Unit - 5 Working with Application Preferences

Lesson Plan: Unit - 05
Subject: P15A2AAD - Android Application Development
Topic of Study: Working with Application Preferences
Grade/Level: Master of Computer Applications
Objective: To understand the mechanism of Application Preferences
Time Allotment: 55 Minutes

Working with Application Preferences

Many applications need a lightweight data storage mechanism called shared preferences.
Use: For storing application state, simple user information, configuration options...
You cant share preferences outside of the package.
Preferences are stored as groups of key/value pairs.
Data types are supported as preference settings: Boolean values, Float values, Integer values, Long values, String values.
Preference functionality can be found in the SharedPreferences interface of the android.content package.
To add preferences support to your application, you must take the following steps:

1. Retrieve an instance of a SharedPreferences object.
2. Create a SharedPreferences.Editor to modify preference content.
3. Make changes to the preferences using the Editor.
4. Commit your changes.

Creating Private Preferences:

Individual activities can have their own private preferences.
These preferences are for the specific Activity only and are not shared with other activities within the application.
The activity gets only one group of private preferences.
Exa.

Creating Shared Preferences:

Difference: We must name our preference set and use a different call to get the preference instance.
There is no limit to the number of different shared preferences you can create.
Exa.
However, you want to declare your preference name as a variable so that you can reuse the name across multiple activities.
Exa.