CODEWITHSUNDEEP
androidfirebasefirebase-realtime-database
Rudro
Rudro

Reputation: 25

How to sum multiple values from firebase

I'm new at android programming as well as firebase. first of all look at the picture

Details image

In there I want to get all the "cost" part in total(sum). I've created the reference like that 

DatabaseReference databaseBazars=firebaseDatabase.getInstance().getReference("BazarList");

now what procedure I can follow to get sum and show it in list view or in a toast message).

I've done this to get all the data from that(BazarList) node . and it perfectly showing on the listview. 

  databaseBazars.addValueEventListener(new ValueEventListener() {

            @Override
            public void onDataChange(DataSnapshot dataSnapshot) {

                 bazarList.clear();
                 for( DataSnapshot ds :dataSnapshot.getChildren()) {
                     Bazar bazar = ds.getValue(Bazar.class);
                     bazarList.add(bazar);
                 }
            BazarList adapter = new BazarList(Bazar_Data_Input.this,bazarList);
                listViewBazars.setAdapter(adapter);
            }


            @Override
            public void onCancelled(DatabaseError databaseError) {

            }
        });

now, how can I get the sum part of the cost. anyone, please help me

here is the Bazar Class 

public class Bazar {
    String bid;
    String date;
    String cost;
    String name;
    String item;

    public Bazar(){

    }

    public Bazar(String bid, String date, String cost, String name,String item) {
        this.bid = bid;
        this.date = date;
        this.cost = cost;
        this.name = name;
        this.item= item;
    }

    public String getBid() {
        return bid;
    }

    public String getDate() {
        return date;
    }

    public String getCost() {
        return cost;
    }

    public String getName() {
        return name;
    }

    public String getItem() {
        return item;
    }
}

Upvotes: 2

Views: 7164

Answers (4)

Joel Kanyi
Joel Kanyi

Reputation: 491

 mReference.addValueEventListener(object : ValueEventListener {
        override fun onDataChange(snapshot: DataSnapshot) {
            if (snapshot.exists()) {
                for (i in snapshot.children) {
                    val item = i.getValue(CartItem::class.java)
                    cartList!!.add(item!!)
                }

                var sum = 0.0
                for (itm: CartItem in cartList!!) {
                    sum += itm.itemPrice.toDouble()
                }
                total_value.text = sum.toString()


                //Initialise my adapter
                mRecyclerView.adapter = CartItemsAdapter(applicationContext, cartList!!)
            }
        }

        override fun onCancelled(error: DatabaseError) {
        }
    })

Upvotes: 0

Alex Mamo
Alex Mamo

Reputation: 138824

To solve this, please use the following code:

databaseBazars.addValueEventListener(new ValueEventListener() {
    @Override
    public void onDataChange(DataSnapshot dataSnapshot) {
        bazarList.clear();
        Integer total = 0;

        for( DataSnapshot ds :dataSnapshot.getChildren()) {
            Bazar bazar = ds.getValue(Bazar.class);
            Integer cost = Integer.valueOf(bazar.getCost());
            total = total + cost;
            bazarList.add(bazar);
        }
        BazarList adapter = new BazarList(Bazar_Data_Input.this,bazarList);
        listViewBazars.setAdapter(adapter);
        Log.d("TAG", total + "");
    }

    @Override
    public void onCancelled(DatabaseError databaseError) {}
});

The output will be: 59512.

Upvotes: 1

rimonmostafiz
rimonmostafiz

Reputation: 1471

databaseBazars.addValueEventListener(new ValueEventListener() {

    @Override
    public void onDataChange (DataSnapshot dataSnapshot){

        bazarList.clear();
        for (DataSnapshot ds : dataSnapshot.getChildren()) {
            Bazar bazar = ds.getValue(Bazar.class);
            bazarList.add(bazar);
        }

        // Iterate and add all costs to sum
        double sum = 0;
        for (Bazar b : bazarList) {
            sum += Double.parseDouble(b.getCost())
        }

        BazarList adapter = new BazarList(Bazar_Data_Input.this, bazarList);
        listViewBazars.setAdapter(adapter);
    }


    @Override
    public void onCancelled (DatabaseError databaseError){

    }
});

Upvotes: 0

Zaid Mirza
Zaid Mirza

Reputation: 3699

when you have bazarList with items from firebase then simply iterate over list and do sum

databaseBazars.addValueEventListener(new ValueEventListener() {

            @Override
            public void onDataChange(DataSnapshot dataSnapshot) {

                 bazarList.clear();
                 for( DataSnapshot ds :dataSnapshot.getChildren()) {
                     Bazar bazar = ds.getValue(Bazar.class);
                     bazarList.add(bazar);
                 }
            BazarList adapter = new BazarList(Bazar_Data_Input.this,bazarList);
                listViewBazars.setAdapter(adapter);
            }

            double sum=getSum(); // at this moment your list have results so call getSum to get SUM


            @Override
            public void onCancelled(DatabaseError databaseError) {

            }
        });

below is code which will do the trick

 private double getSum()
          {
            double sum;
            for( int i = 0; i < bazarList.size(); i++)
                {
                     sum += bazarList.get(i).getCost;  // Assuming Bazar class has getCost Method
                }
            return sum;
          }

Upvotes: 0

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