Products.java

package com.rahulmishra.sarasmelaapp.Fragments;

import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.text.Editable;
import android.text.TextWatcher;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

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 com.mancj.materialsearchbar.MaterialSearchBar;
import com.rahulmishra.sarasmelaapp.R;
import com.rahulmishra.sarasmelaapp.Utils.GridAutoFitLayoutManager;
import com.rahulmishra.sarasmelaapp.activites.CategoryActivity;
import com.rahulmishra.sarasmelaapp.adapters.CategoriesRecyclerAdapter;
import com.rahulmishra.sarasmelaapp.adapters.ProductsRecyclerAdapter;
import com.rahulmishra.sarasmelaapp.models.CategoryEntity;
import com.rahulmishra.sarasmelaapp.models.ProductEntity;

import java.util.ArrayList;
import java.util.List;

public class Products extends Fragment {

    private MaterialSearchBar searchBar;
    private RecyclerView categories ;
    private List<CategoryEntity> categoryList ;
    private List<ProductEntity> searchList ;
    private ProductsRecyclerAdapter searchListRecyclerAdapter ;
    private CategoriesRecyclerAdapter categoriesRecyclerAdapter ;
    private DatabaseReference productsRef;

    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        return inflater.inflate(R.layout.fragment_products, container, false) ;
    }

    @Override
    public void onViewCreated(final View view, @Nullable Bundle savedInstanceState) {
        categories = view.findViewById(R.id.categories) ;

        categoryList = feed_data() ;
        categoriesRecyclerAdapter = new CategoriesRecyclerAdapter(categoryList, view.getContext());
        final LinearLayoutManager verticalLayoutManager = new LinearLayoutManager
                (view.getContext(), LinearLayoutManager.VERTICAL, false);
        categories.setLayoutManager(verticalLayoutManager);
        categories.setNestedScrollingEnabled(false);
        categories.setAdapter(categoriesRecyclerAdapter);

        searchList = new ArrayList<>() ;

        searchBar = view.findViewById(R.id.searchBar);
        searchBar.setCardViewElevation(10);
        searchBar.setOnSearchActionListener(new MaterialSearchBar.OnSearchActionListener() {
            @Override
            public void onSearchStateChanged(boolean enabled) {
                if(enabled) {
                    GridAutoFitLayoutManager layoutManager = new GridAutoFitLayoutManager(view.getContext(), 300);
                    categories.setLayoutManager(layoutManager);
                    categories.setNestedScrollingEnabled(false);

                    searchListRecyclerAdapter = new ProductsRecyclerAdapter(searchList, view.getContext()) ;
                    categories.setAdapter(searchListRecyclerAdapter);

                } else {
                    onButtonClicked(MaterialSearchBar.BUTTON_BACK) ;
                }
            }

            @Override
            public void onSearchConfirmed(CharSequence text) {
                productsRef = (DatabaseReference) FirebaseDatabase.getInstance().getReference("products")
                        .orderByValue()
                        .startAt((String) text)
                        .endAt(text+"\uf8ff").addValueEventListener(new ValueEventListener() {
                            @Override
                            public void onDataChange(DataSnapshot dataSnapshot) {

                            }

                            @Override
                            public void onCancelled(DatabaseError databaseError) {

                            }
                        });

                searchList = CategoryActivity.feed_data() ;
                searchListRecyclerAdapter = new ProductsRecyclerAdapter(searchList, view.getContext()) ;
//                searchListRecyclerAdapter.notifyDataSetChanged();
                categories.setAdapter(searchListRecyclerAdapter);
            }

            @Override
            public void onButtonClicked(int buttonCode) {
                if(buttonCode == MaterialSearchBar.BUTTON_BACK) {
                    categoriesRecyclerAdapter = new CategoriesRecyclerAdapter(categoryList, view.getContext());
                    LinearLayoutManager verticalLayoutManager = new LinearLayoutManager
                            (view.getContext(), LinearLayoutManager.VERTICAL, false);
                    categories.setLayoutManager(verticalLayoutManager);
                    categories.setNestedScrollingEnabled(false);
                    categories.setAdapter(categoriesRecyclerAdapter);
                }
            }
        });
    }

    List<CategoryEntity> feed_data() {
        List<CategoryEntity> categoryList = new ArrayList<>();

        categoryList.add(new CategoryEntity("handicrafts","handicrafts","Buy Handicrafts!", "Collection from\nacross India", R.drawable.handicrafts)) ;
        categoryList.add(new CategoryEntity("clothes","clothes","Buy Clothes!", "Collection from\nacross India", R.drawable.clothes)) ;
        categoryList.add(new CategoryEntity("homedecor","home decor", "Buy Home\nDecor!", "Collection from\nacross India", R.drawable.decor)) ;
        categoryList.add(new CategoryEntity("toys","toys","Buy Toys", "Collection from\nacross India", R.drawable.toys)) ;
        categoryList.add(new CategoryEntity("edibles","edibles","Buy Packed\nEdibles", "Collection from\nacross India", R.drawable.edibles)) ;
        categoryList.add(new CategoryEntity( "misc","misc","Miscellaneous", "", R.drawable.more)) ;

        return categoryList ;
    }
}