Save ArrayList to SharedPreferences

Question

I have an ArrayList with custom objects. Each custom object contains a variety of strings and numbers. I need the array to stick around even if the user leaves

Answer 1

following code is the accepted answer, with a few more lines for new folks (me), eg. shows how to convert the set type object back to arrayList, and additional guidance on what goes before '.putStringSet' and '.getStringSet'. (thank you evilone)

// shared preferences
   private SharedPreferences preferences;
   private SharedPreferences.Editor nsuserdefaults;

// setup persistent data
        preferences = this.getSharedPreferences("MyPreferences", MainActivity.MODE_PRIVATE);
        nsuserdefaults = preferences.edit();

        arrayOfMemberUrlsUserIsFollowing = new ArrayList();
        //Retrieve followers from sharedPreferences
        Set set = preferences.getStringSet("following", null);

        if (set == null) {
            // lazy instantiate array
            arrayOfMemberUrlsUserIsFollowing = new ArrayList();
        } else {
            // there is data from previous run
            arrayOfMemberUrlsUserIsFollowing = new ArrayList<>(set);
        }

// convert arraylist to set, and save arrayOfMemberUrlsUserIsFollowing to nsuserdefaults
                Set set = new HashSet();
                set.addAll(arrayOfMemberUrlsUserIsFollowing);
                nsuserdefaults.putStringSet("following", set);
                nsuserdefaults.commit();