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SetAdapter cannot be applied as the adapter of FirestoreRecyclerviewAdapter

I am working on a chat app with firebase and I want to fitch the user information to the recyclerview...my code is correct by when I set the adapter to the recycler view its show an error.
Here is my code:
package com.abdelatif.chatapp;
import android.graphics.Color;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.Toast;
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.fragment.app.Fragment;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;
import androidx.recyclerview.widget.RecyclerView.ViewHolder;
import com.firebase.ui.firestore.FirestoreRecyclerAdapter;
import com.firebase.ui.firestore.FirestoreRecyclerOptions;
import com.google.firebase.auth.FirebaseAuth;
import com.google.firebase.firestore.FirebaseFirestore;
import com.google.firebase.firestore.Query;
import com.squareup.picasso.Picasso;
public class ChatFragment extends Fragment {
private FirebaseFirestore firebaseFirestore;
LinearLayoutManager linearLayoutManager;
private FirebaseAuth firebaseAuth;
ImageView mimageviewofuser;
FirestoreRecyclerAdapter<FireBaseModel, NoteViewHolder> chatAdapter = null;
RecyclerView mrecyclerview;
#Nullable
#Override
public View onCreateView(#NonNull LayoutInflater inflater, #Nullable ViewGroup container, #Nullable Bundle savedInstanceState) {
View v=inflater.inflate(R.layout.chatfragment,container,false);
firebaseAuth=FirebaseAuth.getInstance();
firebaseFirestore= FirebaseFirestore.getInstance();
mrecyclerview=v.findViewById(R.id.recyclerView);
// Query query=firebaseFirestore.collection("Users");
Query query=firebaseFirestore.collection("Users").whereNotEqualTo("uid",firebaseAuth.getUid());
FirestoreRecyclerOptions<FireBaseModel> allusername=new FirestoreRecyclerOptions.Builder<FireBaseModel>().setQuery(query,FireBaseModel.class).build();
chatAdapter=new FirestoreRecyclerAdapter<FireBaseModel, NoteViewHolder>(allusername) {
#Override
protected void onBindViewHolder(#NonNull NoteViewHolder noteViewHolder, int i, #NonNull FireBaseModel firebasemodel) {
noteViewHolder.particularusername.setText(firebasemodel.getName());
String uri=firebasemodel.getImage();
Picasso.get().load(uri).into(mimageviewofuser);
if(firebasemodel.getStatus().equals("Online"))
{
noteViewHolder.statusofuser.setText(firebasemodel.getStatus());
noteViewHolder.statusofuser.setTextColor(Color.GREEN);
}
else
{
noteViewHolder.statusofuser.setText(firebasemodel.getStatus());
}
noteViewHolder.itemView.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Toast.makeText(getActivity(), "contactClicked", Toast.LENGTH_SHORT).show();
}
});
}
#NonNull
#Override
public NoteViewHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
View view=LayoutInflater.from(parent.getContext()).inflate(R.layout.chat_view_layout,parent,false);
return new NoteViewHolder(view);
}
};
mrecyclerview.setHasFixedSize(true);
linearLayoutManager=new LinearLayoutManager(getContext());
linearLayoutManager.setOrientation(RecyclerView.VERTICAL);
mrecyclerview.setLayoutManager(linearLayoutManager);
mrecyclerview.setAdapter(chatAdapter);
chatAdapter.startListening();
return v;
}
public class NoteViewHolder extends android.support.v7.widget.RecyclerView.ViewHolder
{
private TextView particularusername;
private TextView statusofuser;
public NoteViewHolder(#NonNull View itemView) {
super(itemView);
particularusername=itemView.findViewById(R.id.nameOfUser);
statusofuser=itemView.findViewById(R.id.statusOfUser);
mimageviewofuser=itemView.findViewById(R.id.imageViewOfUser);
}
}
}
the error is in the line: mrecyclerview.setAdapter(chatAdapter);
and the error is:
'setAdapter(androidx.recyclerview.widget.RecyclerView.Adapter)' in 'androidx.recyclerview.widget.RecyclerView' cannot be applied to '(com.firebase.ui.firestore.FirestoreRecyclerAdapter<com.abdelatif.chatapp.FireBaseModel,com.abdelatif.chatapp.ChatFragment.NoteViewHolder>)'
I hope someone give me a solution...i searched many time but nothing.

Make sure you call chatAdapter.startListening(); before calling mrecyclerview.setAdapter(chatAdapter);

How to pass Hashmap to another Activity and show it in Recycler View?

Cart Activity(Here I want to show this hashmap data in Recycler View...Any Help will be Highly Appreciated)
package com.example.silkenscoops;
import androidx.appcompat.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Pair;
import java.util.HashMap;
public class CartActivity extends AppCompatActivity {
private HashMap<String, Pair<String,String>> cartMap=new HashMap<>();
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.cart_view);
cartMap= (HashMap<String, Pair<String, String>>) getIntent().getSerializableExtra("h");
}
}
My Adapter class
package com.example.silkenscoops;
import androidx.recyclerview.widget.RecyclerView;
import android.util.Pair;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.TextView;
import androidx.annotation.NonNull;
import com.firebase.ui.database.FirebaseRecyclerAdapter;
import com.firebase.ui.database.FirebaseRecyclerOptions;
import java.util.HashMap;
public class MainAdapter extends FirebaseRecyclerAdapter<Items, MainAdapter.myViewHolder> {
private HashMap<String, Pair<String,String>> cartMap=new HashMap<>();
public MainAdapter(#NonNull FirebaseRecyclerOptions<Items> options) {
super(options);
}
#Override
protected void onBindViewHolder(#NonNull myViewHolder holder, int position, #NonNull Items model) {
holder.Price.setText(model.getPrice());
holder.Product.setText(model.getProduct());
holder.Stock.setText(model.getStock());
holder.increment.setVisibility(View.GONE);
holder.decrement.setVisibility(View.GONE);
holder.add.setOnClickListener(new View.OnClickListener() {
int count=0;
#Override
public void onClick(View v) {
holder.increment.setVisibility(View.VISIBLE);
holder.decrement.setVisibility(View.VISIBLE);
if(count<Integer.parseInt(model.getStock())) {
count++;
holder.add.setText(String.valueOf(count));
cartMap.put(model.getProduct(),new Pair<String,String>(String.valueOf(count),model.getPrice()));
}
holder.decrement.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
if(count>0) {
count--;
holder.add.setText(String.valueOf(count));
cartMap.put(model.getProduct(),new Pair<String,String>(String.valueOf(count),model.getPrice()));
}
if(count<=0){
holder.add.setText("ADD");
holder.increment.setVisibility(View.GONE);
holder.decrement.setVisibility(View.GONE);
cartMap.remove(model.getProduct());
}
}
});
}
});
}
#NonNull
#Override
public myViewHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
View view= LayoutInflater.from(parent.getContext()).inflate(R.layout.display,parent,false);
return new MainAdapter.myViewHolder(view);
}
class myViewHolder extends RecyclerView.ViewHolder{
TextView Product, Price, Stock,add;
ImageView decrement,increment;
public myViewHolder(#NonNull View itemView) {
super(itemView);
Price=itemView.findViewById(R.id.Price);
Product=itemView.findViewById(R.id.Product);
Stock=itemView.findViewById(R.id.Stock);
add=itemView.findViewById(R.id.add);
increment=itemView.findViewById(R.id.increment);
decrement=itemView.findViewById(R.id.decrement);
}
}
public HashMap<String, Pair<String, String>> getCartMap() {
return cartMap;
}
}
My MainActivity(Actually it is the menu list..)
package com.example.silkenscoops;
import androidx.appcompat.app.AppCompatActivity;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;
import android.content.Intent;
import android.os.Bundle;
import android.util.Pair;
import android.view.View;
import android.widget.ImageView;;
import com.firebase.ui.database.FirebaseRecyclerOptions;
import com.google.firebase.database.DatabaseReference;
import com.google.firebase.database.FirebaseDatabase;
import com.google.firebase.database.Query;
import java.util.HashMap;
public class MainItems extends AppCompatActivity {
private RecyclerView recyclerView;
private ImageView cart_btn;
MainAdapter adapter;
DatabaseReference databasereference;
private HashMap<String, Pair<String,String>> cartMap=new HashMap<>();
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main_display);
getSupportActionBar().hide();
cart_btn=findViewById(R.id.cart_btn);
databasereference = FirebaseDatabase.getInstance().getReference();
recyclerView = findViewById(R.id.recyclerView);
recyclerView.setLayoutManager(new LinearLayoutManager(this));
//This is the right Query that should be passed to the setQuery() method
//The fields should stay as in the Items class (I capital)
Query query = FirebaseDatabase.getInstance().getReference().child("Cups");
FirebaseRecyclerOptions<Items> options = new FirebaseRecyclerOptions.Builder<Items>()
.setQuery(query, Items.class)
.build();
adapter = new MainAdapter(options);
recyclerView.setAdapter(adapter);
cart_btn.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
cartMap=adapter.getCartMap();
Intent intent = new Intent(MainItems.this, CartActivity.class);
intent.putExtra("list", cartMap);
startActivity(intent);
}
});
}
#Override
protected void onStart() {
super.onStart();
adapter.startListening();
}
#Override
protected void onStop() {
super.onStop();
adapter.stopListening();
}
}
There is no error , but how am I supposed to pass my hashmap from ActivityMain to Cart Activity and show it in recycler View...I have no idea now and after working and thinking for 10-15 days I'm asking here..Please help me..
Thanks

Unable to fetch data from firestore using firestore recycler adapter getting empty recycler view

I am unable to fetch data from firestore and i am not getting any error and no app crash.
dependencies using:
implementation 'com.firebaseui:firebase-ui-firestore:7.1.1'
implementation 'com.google.firebase:firebase-firestore:22.0.0'
my firestore rules:
service cloud.firestore {
match /databases/{database}/documents {
match /{document=**} {
allow read, write;
}
}
}
my adapter:
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
import androidx.annotation.NonNull;
import androidx.recyclerview.widget.RecyclerView;
import com.firebase.ui.firestore.FirestoreRecyclerAdapter;
import com.firebase.ui.firestore.FirestoreRecyclerOptions;
public class Adapter extends FirestoreRecyclerAdapter<Information, Adapter.nameHolder> {
public Adapter(#NonNull FirestoreRecyclerOptions<Information> options) {
super(options);
}
#Override
protected void onBindViewHolder(#NonNull nameHolder holder, int position, #NonNull Information model) {
holder.myName.setText(model.getMyName());
Log.e("hi",model.getMyName());
}
#NonNull
#Override
public nameHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.name_card,parent,false);
return new nameHolder(v);
}
class nameHolder extends RecyclerView.ViewHolder{
TextView myName;
public nameHolder(#NonNull View itemView) {
super(itemView);
myName = itemView.findViewById(R.id.myName);
}
}
}
Main Class:
import androidx.appcompat.app.AppCompatActivity;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;
import android.os.Bundle;
import android.util.Log;
import android.widget.TextView;
import com.firebase.ui.firestore.FirestoreRecyclerOptions;
import com.google.firebase.auth.FirebaseAuth;
import com.google.firebase.firestore.CollectionReference;
import com.google.firebase.firestore.FirebaseFirestore;
import com.google.firebase.firestore.Query;
public class allNames extends AppCompatActivity {
private TextView nameType;
private RecyclerView myRecyclerView;
private FirebaseAuth fAuth;
private String userId;
private FirebaseFirestore firebaseFirestore = FirebaseFirestore.getInstance();
private CollectionReference collectionReference = firebaseFirestore.collection("Hi");
private Adapter adapter;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_all_names);
nameType = findViewById(R.id.nameType);
myRecyclerView = findViewById(R.id.myRecyclerView);
/*fAuth = FirebaseAuth.getInstance();
userId = fAuth.getCurrentUser().getUid();*/
setUpRecyclerView();
}
private void setUpRecyclerView(){
Query query = collectionReference.orderBy("priority",Query.Direction.DESCENDING);
FirestoreRecyclerOptions<Information> options = new FirestoreRecyclerOptions.Builder<Information>()
.setQuery(query,Information.class).build();
adapter = new Adapter(options);
myRecyclerView.setHasFixedSize(true);
myRecyclerView.setLayoutManager(new LinearLayoutManager(this));
myRecyclerView.setAdapter(adapter);
}
#Override
protected void onStart() {
super.onStart();
adapter.startListening();
}
#Override
protected void onStop() {
super.onStop();
adapter.stopListening();
}
}
I want to fetch only name from firestore.
what can be done?

How to get Int value from an Adapter to Activity in android

I want to get an int value from my adapter class to my activity but I am getting nothing while using this code:
Here is my adapter:
package com.capi.ccecommerceapp.Adapter;
import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.TextView;
import androidx.annotation.NonNull;
import androidx.recyclerview.widget.RecyclerView;
import com.bumptech.glide.Glide;
import com.capi.ccecommerceapp.Model.Cart;
import com.capi.ccecommerceapp.R;
import com.google.firebase.auth.FirebaseAuth;
import com.google.firebase.auth.FirebaseUser;
import com.google.firebase.database.DataSnapshot;
import com.google.firebase.database.DatabaseError;
import com.google.firebase.database.DatabaseReference;
import com.google.firebase.database.FirebaseDatabase;
import com.google.firebase.database.ValueEventListener;
import java.util.List;
public class CartAdapter extends RecyclerView.Adapter<CartAdapter.ViewHolder>
{
private Context context;
private List<Cart> cartList;
private String productImage;
public int overTotalPrice = 0;
public CartAdapter(Context context, List<Cart> cartList ) {
this.context = context;
this.cartList = cartList;
}
#NonNull
#Override
public ViewHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
View view = LayoutInflater.from(context).inflate(R.layout.cart_item, parent, false);
return new ViewHolder(view);
}
#Override
public void onBindViewHolder(#NonNull final ViewHolder holder, final int position) {
holder.cartName.setText(cartList.get(position).getProductName());
holder.cartPrice.setText(cartList.get(position).getProductPrice());
holder.cart_qty.setText(String.valueOf(cartList.get(position).getProductQuantity()));
int oneTypeProductTPrice = ((Integer.parseInt(cartList.get(position).getProductPrice()))) * cartList.get(position).getProductQuantity();
overTotalPrice = overTotalPrice + oneTypeProductTPrice;
/*FirebaseAuth auth = FirebaseAuth.getInstance();
FirebaseUser user = auth.getCurrentUser();*/
/* holder.cartPlus.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
if (cartQty<10)
{
cartQty++;
}
}
});
holder.cartMinus.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
if (cartQty>1)
{
cartQty--;
}
}
});
holder.cart_qty.setText(cartQty);
holder.deleteBtn.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
cartList.remove(cartList.get(position));
}
});*/
/* holder.wishlistBtn.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
if (holder.wishlistBtn.getTag().equals("add"))
{
holder.wishlistBtn.setImageResource(R.drawable.ic_love_fill);
holder.wishlistBtn.setTag("added");
}
else
{
holder.wishlistBtn.setImageResource(R.drawable.love);
holder.wishlistBtn.setTag("add");
}
}
});*/
DatabaseReference reference = FirebaseDatabase.getInstance().getReference()
.child("Products")
.child(cartList.get(position).getProductId())
.child("productImage");
reference.addValueEventListener(new ValueEventListener() {
#Override
public void onDataChange(#NonNull DataSnapshot snapshot)
{
if (snapshot.exists()) {
productImage = snapshot.getValue(String.class);
Glide.with(context).load(productImage).into(holder.cartImage);
}
}
#Override
public void onCancelled(#NonNull DatabaseError error) {
}
});
}
#Override
public int getItemCount() {
return cartList.size();
}
public static class ViewHolder extends RecyclerView.ViewHolder {
ImageView cartImage;
TextView cartName;
TextView cartPrice;
ImageView wishlistBtn;
ImageView deleteBtn;
ImageView cartPlus;
ImageView cartMinus;
TextView cart_qty;
public ViewHolder(#NonNull View itemView) {
super(itemView);
cartImage = itemView.findViewById(R.id.cart_image);
cartName = itemView.findViewById(R.id.cart_name);
cartPrice = itemView.findViewById(R.id.cart_price);
wishlistBtn = itemView.findViewById(R.id.add_to_wishlist);
deleteBtn = itemView.findViewById(R.id.delete_cart);
cartPlus = itemView.findViewById(R.id.cart_add);
cartMinus = itemView.findViewById(R.id.cart_minus);
cart_qty = itemView.findViewById(R.id.cart_quantity);
}
}
}
and here is my activity code where I want to set it in textView:
package com.capi.ccecommerceapp.Fragment;
import android.content.Intent;
import android.os.Bundle;
import androidx.annotation.NonNull;
import androidx.fragment.app.Fragment;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.TextView;
import com.capi.ccecommerceapp.Adapter.CartAdapter;
import com.capi.ccecommerceapp.address.ShiptoActivity;
import com.capi.ccecommerceapp.Model.Cart;
import com.capi.ccecommerceapp.R;
import com.google.firebase.auth.FirebaseAuth;
import com.google.firebase.auth.FirebaseUser;
import com.google.firebase.database.DataSnapshot;
import com.google.firebase.database.DatabaseError;
import com.google.firebase.database.DatabaseReference;
import com.google.firebase.database.FirebaseDatabase;
import com.google.firebase.database.ValueEventListener;
import java.util.ArrayList;
import java.util.List;
public class CartFragment extends Fragment
{
private RecyclerView cartRecyclerView;
private List<Cart> cartList;
private CartAdapter cartAdapter;
private Button next;
private FirebaseAuth auth;
private FirebaseUser user;
private TextView subtotal;
private TextView items;
private TextView shipping;
private TextView totalPrice;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_cart, container, false);
cartRecyclerView = view.findViewById(R.id.cartRecycler);
next = view.findViewById(R.id.checkout_btn);
auth = FirebaseAuth.getInstance();
user = auth.getCurrentUser();
next.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
startActivity(new Intent(getContext(), ShiptoActivity.class));
}
});
subtotal = view.findViewById(R.id.subtotal_price);
items = view.findViewById(R.id.items);
shipping = view.findViewById(R.id.shipping_price);
LinearLayoutManager layoutManager = new LinearLayoutManager(getContext());
cartRecyclerView.setLayoutManager(layoutManager);
cartList = new ArrayList<>();
cartAdapter = new CartAdapter(getContext(), cartList);
cartRecyclerView.setAdapter(cartAdapter);
loadCart();
return view;
}
private void loadCart()
{
DatabaseReference reference = FirebaseDatabase.getInstance().getReference().child("Cart")
.child(user.getUid());
reference.addValueEventListener(new ValueEventListener() {
#Override
public void onDataChange(#NonNull DataSnapshot snapshot) {
for (DataSnapshot dataSnapshot : snapshot.getChildren())
{
Cart cart = dataSnapshot.getValue(Cart.class);
cartList.add(cart);
}
cartAdapter.notifyDataSetChanged();
subtotal.setText("$" + cartAdapter.overTotalPrice);
items.setText("Items("+cartAdapter.getItemCount()+")");
int shippingPrice = (cartAdapter.overTotalPrice / 20);
shipping.setText("$" + shippingPrice);
/*int totalPriceFinal = shippingPrice + cartAdapter.getOverTotalPrice();
totalPrice.setText("$" + totalPriceFinal);*/
}
#Override
public void onCancelled(#NonNull DatabaseError error) {
}
});
}
}
I want to get this int:public int overTotalPrice = 0;
And I am getting it as:subtotal.setText("$"+cartAdapter.overTotalPrice);
Anyone have a solution?
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RecyclerView is not displaying any data from the firestore

I have list of Categories of Subjects in my firestore database and i want it to be displayed in my app ( which i thought can be done by recyclerView).But my RecyclerView is not populating any data.You can see my code below:
Question_list.java
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.util.Log;
import com.google.firebase.firestore.DocumentChange;
import com.google.firebase.firestore.EventListener;
import com.google.firebase.firestore.FirebaseFirestore;
import com.google.firebase.firestore.FirebaseFirestoreException;
import com.google.firebase.firestore.QuerySnapshot;
import java.util.ArrayList;
import java.util.List;
import javax.annotation.Nullable;
public class Question_list extends AppCompatActivity {
private static final String TAG ="Firelog" ;
private RecyclerView mMainList;
private FirebaseFirestore mFirestore;
private CategoryAdapter categoryAdapter;
private List<Categories> list_category;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_question_list);
mMainList = (RecyclerView)findViewById(R.id.main_list_id);
//mMainList.setHasFixedSize(true);
mMainList.setLayoutManager(new LinearLayoutManager(this));
mMainList.setAdapter(categoryAdapter);
mFirestore = FirebaseFirestore.getInstance();
categoryAdapter = new CategoryAdapter(list_category);
list_category = new ArrayList<>();
mFirestore.collection("Questions").addSnapshotListener(new EventListener<QuerySnapshot>() {
#Override
public void onEvent(#Nullable QuerySnapshot queryDocumentSnapshots, #Nullable FirebaseFirestoreException e) {
if(e!=null){
Log.d(TAG, "Error: "+ e.getMessage());
}
for(DocumentChange doc: queryDocumentSnapshots.getDocumentChanges()){
if(doc.getType() == DocumentChange.Type.MODIFIED){
//String document = doc.getDocument().getString("Category");
Categories categories = doc.getDocument().toObject(Categories.class);
list_category.add(categories);
Log.d(TAG, "Category: "+ categories);
categoryAdapter.notifyDataSetChanged();
}
}
}
});
}
}
CategoryAdapter.java
import android.support.annotation.NonNull;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
import java.util.List;
public class CategoryAdapter extends
RecyclerView.Adapter<CategoryAdapter.ViewHolder> {
public List<Categories> list_categorie;
public CategoryAdapter(List<Categories> list_categorie){
this.list_categorie = list_categorie;
}
#NonNull
#Override
public ViewHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.category_list,parent,false);
return new ViewHolder(view);
}
#Override
public void onBindViewHolder(#NonNull ViewHolder holder, int position) {
holder.mCategoryText.setText(list_categorie.get(position).getCategory());
}
#Override
public int getItemCount() {
return list_categorie.size();
}
public class ViewHolder extends RecyclerView.ViewHolder {
View mview;
public TextView mCategoryText;
public ViewHolder(View itemView) {
super(itemView);
mview = itemView;
mCategoryText = (TextView)mview.findViewById(R.id.category_text_id);
}
}
}
Categories.java
public class Categories {
String category;
public Categories(){}
public Categories(String category) {
this.category = category;
}
public String getCategory() {
return category;
}
}
Above are my all java classes. I haven't uploaded my XML file as i think the problem is in the java class.

categoryAdapter = new CategoryAdapter(list_category);
list_category = new ArrayList<>();
list_category should be initialized before passing it to the adapter
list_category = new ArrayList<>();
categoryAdapter = new CategoryAdapter(list_category);