Learning Android™ Application Programming: A Hands-On Guide to Building Android Applications

Saving an Application’s State

Application state can be stored in many ways, either as static properties stored globally in the application or through the use of the singleton pattern. This pattern is designed to control object creation, limiting the number of objects to one. Because there is only ever one instance of the application class, you can use that to act as a singleton.

Here’s how to create a class to save and retrieve the application settings.

1. Create a new Java class called Settings. Add a private static (of type String) CLASS_NAME, and assign the class name in the class constructor:

Click here to view code image

public class Settings {    private static String CLASS_NAME;    public Settings() {        CLASS_NAME = getClass().getName(); ...