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

My utils class for save list to SharedPreferences

public class SharedPrefApi {
    private SharedPreferences sharedPreferences;
    private Gson gson;

    public SharedPrefApi(Context context, Gson gson) {
        this.sharedPreferences = context.getSharedPreferences(PREFS_NAME, Context.MODE_PRIVATE);
        this.gson = gson;
    } 

    ...

    public  void putList(String key, List list) {
        SharedPreferences.Editor editor = sharedPreferences.edit();
        editor.putString(key, gson.toJson(list));
        editor.apply();
    }

    public  List getList(String key, Class clazz) {
        Type typeOfT = TypeToken.getParameterized(List.class, clazz).getType();
        return gson.fromJson(getString(key, null), typeOfT);
    }
}

Using

// for save
sharedPrefApi.putList(SharedPrefApi.Key.USER_LIST, userList);

// for retrieve
List userList = sharedPrefApi.getList(SharedPrefApi.Key.USER_LIST, User.class);

.
Full code of my utils // check using example in Activity code