how to add google map marker from firebase database

Question

I want to retrieve location markers from firebase database but I can\'t see any markers after running this code. I tried to make EventListener but the map runs

Answer 1

You need to use a ValueEventListener to obtain data from the Firebase database. This is explained in the documentation.

@Override
public void onMapReady(GoogleMap googleMap) {
    mMap = googleMap;
    DatabaseReference ref = FirebaseDatabase.getInstance().getReference();

    ref.addListenerForSingleValueEvent(new ValueEventListener() {
        @Override
        public void onDataChange(DataSnapshot dataSnapshot) {
            if (dataSnapshot.exists()) {
                double location_left = dataSnapshot.child("location_left").getValue(Double.class);
                double location_right = dataSnapshot.child("location_right").getValue(Double.class);
                LatLng sydney = new LatLng(location_left, location_right);
                mMap.addMarker(new MarkerOptions().position(sydney).title("Marker in Sydney"));
                mMap.moveCamera(CameraUpdateFactory.newLatLngZoom(sydney,18));
            } else {
                Log.e(TAG, "onDataChange: No data");
            }

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