Add Count On Item Viewed

DatabaseReference refCount;
DataSnapshot datCount;

public void initCountFoodInstances(){
    refCount = data.getReference("contador");
refCount.addValueEventListener(new ValueEventListener() {
            @Override
            public void onDataChange(DataSnapshot ds) {
                datCount = ds;
            }

            @Override
            public void onCancelled(DatabaseError de) {
                System.out.println("Error");
            }

        });
}

public void addCountFood(){
     int size = Integer.parseInt(datCount.getValue(String.class));
     refCount.setValue((size+1)+"");
}