Android : How can i open my Fragment class in a new intent?

How can i open my fragment class in a new intent? i know fragments cannot be opened by a activity. How do i fix this? i want to know how i can put my fragment class into a activity. I have a gridView.what i want it to open my fragment class when items in it are clicked

my code

package com.fortuna.cinemalk;

import java.util.ArrayList;

import android.app.Activity;
import android.os.AsyncTask;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.GridView;
import android.content.Intent;
import android.widget.AdapterView;


import com.fortuna.cinemalk.adapter.LazyAdapter;
import com.fortuna.cinemalk.model.BaseElement;
import com.fortuna.cinemalk.service.CommonVariable;
import com.fortuna.cinemalk.service.JSONServices;
import com.fortuna.cinemalk.util.Element;

public class TheaterFragment extends Fragment {

    private GridView gridView;

    private ArrayList<BaseElement> filmTheater;
    private LazyAdapter adapter;
    private Activity activity;
    private CommonVariable commonVariable;

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {

        View view = inflater.inflate(R.layout.theater_fragment, container,
                false);

        activity = this.getActivity();

        commonVariable = (CommonVariable) activity.getApplication();

        gridView = (GridView) view.findViewById(R.id.gridView1);


        gridView.setOnItemClickListener(new  AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view,
                    int position, long id) {
                Intent i = new Intent(TheaterFragment .this.getActivity(),MovieDetailFragment.class);
                startActivity(i);
            } 

        });

            new BackGround().execute();

        return view;
    } 




    public class BackGround extends AsyncTask<Void, Void, Void> {

        @Override
        protected Void doInBackground(Void... params) {

            filmTheater = JSONServices.getTheater();
            return null;
        }

        @Override
        /* check again */
        protected void onPostExecute(Void result) {

            commonVariable.setTheater(filmTheater);

            adapter = new LazyAdapter(filmTheater, activity,
                    Element.THEATER_LIST.getType());

            gridView.setAdapter(adapter);

            super.onPostExecute(result);
        }

        @Override
        protected void onPreExecute() {
            // TODO Auto-generated method stub
            super.onPreExecute();
        }

    }







}