HomeFragment.java

package com.team10.wastetomoney.buyerFragment;

import android.os.Bundle;
import android.support.annotation.NonNull;
import android.support.v4.app.Fragment;
import android.support.v7.widget.DefaultItemAnimator;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
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.FirebaseDatabase;
import com.google.firebase.database.ValueEventListener;
import com.team10.wastetomoney.R;
import com.team10.wastetomoney.adapter.AddSellListAdapter;
import com.team10.wastetomoney.adapter.SellAdapter;
import com.team10.wastetomoney.model.SellModel;
import com.team10.wastetomoney.model.SellerModel;

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

import io.reactivex.Observable;
import io.reactivex.Observer;
import io.reactivex.android.schedulers.AndroidSchedulers;
import io.reactivex.disposables.CompositeDisposable;
import io.reactivex.disposables.Disposable;
import io.reactivex.functions.BiFunction;
import io.reactivex.schedulers.Schedulers;

public class HomeFragment extends Fragment {

    private SellAdapter mAdapter;
    RecyclerView recyclerView;
    private List<SellModel.Sell> sellList = new ArrayList<>();
    private AddSellListAdapter addSellListAdapter;
    CompositeDisposable mCompositeDisposable;

    public HomeFragment() {
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.fragment_post, container, false);

        mCompositeDisposable = new CompositeDisposable();

        addSellListAdapter = new AddSellListAdapter(getContext(), sellList);

        recyclerView = view.findViewById(R.id.recycler_view);
        RecyclerView.LayoutManager layoutManager = new LinearLayoutManager(getContext());
        recyclerView.setLayoutManager(layoutManager);
        recyclerView.setItemAnimator(new DefaultItemAnimator());
        recyclerView.setAdapter(addSellListAdapter);

        bindFirebase();

        bindData();
        return view;


    }

    private void bindFirebase() {
        FirebaseDatabase.getInstance().getReference().child("SellTable").addValueEventListener(new ValueEventListener() {
            @Override
            public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
                List<SellModel.Sell> sellList = new ArrayList<>();
                for (DataSnapshot ds : dataSnapshot.getChildren()) {
                    SellModel.Sell sell = ds.getValue(SellModel.Sell.class);
                    sell.setSellId(ds.getKey());
                    sellList.add(sell);
                }
//                observer.onNext(sellList);
            }

            @Override
            public void onCancelled(@NonNull DatabaseError databaseError) {
//                observer.onError(databaseError.toException());
            }
        });
    }

    private void bindData() {
        Observable.combineLatest(
                getAllSell(),
                getAllSeller(),
                new BiFunction<List<SellModel.Sell>, List<SellerModel.Seller>, List<SellModel.Sell>>() {
                    @Override
                    public List<SellModel.Sell> apply(List<SellModel.Sell> sell, List<SellerModel.Seller> sellerModel) throws Exception {
                        List<SellModel.Sell> finalItem = new ArrayList<>();
                        for (SellModel.Sell item : sell) {
                            boolean isHas = false;
                            for (int index = 0; index < sellerModel.size() && !isHas; index++) {
                                if (item.getSellerId().equals(sellerModel.get(index).getSellerId())) {
                                    isHas = true;
                                    SellModel.Sell foundItem = item;
                                    foundItem.setSellerName(sellerModel.get(index).getSellerName());
                                    foundItem.setSellerImage(sellerModel.get(index).getSellerImage());
                                    foundItem.setSellerCity(sellerModel.get(index).getSellerCity());
                                    foundItem.setSellerTownship(sellerModel.get(index).getSellerTownship());
                                    finalItem.add(foundItem);
                                }
                            }
                        }
                        return finalItem;
                    }
                }
        ).subscribeOn(Schedulers.io())
                .observeOn(AndroidSchedulers.mainThread())
                .subscribe(new Observer<List<SellModel.Sell>>() {
                    @Override
                    public void onSubscribe(Disposable d) {
                        mCompositeDisposable.add(d);
                    }

                    @Override
                    public void onNext(List<SellModel.Sell> sellList) {
                        addSellListAdapter.swipeData(sellList);
                    }

                    @Override
                    public void onError(Throwable e) {
                        e.printStackTrace();
                    }

                    @Override
                    public void onComplete() {

                    }
                });
    }

    private Observable<List<SellModel.Sell>> getAllSell() {
        return new Observable<List<SellModel.Sell>>() {
            @Override
            protected void subscribeActual(final Observer<? super List<SellModel.Sell>> observer) {
                FirebaseDatabase.getInstance().getReference().child("SellTable").addValueEventListener(new ValueEventListener() {
                    @Override
                    public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
                        List<SellModel.Sell> sellList = new ArrayList<>();
                        for (DataSnapshot ds : dataSnapshot.getChildren()) {
                            SellModel.Sell sell = ds.getValue(SellModel.Sell.class);
                            sell.setSellId(ds.getKey());
                            sellList.add(sell);
                        }
                        observer.onNext(sellList);
                    }

                    @Override
                    public void onCancelled(@NonNull DatabaseError databaseError) {
                        observer.onError(databaseError.toException());
                    }
                });
            }
        };
    }

    private Observable<List<SellerModel.Seller>> getAllSeller() {
        return new Observable<List<SellerModel.Seller>>() {
            @Override
            protected void subscribeActual(final Observer<? super List<SellerModel.Seller>> observer) {
                FirebaseDatabase.getInstance().getReference().child("SellerTable").addValueEventListener(new ValueEventListener() {
                    @Override
                    public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
                        List<SellerModel.Seller> userList = new ArrayList<>();
                        for (DataSnapshot ds : dataSnapshot.getChildren()) {
                            SellerModel.Seller user = ds.getValue(SellerModel.Seller.class);
                            user.setSellerId(ds.getKey());
                            userList.add(user);
                        }
                        observer.onNext(userList);
                    }

                    @Override
                    public void onCancelled(@NonNull DatabaseError databaseError) {
                        observer.onError(databaseError.toException());
                    }
                });
            }
        };
    }

    @Override
    public void onStop() {
        super.onStop();
        mCompositeDisposable.clear();
    }
}