Shouldn't DiffUtil compare with hashCode? - android

I am developing the Workout log app now.
Two items (routine and routine detail) are expressed using one recycler view and adapter.
If i click the Add Routine button, a routine item is added, and the routine basically has one routine detail item.
Routine items have buttons to add or delete routine detail items.
I used DiffUtil to update the item.
In areItemsTheSame(), I used hashCode to compare oldList and newList.
However, there is a problem of unknown cause when adding or deleting items. (Not an error).
If i click the delete button after adding the routine item and the detail item, it works well at first.
The routine detail buttons of the next routine item cannot be added or deleted unless the delete button of the previous routine item is pressed.
If the delete button of the previous routine item is pressed and then the button of the next item is pressed, the addition or deletion is performed.
Why is this?
This happens when you use hashCode comparison.
However, with equals() this does not happen and works fine.
Instead, every time an item is added or deleted, the entire item is updated with blinking.
How did I have to define the DiffUtil class?
CODE
RoutineModel.java
public class RoutineModel {
private ArrayList<RoutineDetailModel> routineDetailList;
private String routine;
public RoutineModel(String routine) {
this.routine = routine;
}
public void addDetail(RoutineDetailModel item) {
if(routineDetailList == null) {
routineDetailList = new ArrayList<>();
}
this.routineDetailList.add(item);
}
public ArrayList<RoutineDetailModel> getDetailItemList() {
return routineDetailList;
}
public int getDetailItemSize() {
return routineDetailList.size();
}
public String getRoutine() {
return routine;
}
public void removeDetails(int index) throws Exception {
this.routineDetailList.remove(index);
}
#Override
public int hashCode() {
return Objects.hash(routineDetailList, routine);
}
#Override
public boolean equals(#Nullable Object obj) {
if (this == obj) {
return true;
}
if (obj == null || getClass() != obj.getClass()) {
return false;
}
RoutineModel that = (RoutineModel) obj;
return Objects.equals(routine, that.routine) && Objects.equals(routineDetailList, that.routineDetailList);
}
}
RoutineAdapter.java
public class RoutineAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder>{
final static int TYPE_ROUTINE = 1;
final static int TYPE_ROUTINE_DETAIL = 2;
private Context context;
private List<Object> mItems = new ArrayList<>();
OnRoutineItemClickListener listener;
public void updateRoutineList(List<Object> newRoutineList) {
final RoutineDiffUtil diffCallback = new RoutineDiffUtil(this.mItems, newRoutineList);
final DiffUtil.DiffResult diffResult = DiffUtil.calculateDiff(diffCallback);
this.mItems.clear();
this.mItems.addAll(newRoutineList);
diffResult.dispatchUpdatesTo(this);
}
#NonNull
#Override
public RecyclerView.ViewHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
context = parent.getContext();
if (viewType == TYPE_ROUTINE) {
View itemView = LayoutInflater.from(context).inflate(R.layout.routine_item, parent, false);
return new RoutineViewHolder(itemView);
}
View itemView = LayoutInflater.from(context).inflate(R.layout.routine_detail_item, parent, false);
return new RoutineDetailViewHolder(itemView);
}
#Override
public void onBindViewHolder(#NonNull RecyclerView.ViewHolder holder, int position) {
Object object = mItems.get(position);
if(object instanceof RoutineModel) {
setRoutineData((RoutineViewHolder) holder, (RoutineModel) object, position);
}
else if(object instanceof RoutineDetailModel) {
}
}
private void setRoutineData(RoutineViewHolder holder, RoutineModel routineItem, int position){
holder.routine.setText(routineItem.getRoutine());
holder.addSet.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
if(listener != null) listener.OnAddBtnClick(position);
}
});
holder.deleteSet.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
if(listener != null) listener.OnDeleteBtnClick(position);
}
});
}
public Object getRoutineItem(int position) {
if(mItems == null || position < 0 || position >= mItems.size())
return null;
return mItems.get(position);
}
#Override
public int getItemCount() {
if(mItems == null)
return -1;
return mItems.size();
}
#Override
public int getItemViewType(int position) {
Object obj = mItems.get(position);
if(obj instanceof RoutineModel) {
return TYPE_ROUTINE;
}
return TYPE_ROUTINE_DETAIL;
}
// detail add,delete click interface
public interface OnRoutineItemClickListener {
public void OnAddBtnClick(int curRoutinePos);
public void OnDeleteBtnClick(int curRoutinePos);
}
public void setOnRoutineClickListener(OnRoutineItemClickListener listener) {
this.listener = listener;
}
public class RoutineViewHolder extends RecyclerView.ViewHolder {
public TextView routine;
public Button addSet;
public Button deleteSet;
public RoutineViewHolder(#NonNull View itemView) {
super(itemView);
routine = itemView.findViewById(R.id.routine);
addSet = itemView.findViewById(R.id.add_set);
deleteSet = itemView.findViewById(R.id.delete_set);
}
}
public class RoutineDetailViewHolder extends RecyclerView.ViewHolder {
public TextView set;
public TextView weight;
public RoutineDetailViewHolder(#NonNull View itemView) {
super(itemView);
set = itemView.findViewById(R.id.set);
weight = itemView.findViewById(R.id.weight);
}
}
}
RoutineDiffUtil.java
public class RoutineDiffUtil extends DiffUtil.Callback {
private List<Object> oldRoutineList;
private List<Object> newRoutineList;
public RoutineDiffUtil(List<Object> oldRoutineList) {
this.oldRoutineList = oldRoutineList;
newRoutineList = new ArrayList<>();
}
public RoutineDiffUtil(List<Object> oldRoutineList, List<Object> newRoutineList) {
this.oldRoutineList = oldRoutineList;
this.newRoutineList = newRoutineList;
}
#Override
public int getOldListSize() {
return oldRoutineList.size();
}
#Override
public int getNewListSize() {
return newRoutineList.size();
}
#Override
public boolean areItemsTheSame(int oldItemPosition, int newItemPosition) {
// boolean result = oldRoutineList.equals(newRoutineList); // work well
boolean result = oldRoutineList.get(oldItemPosition).hashCode() == newRoutineList.get(newItemPosition).hashCode();
return result;
}
#Override
public boolean areContentsTheSame(int oldItemPosition, int newItemPosition) {
return oldRoutineList.get(oldItemPosition).equals(newRoutineList.get(newItemPosition));
}
}
MainActivity.java
public class WriteRoutineActivity extends AppCompatActivity {
Button add_routine_btn;
TextView title;
RecyclerView routine_rv;
LinearLayoutManager routineLayoutManger;
RoutineAdapter routineAdapter;
List<RoutineModel> items;
List<String> titleData;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_write_routine);
initViews();
setPageTitle(getIntent());
setRoutineRecyclerview();
items = new ArrayList<>();
routineAdapter = new RoutineAdapter();
routine_rv.setAdapter(routineAdapter);
add_routine_btn.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
WorkoutListDialogFragment routineDialog = new WorkoutListDialogFragment();
routineDialog.show(getSupportFragmentManager(), "RoutineListDialog");
}
});
routineAdapter.setOnRoutineClickListener(new RoutineAdapter.OnRoutineItemClickListener() {
#Override
public void OnAddBtnClick(int routinePos) {
Object obj = routineAdapter.getRoutineItem(routinePos);
if(obj instanceof RoutineModel) {
RoutineModel item = (RoutineModel) obj;
item.addDetail(new RoutineDetailModel());
routineAdapter.updateRoutineList(getDataToBeDisplayed());
}
}
#Override
public void OnDeleteBtnClick(int routinePos) {
Object item = routineAdapter.getRoutineItem(routinePos);
if(item instanceof RoutineModel) {
RoutineModel routineModel = (RoutineModel) item;
if(routineModel.getDetailItemSize() > 1) {
try {
routineModel.removeDetails(routineModel.getDetailItemSize() - 1);
} catch (Exception e) {
e.printStackTrace();
}
}
else { // if delete item exists only one
items.remove(routineModel);
}
routineAdapter.updateRoutineList(getDataToBeDisplayed());
}
}
});
}
public void addRoutine(String routine) {
RoutineModel routineModel = new RoutineModel(routine);
RoutineDetailModel routineDetailModel = new RoutineDetailModel();
routineModel.addDetail(routineDetailModel);
items.add(routineModel);
routineAdapter.updateRoutineList(getDataToBeDisplayed());
}
private List<Object> getDataToBeDisplayed() {
List<Object> mixedList = new ArrayList<>();
for(RoutineModel rm: items){
mixedList.add(rm);
if(rm.getDetailItemList() != null && rm.getDetailItemSize() > 0){
for(RoutineDetailModel rmdetilas: rm.getDetailItemList()){
mixedList.add(rmdetilas);
}
}
}
return mixedList;
}
}

Related

how to remove all items from RecyclerView on toolbar icon delete in android

Hello friend a lot of search but not working plz help me.
my probem is delete all history from adaptor using on toolbar delete icon how to remove adaptor data
below code first show adaptor and mainactivity
public void removehistory(View view)
button click to remove items from adaptor how to solve this problem sorry for bad english and advance thanks
HistoryAdaptor
public class HistoryAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {
private ArrayList<Object> data;
private GenCallback<HistoryModel> clickListener;
private static final int NATIVE_AD = 1;
private static final int HISTORY_ITEM = 2;
private LayoutInflater inflater;
// private Button removedata;
public HistoryAdapter() {
this.data = new ArrayList<>();
inflater = (LayoutInflater) App.getInstance().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
}
#NonNull
#Override
public RecyclerView.ViewHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
View view;
switch (viewType) {
case NATIVE_AD:
view = LayoutInflater.from(parent.getContext()).inflate(R.layout.ad_unified, null, false);
return new NativeAdHolder(view);
case HISTORY_ITEM:
default:
view = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_history, null, false);
return new ViewHolder(view);
}
// return new ViewHolder(LayoutInflater.from(parent.getContext()).inflate(R.layout.item_history, null, false));
}
#Override
public void onBindViewHolder(#NonNull RecyclerView.ViewHolder holder, int position) {
switch (getItemViewType(position)) {
case NATIVE_AD:
((NativeAdHolder) holder).bind((UnifiedNativeAd) data.get(position));
break;
case HISTORY_ITEM:
default:
((ViewHolder) holder).bind((HistoryModel) data.get(position));
break;
}
}
#Override
public int getItemViewType(int position) {
if (data.get(position) instanceof UnifiedNativeAd) {
return NATIVE_AD;
} else {
return HISTORY_ITEM;
}
}
#Override
public int getItemCount() {
return data.size();
}
public void addItem(Object obj, int pos) {
this.data.add(pos, obj);
notifyItemInserted(pos);
}
public void updateData(ArrayList<HistoryModel> list) {
this.data.clear();
this.data.addAll(list);
notifyDataSetChanged();
}
public void clear() {
if (this.data != null && this.data.size() != 0) {
this.data.clear();
notifyDataSetChanged();
}
}
public void setClickListener(GenCallback<HistoryModel> clickListener) {
this.clickListener = clickListener;
}
public void showStarredOnly() {
/*Iterator<Object> iterator = data.iterator();
int pos = 0;
while (iterator.hasNext()) {
if (iterator.next() instanceof HistoryModel) {
HistoryModel historyModel = (HistoryModel) iterator.next();
if (!historyModel.isStarred()) {
iterator.remove();
// notifyItemRemoved(pos);
}
}
pos++;
}
notifyDataSetChanged();*/
}
public class ViewHolder extends RecyclerView.ViewHolder {
#BindView(R.id.tvFromLang)
TextView tvFromLang;
#BindView(R.id.tvFromText)
TextView tvFromText;
#BindView(R.id.tvToLang)
TextView tvToLang;
#BindView(R.id.tvToText)
TextView tvToText;
#BindView(R.id.ivStar)
ImageView ivStar;
#BindView(R.id.llMain)
CardView llMain;
#BindView(R.id.tvDate)
TextView tvDate;
public ViewHolder(#NonNull View itemView) {
super(itemView);
ButterKnife.bind(this, itemView);
llMain.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
if (clickListener != null) {
clickListener.onCallback((HistoryModel) data.get(getAdapterPosition()));
}
}
});
llMain.setOnLongClickListener(new View.OnLongClickListener() {
#Override
public boolean onLongClick(View view) {
int pos = getAdapterPosition();
HistoryModel historyModel = (HistoryModel) data.get(pos);
boolean isStar = historyModel.isStarred();
String from = historyModel.getFromLang();
String to = historyModel.getToLang();
Dialogs.INSTANCE.showActionsDialog(llMain.getContext(), isStar, from, to, new HistoryActionCallback() {
#Override
public void onClickCopyFrom() {
Utils.copyText(historyModel.getFromText());
Logger.logFabric(Constants.Events.COPY_FROM);
}
#Override
public void onClickCopyTo() {
Utils.copyText(historyModel.getToText());
Logger.logFabric(Constants.Events.COPY_TO);
}
#Override
public void onClickStar() {
Logger.logFabric(Constants.Events.MARKED_AS_FAV);
historyModel.setStarred(!isStar);
notifyItemChanged(pos);
RoomRepository.getNew().updateHistoryItem(historyModel);
// notifyDataSetChanged();
}
#Override
public void onClickDelete() {
String message = "Are you sure you want to delete?";
Dialogs.INSTANCE.showConfirmationDialog(view.getContext(), message, new View.OnClickListener() {
#Override
public void onClick(View view) {
RoomRepository.getNew().deleteHistoryRecord(historyModel.getTimeStamp());
data.remove(pos);
notifyItemRemoved(pos);
Dialogs.INSTANCE.dismissDialog();
Logger.logFabric(Constants.Events.ITEM_DELETED);
}
});
}
});
return false;
}
});
}
public void bind(HistoryModel item) {
StringBuilder builder = new StringBuilder();
builder.append(item.getFromLang()).append("(").append(item.getFromCode()).append(")");
tvFromLang.setText(builder);
tvFromText.setText(item.getFromText());
builder.setLength(0);
builder.append(item.getToLang()).append("(").append(item.getToCode()).append(")");
tvToLang.setText(builder);
tvToText.setText(item.getToText());
String date = Utils.formatDate(item.getTimeStamp(), "EEE, MMM d, yyyy");
tvDate.setText(date);
ivStar.setVisibility(item.isStarred() ? View.VISIBLE : View.GONE);
}
MainActivity
public class HistoryActivity extends AppCompatActivity {
private HistoryAdapter mAdapter;
private ArrayList<Object> data;
private Activity mCurrentActivity;
private RecyclerView rvHistory;
private Button clearh;
private GenCallback<HistoryModel> clickListener;
private ArrayList<HistoryModel> datamodel = new ArrayList<>();
private ArrayList<String> arrayList = new ArrayList<>();
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_history);
rvHistory = findViewById(R.id.rvHistory);
ImageView imgb = findViewById(R.id.imgback);
initAdapter();
getAdapter();
imgb.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
HistoryActivity.super.onBackPressed();
}
});
}
private void getAdapter() {
RoomRepository.getNew().getAllHistory(mCallback);
}
private void initAdapter() {
mAdapter = new HistoryAdapter();
LinearLayoutManager layoutManager = new LinearLayoutManager(mCurrentActivity);
rvHistory.setLayoutManager(layoutManager);
rvHistory.setAdapter(mAdapter);
}
private IRoomDataHandler mCallback = new RoomDataHandler() {
#Override
public void onGetAllHistory(ArrayList<HistoryModel> list) {
// if (isSafe()) {
mAdapter.updateData(list);
// showLoader(false);
// checkForNoData();
// if (AdUtils.getInstance().getNativeAd() != null) {
//
// }
}
#Override
public void onError(String error) {
// showLoader(false);
// checkForNoData();
}
};
public void removehistory(View view) {
//problem is here
mAdapter.notifyItemRemoved(i);
}
}
call clear() method from on click oh that button like this.
public void removehistory(View view) {
//problem is here
mAdapter.clear()
}

Problem of automatic change of data value when scrolling in RecyclerView

I have attached a picture to help you understand my problem.
I'm making an Workout app.
When the button is pressed, the routine is added
In the added routine, it can use the button again to add detailed data (set, lbs, reps).
So, I am using a two type RecyclerView (except footer).
I used DiffUtil to update the items being added.
I found a strange phenomenon while experimenting for testing. (See photo)
It wasn't an error, so I can't figure out what's wrong with it.
After entering the data, when i added a number of detailed items, the value of the data entered first appeared in the items added later.
And if i scrolled after many items were added, the data moved randomly.
However, what is expected is this phenomenon when you add a lot of items or scroll.
What's wrong?
RoutineAdapter.java
public class RoutineAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {
final static int TYPE_ROUTINE = 1;
final static int TYPE_ROUTINE_DETAIL = 2;
final static int TYPE_ROUTINE_FOOTER = 3;
private Context context;
private List<Object> mItems = new ArrayList<>();
OnRoutineItemClickListener routinelistener;
OnRoutineAddClickListener routineAddListener;
public void updateRoutineList(List<Object> newRoutineList) {
final RoutineDiffUtil diffCallback = new RoutineDiffUtil(this.mItems, newRoutineList);
final DiffUtil.DiffResult diffResult = DiffUtil.calculateDiff(diffCallback);
this.mItems.clear();
this.mItems.addAll(newRoutineList);
diffResult.dispatchUpdatesTo(this);
}
#NonNull
#Override
public RecyclerView.ViewHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
context = parent.getContext();
View itemView;
if(viewType == TYPE_ROUTINE){
itemView = LayoutInflater.from(parent.getContext()).inflate(R.layout.routine_item, parent, false);
return new RoutineViewHolder(itemView);
}
else if(viewType == TYPE_ROUTINE_DETAIL){
itemView = LayoutInflater.from(context).inflate(R.layout.routine_detail_item, parent, false);
return new RoutineDetailViewHolder(itemView);
}
else {
itemView = LayoutInflater.from(context).inflate(R.layout.add_routine_item, parent, false);
return new RoutineAddFooterViewHolder(itemView);
}
}
#Override
public void onBindViewHolder(#NonNull RecyclerView.ViewHolder holder, int position) {
Object obj;
switch (getItemViewType(position)) {
case TYPE_ROUTINE:
obj = mItems.get(position);
setRoutineData((RoutineViewHolder) holder, (RoutineModel) obj);
break;
case TYPE_ROUTINE_DETAIL:
obj = mItems.get(position);
RoutineDetailModel item = (RoutineDetailModel) obj;
((RoutineDetailViewHolder) holder).setDetailItem(item);
break;
case TYPE_ROUTINE_FOOTER:
break;
}
}
#Override
public int getItemCount() {
if(mItems == null)
return -1;
return mItems.size() + 1; // for footer
}
#Override
public int getItemViewType(int position) {
if(position == mItems.size()) {
return TYPE_ROUTINE_FOOTER;
}
else {
Object obj = mItems.get(position);
if(obj instanceof RoutineModel) {
return TYPE_ROUTINE;
}
else {
// obj instanceof RoutineDetailModel
return TYPE_ROUTINE_DETAIL;
}
}
}
// add routine interface
public interface OnRoutineAddClickListener {
public void onAddRoutineClick();
}
public void setOnAddRoutineClickListener(OnRoutineAddClickListener listener) {
this.routineAddListener = listener;
}
// details add / remove interface
public interface OnRoutineItemClickListener {
public void onAddBtnClicked(int curRoutinePos);
public void onDeleteBtnClicked(int curRoutinePos);
public void onWritingCommentBtnClicked(int curRoutinePos);
}
public void setOnRoutineClickListener(OnRoutineItemClickListener listener) {
this.routinelistener = listener;
}
private class RoutineViewHolder extends RecyclerView.ViewHolder {
public TextView routine;
public Button addSet;
public Button deleteSet;
public Button comment;
public RoutineViewHolder(#NonNull View itemView) {
super(itemView);
initViews();
addSet.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
if(routinelistener != null && getAdapterPosition() != RecyclerView.NO_POSITION)
routinelistener.onAddBtnClicked(getAdapterPosition());
}
});
deleteSet.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
if(routinelistener != null && getAdapterPosition() != RecyclerView.NO_POSITION)
routinelistener.onDeleteBtnClicked(getAdapterPosition());
}
});
comment.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
if(routinelistener != null && getAdapterPosition() != RecyclerView.NO_POSITION)
routinelistener.onWritingCommentBtnClicked(getAdapterPosition());
}
});
}
}
private class RoutineDetailViewHolder extends RecyclerView.ViewHolder {
public TextView set;
public TextView weight;
public RoutineDetailViewHolder(#NonNull View itemView) {
super(itemView);
initViews();
}
private void initViews() {
set = itemView.findViewById(R.id.set);
weight = itemView.findViewById(R.id.weight);
}
private void setDetailItem(RoutineDetailModel item) {
set.setText(item.getSet().toString() + "set");
}
}
}
RoutineDiffUtil.java
public class RoutineDiffUtil extends DiffUtil.Callback {
private List<Object> oldRoutineList;
private List<Object> newRoutineList;
public RoutineDiffUtil(List<Object> oldRoutineList, List<Object> newRoutineList) {
this.oldRoutineList = oldRoutineList;
this.newRoutineList = newRoutineList;
}
#Override
public int getOldListSize() {
return oldRoutineList.size();
}
#Override
public int getNewListSize() {
return newRoutineList.size();
}
#Override
public boolean areItemsTheSame(int oldItemPosition, int newItemPosition) {
Object oldObj = oldRoutineList.get(oldItemPosition);
Object newObj = newRoutineList.get(newItemPosition);
if (oldObj instanceof RoutineModel && newObj instanceof RoutineModel) {
return ((RoutineModel) oldObj).id == ((RoutineModel) newObj).id;
}
else if (oldObj instanceof RoutineDetailModel && newObj instanceof RoutineDetailModel) {
return ((RoutineDetailModel) oldObj).id == ((RoutineDetailModel) newObj).id;
}
else if(oldObj instanceof RoutineModel && newObj instanceof RoutineDetailModel) {
return false;
}
else {
return false;
}
}
#Override
public boolean areContentsTheSame(int oldItemPosition, int newItemPosition) {
return (oldRoutineList.get(oldItemPosition)).equals(newRoutineList.get(newItemPosition));
}
}
RoutineDetailModel.java
public class RoutineDetailModel {
public int id;
private int set = 1;
private int weight;
public RoutineDetailModel() {
Random random = new Random();
this.id = random.nextInt();
}
public RoutineDetailModel(int set) {
Random random = new Random();
this.id = random.nextInt();
this.set = set+1;
}
public Integer getSet() {
return set;
}
public int getId() {
return id;
}
#Override
public int hashCode() {
return Objects.hash(set, weight);
}
#Override
public boolean equals(#Nullable Object obj) {
if(obj != null && obj instanceof RoutineDetailModel) {
RoutineDetailModel model = (RoutineDetailModel) obj;
if(this.id == model.getId()) {
return true;
}
}
return false;
}
}
First of all, you should use ListAdapter class with diff util. The problem with your adapter is that, Recycler view recycles views again and again. That is to say that when you entered a text for your first item, this item is used for other views. To solve it after any text change you should keep this text in your model class then you should set this text to the field in onBind() method. To sum up, recycler view uses same view for different items so any data related to any item should be kept in a model and the model should be set to the view in onBind().

How to add dividers, spacers, or header with text to a recylerview

I've got a RecylerView that is displaying a list of data. I need to add dividers or spacers that I need to add two Dividers or spacers too that I can add text to as shown in the image below(with the text DEFAULT or OTHER).
*NOTE Headers are in the image below with the text "DEFAULT" and another that says "OTHER".
The CC's shown are drag and drop items but i don't want the "spaces or headers" marked as default and other to be moved.
I've started adding the divider as shown in the code below but I cannot figure out how to add text.
#Override
public void onViewCreated(#NonNull View view, Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
ButterKnife.bind(this, view);
LinearLayoutManager mAdapterLayoutManager = new LinearLayoutManager(context);
recyclerView.setLayoutManager(mAdapterLayoutManager);
billingMethodRecyclerViewAdapter = new BillingMethodRecyclerViewAdapter(context, billingMethods, paymentService, ListPaymentMethods.this );
billingMethodRecyclerViewAdapter.setMasterpassService(masterpassService);
billingMethodRecyclerViewAdapter.setChoosePaymentMode(choosePaymentMode);
DividerItemDecoration itemDecor = new DividerItemDecoration(context, mAdapterLayoutManager.getOrientation());
recyclerView.addItemDecoration(itemDecor);
recyclerView.setAdapter(billingMethodRecyclerViewAdapter);
billingMethodRecyclerViewAdapter.clear();
if (!choosePaymentMode) {
setupSwipeListener(billingMethodRecyclerViewAdapter);
}
if (!BuildConfig.SHOW_AVAILABILITY_INRIX) {
parkmobileProAd.setVisibility(View.GONE);
}
if (getArguments() != null) {
isAddPaymentZoneDetails = getArguments().getBoolean(AddPaymentActivity.ADD_PAYMENT_FROM_ZONE_DETAIL);
}
}
and the xml for the recylcerview
<androidx.recyclerview.widget.RecyclerView
android:id="#+id/recycler_view"
android:layout_width="match_parent"
android:layout_height="wrap_content"/>
EDIT
Adapter:
public class BillingMethodRecyclerViewAdapter extends RecyclerView.Adapter<BillingMethodHolder> {
private static final int PENDING_REMOVAL_TIMEOUT = 3000; // in milliseconds
private ArrayList<BillingMethod> billingMethods;
private Handler handler = new Handler(); // handler for running delayed runnables
private HashMap<BillingMethod, Runnable> pendingRunnables = new HashMap<>(); // map of items to pending runnables, so we can cancel a removal if need be
private BillingMethodHolder.BillingMethodListener billingMethodListener;
private PaymentService paymentService;
private MasterpassService masterpassService;
private boolean choosePaymentMode = false;
private Context mContext;
private int maxPaymentMethods = 6;
public BillingMethodRecyclerViewAdapter(Context context, ArrayList<BillingMethod> objects, PaymentService paymentService, BillingMethodHolder.BillingMethodListener billingMethodListener) {
this.billingMethods = objects;
this.billingMethodListener = billingMethodListener;
this.mContext = context.getApplicationContext();
this.paymentService = paymentService;
}
public int getMaxPaymentMethods() {
return maxPaymentMethods;
}
public void setMaxPaymentMethods(int maxPaymentMethods) {
this.maxPaymentMethods = maxPaymentMethods;
}
public void setMasterpassService(MasterpassService masterpassService) {
this.masterpassService = masterpassService;
}
public boolean onItemMove(int fromPosition, int toPosition) {
if (fromPosition < toPosition) {
for (int i = fromPosition; i < toPosition; i++) {
Collections.swap(billingMethods, i, i + 1);
}
} else {
for (int i = fromPosition; i > toPosition; i--) {
Collections.swap(billingMethods, i, i - 1);
}
}
notifyItemMoved(fromPosition, toPosition);
return true;
}
public List<BillingMethod> getBillingMethods() {
return billingMethods;
}
public void setChoosePaymentMode(boolean choosePaymentMode) {
this.choosePaymentMode = choosePaymentMode;
}
#NonNull
#Override
public BillingMethodHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_payment_methods, parent, false);
return new BillingMethodHolder(v);
}
#Override
public void onBindViewHolder(#NonNull BillingMethodHolder holder, final int position) {
holder.bind(getBillingMethods().get(position), billingMethodListener, choosePaymentMode);
}
#Override
public int getItemCount() {
return billingMethods.size();
}
public void pendingRemoval(int position) {
final BillingMethod billingMethod = billingMethods.get(position);
billingMethod.setPendingDeletion(true);
this.notifyItemChanged(position); // redraw row in "undo" state
Runnable pendingRemovalRunnable = () -> {
deleteBillingMethod(position);
};
handler.postDelayed(pendingRemovalRunnable, PENDING_REMOVAL_TIMEOUT);
pendingRunnables.put(billingMethod, pendingRemovalRunnable);
}
public void savePaymentOrder() {
List<BillingMethod> newOrder = new ArrayList<>();
int order = 0;
for (BillingMethod method : billingMethods) {
if (order == 0) {
method.setPreferred(true);
LocalyticsUtil.getInstance(mContext).setPrimaryPaymentMethod(method);
} else {
method.setPreferred(false);
}
method.setSortOrder(order);
newOrder.add(method);
order++;
}
paymentService.setPaymentMethodsOrder(newOrder, new PaymentService.GenericListener() {
#Override
public void onSuccess() {
Log.d("TAG", "Saved");
}
#Override
public void onError(String errorMessage) {
Log.d("TAG", "Saved");
}
});
}
private void deleteBillingMethod(int position) {
BillingMethod method = billingMethods.get(position);
if (method.getBillingType() == BillingType.CREDIT_CARD) {
paymentService.deleteCreditCard(method.getCreditCard().getCardStatus(), new PaymentService.GenericListener() {
#Override
public void onSuccess() {
billingMethods.remove(position);
notifyItemRemoved(position);
}
#Override
public void onError(String errorMessage) {
}
});
} else if (method.getBillingType() == BillingType.PREPAID) {
paymentService.deleteWallet(new PaymentService.GenericListener() {
#Override
public void onSuccess() {
billingMethods.remove(position);
notifyItemRemoved(position);
}
#Override
public void onError(String errorMessage) {
}
});
} else if (method.getBillingType() == BillingType.PAYPAL) {
paymentService.deletePaypal(new PaymentService.GenericListener() {
#Override
public void onSuccess() {
billingMethods.remove(position);
notifyItemRemoved(position);
}
#Override
public void onError(String errorMessage) {
}
});
} else if (method.getBillingType() == BillingType.CHASEPAY) {
paymentService.deleteChasepay(new PaymentService.GenericListener() {
#Override
public void onSuccess() {
billingMethods.remove(position);
notifyItemRemoved(position);
}
#Override
public void onError(String errorMessage) {
}
});
} else if (method.getBillingType() == BillingType.MASTERPASSV7) {
masterpassService.deleteMasterpassV7(String.valueOf(method.getBillingMethodId()), new MasterpassService.GenericListener() {
#Override
public void onSuccess() {
billingMethods.remove(position);
notifyItemRemoved(position);
}
#Override
public void onError(String errorMessage) {
}
});
} else {
notifyDataSetChanged();
}
}
public void clear() {
billingMethods.clear();
notifyDataSetChanged();
}
public void stopRemoval(BillingMethod billingMethod) {
Runnable pendingRemovalRunnable = pendingRunnables.get(billingMethod);
pendingRunnables.remove(billingMethod);
if (pendingRemovalRunnable != null) {
handler.removeCallbacks(pendingRemovalRunnable);
}
billingMethod.setPendingDeletion(false);
this.notifyItemChanged(billingMethods.indexOf(billingMethod));
}
}
I took a bit of time but I was able to do it.
This is the output
1) MainActivity.java
public class MainActivity extends AppCompatActivity implements OnStartDragListener{
RecyclerView recyclerView;
private ItemTouchHelper mItemTouchHelper;
private List<Item> itemList = new ArrayList<>();
private RecyclerViewAdapter mAdapter;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
recyclerView = (RecyclerView) findViewById(R.id.recyclerView);
mAdapter = new RecyclerViewAdapter(itemList, MainActivity.this);
RecyclerView.LayoutManager mLayoutManager = new LinearLayoutManager(getApplicationContext());
recyclerView.setLayoutManager(mLayoutManager);
recyclerView.setItemAnimator(new DefaultItemAnimator());
recyclerView.addItemDecoration(new SeparationDecorator());
recyclerView.setAdapter(mAdapter);
ItemTouchHelper.Callback callback = new SimpleItemTouchHelperCallback(mAdapter);
mItemTouchHelper = new ItemTouchHelper(callback);
mItemTouchHelper.attachToRecyclerView(recyclerView);
prepareItemData();
}
private void prepareItemData() {
Item item = new Item("Apple Pay");
itemList.add(item);
item = new Item("1706-XXXX-XXXX-1112");
itemList.add(item);
item = new Item("Google pay");
itemList.add(item);
mAdapter.notifyDataSetChanged();
}
#Override
public void onStartDrag(RecyclerView.ViewHolder viewHolder) {
mItemTouchHelper.startDrag(viewHolder);
}
}
2) OnStartDragListener.java
public interface OnStartDragListener {
void onStartDrag(RecyclerView.ViewHolder viewHolder);
}
3) SimpleItemTouchHelperCallback.java
public class SimpleItemTouchHelperCallback extends ItemTouchHelper.Callback {
private final ItemTouchHelperAdapter mAdapter;
public SimpleItemTouchHelperCallback(ItemTouchHelperAdapter adapter) {
mAdapter = adapter;
}
#Override
public boolean isLongPressDragEnabled() {
return true;
}
#Override
public boolean isItemViewSwipeEnabled() {
return false; // make this true to enable swipe to delete
}
#Override
public int getMovementFlags(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder) {
int dragFlags = ItemTouchHelper.UP | ItemTouchHelper.DOWN;
int swipeFlags = ItemTouchHelper.START | ItemTouchHelper.END;
return makeMovementFlags(dragFlags, swipeFlags);
}
#Override
public boolean onMove(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder,
RecyclerView.ViewHolder target) {
mAdapter.onItemMove(viewHolder.getAdapterPosition(), target.getAdapterPosition());
return true;
}
#Override
public void onSwiped(RecyclerView.ViewHolder viewHolder, int direction) {
mAdapter.onItemDismiss(viewHolder.getAdapterPosition());
}
}
4) ItemTouchHelperAdapter.java
public interface ItemTouchHelperAdapter {
void onItemMove(int fromPosition, int toPosition);
void onItemDismiss(int position);
}
5) SeparationDecorator.java
public class SeparationDecorator extends RecyclerView.ItemDecoration {
private int textSize = 50;
private int groupSpacing = 100;
private Paint paint = new Paint();
{
paint.setTextSize(textSize);
}
#Override
public void onDrawOver(Canvas c, RecyclerView parent, RecyclerView.State state) {
for (int i = 0; i < parent.getChildCount(); i++) {
View view = parent.getChildAt(i);
int position = parent.getChildAdapterPosition(view);
if (position == 0) {
c.drawText("DEFAULT", view.getLeft(),
view.getTop() - groupSpacing / 2 + textSize / 3, paint);
} else if(position == 1) {
c.drawText("OTHER", view.getLeft(),
view.getTop() - groupSpacing / 2 + textSize / 3, paint);
}
}
}
#Override
public void getItemOffsets(Rect outRect, View view, RecyclerView parent, RecyclerView.State state) {
if (parent.getChildAdapterPosition(view) == 0 || parent.getChildAdapterPosition(view) == 1) {
outRect.set(0, groupSpacing, 0, 0);
}
}
}
6) RecyclerViewAdapter.java
public class RecyclerViewAdapter extends RecyclerView.Adapter<RecyclerViewAdapter.MyViewHolder> implements ItemTouchHelperAdapter{
private List<Item> itemList;
private Context context;
#Override
public void onItemMove(int fromPosition, int toPosition) {
Item prev = itemList.remove(fromPosition);
itemList.add(toPosition > fromPosition ? toPosition - 1 : toPosition, prev);
notifyItemMoved(fromPosition, toPosition);
}
#Override
public void onItemDismiss(int position) {
itemList.remove(position);
notifyItemRemoved(position);
}
public class MyViewHolder extends RecyclerView.ViewHolder {
public TextView title;
public MyViewHolder(View view) {
super(view);
title = (TextView) view.findViewById(R.id.title);
}
}
public RecyclerViewAdapter(List<Item> itemList, Context context) {
this.itemList = itemList;
this.context = context;
}
#Override
public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View itemView = LayoutInflater.from(parent.getContext())
.inflate(R.layout.view_item, parent, false);
return new MyViewHolder(itemView);
}
#Override
public void onBindViewHolder(MyViewHolder holder, int position) {
Item movie = itemList.get(position);
holder.title.setText(movie.getTitle());
}
#Override
public int getItemCount() {
return itemList.size();
}
}
7) Item.java
public class Item {
private String title;
public Item(String title) {
this.title = title;
}
public void setTitle(String title) {
this.title = title;
}
public String getTitle() {
return title;
}
}
This is it. This was able to solve your problem.
I am not able to explain you the complete code, I will take some time in future definitely and explain it.
public class MyAdapter extends RecyclerView.Adapter<MyViewHolder> {
// other methods..
#Override
public void onBindViewHolder(MyViewHolder holder, int position) {
// initialize your other views
if (your condition){
// display header
}else{
// hide header
}
}
}
You can do some thing like this by adding header view to the item and displaying for the required set and making it gone for un necessary items.
Simply coming towards what you need, just add an empty view with layout_height="1dp" and background="#bcbcbc" like:
<View
android:layout_width="match_parent"
android:layout_height="1dp"
android:background="#bcbcbc"/>
it'll get a line drawn for you, use it as a divider, while for making format difference just use a change text size for texts.
Hope it'll help you.

Animation on notifyDataSetChanged() in FragmentStatePagerAdapter

By overwriting getItemPosition() method I can refresh my FragmentStatePagerAdapter, which works fine. But the change of the contents is not nice to see.
Is there possibility to apply any kind of animation as I refresh the FragmentStatePagerAdapter?
I was also facing same issue.So, what should you do. Make global variables in your adapter for what you want continuous animate.
Now when you start animation on button click. Pass value to global variables.
When you notifydatasetchanged it doesn't effect your animation.
I haven't found any correct way. So, did this thing.It's working perfect.
public class HomeAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {
private Context mContext;
private ArrayList<Response.DataBean> feedArrayList = new ArrayList<>();
FeedClickListener mListener;
#Inject
ImageUtility mImageUtility;
#Inject
AppUtils mAppUtils;
#Inject
PreferenceManager mPref;
private float prevPosition = -1;
private YoYo.YoYoString ropeText,ropeImage;
private int tempHandlePlayPause = 0;
private TextView tempTextView;
private ImageView tempImageView;
/**
* click listeners
*/
interface FeedClickListener {
void onPlayAudioClicked( FeedResponse.DataBean feedItem, SeekBar audioProgress, int position);
void onPauseAudioClicked(FeedResponse.DataBean feedItem);
}
public HomeAdapter(Context context, ArrayList<Response.DataBean> mDataArrayList, HomeClickListener mFeedListener) {
((BaseApplication) context.getApplicationContext()).getAppComponent().inject(this);
this.mContext = context;
this.feedArrayList = mDataArrayList;
mListener = mFeedListener;
}
#Override
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
return new ItemViewHolder(LayoutInflater.from(parent.getContext()).inflate(R.layout.item_layout, parent, false));
}
#Override
public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {
switch (holder.getItemViewType()) {
ItemViewHolder holderItem = (ItemViewHolder) holder;
int adapterPosition = holder.getAdapterPosition() - 1;
holderItem.normalContainer.setVisibility(View.VISIBLE);
holderItem.bannerContainer.setVisibility(View.GONE);
setUpNormalItem(adapterPosition, holderItem);
}
}
private void setUpNormalItem(int adapterPosition, ItemViewHolder holder) {
FeedResponse.DataBean feedItem = feedArrayList.get(adapterPosition);
// set up data to current view holder items
setUpItems(holder, feedItem, adapterPosition);
}
private void setUpItems(ItemViewHolder holder, FeedResponse.DataBean feedItem, int position) {
if (feedItem.isstop()) {
holder.playImageView.setVisibility(View.GONE);
holder.pauseImageView.setVisibility(View.VISIBLE);
} else {
holder.playImageView.setVisibility(View.VISIBLE);
holder.pauseImageView.setVisibility(View.GONE);
holder.audioProgress.setProgress(0);
}
holder.playImageView.setOnClickListener(v -> {
feedItem.setIscomplete(false);
if (prevPosition >= 0) {
feedArrayList.get((int)prevPosition).setIsstop(false);
feedArrayList.get((int)prevPosition).setIsPrepare(false);
}
feedArrayList.get(position).setIsstop(true);
feedArrayList.get(position).setIsPrepare(true);
mListener.onPlayAudioClicked(feedItem, holder.audioProgress, position);
prevPosition = position;
tempHandlePlayPause = 1;
tempTextView = holder.tvPlayingBlink;
tempImageView = holder.pauseImageView;
notifyDataSetChanged();
});
holder.pauseImageView.setOnClickListener(v -> {
feedArrayList.get(position).setIsstop(false);
tempTextView = holder.tvPlayingBlink;
tempImageView = holder.pauseImageView;
tempHandlePlayPause = 0;
mListener.onPauseAudioClicked(feedItem);
notifyDataSetChanged();
});
if (feedItem.isPrepare()) {
holder.tvPlayingBlink.setVisibility(View.VISIBLE);
if (tempHandlePlayPause == 1){
startAnimation();
}else {
stopAnimation();
}
} else {
holder.tvPlayingBlink.setVisibility(View.INVISIBLE);
if (tempHandlePlayPause == 1){
startAnimation();
}else {
stopAnimation();
}
}
// play on complete audio
if (feedItem.iscomplete()) {
holder.playImageView.setVisibility(View.VISIBLE);
holder.pauseImageView.setVisibility(View.GONE);
}
if ((!feedItem.iscomplete()) && feedItem.getTotalLength() > 0) {
holder.audioProgress.setMax(feedItem.getTotalLength());
holder.audioProgress.setProgress(0);
}
}
private void startAnimation(){
if (ropeText != null || ropeImage != null) {
ropeText.stop(true);
ropeImage.stop(true);
}
ropeText = YoYo.with(Techniques.Pulse)
.duration(800)
.repeat(YoYo.INFINITE)
.pivot(YoYo.CENTER_PIVOT, YoYo.CENTER_PIVOT)
.interpolate(new AccelerateDecelerateInterpolator())
.playOn(tempTextView);
ropeImage = YoYo.with(Techniques.Pulse)
.duration(800)
.repeat(YoYo.INFINITE)
.pivot(YoYo.CENTER_PIVOT, YoYo.CENTER_PIVOT)
.interpolate(new AccelerateDecelerateInterpolator())
.playOn(tempImageView);
}
private void stopAnimation(){
if (ropeText != null || ropeImage != null) {
ropeText.stop(true);
ropeImage.stop(true);
}
}
public void updateData(List<FeedResponse.DataBean> items) {
feedArrayList.clear();
feedArrayList.addAll(items);
notifyDataSetChanged();
}
public void deleteItem(int position) {
feedArrayList.remove(position);
notifyDataSetChanged();
}
#Override
public int getItemCount() {
return (feedArrayList.size());
}
public static class ItemViewHolder extends RecyclerView.ViewHolder {
#BindView(R.id.image_view_3)
ImageView imageView3;
#BindView(R.id.tvplayingblink)
TextView tvPlayingBlink;
public ItemViewHolder(View itemView) {
super(itemView);
ButterKnife.bind(this, itemView);
}
}
}

Sticky Header RecyclerView with multiple ArrayLists

I am implementing sticky header with RecyclerView. I have three sections (i.e 3 sticky headers) and they are working fine.Now I have taken three arraylists inside each section, I have initialized these list in my adapter and I am trying to get data of these lists on basis of header id inside onBindViewHolder. But it is not giving me the full list,just one string from each list (i.e under first section--data on first position of mylist,,,under second section-- data on second position of mylist1 ---under third section-- data on third position of mylist2)
Please Help !!
Code in Context:
StickyTestAdapter
public class StickyTestAdapter extends RecyclerView.Adapter<StickyTestAdapter.ViewHolder> implements
StickyHeaderAdapter<StickyTestAdapter.HeaderHolder> {
private Context mContext;
private ArrayList<String> mylist;
private ArrayList<String> mylist1;
private ArrayList<String> mylist2;
private static int countposition;
private String HEADER_FIRIST="HEADER_FIRIST";
private String HEADER_SECOND="HEADER_SECOND";
private String HEADER_THIRD="HEADER_THIRD";
public StickyTestAdapter(Context context) {
prepareData();
prepareData1();
prepareData2();
this.mContext=context;
}
#Override
public ViewHolder onCreateViewHolder(ViewGroup viewGroup, int i) {
final View view = LayoutInflater.from(mContext).inflate(R.layout.item_test, viewGroup, false);
return new ViewHolder(view);
}
#Override
public void onBindViewHolder(ViewHolder viewHolder, int position) {
long rowType= getHeaderId(position);
Log.e("getHeaderId----",""+rowType);
if (rowType==0){
if(!mylist.equals(""))
{
Log.e("list_data----", "" + mylist.get(position));
viewHolder.item.setText(mylist.get(position));
}
else
{
Log.e("Error--0--", "" + "error");
}
} else if (rowType==1){
if(!mylist1.equals(""))
{
Log.e("list_data1----", "" + mylist1.get(position));
viewHolder.item.setText(mylist1.get(position));
}
else
{
Log.e("Error---1-", "" + "error");
}
} else if (rowType==2){
if(!mylist2.equals(""))
{
Log.e("list_data2----", "" + mylist2.get(position));
viewHolder.item.setText(mylist2.get(position));
}
else
{
Log.e("Error----2", "" + "error");
}
}
}
#Override
public int getItemCount() {
if (getHeaderId(countposition)==0){
Log.e("mylist",""+mylist.size());
return mylist.size();
}else if (getHeaderId(countposition)==1){
Log.e("mylist1",""+mylist1.size());
return mylist1.size();
}else if (getHeaderId(countposition)==2){
Log.e("mylist2",""+mylist2.size());
return mylist2.size();
}
return 0;
}
#Override
public long getHeaderId(int pos) {
return pos;
}
#Override
public HeaderHolder onCreateHeaderViewHolder(ViewGroup parent) {
final View view = LayoutInflater.from(mContext).inflate(R.layout.header_test, parent, false);
return new HeaderHolder(view);
}
#Override
public void onBindHeaderViewHolder(HeaderHolder viewholder, int count) {
countposition=count;
if (getItemViewType(count)==0){
viewholder.headertext.setText(HEADER_FIRIST);
}else if (getItemViewType(count)==1){
viewholder.headertext.setText(HEADER_SECOND);
}else if (getItemViewType(count)==2){
viewholder.headertext.setText(HEADER_THIRD);
}
}
static class ViewHolder extends RecyclerView.ViewHolder {
public TextView item;
public ViewHolder(View itemView) {
super(itemView);
item = (TextView)itemView.findViewById(R.id.text_item);
}
}
static class HeaderHolder extends RecyclerView.ViewHolder {
public TextView headertext;
public HeaderHolder(View itemView) {
super(itemView);
headertext = (TextView)itemView.findViewById(R.id.header_text);
}
}
#Override
public int getItemViewType(int position) {
return position;
}
public void prepareData()
{
mylist=new ArrayList<>();
mylist.add("rajendra");
mylist.add("rani");
mylist.add("rahul");
}
public void prepareData1()
{
mylist1=new ArrayList<>();
mylist1.add("ravi");
mylist1.add("vikram");
mylist1.add("rakesh");
}
public void prepareData2()
{
mylist2=new ArrayList<>();
mylist2.add("apple");
mylist2.add("ashok");
mylist2.add("vikash");
}
}
Question is quite old. But that code looks complicated to read, personally I try to not reinvent what others did quite well by creating libraries.
GitHub is full of source that you can import. Some examples: FlexibleAdapter, FastAdapter, Epoxy and others.
I have build the first one, but you can try the others as well.
With mine, having multiple views and headers with sections is quite easy, I point here the wiki page where I define the section and how to initialize it.
Along with this feature, you have a lot more functionalities that makes your life easier.
I divide arraylist into 3 section based on alphabet like contactlist.
For that i use SectionedRecyclerViewAdapter
MainActivity.java
public class MainActivity extends AppCompactActivity {
private SectionedRecyclerViewAdapter sectionAdapter;
#Override
public View onCreate(Bundle savedInstanceState) {
setContentView(R.layout.activity_main);
sectionAdapter = new SectionedRecyclerViewAdapter();
for(char alphabet = 'a'; alphabet <= 'z';alphabet++) {
List<String> contacts = getContactsWithLetter(alphabet);
if (contacts.size() > 0) {
sectionAdapter.addSection(new ContactsSection(String.valueOf(alphabet), contacts));
}
}
RecyclerView recyclerView = (RecyclerView) findViewById(R.id.recyclerview);
recyclerView.setLayoutManager(new LinearLayoutManager(getContext()));
recyclerView.setAdapter(sectionAdapter);
return view;
}
#Override
public void onResume() {
super.onResume();
if (getActivity() instanceof AppCompatActivity) {
AppCompatActivity activity = ((AppCompatActivity) getActivity());
if (activity.getSupportActionBar() != null)
activity.getSupportActionBar().setTitle(R.string.nav_example1);
}
}
private List<String> getContactsWithLetter(char letter) {
List<String> contacts = new ArrayList<>();
for (String contact : getResources().getStringArray(R.array.names_)) {
if (contact.charAt(0) == letter) {
contacts.add(contact);
}
}
return contacts;
}
private class ContactsSection extends StatelessSection {
String title;
List<String> list;
ContactsSection(String title, List<String> list) {
super(new SectionParameters.Builder(R.layout.section_ex1_item)
.headerResourceId(R.layout.section_ex1_header)
.build());
this.title = title;
this.list = list;
}
#Override
public int getContentItemsTotal() {
return list.size();
}
#Override
public RecyclerView.ViewHolder getItemViewHolder(View view) {
return new ItemViewHolder(view);
}
#Override
public void onBindItemViewHolder(RecyclerView.ViewHolder holder, int position) {
final ItemViewHolder itemHolder = (ItemViewHolder) holder;
String name = list.get(position);
itemHolder.tvItem.setText(name);
itemHolder.imgItem.setImageResource(name.hashCode() % 2 == 0 ? R.drawable.ic_face_black_48dp : R.drawable.ic_tag_faces_black_48dp);
itemHolder.rootView.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Toast.makeText(getContext(), String.format("Clicked on position #%s of Section %s", sectionAdapter.getPositionInSection(itemHolder.getAdapterPosition()), title), Toast.LENGTH_SHORT).show();
}
});
}
#Override
public RecyclerView.ViewHolder getHeaderViewHolder(View view) {
return new HeaderViewHolder(view);
}
#Override
public void onBindHeaderViewHolder(RecyclerView.ViewHolder holder) {
HeaderViewHolder headerHolder = (HeaderViewHolder) holder;
headerHolder.tvTitle.setText(title);
}
}
private class HeaderViewHolder extends RecyclerView.ViewHolder {
private final TextView tvTitle;
HeaderViewHolder(View view) {
super(view);
tvTitle = (TextView) view.findViewById(R.id.tvTitle);
}
}
private class ItemViewHolder extends RecyclerView.ViewHolder {
private final View rootView;
private final ImageView imgItem;
private final TextView tvItem;
ItemViewHolder(View view) {
super(view);
rootView = view;
imgItem = (ImageView) view.findViewById(R.id.imgItem);
tvItem = (TextView) view.findViewById(R.id.tvItem);
}
}
}
use structure similar to
public class MultiArray<T> {
List<ItemGroup> lists = new ArrayList<>();
public void addList(String headerText, List<T> list) {
lists.add(new ItemGroup(headerText, list));
}
public int itemCount() {
int count = 0;
for (ItemGroup group : lists) {
count += group.count();
}
return count;
}
public T getItem(int position) {
int count = 0;
for (ItemGroup group : lists) {
if (count + group.count() >= position) {
return group.item(position - count);
}
count += group.count();
}
return null;
}
public int getGroupIndex(int position) {
int count = 0;
int groupIndex = 0;
for (ItemGroup group : lists) {
if (count + group.count() >= position) {
return groupIndex;
}
count += group.count();
groupIndex++;
}
return -1;
}
public String getHeaderText(int position){
int count = 0;
for (ItemGroup group : lists) {
if (count + group.count() >= position) {
return group.headerText;
}
count += group.count();
}
return "";
}
class ItemGroup {
public final String headerText;
public final List<T> list;
public ItemGroup(String headerText, List<T> list) {
this.headerText = headerText;
this.list = list;
}
public int count() {
return list.size();
}
public T item(int position) {
return list.get(position);
}
}
}
you can optimize it for faster performance

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