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Flutter – Error Trying To Store User Data Using Shared Preferences

I am trying to store user data after logging in using Shared Preferences but my code is giving me this error message:

The argument type 'Map<String, dynamic>' can't be assigned to the parameter type 'String'.

Here is my code:

class UserPerfs
{
  static Future<void> saveUserPerfs(User userData) async
  {
    SharedPreferences prefs = await SharedPreferences.getInstance();
    String userJsonData = jsonDecode(userData.toJson());
    await prefs.setString('currentUser', userJsonData);
  }
}

How can I resolve this?

Tags:

2

Answers


  1. 0

    jsonDecode(userData.toJson()) must be converting data to Map<String, dynamic>. You can convert to jsonString then can store in sharedPrefereces.

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  2. 0

    you are using decode function which requires a json string
    if you want to store the user object then you have to encode it instead

    static Future<void> saveUserPerfs(User userData) async
{
  SharedPreferences prefs = await SharedPreferences.getInstance();
  String userJsonData = json.encode(userData.toJson());
  await prefs.setString('currentUser', userJsonData);
}

    and for retrieving the data use json.decode

    static Future<User> getUserData() async
{
  SharedPreferences prefs = await SharedPreferences.getInstance();
   final encodedUser=  prefs.getString('currentUser');
   return User.fromJson(json.decode(encodedUser!));
}
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