How to clear shared preferences value based on daily basis

Question

I am working on an android project where I have a scenario such as :

Task 1:

I have to get the user activity count "when ever the user starts the activity a count has to be made and stored in shared preference. (completed successfully)

Task 2:

I have to clear the user shared preference on daily basis for example ( if the user is using the app on 13-08-2017 and have count around 20 (this means he has opened the app for 20 times). For the next day that is on 14-08-2017 I want the shared preference value to be cleared in the editor.

I am unable to do the second task. How can I compare the previous and today date and clear the shared preference editor?

Below is my code where I am getting count and current date successfully :

public class Fragment_Greetings extends Fragment
{
    private SharedPreferences prefs;
    private SharedPreferences.Editor editor;
    private int totalCount;
    Date currentDate;
    String dateValue;
    public Fragment_Greetings()
    {
        // Required empty public constructor
    }

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

        // code for getting user daily basis count

        // getting the current date
        Calendar c = Calendar.getInstance();
        c.add(Calendar.DATE,0);
        SimpleDateFormat df = new SimpleDateFormat("dd-MMM-yyyy");
        String curentDate = df.format(c.getTime());

        // setting up the editor
        prefs = getActivity().getPreferences(getActivity().MODE_PRIVATE);
        editor = prefs.edit();


        totalCount = prefs.getInt("counter", 0);
        totalCount++;
        editor.putInt("counter", totalCount);

        editor.commit();
        //System.out.println("Total Application counter Reach to :"+totalCount);

        Toast.makeText(getActivity(), "Hello user , you have entered into the app for "+totalCount+" th time on "+curentDate, Toast.LENGTH_SHORT).show();
        return rootView;
    }

}