You should post a logcat if you are getting an error. It helps to see which line is causing your problem.
From the Android docs.
close()
Closes the Cursor, releasing all of its resources and making it completely invalid.
Your call to mcursor.getCount()
after you have closed it is likely causing the error
Maybe try something like this.
int count = mcursor.getCount();
mcursor.close();
// return count
return count ;