ref = FirebaseDatabase.getInstance().getReference().child("users");

        ref.addListenerForSingleValueEvent(
                new ValueEventListener() {
                    @Override
                    public void onDataChange(DataSnapshot dataSnapshot) {

                        //Get map of users in datasnapshot
                        for(DataSnapshot ds : dataSnapshot.getChildren()) {
                            names.add(ds.child("nameOfUser").getValue(String.class));
                            phone.add(ds.child("phone").getValue(String.class));
                            uid.add(ds.child("id").getValue(String.class));
                            points.add(ds.child("points").getValue(int.class));
                            gender.add((Boolean) ds.child("gender").getValue(Boolean.class));
                        }
                        Log.d("names array", names.toString());
                        Log.d("phone array", phone.toString());
                        Log.d("uid array", uid.toString());
                        Log.d("points array", points.toString());
                        Log.d("gender array", gender.toString());
                        continueList();
                    }

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