Android SharedPreferences String Set - some items are removed after app restart

Question

I save a string set in the shared preferences, if I read it out it\'s ok. I start other activities, go back and read it again, it\'s ok. If I close the application, and start it

Answer 1

According to the document, the String Set in SharedPreferences should treated as immutable, things go south when trying to modify it. A work around would be: Get the existing set, make a copy of it, update the copy and then save it back to the shared preferences like it was a new set.

Set feedbackSet = getFeedbacksSet();
if(feedbackSet == null){
    feedbackSet = new HashSet();
}

//make a copy of the set, update the copy and save the copy
Set newFeedbackSet = new HashSet();
JSONObject json = createJSONObjectfromFeedback(feedbackItem);
newFeedbackSet.add(json.toString());
newFeedbackSet.addAll(feedbackSet);
ed.putStringSet(CoreSetup.KEY_FEEDBACK, newFeedbackSet);
ed.commit();