}
And this is my Activity:
public abstract class FeedActivity extends UltraBaseActivity implements FeedAdapter.FeedItemListener, AudioManager.OnAudioFocusChangeListener, MediaPlayer.OnErrorListener, MediaPlayer.OnCompletionListener {
private static final String EXTRA_PROJECT_ID = "extra_project_id";
private static final String EXTRA_PROJECT_NAME = "extra_project_name";
private static final String EXTRA_RESOURCE_ID = "extra_resource_id";
private static final String EXTRA_RESOURCE_NAME = "extra_resource_name";
private static final String EXTRA_RESOURCE_KIND = "extra_resource_kind";
#BindView(R.id.swipeLayout) SwipeRefreshLayout mRefreshLayout;
#BindView(R.id.recyclerView) RecyclerView mRecyclerView;
#BindView(R.id.feedCreateFragment) View mFeedCreateLayout;
#BindView(R.id.mic) ImageView mMicView;
private WeakReference<FeedCreateFragment> mFeedCreateFragment;
protected FeedViewModel mViewModel;
protected FeedAdapter mAdapter;
private Feed mLongClick;
private Toolbar mToolbar;
protected int mScrollTo = -1;
protected WrapContentLinearLayoutManager mLayoutManager;
private String mPlayingFeedId;
private int mPlayingPos;
private int mActionResourcePause = R.drawable.ic_pause_black_24dp;
private int mActionResourcePlay = R.drawable.ic_play_black_24dp;
private MediaPlayer mPlayer;
private AudioManager mAudioManager;
protected Handler mAudioHandler;
protected Runnable mUpdateAudioHolderRunnable = new Runnable() {
#Override
public void run() {
try {
if (mPlayer != null && mPlayer.isPlaying()) {
notifyAdapterAudioUpdate(mPlayer.getCurrentPosition(), mActionResourcePause);
mAudioHandler.postDelayed(this, 100);
} else {
mAudioHandler.removeCallbacks(mUpdateAudioHolderRunnable);
}
} catch (IllegalStateException e){
MyLog.e(TAG, "Error while updating seed bar", e);
mAudioHandler.removeCallbacks(mUpdateAudioHolderRunnable);
}
}
};
public static void start(#NonNull Context context, #NonNull String projectId, #NonNull String projectName, #NonNull String resourceId, #NonNull String resourceName, #NonNull String resourceKind){
Intent intent = setIntent(context, projectId, projectName, resourceId, resourceName, resourceKind);
if (intent == null) return;
context.startActivity(intent);
}
public static void startForResult(#NonNull Fragment fragment, #NonNull String projectId, #NonNull String projectName, #NonNull String resourceId, #NonNull String resourceName, #NonNull String resourceKind){
Intent intent = setIntent(fragment.getContext(), projectId, projectName, resourceId, resourceName, resourceKind);
if (intent == null) return;
fragment.startActivityForResult(intent, Constants.Intents.INTENT_REQUEST_VIEW_FEED);
}
#Nullable
protected static Intent setIntent(#NonNull Context context, #NonNull String projectId, #NonNull String projectName, #NonNull String resourceId, #NonNull String resourceName, #NonNull String resourceKind) {
Intent intent;
if (resourceKind.equals(Task.ROUTE)) {
intent = new Intent(context, FeedTaskActivity.class);
}else if(resourceKind.equals(Chat.ROUTE)){
intent = new Intent(context, FeedChatActivity.class);
} else {
MyLog.e(TAG, "Error invalid resource Kind - " + resourceKind);
return null;
}
intent.putExtra(EXTRA_PROJECT_ID, projectId);
intent.putExtra(EXTRA_PROJECT_NAME, projectName);
intent.putExtra(EXTRA_RESOURCE_ID, resourceId);
intent.putExtra(EXTRA_RESOURCE_NAME, resourceName);
intent.putExtra(EXTRA_RESOURCE_KIND, resourceKind);
return intent;
}
public FeedActivity() {
super(R.layout.activity_feed);
}
#Override
protected void onCreate(Bundle savedInstanceState) {
isLogged();
init(getIntent(), savedInstanceState);
super.onCreate(savedInstanceState);
initAdapter();
mAudioManager = (AudioManager) getSystemService(AUDIO_SERVICE);
mAudioHandler = new Handler();
mViewModel.subscribe()
.compose(this.<Resource<List<Feed>>>bindUntilEvent(ActivityEvent.DESTROY))
.flatMap(flatMapDiffUtils())
.subscribeOn(Schedulers.newThread())
.observeOn(AndroidSchedulers.mainThread())
.subscribe(onNext(), onError(), onCompleted());
}
#NonNull
private Func1<Resource<List<Feed>>, Observable<FeedViewModel.Pipe>> flatMapDiffUtils() {
return new Func1<Resource<List<Feed>>, Observable<FeedViewModel.Pipe>>() {
#Override
public Observable<FeedViewModel.Pipe> call(Resource<List<Feed>> r) {
if (mViewModel.hasResource()) {
List<Feed> old = mAdapter.getItems();
MyLog.i(TAG, "New length: " + (r.data != null ? r.data.size() : 0) + " - Old: " + old.size());
final FeedDiffCallback cb = new FeedDiffCallback(old, r.data, mUser.getId());
final DiffUtil.DiffResult result = DiffUtil.calculateDiff(cb);
return Observable.just(new FeedViewModel.Pipe(r.data, result, r.status == Status.LOADING && (r.data ==null || r.data.size() == 0)));
} else {
MyLog.i(TAG, "Loading resource from server");
return Observable.empty();
}
}
};
}
private Action1<? super FeedViewModel.Pipe> onNext() {
return new Action1<FeedViewModel.Pipe>() {
#Override
public void call(FeedViewModel.Pipe pipe) {
if (pipe != null) {
initFeedFragment();
mRefreshLayout.setRefreshing(false);
pipe.mDiffResult.dispatchUpdatesTo(mAdapter);
mAdapter.setSkeletonMode(pipe.mSkeletonMode);
//List<List<Feed>> list = new ArrayList<>();
//list = tranformList(pipe.mList);
mAdapter.swap(transformList(pipe.mList));
System.out.println("Tamanho desse troço: " + transformList(pipe.mList).size());
//mAdapter.notifyDataSetChanged();
//mAdapter.notifyItemRangeRemoved(0, pipe.mList.size());
if (mScrollTo == -1) {
mRecyclerView.scrollToPosition(mAdapter.getItemCount()-1);
}else {
mRecyclerView.scrollToPosition(mScrollTo);
}
updateMenuOptions();
showLoading(false);
}
}
};
}
protected Action0 onCompleted() {
return new Action0() {
#Override
public void call() {
MyLog.i(TAG, "Finishing feed activity");
finish();
}
};
}
protected Action1<Throwable> onError() {
return new Action1<Throwable>() {
#Override
public void call(Throwable throwable) {
MyLog.e(TAG, "Error", throwable);
}
};
}
#Override
protected void initToolbar() {
mToolbar = (Toolbar) findViewById(R.id.toolbar);
if(mToolbar !=null) {
if (mViewModel != null) {
mToolbar.setTitle(mViewModel.getProjectName());
mToolbar.setSubtitle(mViewModel.getResourceName());
}
mToolbar.setSubtitleTextColor(ContextCompat.getColor(this, R.color.palette_black));
mToolbar.setNavigationIcon(R.drawable.ic_action_back_black);
}
setSupportActionBar(mToolbar);
if (mToolbar != null) {
mToolbar.setNavigationOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
onBackPressed();
}
});
}
}
protected void updateTitle(){
if(mToolbar !=null && mViewModel != null) {
mToolbar.setTitle(mViewModel.getProjectName());
mToolbar.setSubtitle(mViewModel.getResourceName());
}
}
#Override
protected void userUpdated(User user) { }
private void init(Intent i, Bundle b){
if (i != null) {
initViewModel(
i.getStringExtra(EXTRA_PROJECT_ID),
i.getStringExtra(EXTRA_PROJECT_NAME),
i.getStringExtra(EXTRA_RESOURCE_ID),
i.getStringExtra(EXTRA_RESOURCE_NAME),
i.getStringExtra(EXTRA_RESOURCE_KIND));
}else if(b != null){
initViewModel(
b.getString(EXTRA_PROJECT_ID),
b.getString(EXTRA_PROJECT_NAME),
b.getString(EXTRA_RESOURCE_ID),
b.getString(EXTRA_RESOURCE_NAME),
b.getString(EXTRA_RESOURCE_KIND));
}else {
MyLog.i(TAG, "Error while initializing view model");
finish();
}
}
#Override
protected void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
outState.putString(EXTRA_PROJECT_ID, mViewModel.getProjectId());
outState.putString(EXTRA_PROJECT_NAME, mViewModel.getProjectName());
outState.putString(EXTRA_RESOURCE_ID, mViewModel.getResourceId());
outState.putString(EXTRA_RESOURCE_NAME, mViewModel.getResourceName());
outState.putString(EXTRA_RESOURCE_KIND, mViewModel.getResourceKind());
}
private void initAdapter(){
mAdapter = new FeedAdapter(
this,
mUser.getId(),
getResources().getDimensionPixelSize(R.dimen.task_avatar_size),
(int) (AndroidUtils.getScreenWidth(this) * 0.6),
ContextCompat.getColor(this, R.color.bg_skeleton)
);
mRefreshLayout.setColorSchemeResources(R.color.yellow, android.R.color.darker_gray, R.color.yellow_edit_note, android.R.color.background_dark);
mRefreshLayout.setOnRefreshListener(new SwipeRefreshLayout.OnRefreshListener() {
#Override
public void onRefresh() {
mScrollTo = -1;
mViewModel.reload();
}
});
mLayoutManager = new WrapContentLinearLayoutManager(this);
mRecyclerView.setLayoutManager(mLayoutManager);
mRecyclerView.setAdapter(mAdapter);
}
private void initFeedFragment(){
if(!(mFeedCreateFragment != null && mFeedCreateFragment.get() != null && getSupportFragmentManager().findFragmentById(R.id.feedCreateFragment) instanceof FeedCreateFragment)){
mFeedCreateFragment = new WeakReference<>(FeedCreateFragment.newInstance(mViewModel.getProjectId(), mViewModel.getResourceId(), mViewModel.getResourceKind(), mViewModel.getResourceUsers()));
getSupportFragmentManager()
.beginTransaction()
.add(R.id.feedCreateFragment, mFeedCreateFragment.get())
.commitAllowingStateLoss();
if (mViewModel.canCreateFeed()) {
mFeedCreateLayout.setVisibility(View.VISIBLE);
}else {
mFeedCreateLayout.setVisibility(View.GONE);
}
}
}
protected abstract void initViewModel(String projectId, String projectName, String resourceId, String resourceName, String resourceKind);
protected abstract void updateMenuOptions();
}
This is part of the Error (the text reached the maximum size):
10-18 17:29:14.702 23722-23722/com.construct.test E/WrapContentLinearLayoutManager: IndexOutOfBoundsException in RecyclerView happens
java.lang.IndexOutOfBoundsException: Inconsistency detected. Invalid view holder adapter positionViewHolder{615b449 position=3 id=-1, oldPos=0, pLpos:0 scrap [attachedScrap] tmpDetached no parent}
at android.support.v7.widget.RecyclerView$Recycler.validateViewHolderForOffsetPosition(RecyclerView.java:5297)
at android.support.v7.widget.RecyclerView$Recycler.tryGetViewHolderForPositionByDeadline(RecyclerView.java:5479)
at android.support.v7.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:5440)
at android.support.v7.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:5436)
at android.support.v7.widget.LinearLayoutManager$LayoutState.next(LinearLayoutManager.java:2224)
at android.support.v7.widget.LinearLayoutManager.layoutChunk(LinearLayoutManager.java:1551)
at android.support.v7.widget.LinearLayoutManager.fill(LinearLayoutManager.java:1511)
at android.support.v7.widget.LinearLayoutManager.onLayoutChildren(LinearLayoutManager.java:595)
at com.construct.v2.adapters.WrapContentLinearLayoutManager.onLayoutChildren(WrapContentLinearLayoutManager.java:20)

My problem was caused by the BaseSkeletonAdapter<Feed> that my FeedAdapter was extending. BaseSkeletonAdapter was using the original list and not the List of Lists I had to use. So I created a new class SkeletonAdapterFeed that is basically equal to the previous one, but the new one is receiving a List of Lists instead of just the List.
I know that it sounds a little confusing. I don't have full understanding of the project I am working right now so that's why I don't know everything about the classes, etc.

How to load more data in recycler view from server?

I have a recycler view in which I load some data from the server when user scroll to bottom I want to show a progress bar and send another request to the server for more data. I have tried below code but it not able to load more data from the server. please help
private RecyclerView mRecyclerView;
private List<User> mUsers = new ArrayList<>();
private UserAdapter mUserAdapter;
private static String sz_RecordCount;
private static String sz_LastCount;
private final int m_n_DefaultRecordCount = m_kDEFAULT_RECORD_COUNT;
private static final int m_kDEFAULT_RECORD_COUNT = 5;
private ArrayList<CDealAppDatastorage> s_oDataset;
private String TAG = MainActivity.class.getSimpleName();
private CDealAppDatastorage item;
private static int arrayCount;
private Context context;
private PreferenceHelper m_oPreferenceHelper;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
context = MainActivity.this;
m_oPreferenceHelper = new PreferenceHelper(context);
sz_RecordCount = String.valueOf(m_n_DefaultRecordCount);// increment of record count
int intialLastCount = 0;
sz_LastCount = String.valueOf(intialLastCount);// increment of last count...
s_oDataset = new ArrayList<>();// making object of Arraylist
//initial request for data
initalDealListing();
mRecyclerView = (RecyclerView) findViewById(R.id.recycleView);
mRecyclerView.setLayoutManager(new LinearLayoutManager(this));
mUserAdapter = new UserAdapter();
mUserAdapter.setOnLoadMoreListener(new OnLoadMoreListener() {
#Override
public void onLoadMore() {
Log.e("haint", "Load More");
mUsers.add(null);
mUserAdapter.notifyItemInserted(mUsers.size() - 1);
//Load more data for reyclerview
new Handler().postDelayed(new Runnable() {
#Override
public void run() {
Log.e("haint", "Load More 2");
//Remove loading item
mUsers.remove(mUsers.size() - 1);
mUserAdapter.notifyItemRemoved(mUsers.size());
//sending request to server for more data
moreDealsRequest();
mUserAdapter.notifyDataSetChanged();
mUserAdapter.setLoaded();
}
}, 5000);
}
});
}
private void initalDealListing() {
String m = "9565656565";
String p = "D55A8077E0208A5C5B25176608EF84BD";
// 3. build jsonObject
try {
final JSONObject jsonObject = new JSONObject();// making object of Jsons.
jsonObject.put("agentCode", m.trim());// put mobile number
jsonObject.put("pin", p.trim());// put password
jsonObject.put("recordcount", sz_RecordCount.trim());// put record count
jsonObject.put("lastcountvalue", sz_LastCount.trim());// put last count
Log.e("CAppList:", sz_RecordCount);
Log.e("Capplist:", sz_LastCount);
Log.d(TAG, "Server Request:-" + jsonObject.toString());
final String m_DealListingURL = APIStorage.IREWARDS_URL + APIStorage.DEALLISTING_URL;
JsonObjectRequest jsonObjectRequest = new JsonObjectRequest(Request.Method.POST, m_DealListingURL, jsonObject, new Response.Listener<JSONObject>() {
#Override
public void onResponse(JSONObject response) {
Log.d(TAG, "Server Response:-" + response);
try {
int nResultCodeFromServer = Integer.parseInt(response.getString(ServerResponseStorage.s_szRESULT_CODE));
if (nResultCodeFromServer == ConstantInt.m_kTRANSACTION_SUCCESS) {
JSONArray posts = response.optJSONArray(ServerResponseStorage.s_szDEAL_ARRAY);// get Deal list in array from response
s_oDataset.clear();
for (int i = 0; i < posts.length(); i++) {// loop for counting deals from server
try {
JSONObject post = posts.getJSONObject(i);// counting deal based on index
item = new CDealAppDatastorage();// creating object of DealAppdata storage
item.setM_szHeaderText(post.getString(ServerResponseStorage.s_szDEAL_NAME));// get deal name from response
item.setM_szsubHeaderText(post.getString(ServerResponseStorage.s_szDEAL_CODE));// get dealcode from response
s_oDataset.add(item);// add all items in ArrayList
} catch (Exception e) {
e.printStackTrace();
}
}
arrayCount = posts.length();
Log.d(TAG, "ArrayCount::" + arrayCount);
/*here we are storing no. of deals coming from server*/
// write
m_oPreferenceHelper.saveIntegerValue("LastCountLength", arrayCount);
if (!s_oDataset.isEmpty()) {// condition if data in arraylist is not empty
mRecyclerView.setAdapter(mUserAdapter);
}
}
} catch (JSONException e) {
e.printStackTrace();
}
}
}, new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
Log.d(TAG, "Server error:-" + error);
}
});
RequestQueue requestQueue = Volley.newRequestQueue(context);
jsonObjectRequest.setRetryPolicy(new DefaultRetryPolicy(ConstantInt.INITIAL_TIMEOUT_MS, DefaultRetryPolicy.DEFAULT_MAX_RETRIES, DefaultRetryPolicy.DEFAULT_BACKOFF_MULT));
requestQueue.add(jsonObjectRequest);
} catch (JSONException e) {
e.printStackTrace();
}
}
/*This method send request to server for more deals*/
private void moreDealsRequest() {
try {
// 3. build jsonObject
final JSONObject jsonObject = new JSONObject();// making object of Jsons.
jsonObject.put(ServerRequestKeyStorage.s_szAGENT_CODE, "9565656565");// put mobile number
jsonObject.put(ServerRequestKeyStorage.s_szPASSWORD, "D55A8077E0208A5C5B25176608EF84BD");// put password
jsonObject.put(ServerRequestKeyStorage.s_szRECORD_COUNT, sz_RecordCount.trim());// put record count
jsonObject.put(ServerRequestKeyStorage.s_szLAST_COUNT, sz_LastCount.trim());// put last count
Log.e("CAppList:", sz_RecordCount);
Log.e("Capplist:", sz_LastCount);
// 4. convert JSONObject to JSON to String
Log.e(TAG, "Server Request:-" + jsonObject.toString());
RequestQueue requestQueue = Volley.newRequestQueue(context);
final String imgPath = APIStorage.IREWARDS_URL + APIStorage.DEAL_IMAGE_PATH;
final String m_DealListingURL = APIStorage.IREWARDS_URL + APIStorage.DEALLISTING_URL;
JsonObjectRequest jsonObjectRequest = new JsonObjectRequest(Request.Method.POST, m_DealListingURL, jsonObject, new Response.Listener<JSONObject>() {
#Override
public void onResponse(JSONObject response) {
Log.e(TAG, "Server Response:-" + response);
try {
int nResultCodeFromServer = Integer.parseInt(response.getString(ServerResponseStorage.s_szRESULT_CODE));
if (nResultCodeFromServer == ConstantInt.m_kTRANSACTION_SUCCESS) {
// Select the last row so it will scroll into view...
JSONArray posts = response.optJSONArray(ServerResponseStorage.s_szDEAL_ARRAY);// GETTING DEAL LIST
for (int i = 0; i < posts.length(); i++) {
try {
JSONObject post = posts.getJSONObject(i);// GETTING DEAL AT POSITION AT I
item = new CDealAppDatastorage();// object create of DealAppdatastorage
item.setM_szHeaderText(post.getString(ServerResponseStorage.s_szDEAL_NAME));//getting deal name
item.setM_szsubHeaderText(post.getString(ServerResponseStorage.s_szDEAL_CODE));// getting deal code
s_oDataset.add(item);
} catch (Exception e) {
e.printStackTrace();
}
}
}
} catch (JSONException e) {
e.printStackTrace();
}
}
}, new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
Log.d(TAG, "Server Error::" + error);
}
});
jsonObjectRequest.setRetryPolicy(new DefaultRetryPolicy(ConstantInt.INITIAL_TIMEOUT_MS, DefaultRetryPolicy.DEFAULT_MAX_RETRIES, DefaultRetryPolicy.DEFAULT_BACKOFF_MULT));
requestQueue.add(jsonObjectRequest);
} catch (JSONException e) {
e.printStackTrace();
}
}
static class UserViewHolder extends RecyclerView.ViewHolder {
public TextView tvName;
public TextView tvEmailId;
public UserViewHolder(View itemView) {
super(itemView);
tvName = (TextView) itemView.findViewById(R.id.tvName);
tvEmailId = (TextView) itemView.findViewById(R.id.tvEmailId);
}
}
static class LoadingViewHolder extends RecyclerView.ViewHolder {
public ProgressBar progressBar;
public LoadingViewHolder(View itemView) {
super(itemView);
progressBar = (ProgressBar) itemView.findViewById(R.id.progressBar1);
}
}
class UserAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {
private final int VIEW_TYPE_ITEM = 0;
private final int VIEW_TYPE_LOADING = 1;
private OnLoadMoreListener mOnLoadMoreListener;
private boolean isLoading;
private int visibleThreshold = 5;
private int lastVisibleItem, totalItemCount;
public UserAdapter() {
final LinearLayoutManager linearLayoutManager = (LinearLayoutManager) mRecyclerView.getLayoutManager();
mRecyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
#Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
super.onScrolled(recyclerView, dx, dy);
totalItemCount = linearLayoutManager.getItemCount();
lastVisibleItem = linearLayoutManager.findLastVisibleItemPosition();
if (!isLoading && totalItemCount <= (lastVisibleItem + visibleThreshold)) {
if (mOnLoadMoreListener != null) {
mOnLoadMoreListener.onLoadMore();
}
isLoading = true;
}
}
});
}
public void setOnLoadMoreListener(OnLoadMoreListener mOnLoadMoreListener) {
this.mOnLoadMoreListener = mOnLoadMoreListener;
}
#Override
public int getItemViewType(int position) {
return s_oDataset.get(position) == null ? VIEW_TYPE_LOADING : VIEW_TYPE_ITEM;
}
#Override
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
if (viewType == VIEW_TYPE_ITEM) {
View view = LayoutInflater.from(MainActivity.this).inflate(R.layout.layout_user_item, parent, false);
return new UserViewHolder(view);
} else if (viewType == VIEW_TYPE_LOADING) {
View view = LayoutInflater.from(MainActivity.this).inflate(R.layout.layout_loading_item, parent, false);
return new LoadingViewHolder(view);
}
return null;
}
#Override
public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {
if (holder instanceof UserViewHolder) {
CDealAppDatastorage user = s_oDataset.get(position);
UserViewHolder userViewHolder = (UserViewHolder) holder;
userViewHolder.tvName.setText(user.getM_szHeaderText());
userViewHolder.tvEmailId.setText(user.getM_szsubHeaderText());
} else if (holder instanceof LoadingViewHolder) {
LoadingViewHolder loadingViewHolder = (LoadingViewHolder) holder;
loadingViewHolder.progressBar.setIndeterminate(true);
}
}
#Override
public int getItemCount() {
return s_oDataset == null ? 0 : s_oDataset.size();
}
public void setLoaded() {
isLoading = false;
}
}
}

Use Below Code:
First Declare these global variables:
int visibleItemCount, totalItemCount = 1;
int firstVisiblesItems = 0;
int totalPages = 1; // get your total pages from web service first response
int current_page = 0;
boolean canLoadMoreData = true; // make this variable false while your web service call is going on.
LinearLayoutManager linearLayoutManager;
Assign Layout manager to your Recyclerview:
linearLayoutManager = new LinearLayoutManager(mActivity);
mRecyclerView.setLayoutManager(linearLayoutManager);
Scroll Listener of your recyclerview:
mRecyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
#Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
if (dy > 0) //check for scroll down
{
visibleItemCount = linearLayoutManager.getChildCount();
totalItemCount = linearLayoutManager.getItemCount();
firstVisiblesItems = linearLayoutManager.findFirstVisibleItemPosition();
if (canLoadMoreData) {
if ((visibleItemCount + firstVisiblesItems) >= totalItemCount) {
if (current_page < totalPages) {
canLoadMoreData = false;
/**
* .
* .
* .
* .call your webservice with page index
* .
* .
*
*/
//After completion of web service make 'canLoadMoreData = true'
}
}
}
}
}
});

Too late but i'm also refer same way check with my code it work for me
Here is API call using retrofit and get listnotifications then in this method i create one more method for loadmore getMoreNotificationListApiCall()
public void getNotification()
{
if (listnotifications.size() > 0) {
notificationListAdapter = new NotificationListAdapter(NotificationListActivity.this, listnotifications, notificationListRecyclerview);
notificationListRecyclerview.setAdapter(notificationListAdapter);
notificationListAdapter.setOnLoadMoreListener(new OnLoadMoreListener() {
#Override
public void onLoadMore() {
Log.e("ad", "Load More");
listnotifications.add(null);
Handler handler = new Handler();
final Runnable r = new Runnable() {
public void run() {
if (listnotifications.size()>0) {
notificationListAdapter.notifyItemInserted(listnotifications.size() - 1);
}
}
};
handler.post(r);
try {
if (CommonUtils.isConnectingToInternet(NotificationListActivity.this)) {
// Internet Connection is Present
getMoreNotificationListApiCall();
} else {
//Remove loading item
if (listnotifications.size()>0) {
listnotifications.remove(listnotifications.size() - 1);
}
notificationListAdapter.notifyItemRemoved(listnotifications.size());
CommonUtils.commonToast(NotificationListActivity.this, getResources().getString(R.string.no_internet_exist));
}
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
});
}
}
getMoreNotificationListApiCall() method code in this method i increment startlimit means page index and remove null (i'm using retorfit for api call)
private void getMoreNotificationListApiCall() {
try {
if (CommonUtils.isConnectingToInternet(NotificationListActivity.this)) {
StartLimit = StartLimit + 10;
Call<NotificationBase> call = ApiHandler.getApiService().getNotificationListApi(notificationListJsonMap());
call.enqueue(new Callback<NotificationBase>() {
#Override
public void onResponse(Call<NotificationBase> registerCall, Response<NotificationBase> response) {
Log.e(TAG, " Full json gson => " + "Hi i am here");
try {
Log.e(TAG, " Full json gson => " + new Gson().toJson(response));
JSONObject jsonObj = new JSONObject(new Gson().toJson(response).toString());
Log.e(TAG, " responce => " + jsonObj.getJSONObject("body").toString());
if (response.isSuccessful()) {
int success = response.body().getSuccess();
if (success == 1) {
List<NotificationBean> moreNotication = response.body().getNotificatons();
//Remove loading item
if (listnotifications.size() > 0) {
listnotifications.remove(listnotifications.size() - 1);
}
notificationListAdapter.notifyItemRemoved(listnotifications.size());
for (int i = 0; i < moreNotication.size(); i++) {
listnotifications.add(moreNotication.get(i));
}
notificationListAdapter.notifyDataSetChanged();
notificationListAdapter.setLoaded();
} else if (success == 0) {
if (listnotifications.size() > 0) {
listnotifications.remove(listnotifications.size() - 1);
}
notificationListAdapter.notifyItemRemoved(listnotifications.size());
} else {
if (listnotifications.size() > 0) {
listnotifications.remove(listnotifications.size() - 1);
}
notificationListAdapter.notifyItemRemoved(listnotifications.size());
}
} else {
if (listnotifications.size() > 0) {
listnotifications.remove(listnotifications.size() - 1);
}
notificationListAdapter.notifyItemRemoved(listnotifications.size());
}
} catch (Exception e) {
e.printStackTrace();
try {
Log.e(TAG, "error=" + e.toString());
if (listnotifications.size() > 0) {
listnotifications.remove(listnotifications.size() - 1);
}
notificationListAdapter.notifyItemRemoved(listnotifications.size());
} catch (Resources.NotFoundException e1) {
e1.printStackTrace();
}
}
}
#Override
public void onFailure(Call<NotificationBase> call, Throwable t) {
try {
Log.e(TAG, "error" + t.toString());
if (listnotifications.size() > 0) {
listnotifications.remove(listnotifications.size() - 1);
}
notificationListAdapter.notifyItemRemoved(listnotifications.size());
} catch (Resources.NotFoundException e) {
e.printStackTrace();
}
}
});
} else {
CommonUtils.commonToast(NotificationListActivity.this, getResources().getString(R.string.no_internet_exist));
}
} catch (Resources.NotFoundException e) {
e.printStackTrace();
}
}
Here is my Adapter class in which i implement OnLoadMoreListener
public class NotificationListAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {
public static List<NotificationBean> mList;
private final int VIEW_TYPE_ITEM = 0;
private final int VIEW_TYPE_LOADING = 1;
FragmentActivity mFragmentActivity;
private OnLoadMoreListener mOnLoadMoreListener;
private boolean isLoading;
private int visibleThreshold = 5;
private int lastVisibleItem, totalItemCount;
public NotificationListAdapter(FragmentActivity fragmentActivity, List<NotificationBean> data, RecyclerView mRecyclerView) {
this.mList = data;
this.mFragmentActivity = fragmentActivity;
final LinearLayoutManager linearLayoutManager = (LinearLayoutManager) mRecyclerView.getLayoutManager();
mRecyclerView.addOnScrollListener( new RecyclerView.OnScrollListener() {
#Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
super.onScrolled(recyclerView, dx, dy);
totalItemCount = linearLayoutManager.getItemCount();
lastVisibleItem = linearLayoutManager.findLastVisibleItemPosition();
if (!isLoading && totalItemCount <= (lastVisibleItem + visibleThreshold)) {
if (mOnLoadMoreListener != null) {
mOnLoadMoreListener.onLoadMore();
}
isLoading = true;
}
}
});
}
public void setOnLoadMoreListener(OnLoadMoreListener mOnLoadMoreListener) {
this.mOnLoadMoreListener = mOnLoadMoreListener;
}
#Override
public int getItemViewType(int position) {
return mList.get(position) == null ? VIEW_TYPE_LOADING : VIEW_TYPE_ITEM;
}
public void delete(int position) { //removes the row
Log.e("Position : ", "" + position);
mList.remove(position);
notifyItemRemoved(position);
notifyItemRangeChanged(position, mList.size());
}
// Return the size arraylist
#Override
public int getItemCount() {
return mList == null ? 0 : mList.size();
}
public void setLoaded() {
isLoading = false;
}
#Override
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
if (viewType == VIEW_TYPE_ITEM) {
// create a new view
View itemLayoutView = LayoutInflater.from(parent.getContext()).inflate(
R.layout.item_notification_list, parent, false);
return new ViewHolder(itemLayoutView);
} else if (viewType == VIEW_TYPE_LOADING) {
View itemLayoutView = LayoutInflater.from(parent.getContext()).inflate(
R.layout.loading_layout, parent, false);
return new LoadingViewHolder(itemLayoutView);
}
return null;
}
#Override
public void onBindViewHolder(RecyclerView.ViewHolder holder, final int position) {
if (holder instanceof ViewHolder) {
try {
final ViewHolder viewHolder = (ViewHolder) holder;
viewHolder.singleBean = mList.get(position);
viewHolder.pos = position;
final NotificationBean list = mList.get(position);
String notificationTitle = list.getMessage();
String notificationTimeDate = list.getCreatedDatetime();
String notificationIsRead = list.getIsRead();
} catch (Exception e) {
e.printStackTrace();
}
} else if (holder instanceof LoadingViewHolder) {
LoadingViewHolder loadingViewHolder = (LoadingViewHolder) holder;
loadingViewHolder.progressBar.setIndeterminate(true);
}
}
static class LoadingViewHolder extends RecyclerView.ViewHolder {
public ProgressBar progressBar;
public LoadingViewHolder(View itemView) {
super(itemView);
progressBar = (ProgressBar) itemView.findViewById(R.id.progressBar1);
}
}
public class ViewHolder extends RecyclerView.ViewHolder {
public NotificationBean singleBean;
int pos;
TextView txt_notification_time_date;
CustomTextview checkbox_notification;
RelativeLayout rl_row_background;
public ViewHolder(final View v) {
super(v);
checkbox_notification = (CustomTextview) v.findViewById(R.id.checkbox_notification);
//checkbox_notification.setButtonDrawable(android.R.color.transparent);//custom_checkbox
// txt_notification_title= (TextView) v.findViewById(R.id.txt_notification_title);
txt_notification_time_date = (TextView) v.findViewById(R.id.txt_notification_time_date);
rl_row_background = (RelativeLayout) v.findViewById(R.id.rl_row_background);
}
}
public void refreshAdapter() {
notifyDataSetChanged();
}
}
here is xml file loading_layout.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="center_horizontal"
android:gravity="center_horizontal"
android:orientation="vertical">
<ProgressBar
android:id="#+id/progressBar1"
style="#style/Widget.AppCompat.ProgressBar.Horizontal"
android:layout_width="match_parent"
android:layout_height="wrap_content" android:layout_marginBottom="5dp"
android:layout_marginTop="5dp"
android:indeterminate="true" />
</LinearLayout>

Fetching the data from server is a Async Task. So you need to enclose the
updation code in a runOnUiThread runnable. to change UI.
runOnUiThread(new Runnable() {
#Override
public void run() {
mUsers.remove(mUsers.size() - 1);
mUserAdapter.notifyItemRemoved(mUsers.size());
//sending request to server for more data
moreDealsRequest();
mUserAdapter.notifyDataSetChanged();
mUserAdapter.setLoaded();
}});

How do I update my RecyclerViewAdapter correctly when I have added, removed and moved items?

I was looking for a library, gist, snippet or best practice to help me update my RecyclerView.Adapter when I receive a list of items where some items are newly added, some have moved, some are kept and some have been removed. I didn't want to use notifyDatasetChanged, because I wanted the moved items to be visually moved.
I couldn't find anything. So I ended up doing it manually by my self.
Two things:
1. Is there a a library, gist, snippet or best practice?
2. Could you guys give feedback on my solution? Is it awful? What can I do different? Would you use it?
I tried to do my solution as generic as possible. You can use it two ways; make it put the items into the adapter and update it, or it can return a list of status's for each item, so that you can handle the updates yourself.
public class RecyclerViewAdapterItemsUpdatedHelper<T, A extends RecyclerView.Adapter>{
List<T> currentItems;
List<T> newItems;
public RecyclerViewAdapterItemsUpdatedHelper(
List<T> currentItems,
List<T> newItems) {
this.currentItems = currentItems;
this.newItems = newItems;
}
public enum State {
ADDED, MOVED, REMOVED, KEPT
}
public boolean helpMeHandleIt(A adapter) {
log(currentItems, newItems);
boolean moved = false;
boolean added = false;
boolean removed = false;
for (int i = currentItems.size() -1; i > -1; i--) {
if (!newItems.contains(currentItems.get(i))) {
currentItems.remove(i);
adapter.notifyItemRemoved(i);
removed = true;
}
}
for (int i = 0; i < newItems.size(); i++) {
State state;
try {
if (!newItems.get(i).equals(currentItems.get(i))) {
state = currentItems.contains(newItems.get(i)) ? State.MOVED : State.ADDED;
if (state.equals(State.ADDED)) {
currentItems.add(i, newItems.get(i));
adapter.notifyItemInserted(i);
added = true;
} else if (state.equals(State.MOVED)) {
int from = currentItems.indexOf(newItems.get(i));
currentItems.remove(from);
currentItems.add(i, newItems.get(i));
adapter.notifyItemMoved(from, i);
moved = true;
}
}
} catch (IndexOutOfBoundsException e) {
currentItems.add(i, newItems.get(i));
adapter.notifyItemInserted(i);
added = true;
}
}
return moved && !added && !removed;
}
public List<StatusItem> justGiveMeStatus() {
log(currentItems, newItems);
List<StatusItem> statusItems = new ArrayList<>();
for (int i = currentItems.size() -1; i > -1; i--) {
if (!newItems.contains(currentItems.get(i))) {
statusItems.add(new StatusItem(currentItems.get(i), State.REMOVED, i, -1));
}
}
for (int i = 0; i < newItems.size(); i++) {
State state;
try {
if (!newItems.get(i).equals(currentItems.get(i))) {
state = currentItems.contains(newItems.get(i)) ? State.MOVED : State.ADDED;
if (state.equals(State.ADDED)) {
statusItems.add(new StatusItem(newItems.get(i), State.ADDED, -1, i));
} else if (state.equals(State.MOVED)) {
int from = currentItems.indexOf(newItems.get(i));
statusItems.add(new StatusItem(newItems.get(i), State.MOVED, from, i));
}
} else {
statusItems.add(new StatusItem(newItems.get(i), State.KEPT, i, i));
}
} catch (IndexOutOfBoundsException e) {
statusItems.add(new StatusItem(newItems.get(i), State.ADDED, -1, i));
}
}
return statusItems;
}
private void log(List<T> currentItems, List<T> newItems) {
for (T obj :
currentItems) {
Log.i("current item", obj.toString());
}
for (T obj :
newItems) {
Log.i("new item", obj.toString());
}
}
public class StatusItem {
private T item;
private State status;
private int from = -1;
private int to = -1;
public StatusItem(T item, State status) {
this.item = item;
this.status = status;
}
public StatusItem(T item, State status, int from, int to) {
this.item = item;
this.status = status;
this.from = from;
this.to = to;
}
public T getItem() {
return item;
}
public State getStatus() {
return status;
}
public int getFrom() {
return from;
}
public int getTo() {
return to;
}
#Override
public String toString() {
return item.toString() + " | " + status +
" | " + from + " -> " + to;
}
}

(Pagination) Endless list from API - Android Recycler View

I've created an endless list to deal with my pagination coming from an API, I get the next page data in a JSON and it getting parsed to my activity. But, my adapter is not updating with the new items. I've called notifyDataSetChanged and it's just not updating. Any idea what I'm doing wrong? Here is my code below:
private void loadData(final boolean firstLoad) {
mDataFactory.getPostFeed(mThreads.getId(), mCurrentPage, new PostFeedDataFactory.PostFeedDataFactoryCallback() {
#Override
public void onPostDataReceived(PostResponse response) {
mData = response;
if (mData.getItems() != null) {
for (int i = 0; i < mData.getItems().size(); i++) {
Posts singlePost = response.getItems().get(i);
postList.add(singlePost);
}
if (firstLoad) {
mIsLoading = false;
mData.getItems().clear();
mData.getItems().addAll(postList);
mEmoticonDataFactory.getEmoticonFeed(new EmoticonFeedDataFactory.EmoticonFeedDataFactoryCallback() {
#Override
public void onEmoticonDataReceived(EmoticonResponse response) {
mEmoticon = response;
populateUIWithData();
}
#Override
public void onEmoticonDataFailed(Exception exception) {
}
});
} else {
mIsLoading = false;
refreshPosts(postList);
}
if (mData.getItems().size() > 0) {
if (Integer.valueOf(mData.getTotalPosts()) >= response.getItems().size()) {
mCurrentPage++;
} else {
mIsLastPage = true;
}
}
}
}
#Override
public void onPostDataFailed(Exception exception) {
}
});
}
private void populateUIWithData() {
mThreadText = (TextView) findViewById(R.id.threadText);
if (mThreads != null) {
if (mThreads.getName() != null) {
mThreadText.setText(mThreads.getName());
}
}
if (mAdapter == null){
mAdapter = new PostAdapter(this, mData, mEmoticon);
mRecyclerView.setAdapter(mAdapter);
} else {
mAdapter.setData(postList);
mAdapter.notifyDataSetChanged();
}
mRecyclerView.addOnScrollListener(paginationListener);
}
private RecyclerView.OnScrollListener paginationListener = 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 visibleItemCount = mLayoutManager.getChildCount();
int totalItemCount = mLayoutManager.getItemCount();
int firstVisibleItemPosition = mLayoutManager.findFirstVisibleItemPosition();
if (!mIsLoading && !mIsLastPage) {
if ((visibleItemCount + firstVisibleItemPosition) >= totalItemCount) {
loadMoreItems();
}
}
}
};
private void loadMoreItems() {
mIsLoading = true;
loadData(false);
}
private void refreshPosts(ArrayList<Posts> newObjects) {
postList.addAll(newObjects);
populateUIWithData();
}
Also, here is my adapter
PostAdapter.java
#Override
public void onBindViewHolder(ViewHolder holder, int position) {
Posts posts = mPost.getItem(position);
emoticons = mEmoticon.getItems();
String message = null;
String emoMessage = null;
if (posts.getPost() != null) {
if (posts.getPost().getMessage() != null) {
message = posts.getPost().getMessage();
emoMessage = message;
if (emoticons != null) {
for(Emoticons emoticon : this.emoticons) {
if (message.contains(emoticon.getEmoticon().getCode())) {
emoMessage = message.replaceAll(Constants.EMO_REGEX, emoticon.getEmoticon().getUrl());
}
}
}
}
if (posts.getPost().getUsername() != null) {
holder.mAuthorTextView.setText("Posted by: " + posts.getPost().getUsername());
}
if (posts.getPost().getHighlighting().equals("op")) {
holder.mPostTextView.setTypeface(Typeface.DEFAULT_BOLD);
}
}
holder.mPostTextView.setText(Html.fromHtml(emoMessage, new Html.ImageGetter() {
#Override
public Drawable getDrawable(String source) {
Drawable d = null;
try {
StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
StrictMode.setThreadPolicy(policy);
URL url = new URL(source);
InputStream is = url.openStream();
Bitmap b = BitmapFactory.decodeStream(is);
d = new BitmapDrawable(Resources.getSystem(), b);
d.setBounds(0, 0, d.getIntrinsicWidth(), d.getIntrinsicHeight());
} catch (IOException e) {
e.printStackTrace();
}
return d;
}
}, new Html.TagHandler() {
#Override
public void handleTag(boolean opening, String tag, Editable output, XMLReader xmlReader) {
if(tag.equalsIgnoreCase("strike") || tag.equals("s")) {
processStrike(opening, output);
}
}
private void processStrike(boolean opening, Editable output) {
int len = output.length();
if(opening) {
output.setSpan(new StrikethroughSpan(), len, len, Spannable.SPAN_MARK_MARK);
} else {
Object obj = getLast(output, StrikethroughSpan.class);
int where = output.getSpanStart(obj);
output.removeSpan(obj);
if (where != len) {
output.setSpan(new StrikethroughSpan(), where, len, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
}
}
}
private Object getLast(Editable text, Class kind) {
Object[] objs = text.getSpans(0, text.length(), kind);
if (objs.length == 0) {
return null;
} else {
for(int i = objs.length;i>0;i--) {
if(text.getSpanFlags(objs[i-1]) == Spannable.SPAN_MARK_MARK) {
return objs[i-1];
}
}
return null;
}
}
}));
}
#Override
public int getItemCount() {
return mPost.getItems().size();
}
public void setData(ArrayList<Posts> array) {
ArrayList<Posts> postList = this.mPost.getItems();
postList = array;
}

I found the answer thanks to #cYrixmorten I changed my setData method to look like this
public void setData(ArrayList<Posts> array) {
mPost.getItems().addAll(array);
}
I basically just forgot to update my adapter to populate for me... But I just want to say thank you to those who helped. :)