Closing cursor in onPostExecute renders nothing

I am using AsyncTask to load data from a SQLite Database and then providing data to a Recycler View using a StaggeredLayoutManager and CustomListAdapter.

If I don't close the cursor of doInBackground method in the onPostExecuteMethod, the transition from the previous activity is laggy, and android logcat says "Skipped 52 frames".

If I do close the cursor, at the end of the Post Execute method, the lag doesn't occur, but nothing is rendered inside the Activity. (Recycler View renders nothing.)

 @Override
    protected void onPostExecute(Void Void) {             
c.close();
        swipeRefreshLayout.setRefreshing(false);
        swipeRefreshLayout.setOnRefreshListener(new                  SwipeRefreshLayout.OnRefreshListener() {
            @Override
            public void onRefresh() {
                new MyTask().execute();
            }
        });
        swipeRefreshLayout.setColorSchemeColors(getResources().getIntArray(R.array.swipeRefreshColors));

    }