android-sharedpreferences-api

API for sharing data stored in SharedPreferences between android apps/processes using a ContentProvider

Consider you have two apps and App X wants to share some data that it stores in its SharedPreferences with App Y

App X will save Preferences the normal way.

    //Confused? Check http://stackoverflow.com/questions/3783848/android-possible-to-have-multiple-distinct-shared-preferences-per-app
    
    SharedPreferences configurationPrefs = getApplicationContext().getSharedPreferences(SharedPreferenceAPI.CONFIGURATION_PREFERENCE_FILE_NAME, Context.MODE_PRIVATE);

    SharedPreferences.Editor editor =  configurationPrefs.edit();

    editor.putInt(INT_KEY, INT_VALUE);
    editor.putFloat(FLOAT_KEY, FLOAT_VALUE);
    editor.putLong(LONG_KEY, LONG_VALUE);
    editor.putString(STRING_KEY, STRING_VALUE);
    editor.putBoolean(BOOLEAN_KEY, BOOL_VALUE);

    Log.d(TAG, "Wrote configuration prefs");

    editor.commit();

App X will include the API backend i.e SharedPreferenceAPI.java and add the below to its AndroidManifest.xml

      <provider
        android:name="com.pm.sharedpreferenceapi.SharedPreferenceAPI"
        android:authorities="@string/api_authority"
        android:exported="true"
        />

Note that if you know that all apps that might consume data from your App X will be created by you and you would like to keep things private, change exported=false.

In that case all your other apps would need to have the same android:sharedUserId as used by this app in its manifest. Also the other apps would need to be exported as APKs with the same cerificate as the App X.

Now App Y wants to access App X's data.

Include SharedPreferenceAPIClient.java within App Y.

App Y will need to know the authority which can be considered as the root api url which App X will share with it.

Now wherever you need the data do,

SharedPreferenceAPIClient apiClient = new SharedPreferenceAPIClient(getApplicationContext(), getApplicationContext().getString(R.string.api_authority));

And use the client to fetch the data you want

apiClient.getString("one_key_that_rules_them_all_key_name", "a_default_if_not_found");
apiClient.getFloat("float_key", 0.0f);

App Y can now access App X data.

The default implementation is only for Read Only Access but this can easily be extended to Inserting, Modifying or Deleting values.

That's it!