android

If you want to save Activity information that doesn’t need to be shared with other components (e.g., class instance variables), you can call Activity.getPreferences() without specifying a Shared Preferences name. This returns a Shared Preference using the calling Activity’s class name as the Shared Preference name

The Shared Preference values recorded for the options presented in a Preference Activity are stored within the application’s sandbox. This lets any application component, including Activities, Services, and Broadcast Receivers, access the values, as shown in the following snippet: Introducing On Shared Preference Change Listeners The onSharedPreferenceChangeListener can be implemented to invoke a callback whenever … Read more

The PreferenceActivity class is used to host the Preference Fragment hierarchy defined by a preference headers resource. Prior to Android 3.0, the Preference Activity was used to host Preference Screens directly. For applications that target devices prior to Android 3.0, you may still need to use the Preference Activity in this way To create a … Read more

Android includes several preference controls to build your Preference Screens: CheckBoxPreference — A standard preference check box control used to set preferences to true or false. EditTextPreference — Allows users to enter a string value as a preference. Selecting the preference text at run time will display a text-entry dialog ListPreference — The preference equivalent … Read more

Android offers an XML-driven framework to create system-style Preference Screens for your applications. By using this framework you can create Preference Activities that are consistent with those used in both native and other third-party applications This has two distinct advantages: Users will be familiar with the layout and use of your settings screens You can … Read more

Like other complex software-engineering problems, the approach here involves abstraction, encapsulation, and software layering. Specifically, we can abstract away the detailed differences in I/O devices by identifying a few general kinds. Each general kind is accessed through a standardized set of functions—an interface. The differences are encapsulated in kernel modules called device drivers that internally … Read more

Using the SharedPreferences class, you can create named maps of name/value pairs that can be persisted across sessions and shared among application components running within the same application sandbox. To create or modify a Shared Preference, call getSharedPreferences on the current Context, passing in the name of the Shared Preference to change. Shared Preferences are … Read more

The data-persistence techniques in Android provide options for balancing speed, efficiency, and robustness. Shared Preferences — When storing UI state, user preferences, or application settings, you want a lightweight mechanism to store a known set of values. Shared Preferences let you save groups of name/value pairs of primitive data as named preferences. Saved application UI … Read more