5. Persistence and sharing

5.1 Shared preferences

This is a mechanism for sharing data between application components, independent of the activity lifecycle. Saved preferences persist across user sessions.

Multiple sets of shared preferences can be created. Preferences are managed by an instance of the SharedPreferences class.

Shared preferences are retrieved by the SharedPreferences getSharedPreferences( String name, int mode ) method, where name is the name of the set of preferences.

Preferences are stored as pairs (key/value) of primitive types. To store data, you need to obtain an Editor object before adding it, and then save it.