Android - How to use SharedPreferences in non-Activity class?

Question

How do you use SharedPreferences in a non-Activity class? I tried making a generic Preferences utility class and importing android.content.Context but Eclipse still wouldn't let me use getSharedPreferences().

Answer 1

SharedPreferences are related to context. You can only reference it through a context.

You can simply pass context as a parameter to your class. For example in the constructor.

In your activity do:

MyClass myClass = new MyClass(this); 

Answer 2

The solution i found to this was:

1-In an MainActivity class (i.e always launched before getting any context in project) create a static variable for the context:

public static Context contextOfApplication;

2-In an important method of this class (Such as onCreate, the constructor, etc) initialize this variable using the getApplicationContext method:

public void onCreate() {     contextOfApplication = getApplicationContext(); } 

3-In the same class Create a "getter" method for this variable (it must also be static):

public static Context getContextOfApplication(){     return contextOfApplication; } 

4-In the non-activity class get the context by calling the created method statically:

Context applicationContext = MyActivityClass.getContextOfApplication();

5-Use the PreferenceManager Class to get the SharedPreferences variable:

SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(applicationContext); 

Hope it helps.