Android Programming: The Big Nerd Ranch Guide, 2nd Edition

Simple Persistence with Shared Preferences

The last piece of functionality you need to add is to actually use the query entered in the SearchView when the search request is submitted.

In your app, there will only be one active query at a time. That query should be persisted (remembered by the app) between restarts of the app (even after the user turns off the device). You will achieve this by writing the query string to shared preferences. Any time the user submits a query, you will first write the query to shared preferences, overwriting whatever query was there before. When a search is executed against Flickr, you will pull the query string from shared preferences and use it as the value for the text parameter.

Shared preferences ...