flutter how to save and get a list using shared preferences

Question

so ive been trying to set and get a list with shared preferences, but i'm having a problem with retrieving it

import 'package:justatest/model/arguments.dart';
import 'package:provider/provider.dart';
import 'package:flutter/material.dart';
import 'package:shared_preferences/shared_preferences.dart';

class transactionsAdd extends ChangeNotifier {
  List<Addtx> _addtx = [];
  List<Addtx> get getAddtx {
    return _addtx;
  }

  void addTrx(var balance, String note, String category, bool plusorminus,
      DateTime selectedDate) async {
    SharedPreferences prefs = await SharedPreferences.getInstance();
    Addtx tdl = new Addtx(note, balance, category, plusorminus, selectedDate);
    _addtx.insert(0, tdl);

    prefs.setStringList("title1", [_addtx.toString()]);

    notifyListeners();
  }

  loadC2() async {
    SharedPreferences prefs = await SharedPreferences.getInstance();

    _addtx = prefs.getStringList('title1')?? [] ;

    notifyListeners();
  }
}

`

The problem is with

_addtx = prefs.getStringList('title1')?? [] ;

A value of type 'List' can't be assigned to a variable of type 'List'. Try changing the type of the variable, or casting the right-hand type to 'List'.dartinvalid_assignment

score 0 · Answer 1 · answered Feb 22 '22 at 17:18

Although the message is confusing it has sense if you realize that your list _addtx is only for Addtx objects, meanwhile sharedpreferences getStringList is of strings. So you can´t assign a List to a List. You should do something like this:

How to save List<Object> to SharedPreferences in Flutter?

flutter how to save and get a list using shared preferences

1 Answers1