How to filter RecyclerView inside a Fragment using SearchView

Question

I'm just new to Android and have to build an App using MVVM and Fragments. I have my Recyclerview within Basefragment and i want to filter it using SearchView. When I type something on it, it doesn't filter the list (nothing happens).

If someone could solve it, then I would be really very thankful.

Basefragment

public class BaseFragment extends Fragment implements CarAdapterEvent, SearchView.OnQueryTextListener {

    private RecyclerView recyclerView;
    private RecyclerView.LayoutManager layoutManager;
    private ArrayList<Car>list=new ArrayList<>();
    private MyViewModel myViewModel;
    public RecyclerAdapter recyclerAdapter;

    // Required empty public constructor
    public BaseFragment() { }

    @Override
    public void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
    }
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
    {
        setHasOptionsMenu(true);
        // Inflate the layout for this fragment
        View view= inflater.inflate(R.layout.fragment_base, container, false);
        //Inflate recyclerView
        recyclerView=view.findViewById(R.id.recyclerViewId);
        // define and set LayoutManager
        layoutManager= new GridLayoutManager(requireActivity(),2);
        recyclerView.setLayoutManager(layoutManager);
        //define and set RecyclerView Adapter
        recyclerAdapter = new RecyclerAdapter(list, getContext(),this);
        recyclerView.setAdapter(recyclerAdapter);
        //observer
        myViewModel= new ViewModelProvider(this).get(MyViewModel.class);
        myViewModel.getGetAllCars().observe(getViewLifecycleOwner(), new Observer<List<Car>>() {
           @Override
           public void onChanged(List<Car> cars) {
               recyclerAdapter.setData(cars);
           }
       });
        return view;
    }
    @Override
    public void onCreateOptionsMenu(@NonNull Menu menu, @NonNull MenuInflater inflater) {
        inflater = getActivity().getMenuInflater();
        inflater.inflate(R.menu.search_menu, menu);
        MenuItem searchItem = menu.findItem(R.id.action_search);
        SearchView searchView = (SearchView)  searchItem.getActionView();
        searchView.setOnQueryTextListener(this);
    }
    @Override
    public boolean onQueryTextSubmit(String query) {
        return true;
    }
    @Override
    public boolean onQueryTextChange(String newText) {
        if (newText == null || newText.trim().isEmpty()){
            recyclerAdapter.setFilter(list);
            return false;
        }
        newText= newText.toLowerCase();
        ArrayList<Car> filteredList = new ArrayList<>();
        for (Car carItem : list){
            if (carItem.getCarModel().toLowerCase().contains(newText)){
                filteredList.add(carItem);
            }
        }
        recyclerAdapter.setFilter(filteredList);
        return true;
    }
    @Override
    public void onDeleteClicked(Car car) {
      myViewModel.deleteCar(car);
      MainActivity.fragmentManager.beginTransaction().replace(R.id.container,new BaseFragment(),null).commit();
    }
    @Override
    public void onUpdateClicked(Car car) {
        myViewModel.updateCar(car);
        MainActivity.fragmentManager.beginTransaction().replace(R.id.container,new UpdateFragment(),null).commit();
    }


}

Adapter

public class RecyclerAdapter extends RecyclerView.Adapter<RecyclerAdapter.MyViewHolder> {

   private List<Car>list;
   private List<Car> listFull;
   private Context context;
   private MyViewModel myViewModel;
   private CarAdapterEvent carAdapterEvent;
   //Constructor
    public RecyclerAdapter(List<Car> list,Context context,CarAdapterEvent carAdapterEvent ) {
        this.list = list;
        this.context=context;
        this.carAdapterEvent=carAdapterEvent;
    }
    // make a copy of list tu use it later for filter recyclerView
    public RecyclerAdapter(List<Car> list) {
        this.list = list;
        listFull = new ArrayList<>(list);
    }

    @NonNull
    @Override
    public MyViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.car_item,parent,false);
        MyViewHolder myViewHolder = new MyViewHolder(view);
        context=parent.getContext();
        return myViewHolder;
    }
    @Override
    public void onBindViewHolder(@NonNull MyViewHolder holder, int position) {
        Car car = list.get(position);
        holder.tvModel.setText(car.getCarModel());
        holder.tvColor.setText(car.getCarColor());
        holder.tvDpl.setText(car.getCarDpl());
        holder.tvDescription.setText(car.getCarDescription());
        holder.tvPrice.setText(car.getCarPrice());
    }
    @Override
    public int getItemCount() {
        if(list !=null)
        {
            return list.size();
        }
        else return 0;
    }
   public void setData(List<Car>list){
       this.list=list;
       notifyDataSetChanged();
   }
    public  void setFilter(ArrayList<Car> carList){
        carList.clear();
        carList.addAll(carList);
        notifyDataSetChanged();
    }

    // generate ViewHolder
    public class MyViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
        TextView tvModel;
        TextView tvColor;
        TextView tvDpl;
        TextView tvDescription;
        TextView tvPrice;
        Button btnDelete;
        Button updateButtonOnRecyclerView;
        // Constructor of ViewHolder
        public MyViewHolder(@NonNull View itemView) {
            super(itemView);
            // Inflate the views
            tvModel=itemView.findViewById(R.id.model);
            tvColor=itemView.findViewById(R.id.color);
            tvDescription=itemView.findViewById(R.id.description);
            tvDpl=itemView.findViewById(R.id.dpl);
            tvPrice=itemView.findViewById(R.id.price);
            btnDelete=itemView.findViewById(R.id.btn_delete);
            updateButtonOnRecyclerView =itemView.findViewById(R.id.btn_update);

            // Listener for Delete button
            btnDelete.setOnClickListener(this);
            btnDelete.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    int position = getAdapterPosition();
                    carAdapterEvent.onDeleteClicked(list.get(position));
                }
            });
            //Listener for update button
            updateButtonOnRecyclerView.setOnClickListener(this);
            updateButtonOnRecyclerView.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    int position = getAdapterPosition();
                    carAdapterEvent.onUpdateClicked(list.get(position));
                }
            });
        }
       private void CreateAlertDialoge()
       {
           AlertDialog.Builder builder =new AlertDialog.Builder(context);
           builder.setMessage("Are you sure to delete");
           builder.setPositiveButton("Yes", new DialogInterface.OnClickListener() {
               @Override
               public void onClick(DialogInterface dialog, int which) {

                   Car car = new Car();
                   int ID=list.get(getAdapterPosition()).getCarId();
                   car.setCarId(ID);


                  myViewModel.deleteCar(car);


                   MainActivity.fragmentManager.beginTransaction().replace(R.id.container,new BaseFragment(),null).commit();

                   Toast.makeText(context, "Yes", Toast.LENGTH_SHORT).show();
               }
           });
           builder.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
               @Override
               public void onClick(DialogInterface dialog, int which) {
                   Toast.makeText(context, "no", Toast.LENGTH_SHORT).show();

               }
           });
           builder.create();
           builder.show();
       }
        @Override
        public void onClick(View v) { }
    }

MainActivity

public class MainActivity extends AppCompatActivity {

    public static FragmentManager fragmentManager;
     static RoomDatabase roomDatabase;
     private BottomNavigationView bottomNavigationView;

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        return true;
    }
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        bottomNavigationView=findViewById(R.id.bottom_nav);
        bottomNavigationView.setOnNavigationItemSelectedListener(bottomNavMethod);
        if (savedInstanceState != null) {
            // replace fragment
           // getSupportFragmentManager().beginTransaction().replace(R.id.container,new BaseFragment()).commit();
            FragmentManager fragmentManager = getSupportFragmentManager();
            FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
            // make an instance of BaseFragment
            BaseFragment baseFragment=new BaseFragment();
            fragmentTransaction.replace(R.id.container,baseFragment)
                    .addToBackStack(null).commit();
        }
        //for manager
        fragmentManager=getSupportFragmentManager();
        roomDatabase= Room.databaseBuilder(getApplicationContext(), RoomDatabase.class,
                "mydb").allowMainThreadQueries()
                .build();

       if (findViewById(R.id.container)!=null)
       {
           if(savedInstanceState!=null)
           {
               return;
           }
       }
        fragmentManager.beginTransaction().add(R.id.container,
                new BaseFragment(),null).commit();
    }

    private BottomNavigationView.OnNavigationItemSelectedListener bottomNavMethod= new BottomNavigationView.OnNavigationItemSelectedListener() {
        @Override
        public boolean onNavigationItemSelected(@NonNull MenuItem item) {
            Fragment fragment=null;
            switch (item.getItemId())
            {
                case R.id.base_fragment_id:
                    fragment=new BaseFragment();
                    break;
                case R.id.input:
                    fragment=new AddCarFragment();
                    break;
                case R.id.settings:
                    fragment=new SettingsFragment();
                    break;
            }
            getSupportFragmentManager().beginTransaction().replace(R.id.container,fragment).commit();
            return true;
        }
    };

Answer 1

Have you implemented Filterable on recycleview adapter ? I guess, you haven't try moving the filter code you did, onto the overridden method of filterable. you can try this tutorial for further knowledge