title: Read speed of SharedPreferences
body: <p>How fast are <code>SharedPreferences</code>?  Is there a way to put them in memory for reading?  I have a small amount of data that a <code>ListView</code> has to query to display each cell, and I'm worried that a call to flash memory will be too slow.  I'm not worried about write speed, as writes will happen infrequently.  I'm considering just using a JSON object to persist the data instead of <code>SharedPreferences</code>. Any thoughts?</p>