Can I get data from shared preferences inside a service?

问题

I'm developing an android application. I'm using android 2.2

In my application I am capturing GPS data and sending it to service with the 1 hour time interval. If user exits from application it's also working (it is required).

I'm using 2 services (User defined), one for capturing GPS data and other for sending to the server.

Here my doubt

• In service, can we use shared preferences.

• If we store any data in shared preferences in any activity of the application, will we be able to use that data in service with the help of shared preferences?

回答1:

You can access the default shared preferences instance, which is shared across all your Activity and Service classes, by calling PreferenceManager.getDefaultSharedPreferences(Context context):

SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(this);

This is great for storing simple primitives (like booleans) or serializable objects. However, if you're capturing a lot of location data, you might consider using a SQLite database instead.

回答2:

I find the solution.
Inside a service we call the following method to get the shared preferences

myapp.bmodel.getApplicationContext().getSharedPreferences("myPrefs_capture_gps_per_hour", Context.MODE_PRIVATE);

In the above code myapp is a object of the application class which is derived from Application

回答3:

You need a context to get access to shared preferences. The best way is to create MyApplication as a descendant of Application class, instantiate there the preferences and use them in the rest of your application as MyApplication.preferences:

public class MyApplication extends Application {
    public static SharedPreferences preferences;

    @Override
    public void onCreate() {
        super.onCreate();

        preferences = getSharedPreferences( getPackageName() + "_preferences", MODE_PRIVATE);

For example, if you need access to your preferences somewhere else, you may call this to read preferences:

String str = MyApplication.preferences.getString( KEY, DEFAULT );

Or you may call this to save something to the preferences:

MyApplication.preferences.edit().putString( KEY, VALUE ).commit();

(don't forget to call commit() after adding or changing preferences!)

回答4:

Yes Shivkumar, you can use your share preferences in any kind of services as normal as you are using in your Activity.

same like

SharedPreferences preferences = getSharedPreferences("<PrefName>",
            MODE_PRIVATE);

回答5:

There are two ways to create instance of SharedPreference:

Case 1:

SharedPreferences preferences = activity.getSharedPreferences("<PrefName>", MODE_PRIVATE);

Case 2:

SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(this);

Notice if you create a preference with the same name (case 1) or same context (case 2) even at different places, it's still the same, and can share data, obviously.

来源：https://stackoverflow.com/questions/13558550/can-i-get-data-from-shared-preferences-inside-a-service