Storing Application context in SharedPreferences when app crashes

Question

Currently im storing all of my users information and there friends information inside a class i have created called userInfoCore that extends Application so i can store the values in the Context. When my app crashes it gets rid of al those values and my users are forced to relogin, so i would like to store them in SharedPreferences to be grabbed again in the onCreate of my MainActivity.

I know how to store them, thats not the issue. The issue is i dont want to overcrowd my code with repetitive code and put the storing methods in all the onDestroy's of all my Activities, and i cant @Override onDestroy in my userInfoCore class because its not an Activity i imagine?

Some insite would be great. Thank!

EDIT:

Ive found out that this line in the android manifest is causing my Application Context data to be destroyed even when the user presses the home screen. android:launchMode="singleInstance"

My thoughts are YES i could store them in the onPause or do what @CommonsWare suggested. However like i said, i dont want to have to do all of that. If i can find the root of the cause of the issue... which i have. (The singleInstance in manifest) then i would be much happier.

Answer 1

Some insite would be great.

Update your persistent store when the data changes. A custom Application subclass, like any singleton, should only be treated as a cache or other transient spot for data. If you care about the values, persist them, at the point when the data is changed.

Answer 2

This is a good argument for using the Model-View-Presenter (or Model-View-Controller) pattern. By separating your Model (domain data and procedures) from your View and Presenter (Layout and Activity respectively) you only have to write the Store logic once.

Then you have two choices: either do as @CommonsWare suggests, have the model write itself whenever it changes, or add a simple call in each Application's onPause (onDestroy is too late! It may never get called.) to the model to tell it to save itself.

Note: the model can accept a context as a construction parameter for use in finding a shared preferences, or it can create it's own named preferences using the PreferenceManager