How do I get specific values from Firebase Realtime and collect all of them to show the user the total value of all children inside the sales list android studio - with java

Get specific values from Firebase Realtime and collect their values android studio - with java

public class SalesFragment extends Fragment {

TextView otherSalesValue, otherEarnsValue;

DatabaseReference databaseReference;

int sale;

String currentUserId;

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    // Inflate the layout for this fragment
    ViewGroup root = (ViewGroup) inflater.inflate(R.layout.fragment_sales, container, false);

    currentUserId = FirebaseAuth.getInstance().getCurrentUser().getUid();

    databaseReference = FirebaseDatabase.getInstance().getReference("sales");

    otherSalesValue = root.findViewById(R.id.other_sales_value);
    otherEarnsValue = root.findViewById(R.id.other_earns_value);

    databaseReference.child(currentUserId)
            .addValueEventListener(new ValueEventListener() {
        @Override
        public void onDataChange(DataSnapshot dataSnapshot) {
            for (DataSnapshot uniqueKeySnapshot : dataSnapshot.getChildren()) {
                for (DataSnapshot booksSnapshot : uniqueKeySnapshot.child("total").getChildren()) {
                    String sales = booksSnapshot.getValue(String.class);
                    try {
                        sale = Integer.parseInt(sales);
                    } catch (NumberFormatException ex) {
                        ex.printStackTrace();
                    }

                    sale =  sale;

                    otherEarnsValue.setText(String.valueOf(sale));
                }
            }
        }
        @Override
        public void onCancelled(DatabaseError databaseError) {

        }
    });

    return root;
}

}

CodePudding user response：

The sales node you read has two dynamic child levels under it, so you need two nested loops over getChildren() before you can get the total property.

databaseReference.child(currentUserId)
        .addValueEventListener(new ValueEventListener() {
    @Override
    public void onDataChange(DataSnapshot dataSnapshot) {
        for (DataSnapshot userSnapshot : dataSnapshot.getChildren()) {
            for (DataSnapshot dateSnapshot : userSnapshot.getChildren()) {
                                                     //