从 RecyclerView 中删除未使用的项目

Question

I want to show the hospitals near me and also in firestore.So I gave condition that if the hospital near to me within radius of 1 km are equal to those hospital in my firestore data will show in the RecyclerView. Its working that its showing as per condition but if their is four hospital near me and among those One is in my firestore then its showing one hospital name and also showing other three items in RecyclerView as blank which is not in the firestore.

Code of RecyclerView Adapter

public class HospitalAdapter extends RecyclerView.Adapter<HospitalAdapter.MyViewHolder> {
        ArrayList<HospitalData> hospitalDataList;
        Context context;
        private int lastPosition = -1;
        private FirebaseFirestore fStore;
    
        public HospitalAdapter(ArrayList<HospitalData> hospitalDataList, Context context) {
            this.hospitalDataList = hospitalDataList;
            this.context = context;
        }
    
        @NonNull
        @Override
        public MyViewHolder onCreateViewHolder(@NonNull ViewGroup viewGroup, int i) {
            View itemView = LayoutInflater.from(viewGroup.getContext())
                    .inflate(R.layout.hospital_list_view, viewGroup, false);
    
            return new MyViewHolder(itemView);
    
        }
    
    
        @Override
        public void onBindViewHolder(final MyViewHolder viewHolder, final int i) {
            final HospitalData data = hospitalDataList.get(i);
    
            fStore= FirebaseFirestore.getInstance();
            Query query=fStore.collection("Hospital");
            query.get().addOnCompleteListener(new OnCompleteListener<QuerySnapshot>() {
                @Override
                public void onComplete(@NonNull Task<QuerySnapshot> task) {
                    if(task.isSuccessful()){
                        for(QueryDocumentSnapshot queryDocumentSnapshot: Objects.requireNonNull(task.getResult())){
                            if(queryDocumentSnapshot.getString("Name").equals(data.hospitalName)){
    
                                viewHolder.name.setText(data.hospitalName);
                                viewHolder.distance.setText(data.distance + " Km");
                                viewHolder.rating.setText(data.rating);
    
                                setAnimation(viewHolder.parent, i);
                                viewHolder.parent.setOnClickListener(new View.OnClickListener() {
                                    @Override
                                    public void onClick(View view) {
                                        Intent intent = new Intent(context, HospitalDepartment.class);
                                        intent.putExtra("hospitalName", data.hospitalName);
                                        intent.putExtra("Latitude",String.valueOf(data.lat));
                                        intent.putExtra("Longitude",String.valueOf(data.lon));
                                        context.startActivity(intent);
                                    }
                                });
    
                            }
                        }
                    }
                }
            });
    
    
    
        }
    
        private void setAnimation(View viewToAnimate, int position) {
            // If the bound view wasn't previously displayed on screen, it's animated
            if (position > lastPosition) {
                Animation animation = AnimationUtils.loadAnimation(context, android.R.anim.slide_in_left);
                viewToAnimate.startAnimation(animation);
                lastPosition = position;
            }
        }
    
        @Override
        public int getItemCount() {
            return hospitalDataList.size();
        }
    
        static class MyViewHolder extends RecyclerView.ViewHolder {
            TextView name, distance, rating;
            ConstraintLayout parent;
    
            public MyViewHolder(View itemView) {
                super(itemView);
                parent = itemView.findViewById(R.id.parent);
                name = itemView.findViewById(R.id.hName);
                distance = itemView.findViewById(R.id.hDistance);
                rating = itemView.findViewById(R.id.hRating);
            }
        }

Screen Shots

Answer 1

The item count of a recycler view is determined by the getItemCount() method. So, to solve your problem, the simplest I can think of is have a member variable that holds the size of the recycler view in your adapter class. And return that in getItemCount() method. Now you are going to update this size member variable in your onComplete() method according to the size of the result list received. After that, call notifyDataSetChanged() to update your recycler view accordingly.

Now while this may solve your problem, I think you do not have any need to pass the ArrayList with all hospital data to your adapter since you are not displaying all of them anyway. I would suggest you to move the fetch operation of FireStore data to your activity. So fetch the data, compare it with your all HospitalData list and create another List having only the Hospitals that match and feed this particular List to your recycler view.

Answer 2

Don't fetch Hospitals list every time on BindViewHolder , it is a bad practice, instead fetch the hospitals from firestore and filter the data prior to setting data to adapter like below

    ArrayList<HospitalData> hospitalDataList = new ArrayList<>();//fill this with local data
    Query query=fStore.collection("Hospital");
    query.get().addOnCompleteListener(new OnCompleteListener<QuerySnapshot>() {
       @Override
       public void onComplete(@NonNull Task<QuerySnapshot> task) {
           if(task.isSuccessful()){
              ArrayList<QueryDocumentSnapshot> fireStoreData = task.getResult();
               for(HospitalData data: hospitalDataList){
                   for(QueryDocumentSnapshot fireData: fireStoreData){
                         if(queryDocumentSnapshot.getString("Name").equals(list.get(finalI1).name)){
                                HospitalData data = new HospitalData(list.get(finalI1).name, numberFormat.format(distanceKilometer), list.get(finalI1).rating.toString() + "/5.0", true,list.get(finalI1).latitude,list.get(finalI1).longitude);
                                hospitalDataList.add(data);
                         }
                    }
               }
               hospitalAdapter.notifyDataSetChanged();
           }
       }               
  });

Answer 3

in hospital_list_view.xml setVisibility to GONE to parent layout

Answer 4

    RecyclerView recyclerView = findViewById(R.id.recycler_view);
            HospitalAdapter hospitalAdapter = new HospitalAdapter((ArrayList<HospitalData>) hospitalDataList, HospitalListActivity.this);
            RecyclerView.LayoutManager manager = new LinearLayoutManager(this);
            recyclerView.setLayoutManager(manager);
            recyclerView.setAdapter(hospitalAdapter);   
    
    
     fStore= FirebaseFirestore.getInstance();
                    Query query=fStore.collection("Hospital");
                    final int finalI1 = i;
                    query.get().addOnCompleteListener(new OnCompleteListener<QuerySnapshot>() {
                        @Override
                        public void onComplete(@NonNull Task<QuerySnapshot> task) {
                            if(task.isSuccessful()){
                                for(QueryDocumentSnapshot queryDocumentSnapshot: Objects.requireNonNull(task.getResult())){
                                    if(queryDocumentSnapshot.getString("Name").equals(list.get(finalI1).name)){
                                        HospitalData data = new HospitalData(list.get(finalI1).name, numberFormat.format(distanceKilometer), list.get(finalI1).rating.toString() + "/5.0", true,list.get(finalI1).latitude,list.get(finalI1).longitude);
                                        hospitalDataList.add(data);
        
                                    }
                                }
                            }
                        }
                    });
hospitalAdapter.notifyDataSetChanged();

Problem is in hospitalDataList.add(data); not storing data and sending to adapter.Inside the condition if(queryDocumentSnapshot.getString("Name").equals(list.get(finalI1).name)) when I printing list.get(finalI1).name) in log then its printing corectly but problem is not storing data and sending to adapter.