Cacher is the code snippet organizer for pro developers

public void saveData(List<ShoppingCartItem> cartItemArrayList, String key){
        SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(context);
        //Creating editor to store values to shared preferences
        SharedPreferences.Editor editor = sharedPreferences.edit();

        Gson gson = new Gson();
        String json = gson.toJson(cartItemArrayList);
        editor.putString(key,json);
        editor.apply();
}

public ArrayList<ShoppingCartItem> getData(String key){
        SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(context);
        Gson gson = new Gson();
        String json = sharedPreferences.getString(key,null);
        Type type = new TypeToken<ArrayList<ShoppingCart>>() {}.getType();
        return gson.fromJson(json, type);
}