How do I use sharedPreferences outside of an Activity?

Question

I\'ve been stuck on this very simple problem for hours now and Ive been unable to find any suitable solutions through google.

I am trying to use the SharedPreference

Answer 1

Where do you instantiate your Model class?

Just pass either a context or the SharedPreferences to the constructor:

public class Model {
    private final Context context;
    private final SharedPreferences sharedPrefs;

    public Model(Context context) {
        this.context = context;
        sharedPrefs = context.getSharedPreferences("name", 0);
    }

    private String doSomething(){
        return sharedPrefs.getString("key", "defValue");
    }
}

Answer 2

You can use SharedPrederences from any code that holds a Context. From the Activity documentation at http://developer.android.com/reference/android/app/Activity.html:

Activity persistent state is managed with the method getPreferences(int), allowing you to retrieve and modify a set of name/value pairs associated with the activity. To use preferences that are shared across multiple application components (activities, receivers, services, providers), you can use the underlying Context.getSharedPreferences() method to retrieve a preferences object stored under a specific name. (Note that it is not possible to share settings data across application packages -- for that you will need a content provider.)

Answer 3

SharedPreferences isn't called only from Activity, but from Context (which Activity extends) so you can use the application context as well.