Arrange by price from Firebase (Android)

Question

My goal is to arrange my products by price, wherein the lowest price would be on top. Currently, the products are being arranged according to its create date. How do I achieve my goal? Thanks in advance.

SampleActivity.java

public class SampleActivity extends AppCompatActivity {

    private RecyclerView rec;
    private DatabaseReference dref;
    private Query dref2;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_sample);

        rec = (RecyclerView) findViewById(R.id.rec);
        rec.setHasFixedSize(true);
        rec.setLayoutManager(new LinearLayoutManager(this));

        String vegmeat_type = getIntent().getExtras().get("vegmeat_type").toString();
        dref = FirebaseDatabase.getInstance().getReference().child("Products");

        dref2 = dref.orderByChild("name").startAt(vegmeat_type).endAt(vegmeat_type);
    }

    public static class FeedViewHolder extends RecyclerView.ViewHolder{

        View mView;
        public FeedViewHolder(View itemView){
            super(itemView);
            mView = itemView;

        }
        public void setPrice(String Price){
            TextView price = (TextView) mView.findViewById(R.id.TVPrice);
            price.setText(Price);

        }

        public void setStallname(String StallName){
            TextView stallname = (TextView) mView.findViewById(R.id.TVStallName);
            stallname.setText(StallName);
        }



    }

    protected void onStart() {
        super.onStart();

        FirebaseRecyclerAdapter<prive, FeedViewHolder> firebaseRecyclerAdapter = new FirebaseRecyclerAdapter<prive, FeedViewHolder>(
                prive.class,
                R.layout.row,
                FeedViewHolder.class,
                dref2

        ) {
            @Override
            protected void populateViewHolder(FeedViewHolder viewHolder, prive model, int position) {
                viewHolder.setPrice(model.getPrice());
                viewHolder.setStallname(model.getStallname());
            }
        };
        rec.setAdapter(firebaseRecyclerAdapter);
    }
}

Here's a screenshot from my database

Possible duplicate of [Display posts in descending posted order](https://stackoverflow.com/questions/25611356/display-posts-in-descending-posted-order) — Reaz Murshed, Apr 18 '18 at 16:19
@ReazMurshed except that one is in JS and this one is Android — Levi Moreira, Apr 18 '18 at 16:23

score 0 · Answer 1 · answered Apr 18 '18 at 16:26

You can use something like this:

angularFireDB: AngularFireDatabase;
yourProducts: AngularFireList<any>;
orderedProducts: Observable<any[]>;
this.yourProducts = this.angularFireDB.list('/products');
this.orderedProducts = this.yourProducts.valueChanges().map(res => res.sort((a, b) => a.price < b.price ? -1 : 1));

You need to use AngularFireDatabase class to get your database data.

score 0 · Answer 2 · answered Apr 18 '18 at 16:30

0

You need to do the following:

DatabaseReference ref=FirebaseDatabase.getInstance().getReference();
ref.child("Products").orderByChild("price");

more info here:

https://firebase.google.com/docs/database/android/lists-of-data#data-order

answered Apr 18 '18 at 16:30

Peter Haddad

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When I did that, the application would display every product, and still not arranging it by price :( Also, I need the startAt(vegmeat_type) and endAt.. for the system to get the specific product – justlovly Apr 18 '18 at 17:10
you cant use startAt(type) with orderByChild(price) – Peter Haddad Apr 18 '18 at 17:22

Arrange by price from Firebase (Android)

2 Answers2